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Miscellaneous Publication No. 544
Production and Marketing Administration
UNITED STATES DEPARTMENT OF AGRICULTURE
Historic, archived document
Do not assume content reflects current scientific knowledge, policies, or practices.
Acknowledgments
Acknowledgment is made to the following persons for their assistance in the preparation of this publication:
Pearl Lafitte, Home Demonstration Agent, Duval County, Fla., for reviewing and expanding the section on plant management.
Charles M. Merrill, Research Laboratory, National Canners Association, Wash- ington, D. C, for suggestions on canning practices and for reviewing the tables on time and temperature for processing acid and nonacid foods.
R. E. Naugher and D. T. MacDonald, Specialists in Agricultural Education, United States Office of Education, Federal Security Agency, Washington, D. C, for assistance in the preparation of the section on instructing families in canning prac- tices.
Thomas M. Offutt, Washington Gas Light Company, Washington, D. C, for reviewing the section on small canning centers operated with gas burners.
Members of the Research Department, American Can Co., New York, N. Y., for reviewing the section on can seam tests and for supplying photographs and drawings.
Walter F. Stutz, Chief of Engineering Instruments and Mechanical Appliances Section, National Bureau of Standards, Washington, D. C, for assistance in pre- paring the text and photographs for the section on testing pressure gages.
Charles T. Townsend, Laboratory for Research in the Canning Industry, San Francisco, Calif., for his many helpful suggestions.
Dr. E. P. Walls, Food Technologist in Charge of Canning Studies, Department of Horticulture, University of Maryland, for general information on canning practices, with particular reference to lye peeling.
COMMUNITY CANNING CENTERS
Miscellaneous Publication No. 544
UNITED STATES DEPARTMENT OF AGRICULTURE
Production and Marketing Administration
UNITED STATES
GOVERNMENT PRINTING OFFICE
WASHINGTON : 1946
Preface
Community canning centers have found a definite place in the life of many communities. That they fill a need is shown by the fact that there has been a con- tinual increase in their number and an expansion of the facilities of those already established. These centers serve many useful purposes. They prevent waste of locally abundant foods and improve the nutritional level of lower income groups by preserving home-grown foods for use at a time when fresh produce is relatively high in price. Schools have found that by using these centers to can produce for their school-lunch programs they have been able to provide better lunches without increas- ing their cost to the children.
As a result of the development of interest in community canning centers many requests for information on their establishment and operation have been received. This publication, a revision of Miscellaneous Publication No. 544, is intended to provide answers to these requests. The information contained in the April 1944 issue of Miscellaneous Publication No. 544 and the supplements released in August and September 1944 have been incorporated in this edition with slight revisions. In response to numerous demands, a section has been added on the establishment and operation of small canning centers that use gas burners.
The instructions given are based on experience acquired in the organization and operation of successful food-preservation centers and on information obtained from authorities in the field of canning. The canning techniques presented are for approved steam-pressure and water-bath methods and are based on ungraded products packed in a clean, sanitary manner. Since it was necessary to prepare this material for use on a national basis it may be found that the techniques here recommended need slight modification in some cases in order to conform with State laws on food, safety, health, and sanitation.
Although the scope of this publication has been limited to canning, many communities have found it desirable to provide facilities for other methods of preserva- tion, such as quick freezing, dehydrating, salting, and brining. Much of the equip- ment used for the preparation of foods for canning may be used for the preparation of foods to be preserved by any of these methods, thus effecting a saving in space and cost of equipment.
Washington, D. C. Issued April 1944
Revised March 1946
CONTENTS
Page
Getting the community organized 1
Plan for financing 1
Selecting a supervisor 2
Deciding on the size and type of cannery 2
Selecting the site and building 2
Making the floor plans 5
Steam-operated canning centers 7
Boilers 7
Water-feed system 8
Location 10
Boiler fittings and steam and water lines 10
Boiler operation 11
Retorts 12
Type and number of retorts 12
Retort equipment 13
Mercury-in-glass thermometer 13
Pressure gage 13
Vent and bleeder 13
Safety valve 13
Retort inset crate 13
Installation of retorts • 13
Care of retorts 16
Retort operation 16
Venting retorts 17
Processing 18
Pressure cooling of cans in retorts of 106 No. 3 can capacity or larger (pressure maintained with
steam) 18
Testing pressure gages 20
Open-process tanks 24
Cooling tank 24
Chain hoist and track 24
Steam-jacketed kettles 25
Steam cooking coil 25
Sealers 26
Operation of sealers (double seamers) 28
Examination of the can seam 29
Adjusting sealers 31
Exhaust boxes 32
Wash sinks 32
Blanch and scald tanks 33
Cold-dip tanks : 34
Tanks for the medium 34
Preparation and fill tables 35
Meat-cutting tables 35
Other equipment 35
Cutting boards -. . 35
Blanching baskets 35
Can trays .- 35
Canning thermometers 35
Dishpans 35
Cutlery 36
Can-scam-inspection equipment 37
Can-straightening device : 37
Gloves 37
Utility trucks 37
Garbage cans 37
Steam aad water hose 37
Fire extinguishers 37
Page Other equipment — Continued
Tools for adjusting and repairing equipment 37
Replacement parts 38
Cleaning equipment ■ 38
Containers generally used 38
Size of cans 38
Type of finish 38
Purchase of cans 38
Small canning centers operated with gas burners 39
Operation of gas-heated retorts 42
Operation of pressure canners 42
Care of pressure canners 44
Care of idle equipment 45
Sanitation 45
Safety 45
Management 46
Personnel — employed and volunteer 46
Protection for employees and patrons 46
Getting information to the public 46
Education and training for patrons 47
Planning food for the family 47
Nutritional requirements of the family 48
Quantity of each food to be canned 48
Food-production possibilities 49
Producing food for family use . 49
Instructing families in canning practices 49
Patron's agreement 50
Appointments and scheduling 50
Canning procedure 52
Receiving produce 52
Preparation of produce 52
Grading 52
Sorting 52
Soaking 52
Washing 52
Cutting, breaking, peeling 52
Discoloration 53
Scalding 53
Lye peeling 53
Steaming 53 '
Pulping 53
Reducing ; 54
Blanching 54
Preparation of containers 54
Filling of cans 54
Checking weight of can contents 55
Allowing for head space 55
Adding canning medium 55
Exhausting 55
Center-can closing temperature 55
Vacuum . . . . : 56
Initial temperature 56
Sealing . 57
Marking cans 57
Stacking cans 57
Processing 57
Water-bath processing 58
Steam-pressure processing 58
111
Canning procedure — Continued Page
Cooling 59
Storage 59
Spoilage 59
Flat-sour 59
Botulinus 59
Swells 60
Hydrogen springers 60
Stack burn 60
Foreign flavors 60
Disposal of spoiled foods 60
Canning instructions 60
Canning fruits, tomatoes, and other acid foods 61
Apple butter 61
Apples in sirup 61
Applesauce : 62
Apricots 62
Berries 63
Cherries, sour 63
Cherries, sweet 63
Fruit juices 64
Grapefruit 64
Peaches 63
Pears 65
Pineapple 66
Plums 66
Sauerkraut 66
Tomatoes 67
Tomato juice 68
Canning instructions — Continued Page
Canning nonacid vegetables 68
Asparagus 69
Beans, green and wax 70
Beans, green lima 71
Beets 71
Carrots 72
Corn, cream-style 72
Corn, whole-grain 73
Greens 74
Mixed vegetables for soup or salad 74
Okra 75
Peas, green 75
Pumpkin and squash 75
Summer squash 76
Sweetpotatoes in sirup 76
Sweetpotatoes, solid pack 77
Canning meat 78
Roasts, steaks, and stew meat 79
Ground meat 80
Heart and tongue 80
Corned beef 81
Chicken 81
Chicken giblets 82
Soup stock 83
Partial list of manufacturers of canning equipment and sup- plies 83
Literature cited 85
Additional references 85
IV
Community Canning Centers
Prepared by the Production and Marketing Administration, United States Department of Agriculture
Getting the community organized
Community canning centers will not just happen. They must be planned and arranged for well in ad- vance of the season in -which they are needed. Plan- ning soundly and getting the center operating on a business basis from the beginning are necessary if the center is to be successful over a period that justifies the expenditure of money and effort involved.
Successful canning centers usually are the result of group action spurred on by some individual who sees the need for providing facilities for preserving food and has the energy to do something about it. It doesn't matter who this is — an energetic homemaker, a home demonstration agent, a businessman growing his first garden, a teacher of vocational agriculture or home economics, or a civic leader.
Such a leader will round up a group of interested persons to determine the need, the interest, the terri- tory to be served by the prospective center, whether all families or only a limited number in the territory are to be included among patrons of the center, and •what canning equipment is already on hand in the community. Many communities include school lunch and institutional needs in the initial survey, as such a tie-in is desirable in affording permanency to the program.
A satisfactory method of getting much of the infor- mation needed in the survey is to send circulars or questionnaires to families in the community. Such questionnaires will determine whether or not a family is interested, the kind and amount of food they would like to put up, and whether this food will be home- produced or bought. A more accurate survey can be had if food budgets recommended by State depart- ments of agriculture are used as guides for setting up information to accompany the questionnaires.
Where the initial survey reflects a real need and interest in establishing a canning center, the most effective way of getting the matter in the hands of community members is to have a public meeting. At this meeting a working committee should be elected and given the authority to get the program organized and operating. This committee will then need to report only occasionally to the whole group of persons participating in the program.
On the personnel of this committee will depend the effectiveness of the program. Its membership should include representative citizens who can head subcom- mittees to handle specific problems involved, thus
building up an effective organization. It is well to include on the committee a businessman, a home economist, a teacher of vocational agriculture, an engineer, a newspaper publisher, a health officer or physician, members of civic and service clubs, school boards, and local government. Subcommittees may need to be organized to give direction and supervision on (1) financing, (2) housing and equipment, (3) public relations and arbitration, (4) operation, and
(5) health and sanitation of the plant. By dividing the direction of the program in this way the responsi- bility is left to a group rather than to an individual.
Until the plant has been established and is ready to operate, the working committee will be busy making such decisions as the following: (1) How to finance the cost of the center, (2) selection of a supervisor or manager, (3) size and type of preserving units to be installed, (4) selection of site and building, (5) de- velopment of floor plans for installation of equipment,
(6) purchase and installation of equipment and supplies.
With the supervisor, the working committee will determine what the policies of the plant will be on agreements to be made with patrons, the type of train- ing that patrons will be given, the number of persons required to operate the plant, and the means of inform- ing the public of the plant's progress. As the season gets under way, the supervisor will need the assistance of the committee to solve operating problems and to make improvements or changes in the canning center from time to time.
Plan for Financing
A community cannery must have initial funds for equipment and supplies, housing and utilities, neces- sary labor and supervision, and for protective insurance for workers. Such funds may be obtained through popular subscription or a bond issue in the community. Often, however, the local board of commissioners, welfare board, school board, farmers' cooperatives, chamber of commerce, or civic and fraternal organiza- tions assume these initial costs. Many communities have found it advisable to incorporate the canning center on a nonprofit basis.
In some States, legislatures have appropriated funds to assist in establishing and operating food-preserva- tion centers. Other sources of support for the com- munity cannery are contributions by civic-minded
individuals or groups. Committees should investi- gate all possibilities for financial assistance. They will get helpful information on available Government aid from the State agricultural extension service or the State department for vocational education.
To pay the overhead costs of the center, the usual method is to collect a small service charge for each can of food processed. This cost is based on the price of the can, plus a small charge for services and utilities. If the plant is operated at capacity, a fund may accrue from this source to pay off indebtedness as well as to cover costs of replacements and repairs. Capacity production is more readily assured in those canneries extending their facilities to school-lunch programs, institutions, and welfare needs, as well as to families in the community. Sometimes a toll in canned products is collected from patrons as part of the service charge; such products being donated to school-lunch and other tax-supported programs.
If the committee maintains central control of pur- chases for the seasonal supply of cans and fuel, a real saving in overhead costs can be realized. Containers may be purchased in cooperation with other com- munities if the quantities required do not make up a carload lot. (See Purchase of Cans, p. 38.)
Selecting a supervisor
Every canning center should have, if possible, a paid supervisor who is on the job all the time that the center is in operation. In large canning centers such a supervisor is essential.
The supervisor will have the responsibility of see- ing that patrons, employees, and volunteer workers are well trained in proper methods of preparing and processing foods and in operating the equipment. She will be responsible for making appointments, scheduling produce, scheduling and supervising em- ployees, determining and ordering supplies needed, and maintaining the necessary records for efficient operation. She will also assume responsibility for the care, replacement, and repair of equipment.
From time to time, she may present to the com- mittee plans for improved operation, such as re- arrangement of equipment for a better flow of work, or for additional equipment required to improve or expand operation.
Qualified supervisors are likely to be found among home demonstration agents, teachers of home eco- nomics or vocational agriculture, commercial canners, and canners trained in the former WPA program. If possible, it is well for the supervisor to have had actual experience in operating a canning center. In addition to being able to direct and train others, the supervisor should possess good judgment and ability to meet emergencies.
State training courses, conducted by groups or agencies directing or assisting community food- preservation programs, should be attended by the supervisor selected. Other training experiences, such as visiting a commercial cannery, may prove helpful
in planning and scheduling work and evaluating the plant in terms of improved efficiency.
Where a State agency provides the services of a State-wide technical supervisor and a bacteriologist, communities should request their assistance as necessary.
Deciding on the size and type of cannery
The size of the cannery will be determined by the quantity of produce that will need to be canned daily to meet the total anticipated production requirements for the canning season.
To estimate roughly what the daily capacity of the unit should be, divide the estimated total number of cans to be processed during the season by the approxi- mate number of days the cannery will operate. The canning season will vary with the length of the har- vesting season and the kinds of produce to be canned. Add from 10 to 15 percent of the quotient obtained to allow for the peak production period when the greatest variety and amount of food can be expected. Whenever possible, a year-round plan of operation is advisable and should be encouraged. This is partic- ularly important in areas in which farm animals are slaughtered and canned.
The small center, using pressure canners and small retorts heated by gas burners, is satisfactory for a daily production up to 800 cans of produce. (See Small Canning Centers Operated with Gas Burners, P- 39.)
The steam-operated plant, using small and medium- sized retorts, should be established where the expected daily production is greater than 800 cans. (See Steam-Operated Canning Centers, p. 7.)
In some rural areas canneries are of a size to ac- commodate patrons on a county-wide basis. In other instances it is advisable to establish several plants within a county. This is particularly true where urban families are interested in participating in can- ning activities or where transportation difficulties do not make the county-wide plan feasible.
Selecting the site and building
The site for a community cannery should be consid- ered first of all in the light of a central location for the area to be served. Other factors to be considered are existing regulations regarding the establishment of such a plant in the area, the water supply and other utilities, the availability of parking space, and the avoidance of congested traffic. Where facilities are to be made available for processing foods for schocl- lunch programs, institutions, and welfare groups, consideration will need to be given to the location of the plant in relation to trucking routes and railroads. This would particularly apply to those plants plan- ning to take advantage of the abundant foods made available through Government purchase programs.
Figure 1. — Community canning plant, Frisco City, Ala.
Running water is a minimum requirement because of the varied needs for safe and efficient operation. The water supply line should be of adequate size to deliver an ample supply for all processing and sanitation needs. In the absence of a previously approved water supply, the water should be tested for mineral content, purity, and degree of hardness.
Electric service should be heavy enough to support the load required and should be of the voltage neces- sary to operate the motor-driven equipment.
Gas service for gas-operated units should be ade- quate for operating all units in the plant at the same time.
A tele-phone should be provided to facilitate schedul- ing. In large plants an extension may be necessary.
The building most practical to house a community cannery is one in which the equipment can be located on the ground floor. The size of the building should be determined by the amount of produce to be canned and the type and amount of equipment to be used. A rectangular building is most desirable because its floor space can be used to best advantage when arranging equipment. (See fig. 1.) However, any space having the required number of square feet could be used. While it is desirable to construct a new building specifically designed for this purpose, used buildings that can readily be converted are satisfactory. Suit- able buildings for steam-operated canneries include abandoned bottling works, bakeries, laundries, ga- rages, creameries, and other buildings where steam facilities have already been installed. Buildings ad- jacent to steam facilities may also be used. Check such facilities to make sure that they are of ample
capacity to supply both plants. Pressure-canner units may be located in schools, church basements, or similar places that provide needed space and util- ities.
The building needs to be well lighted and properly ventilated. Sufficient windows should be provided so that artificial lighting will not be necessary during the daylight hours. However, artificial lighting will be required at times and should be planned for and so arranged that each operation will be well lighted. Lights should be suspended above head level and so shaded as to prevent glare.
Windows arranged to take advantage of the pre- vailing winds will provide good cross ventilation. In one -story buildings the ventilation and lighting may be improved by the use of roof ventilators and skylights. It may be necessary to supplement natural ventilation with exhaust and circulating fans.
Be sure the ceiling is high enough to assure a com- fortable room temperature. A minimum ceiling height of 10 feet is required to allow for clearances necessary where a track and hoist are used over re- torts. The floor-load capacity of the building should be determined and should not in any case be exceeded. In Northern States consideration must be given to heating the building during the winter season if the plant is to be in use at that time.
Floors should be constructed of rough-finished con- crete, free from cracks and crevices, and should be well drained at or near the points where quantities of water are used. Drain locations should be pre- determined in relationship to the installation of the equipment. For proper floor drainage the pitch
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from the wall to the drain should be from % to 1 inch for every 10 linear feet. Box gutter drains are most suitable in that they are readily accessible for cleaning. The drain should be connected with an adequate sewage disposal system. In some cases it may be necessary to install a septic tank.
The walls should be in good repair and have a surface that can easily be kept clean.
The building should have at least two doors. A double door should be provided at the most con- venient point for delivering produce to the plant. A single door should be provided for checking out canned goods. It is preferable that doors open outward and that all openings of the building be well screened.
Making the floor plans
The floor plans shown in this publication illustrate the placement of equipment to insure a good flow of work through the plant. They should be carefully studied and adapted to suit best the needs of the community.
Figure 2 is typical of an average-sized steam unit and includes the important details that will need to be considered when making a floor plan for this type of plant.
Figures 3 and 4 illustrate a combination steam and gas-burner unit. This combined service permits the processing of small quantities of produce during slack seasons, thus eliminating the need for operating the boiler during such periods. A floor plan for a com- munity canning plant in which gas burners are used as the sole source of heat is shown in figure 56, page 39.
Several possible floor plans will need to be made showing in detail the placement of all equipment and the continuity of expected operations. Since the sequence of operations varies somewhat with different products, the floor plans drawn up should be checked to determine which ones would best accommodate the kinds of produce to be canned. An effective way to develop floor plans is to place cut-to-scale cardboard models of the equipment on the scaled floor plan of the building.
In determining the placement of equipment to per- mit a steady progressive flow of produce through the plant consider first the receiving area. This area may be inside the plant or outside on a screened porch or platform. This area will necessarily vary in size with the anticipated capacity of the plant. For conven- ience in checking in produce, the area should be pro- vided with a small desk or table for the receiving clerk. The receiving area should be large enough to include a table for rough preparation of produce, such as husking corn or topping vegetables, and also for the rough washing of greens or the soaking of root crops. This area is often used also for the temporary storage of produce that cannot be handled promptly. Space so used should be as close as possible to the line of production to avoid interference with traffic or plant operations.
In planning the preparation area, sufficient space
must be provided for patrons to wash the produce and prepare it for processing. Careful consideration should be given to the placement of equipment so that the maximum use can be made of it and patrons will not interfere with each other in getting the work done. For example, the placement of the wash sinks and the blanch and cold-dip tanks should be considered in relation to the preparation and fill tables, and the ex- haust box and sealer must be conveniently located near the fill table. Storage for pans, trays, hand tools, and supplies should be provided as near the prepara- tion table as possible.
The processing area should be concentrated in a part of the building removed from the working areas where produce is received and prepared. In steam-operated plants, retorts will need to be placed as near as pos- sible to the area where the boiler is housed for effi- cient use of steam and economy of installation. Where a cooling tank is provided, it should be placed between the processing equipment and the checking- out area. This assures the continuity of operations necessary for rapid handling of the canned produce and avoids congestion in this area. Furthermore, in steam-operated units it is thus possible to extend the track and hoist over it to facilitate the transfer of the baskets from the retorts to the cooling tank.
It is best to have the checking-out area at the oppo- site end of the building from the receiving area. However, in some canneries it may be necessary to do the checking out in the same area as that in which the produce is received. This is particularly true in small canneries where one person is responsible for both jobs. Where it is necessary to use the receiving area to check out the products a definite plan will need to be worked out for routing the canned prod- ucts through the cannery so as not to interfere with receiving, preparation, and processing activities. Un- less facilities are provided near the cooling tank for the sorting of patrons' cans, tables and shelves for this purpose should be provided in the checking-out
area.
When making floor plans, provision must also be made for the storage of empty cans. This space may be provided within the building or in some con- venient location nearby. If the can storage space is provided in the building, it should be separated from the rest of the cannery by a partition to keep the area free from steam, which causes the cans to rust. In the larger steam units it is also desirable to provide separate office space. In addition there should be separate dressing rooms and toilet and lavatory facili- ties for men and women, properly segregated from the canning area. Hand-washing facilities should also be provided within the cannery. In steam-operated units, a room adjacent to the cannery will need to be provided for the boiler. For safety reasons the entrance to the boiler room should be outside the cannery proper. The final determination of the floor plan and the arrangement of the equipment should be checked, if possible, by a person who has a thorough knowledge of the sequence of operations and the use of the equipment.
689641=
Steam-operated canning centers
Community canning plants can be operated most efficiently if steam is supplied from a central source as this permits all operations requiring steam to be carried on simultaneously. This factor is important if continuous and maximum production is to be realized.
Equipment required for a steam-operated plant similar to that illustrated in figure 2 is listed in table 1. Since equipment from different manufacturers varies, it is extremely important to study canners' supply catalogs before placing orders. The informa- tion given in this publication regarding each item of equipment should also be studied.
B
oilers
A fire-tube high-pressure boiler is considered most satisfactory for cannery use as this type of boiler has the fastest recovery when sudden demands are made
for steam. It may be of either vertical or horizontal design and can be fired with coal, gas, or oil. Figure 5 shows a vertical coal-fired boiler, the type most commonly used in community canneries.
Boilers specially designed for the fuel used will give better performance than reconverted ones. It is rec- ommended that only those boilers be purchased which meet the specifications of the American Society of Mechanical Engineers' Boiler Construction Code. If second-hand boilers are used they also should have been built originally in accordance with this code and, before being put into service, should be tested for 30 minutes by a competent inspector and should successfully stand a hydrostatic test of double the pressure at which they are to operate. During this test period the hammer test should be applied. Boil- ers in community canneries will vary in size from 15 to 35 horsepower, depending on the anticipated daily output of canned food and the steam-operated equip- ment required to process it.
A 15-horsepower boiler is the minimum-sized boiler recommended for any community cannery operated
Figure 4. — Interior of main part of community canning plant, Jacksonville, Fla.
Table 1. — Canning equipment required for steam -plant of 2,000 to 3,000 No. S-can capacity per 8-hour day
|
Item |
Description |
Number required |
Item |
Description |
Xumber required |
|
Boiler |
20 hp., upright or horizontal. 106 No. 3-can capacity 33 No. 3-can capacity 106 No. 3-can capacity 33 No. 3-can capacity Approximately 50-gallon ca- pacity or a size to accom- modate the largest inset crate. 40-gallon capacity |
1 2 3 2 3 1 1 2 3 1 to 2 2 1 0) 3 1 |
Blanch and scald tank. Cold-dip tank Medium tank Cooling tank ■ Preparation table Meat table Fill table • . |
22" x 22" x 22" (heated with steam coil). 22" x 22" x 22" |
2 |
|
Retort with inset crate. |
2 |
||||
|
Retort with inset crate. Extra inset crate Extra inset crate Open-process tank __ |
15- to 25-gallon capacity for brine, sirup, etc. (heated with steam coil). 6' x3' x3' (metal) 10' x4' x 34" 10' x 4' x 32" 10' x 4' x 34" |
2 1 2 2 2 |
|||
|
Sealer table Blanching basket Can trav Cutting board Dishpans |
2' x4' x34" |
2 |
|||
|
Steam- jacketed kettle. Steam coil |
Wire mesh 18 No. 3-can capacity... _ 18" x 12" (hardwood) 12 to 16 quart |
12 |
|||
|
Tinned copper, to fit stock- pot. Bench-type, heavy-duty, power-driven, 5 to 6 cans per minute. Bench-type, heavy-duty, hand-operated 3 to 4 cans per minute. 3' x 4' x 14" batch-type (covered). }i- to J4-ton capacity 500-pound capacity, mini- mum. Double-compartment sink, 4' x 2' x 18" (for wash- ing produce). 4' x 2' x 18", double-com- partment sink (for wash- ing pots and pans). |
48 (2) 36 |
||||
|
Sealer |
Dollv Thermometer Gage tester Can lifter Gloves Mill file Magnifying lens Metal ruler Garbage can Steam hose |
For general transportation us in cannery. Canning |
2 to 3 |
||
|
8 |
|||||
|
Sealer |
Test gage and pipe assembly for testing pressure gages. For lifting cans from ex- haust box. For handling cans at sealer. 10" for filing can seams Small, for inspecting can seams. Standard, for measuring body and cover hooks of can seam. 20-gallon capacity with cover. |
1 |
|||
|
Exhaust box Chain hoist Track and carriage. _ Wash sink |
2 to 1 (3) 12 1 2 |
||||
|
Wash sink |
6 to 8 (4) (4) |
||||
|
Water hose |
|||||
i 70 feet.
2 Optional.
3 Twelve pairs.
' As needs require.
Note. — Other equipment needed will include fire extinguisher, marking equipment for cans, repair parts for equipment, tools for making repairs, and special equipment, such as large sieves, pulpers, meat grinders, and lard presses as needed. Paring knives, tomato-peeling knives, vegetable knives^ and butcher knives should be provided by the cannery to standardize the types and sizes desirable. It is also desirable to provide labor-saving equipment, such as apple peelers and sheers, cherry pitters, bean cutters, pea shellers, kraut cutters. For suppliers of equipment see Partial List of Manufacturers, p. 83.
with steam. This size of boiler is adequate for plants having a capacity of 1,000 No. 3 cans per day. A plant with a capacity of from 2,000 to 3,000 No. 3 cans a day requires a 20-horsepower boiler. (See fig. 2.) It is preferable that the boiler size be in excess of anticipated needs as this will allow for ex- pansion of the plant, if necessary. Equipment sup- plied with steam from the boiler includes the retorts, open-process tanks, exhaust boxes, steam-jacketed kettle, scald and blanch tanks, medium tanks, and closed coils used for precooking foods. ■
Water-feed system
The boiler must be equipped with a suitable water- feed system to replenish the supply of water in the boiler, as necessary. There is a constant drain on the water supply in the boiler where the condensate of the steam supply is dissipated as is the case in com- munity canneries. While there are several types of water-feed systems, only the injector system is referred to here as it is the most common type used in canner- ies. The water may be supplied to the injector from an overhead tank, city water main, or a tank or barrel placed beside the boiler. The last-named plan is
desirable for several reasons: A reserve water supply is available in case the city water pressure is cut off, the water supply can be easily checked, and there is not the problem of fluctuating water pressure as may be the case when the boiler is connected to a city water main. Figure 6 illustrates the steam injector with water supplied by suction lift from a tank or barrel placed beside the boiler.
Care must be taken to keep the barrel well supplied with water and to keep the water clean. The feed water, in passing through the injector, is heated by the steam to a temperature of about 150° F. ; hence, the strain on the boiler is reduced proportionately. Steam is admitted to the steam nozzle from the supply pipe and, in passing into the combining tube, pro- duces a partial vacuum in the suction, or water supply pipe, which causes the water to rise in the pipe and flow into the chamber surrounding the steam nozzle. The steam, passing at a high velocity into the combining tube, carries the water along with it. The energy contained in the steam is sufficient to carry the water across the opening between the com- bining and delivery tubes, raise the check valve, and force the water into the boiler against the boiler pressure.
8
Figure 5. — Vertical coal-fired boiler.
In installing injectors, the steam supply should be taken directly from the highest point of the boiler, thus insuring dry steam at full boiler pressure. Steam for operating an injector should never be taken from a pipe supplying steam for other purposes, as the drop in pressure would probably be sufficient to prevent successful operation. An ordinary globe valve should be placed in the steam pipe connecting the injector with the boiler, for the purpose of starting and stop- ping.
The suction pipe must be absolutely tight for suc- cessful operation, as a slight leakage of air will destroy the vacuum formed in the pipe by the action of the steam jet. The pipe should be straight, if possible, as bends and elbows increase the friction and consequently decrease the flow of water. For short lifts, such as that illustrated by figure 6, the size of pipe should be the same as the connection to the injector. The suction pipe should run directly from the injector to the water supply. It should not be connected to a pipe supplying water for other purposes.
A globe valve should be placed in the suction pipe for the purpose of regulating the flow of water to the injector. The valve stem must be kept carefully packed at all times, as any leakage of air will prevent operation of the injector. Both a check and a globe valve should be placed in the delivery pipe, the globe valve being between the check valve and the boiler. With this arrangement, boiler pressure can be cut off and the check valve removed for inspection, clean- ing, or repairs. Since it is necessary to supply water to the boiler before the boiler is fired a bypass water line should be provided in the injector assembly. A globe valve is provided in the bypass line for regu-
STEAM CO possible: po
NNLCTION AT HIGHEST Q- 'OINT IN BOILER 47,
STEAM LINE
BOILER
STEAM GLOBE VALVE
INJECTOR SWING CHECK
ULATING GLOBE VALVE
-WATER INTAKE PIPE CONNECTION
Figure 6. — Diagram of injector piping and valve arrangement.
GLOBE SHUT-OFF VALVE
DISCHARGE LINE INTO LOWER PORTION OF BOILER
FAUCET FOR WATER SUPPLY
.-SUCTION STRAINER
lating the supply of water to the boiler. When water is delivered directly to the injector from an overhead tank or from city water mains a heavy pressure frequently exists and, in this instance, to facilitate starting on low steam, two globe valves are used in the water supply line. One valve is placed as near the injector as possible to regulate the water supply, while the second valve, placed several feet away, is employed to reduce the pressure. A strainer should be placed on the end of the suction pipe to prevent any foreign material from entering and possibly clog- ging the injector or check valves.
If the injector should fail to operate, a systematic search should be made to locate the cause. Some of the most common causes of failure to operate are the following:
1. The body of the injector and mixing tube becoming overheated by either —
(a~) leaky steam valve or discharge line check, or (b~) being hooked in too close to the boiler proper.
2. Leaks in the suction-pipe valve.
3. Foreign matter deposited in tubes.
4. Strainer on end of suction pipe clogged.
5. Too low steam pressure for lift.
6. Too high steam pressure for lift.
7. Defective check valve.
8. Valve in suction pipe not properly regulated.
9. Absence of water at source.
It sometimes happens that an injector will lift water but will not force it into the boiler. This may be caused by a leak in the suction pipe, but it is more often caused by an obstruction in the delivery pipe between the injector and the boiler. This pipe often becomes choked with lime deposits. A test for ob- structions in the delivery pipe can be made by connect- ing a steam gage between the injector and the boiler. If this gage shows a pressure much above that of the boiler, it indicates an obstruction of some kind in the delivery pipe.
The capacity of an injector should be at least 50 percent greater than the maximum requirements of the boiler it is to serve, as this provides against any heavy demands, and furthermore, the water supply can be reduced by throttling. On the other hand, if the injector is too small it is impossible to increase its capacity. When ordering injectors state the boiler horsepower, minimum and maximum operating pres- sure, and the method of supplying the water to the injector.
Location
The location of the boiler may be more or less pre- determined by the nature of the building or the loca- tion in relation to surrounding buildings. However, it is most desirable to have the boiler as near as possible to the various pieces of equipment using steam, thereby reducing the length of the steam service lines and increasing the efficiency of the boiler. For safety, comfort, and cleanliness the boiler should be located outside the building if at all possible. (See fig. 2.) Where boilers are installed outside the building they should be properly housed for the pro- tection of the equipment and the comfort of the firemen.
If it is necessary to install the boiler within the building it must be segregated from the main cannery room by a partition — at least a 12-inch brick wall — built in accordance with existing codes on such con- struction and there must be no door between the boiler room and the cannery. The boiler should be set level on a solid foundation, preferably of concrete. The height of the flue or stack should be determined solely by the size and type of boiler and the proximity of surrounding objects. The stack should be substan- tially constructed, properly guyed at intervals not to exceed 10 feet, and equipped with a flame arrester.
Local or State officials should be consulted before installing the boiler, as most States have boiler- inspection laws that must be complied with.
Boiler fittings and steam and water lines
Some important points to be considered in the selec- tion and installation of boiler fittings and steam and water lines are :
1. The pipe size for the main header steam line from the boiler can be readily determined by the size of the tapping. In no instance should this pipe size be reduced if the full efficiency of the boiler is to be realized.
2. Careful consideration should be given in the selection of materials used in the installation of high- pressure steam boilers. It is false economy to pur- chase cheap fittings and valves of unknown quality. All pipes, valves, and fittings should be of standard 250-pound test. The design and construction of water valves differ from those of steam valves; therefore, no attempt should be made to use water valves in a steam line.
3. When cutting and fitting pipe, special care should be taken to see that all threads are clean and that all burs are removed from the ends of the pipes. Failure to do this will result in unsatisfactory operation be- cause of leaky fittings and reduced capacity of the lines.
4. Before pipes are assembled, care should be taken to see that they are free of loose foreign material, such as filings, chips, or shavings, which might later lodge in and damage the delicate mechanism of such fittings as injectors and valves.
5. All thread connections and pipe joint make-ups should be coated with a good pipe thread compound to seal them against leaks and to facilitate uncoupling for repairs.
6. Y-type strainers should be placed in main steam and water feeder lines to catch all types of foreign materials and to facilitate cleaning of the lines.
7. The boiler safety valve and blow-down valve should be attached to the body of the boiler in the respective tappings designated by the manufacturer, and no attempt should be made to attach any other steam outlet or water feed to these openings.
8. Injectors, tube cleaners, or other apparatus re- quiring actual flow of steam should not be connected to the water column or to the gage glass fittings, as
10
this will cause the glass to show a false water level while such appliances are in use.
9. All steam lines should be adequately supported, and provisions should be made for the expansion of these lines when heated.
10. Where steam and water pipes are installed in parallel drops and the control valves are placed at the same height, adequate spacing should be given to insure free manipulation of the valves in order to prevent injury by coming in contact with the hot valve.
11. In making connections with various types of equipment, standard practice should be carried out — locating the steam pipe at the left and the water pipe at the right of the operator when facing them.
12. In the installation of steam and water lines, provision should be made at every low point to provide for the draining of such lines when freezing weather is threatened.
13. To keep steam lines free of condensate water, blow-down valves should be arranged at the end of each line, or steam traps may be provided for this purpose.
14. Where a drop line is provided for the attach- ment of a steam hose the connection should be made in a vertical position to prevent injury to anyone should the steam hose become loosened from the fitting.
15. All steam lines, fittings, and connections lo- cated in an exposed position in the working area should be insulated up to 7 feet above the floor to prevent injury to persons working in the plant.
16. Steam and water lines should be properly identified by the use of different colors of paint to prevent possible scalding of anyone mistaking a steam valve for a water valve.
17- Provisions should be made for the attachment of hose to the water lines at convenient places for washing floors and equipment.
Boiler operation
Because boilers are so varied in type, it is impossible to give specific directions on the operation of all kinds of boilers that will be used in community canneries. However, many of the general principles of operation apply to all boilers. Since the coal-fired vertical boiler is most commonly used, some of the important phases of its operation are given. To supplement these instructions it is recommended that all boiler operators be supplied with a copy of the book, Suggested Rules for Care of Power Boilers (jf).1
The first duty of a fireman in preparing to fire a boiler is to check the water level. This is accom- plished by two methods: (1) Ascertaining the level of the water as shown on the sight glass and check- ing to see if the sight glass is functioning properly. To do this, close both sight glass valves and drain the sight glass. The valves should then be reopened to see that the water returns to the same level as shown
1 Italic numbers in parentheses refer to Literature cited, p. 85.
before. (2) Open and close all three try cocks to determine whether the sight glass shows the correct level. The water should flow only from the center and bottom cocks as the proper level should be half- way between the center and top try cocks.
It should next be determined that all valves in the boiler room are in proper position for operation. The main steam supply or header valve should be closed and valves on the water-feed system should be either opened or closed in accordance with instructions for the particular type of water-feed system used.
When the fire is started the draft door and stack damper should be opened; the grates should be in the proper position for firing and free from clinkers. Ashes should be scattered to a depth of 1 inch over the entire grate area before the fire is kindled. In the case of a new boiler installation, especially where it is bricked in, caution should be used so that the heat is not brought up too fast. Time should be given to allow the boiler to heat and expand slowly. In no case should a boiler be forced to reach the required pressure too rapidly. After the fire has started and while the boiler is warming up, steam valves on all equipment in the plant should be closed.
At this point, the seams, rivets, connections, and fittings should be checked to see that there are no leaks. No defects should be assumed to be safe. When the boiler reaches one-half the normal operating pressure it should be blown down and the safety valve tried by hand to see that it is functioning properly. The purpose of blowing down the boiler is to remove the accumulated sediment around the base *of the tubes and at the bottom of the water pit. This is accomplished by very slowly opening the blow-down valve located at the bottom of the boiler to a fully open position until the water level in the sight glass is lowered by one-half. The blow-down valve is then closed and the water replenished in the boiler to a normal operating position. When the boiler reaches the normal operating pressure the fireman should notify the supervisor that he is ready to turn the steam into the supplv lines. It is important for the supervisor to see that no one is repairing steam lines at this time and that patrons and employees are warned that the steam is being turned into the lines.
The main steam supply valve should be opened very slowly at first, a little time being allowed for the lines in the plant to warm up before opening it widely. This will prevent undue strain on the lines and fittings.
The supervisor should acquaint the fireman with the steam needs for various products and processes so that the fireman will know when extra demands will be made for steam. A more satisfactory opera- tion will result if the fireman is able to build up the steam supply before the demand actually occurs. Fire is maintained in the boiler by adding the fuel in small amounts at frequent intervals. This results in more complete combustion and a quicker response to peak loads of steam when required than do large quantities of fuel added at less frequent intervals.
It is good operating practice at some time during
11
each day's operation to build up tile steam suffi- ciently to check the operation of the safety valve at the pressure for which it has been set. As the safety valve opens, the number of pounds of pressure on the steam gage should be noted and should check with the pressure at which the valve was set.
The water level in the boiler should be watched carefully and the water-feed system should be started to operate well in advance of the actual demand for water. This gives the operator some leeway in case difficulty is encountered in operating the water-feed system. If for any reason the gage shows that the water has fallen to or below the point designated by the manufacturer as a minimum operating level, no attempt should be made to feed water into the boiler. All valves should be left as they are and the fire with- drawn from the grates. The fire door should be left open so that the draft created through the tubes will cool the boiler to a point where it is safe to replenish the water supply. If the gage glass is not equipped with chain-operated, quick-closing valves, it is recom- mended that a common broom be kept near the boiler at all times. In case of a broken glass the broom may be used to prevent scalds in shutting off the sight-glass valves. It should be pushed over the valve stem, the broken glass, and the valve head so that the straws will break the force of the escaping steam and water and give the operator a chance to close the valves without being scalded. The bottom valve should be turned off first; the top valve closed last. With the steam and water shut off, the glass may be replaced.
Owing to the fact that excess oil, gas, compounds, and lime sediment may have accumulated in the boiler, a condition called foaming and priming may occur sometimes. This is indicated by the presence of foam and the rapid rise and fall of the water level in the sight glass. If the water level is high enough, the boiler may be blown down and the water supply re- plenished. By repeating this process several times the condition may be corrected. In extreme cases, how- ever, it may be necessary to wash down the boiler. The job of washing down the boiler should be done when the boiler is cold. It will be necessary to re- move all handhole and manhole plates and start at the top of the boiler, washing inside with a hose. In this manner the sediment is washed down to the lowest point from which it is possible to remove it from the boiler. Before handhole and manhole plates are re- placed, the gaskets and surfaces which they contact should be examined to see that they are clean and smooth. The gaskets should be painted with a mix- ture of graphite and oil to keep them soft and pliable. The necessity for washing down will vary according to the frequency of use and the local water supply but the job should be done often enough so that at no time will there be an excessive accumulation of sedi- ment for the type of boiler used.
An accumulation of soot in the tubes of a boiler reduces the efficiency because it acts as an insulation. It should be removed, therefore, as often as necessary to permit direct contact of the heat. with the tubes. This is usually accomplished by drawing a scraper or
wire brush back and forth through the tubes to dis- lodge the deposits. The frequency of this condition and the need for cleaning will vary with the type and quality of fuel used and the frequency with which the boiler is used. The boiler tubes should be blown out daily with steam.
In some localities where the water supply is of such composition that it is necessary to treat the feed water or to use boiler compounds to prevent scale, corrosion, or wet steam, a qualified water chemist or a steam engineer should be consulted. No attempt should be made to use boiler compounds or to treat feed water without first making an analysis of the feed and blow- down water and the condensate from the steam mains at the plant. If it is determined that treatment is necessary it is recommended that the closed-coil system of heating, rather than the perforated pipes, be used where the food comes in contact with the water or steam, as in blanch and scald tanks, medium tanks, precooking kettles (other than steam-jacketed kettles) and exhaust boxes. (The closed-coil system of heat- ing these items of equipment is illustrated in this publication.)
Caution: The safety valve should be set by a quali- fied boiler inspector at the time the boiler is installed and should never be changed except on the advice of a boiler inspector. The safety valve should be kept free at all times and properly lubricated. The pipe from the blow-down valve should lead to a sump or pit, or a baffle should be placed opposite the end to prevent scalding of persons coming in contact with it. If the boiler grates are equipped with a detachable shaker bar, it should be kept in place, or hanging in a convenient place near the boiler, at all times because its use may be necessary in withdrawing the fire in case of an emergency, such as loss of water in the boiler.
The boiler room should be kept clean and in order at all times and no tools or obstruction should be per- mitted to remain on the floor or at a point that would hamper the operation of the boiler system. Boiler- room doors should open outward and should never be bolted. Boiler rooms should be properly ventilated to prevent an accumulation of gases. Persons not immediately concerned with the operation of the boiler should never be permitted in the boiler room. The boiler should be attended and operated in accordance with State and local codes.
Retorts
A steam retort is a closed pressure vessel designed for processing canned foods under steam pressure. All nonacid vegetables, meats, and fish are processed under steam in order to attain temperatures sufficiently high to destroy spore-forming bacteria that may be present.
Type and number of retorts
Vertical retorts of less than 200 No. 3 can capacity- are most commonlv used in community canneries. It is well to provide retorts of 33 No. 3 can capacity
12
in combination with larger retorts to allow for flexibility necessary for processing small or large quantities. To determine the number of retorts needed, divide the total anticipated daily output of nonacid foods by the daily output per retort. On an average, retorts will be loaded six to eight times a day, depending on the produce processed. It is best to figure the number of retorts needed on a basis of six loadings per day so that capacity is provided for peak production periods.
Retorts, often referred to as unfired pressure vessels, should be purchased from a reputable manufacturer who can be depended on to furnish equipment of a design that is adequate for the intended service. Some States have laws controlling the specifications of unfired pressure vessels used in canning plants, while others do not. It is recommended, however, that in all instances only those retorts be purchased which are constructed in accordance with the Un- fired Pressure Vessel Code of the American Society of Mechanical Engineers (i) and bear its seal.
Retort equipment
Retorts used in community canneries should be of steel welded construction and equipped with a number of lugs for holding on the lid. They should also be equipped with a mercury thermometer, pres- sure gage, safety valve, vent, and pet-cock bleeder. A gasket, preferably fitted into the flange of the retort body, is provided for the purpose of making a seal between the lid and the retort flange.
Mercury-in-glass thermometer
The mercury, or indicating, thermometer is the official instrument by which processing is done. It should be graduated in 1° to 2° divisions and should read from 170° to 270° F. The bulb of the indicating thermometer should be installed preferably in an external well or pipe attached to the side of the retort body. (See figs. 9 and 12.) The thermometer bulb should clear the surrounding walls of the external well or pipe by at least % inch. The well or pipe must be equipped with a }g-inch pet-cock bleeder so located as to provide a full flow of steam past the entire length of the thermometer bulb. The bulb of the indicating thermometer may be installed within the lid of the retort provided the entire bulb extends below the lid where it is com- pletely exposed to the flow of steam.
Pressure gage
The pressure gage should be graduated in 1-pound divisions and should have a range from 0 to 30 pounds. The gage should have a minimum 3-inch and preferably a 5-inch dial and should be of a type in which the operating mechanism is independent of the case. Pressure gages and thermometers should be so placed with respect to light and position that they may be easily read.
Vent and bleeder
All retorts used in community canneries should be equipped with a venting outlet of at least %- to %-inch diameter and preferably larger. The vent should be controlled by a quick-opening gate-type valve which permits a free flow of air from the retort during the coming-up time. A globe valve should not be used as it will greatly reduce the venting effi- ciency. The vent should be placed in the top of the retort opposite the steam inlet at the bottom. In addition to the vent a ^-inch bleeder should be pro- vided in the retort lid. Inasmuch as it is kept par- tially open throughout the processing period it should be arranged in such a way that the operator can observe that the steam is emitting. In many instances the }s-inch pet-cock bleeder is the only pro- vision made for venting the retort. Such a bleeder is very inadequate for venting retorts and should be supplemented with a valve-controlled vent as specified above.
Safety valve
A safety valve of the same size as the steam inlet is recommended because the retort is hand-controlled and it might be possible to develop the full boiler pressure in the retort if this valve were not sufficiently large. The safety valve, located in the lid of the re- tort, should be set to blow from 2 to 5 pounds above operating pressure. Vent valves, safety valves, and pet-cock bleeders should be so placed that steam may not be discharged in the direction of the operator. It is well to provide a shield on the safety valve so that persons near the retort will not be burned by the steam if the valve opens to release the pressure.
Retort inset crate
An inset crate must be provided for holding cans in the retort. It is well to provide an additional crate for each retort to give the capacity needed for loading cans preparatory to processing. These crates should preferably be of strap-iron material or heavy wire. If perforated sheet-metal crates are used they should have 1-inch holes on 1%-inch centers or the equivalent. Sheet-metal crates with too few perforations should not be used, for they retard the removal of air from the retort and do not permit a full flow of steam around the cans. This may cause serious underprocessing owing to air pockets that may be present.
Installation of retorts
For efficient use of steam and economy of operation, retorts are placed near the boiler. In community canneries they are usually installed in a straight line. Where retorts of different sizes are used care must be taken so that they are centered in line to facilitate the removal of retort crates with the overhead hoist. Two ways to make the best use of floor space required for retort installation in a rectangular building are demonstrated in figures 7 and 8.
689641° — 46-
13
-fe
.BUILDING WALL' ///////
_^j_RETORT COVERS IN OPEN POSITION7
Figure 7. — Plan for installing retorts with cover arm assembled for 45° swing.
Figure 8. — Plan for installing retorts with cover arm assembled in horizontal position.
/ / / / / / / /
/BUILDING WALL ////////
RETORT COVERS IN QPEN""P05ITI0N
"V-^
COVER ARM ASSEMBLED, HORIZONTAL
Where it is necessary to make an installation across the narrow end of a building or in any area where the length of the installation is restricted, it is possible by proper location of the cover cranes to group the retorts in such a manner that the minimum distance between retorts will be obtained. This necessitates their installation farther away from the wall than ordi- narily would be necessary. Where retorts are to be installed lengthwise of a rectangular building and where conservation of the width of the building is a prime factor, by proper location of the cover crane the retorts may be placed so that the distance to the wall will be held to a minimum. This method requires more distance between retorts than the first method but valuable space in front of the retort is conserved. The placement of retorts in relation to each other will of necessity vary with the size of the retort. In all cases the distance from the wall and the distance
14
between the retorts should be ample enough for a cover to swing open without striking an adjacent retort or the wall. After being alined, the retort should be fastened securely to a low, sturdy bench or supported by legs secured to the floor, allowing enough space under it for making the necessary pipe connections.
Figure 9 shows a satisfactory piping arrangement for installing a single retort to be used for processing only. The steam line should be % inch in diameter and should enter the retort at the bottom in such a way that steam will be directed up into the load of cans. In retorts that are to be used for processing and pressure cooling it is advisable that the steam line lead to a perforated pipe which crosses at right angles near the bottom of the retort. (See fig. 12.) This will assure an even distribution of steam during proc- essing and pressure cooling. The pipe should be per-
f orated with eight %-inch holes to 1 foot of pipe. The perforations should be on top of the pipe so that the steam can be directed upward around the cans.
Although retorts constructed in accordance with the code set up by the American Society of Mechanical Engineers CI) may be supplied with steam from a high- pressure line, it is recommended that they be supplied from a low-pressure line. Retorts that do not meet the requirements of this code must be supplied with steam from a low-pressure line. This is accomplished either through the use of a pressure-reducing valve installed in the steam line leading to each retort (see fig. 9) or through the use of a single pressure-reducing valve installed in the main steam line leading to a battery of retorts (see fig. 10). The former method is
preferred in that the pressure to each retort is not affected when other retorts are put into operation as might be the case when a single pressure-reducing valve is used to control the pressure to a battery of retorts. Furthermore, if the pressure-reducing valve to an individual retort should fail to function, only that retort would be affected. Either a pilot-operated or spring-type valve may be used for installations to single retorts. If a single pressure-reducing valve is used to control the pressure to a battery of retorts, a pilot-operated valve is recommended as a closer degree of regulation can be obtained than with the spring- type valve. In the latter case a bypass steam line should be installed around the regulator so that the pressure can be controlled manually if for any reason
VENT SAFETY VALVI PETCOCK
Figure 9. — Diagram of piping arrangement to single retort for processing only.
- -3" WATER
m:heck valve
-HIGH-PRESSURE. STEAM
^'i- SHIgh-PK-Essure: gage
-PETCOCK
LOW-PRESSURE GAGE PETCOCK SAFETY VALVE
TEES FOR RETORT 5UPPLY
MANIFOLD LINE
VALVE
ACTUATING
CONTROL
LINE
QpiCD
Figu
gure
10. — Diagram of piping arrangement of pilot-operated pressure-reducing valve in main steam line leading to a battery of
retorts.
15
it is necessary to remove the regulator from service. (See fig. 10.) Only an experienced person should be permitted to adjust the pressure-reducing valve or operate the steam valves of the bypass line.
A pressure-reducing valve should be installed near the equipment it is to control and should be set so as to reduce the pressure from the high-pressure line to a pressure from 3 to 5 pounds above that at which the retorts are operated. As a protection against the failure of the pressure-reducing valve, a safety valve of the same size as the low-pressure pipe line should be provided between the pressure-reducing valve and the retort and should be set to pop off at 5 to 10 pounds higher than the pressure at which the retorts are operated. In all instances where a pressure- reducing valve is used, a strainer should be provided in the steam line leading to the regulator valve to prevent dirt or other foreign matter from accumulat- ing on the seating surface. Individual strainers are not necessary where pressure-reducing valves are pro- vided for each retort if the strainer is placed in the steam supply line. A Y-type strainer is recommended as it may be easily removed for cleaning. The port seats of the valve should be of stainless-steel trim or other equally noncorrosive metal if satisfactory per- formance is to be assured over a long period of time.
It is important from an operating standpoint as well as that of cost that the regulator be correctly sized. The size should be determined on the basis of the work to be done rather than by the size of the existing pipe lines. When ordering pressure-reducing valves, state the boiler pressure and the pressure at which the retorts are to be operated, as well as the number and size of retorts that are to be operated off the low-pressure line.
It is well to provide a water-inlet pipe line to retorts to assure flexibility in operation. Retorts may then be used interchangeably for water-bath and steam- pressure processing. (See fig. 9.) A water-inlet line must be provided for retorts that are to be used for pressure cooling. A retort of 106 No. 3 can capacity is the smallest recommended for pressure cooling. (See fig. 12.) The water pressure should be at least 10 pounds greater than the pressure used in processing. An overflow pipe line not less than 1 inch in diameter, fitted with a gate valve, must be provided on any retort used for pressure cooling. If the discharge end of the overflow line is under water or if the line is connected to a drain line, as shown in figure 12, the overflow line should be broken, as at D, in order to prevent a vacuum from being drawn in the retort. It is preferable to use a funnel connection, as shown in figure 12, as such installation permits ready inspec- tion of the volume of water passing out. All retorts must be provided with an adequate drain not less than 1 inch and preferably 1% inches in diameter connected to a sewer or discharged into a floor drain, as desired. A retort used for pressure cooling requires a minimum drain l}i inches in diameter and, if the drain line is more than a few feet long, a 2-inch drain would be advisable. This provision is necessary to aid in the rapid removal of water from the retort during pres-
sure cooling and the removal of air from the retort when the overflow pipe is used for venting. A smaller drain pipe may restrct the removal of water or air from the retort. All pipes should be reamed in order to assure full capacity. They should also be blown out to remove particles that may cause the valve seats to become scored.
The arrangement of fittings and connections, shown in figures 9 and 12, may need to be modified to meet local conditions. However, steam and water valves should be so located that each may be readily reached and the operator will be able to watch the pressure gage and thermometer.
Care of retorts
In community canneries where retorts are used but seasonally the entire retort hook-up should be exam- ined carefully at the beginning of the canning season and each retort should be brought up to processing temperature without a load. At this time carefully inspect the steam line for leaks; check the vents, bleeders, safety valves, gages, and thermometers. All valves should be gone over to see that they seat properly and operate freely. Gages and thermometers should be tested for accuracy before the plant is put into operation and at least once during the canning season. The retorts should be thoroughly cleaned with a wire brush to prevent loose scale or rust from getting into the valves during operation. The gas- ket in the retort flange must be maintained in good condition by treating it at frequent intervals with a solution of graphite in oil. This prevents it from sticking and helps to make a good seal. When the gasket becomes worn, it should be replaced. An extra gasket should be on hand for replacement. When a new gasket is installed, it should be joined with an angular overlapping join because a certain amount of shrinkage will develop after it has been used a short time and the angular join prevents leak- age when this occurs. Be sure that retorts are thor- oughly drained and permitted to dry at the end of each day's operation to prevent rust and stale odors that might otherwise occur. It is well to fill the retort with water occasionally and boil it out to remove grease or other foreign matter.
Retort operation
When a retort has been idle for an hour or longer, the steam line should be blown out immediately before using. This can be accomplished by closing the lid of the retort and turning on the steam for a minute or two until live steam, free from air or con- densate, flows from the line. Thereafter during the day, if the retort is in constant use, it will not be necessary to repeat this procedure. After blowing out the steam line close the steam valve, open the lid, and place the crate of cans in the retort, readjust- ing the lid into position. Lift all lugs into place. Do not tighten any until they are all up. This in- sures that all lugs can be raised into position. Fasten
16
lugs by hand until tight. Turn opposite lugs, work- ing back and forth across the head of the vessel until all lugs are tight. Do not start at one point and go around the lid because this will put a strain on the lid. Furthermore, it may cause some lugs to become loose when the pressure builds up in the retort, and accidents may occur.
It is necessary to fasten the lid only securely enough to prevent the escape of steam between the lid and the retort. In using a retort for the first time, the position of the cover in relation to the body should be marked so that the cover may be replaced every time in the same position. This will prevent damage to the gasket and avoid the possibility of leaks from that source.
In following the instructions given in this publi- cation for processing nonacid canned foods, the operator must make sure that the product has been heated in the retort in pure steam at the temperature specified for the length of time recommended.
Venting retorts
Retorts, even when fully loaded, contain consider- able air, which must be completely replaced by steam before the process is begun. Retorts only partially filled contain considerably more air than those with a full load. Air trapped between the cans within the retort load produces air pockets or low-temperature spaces in which the cans are not fully processed. Air acts as an insulator and, when present, will cut down the penetration of the steam. The transfer of heat to the cans is very much faster from steam than from a steam-air mixture. It is imperative, therefore, that all air be removed from the retort before starting the process if the full value of the process is to be realized and spoilage avoided. This is accomplished by venting the retort. Since air pockets may persist for a considerable length of time, the retort must be vented for a predetermined period of time.
To determine the adequate venting times for com- munity cannery type retorts, a study by Fitzpatrick, McConnell, and Esselen (7) was conducted at the Massachusetts State College and the following recom- mendations were made:
No. 2 steam retorts (33 No. 3 can capacity) should be vented at least 7 minutes at 0 pound or 10 pounds pressure.
No. 3 steam retorts (106 No. 3 can capacity) should be vented for at least 25 minutes at 0 pound pressure, or 10 minutes at 10 pounds pressure.
It is well to vent all retorts under pressure to assure the removal of air pockets, and in the case of the larger retorts, to shorten the time for venting.
To vent these retorts adequately within the period of time given, it is important that the venting outlet be of sufficient size to permit the rapid removal of air. (Vents provided should be of the size recom- mended on page 13.) The %-inch pet cocks usually provided en retorts are not large enough to function as vents but serve only as bleeders to prevent the accumulation of noncondensable gases that may be introduced with the steam. Other factors that need
to be considered to assure adequate venting of retorts are the steam supply, the equipment used for holding the cans in the retort, and the arrangement of cans in the retort crates. A %-inch steam-inlet line should be the minimum size provided for retorts that are to be vented in the time recommended. Retorts having only a %-inch steam-inlet line will need to be vented at least 5 minutes longer than the time recommended to assure the removal of air pockets. The type of crate and the arrangement of cans which permit a free flow of steam in all directions around the cans are illustrated in figure 11. (For further information on the stacking of cans in retort crates see page 57, and for information on the use of perforated crates see page 13.)
To vent a retort, open wide the vent valve or the pet-cock bleeder on the retort lid. Also open wide the pet-cock bleeder on the thermometer pocket, as air trapped in the pocket will reflect a false reading. Make certain that the water-inlet valve and the drain valve are closed. Open the valve of the steam supply line gradually until a flow of steam comes into the retort. Do not count the venting time until a steady stream of steam issues from the vent or pet-cock bleeders. The presence of air pockets in the retort is not indicated by the retort thermometer or pressure gage, even though they may be in agreement. There- fore, venting must be continued for the predetermined time necessary to assure the removal of all air.
Figure 11. — Slatted retort crate.
17
Processing
At the end of the venting period the vent valve or top pet-cock bleeder and the thermometer bleeder should be partially closed so that approximately half of the full flow of steam is emitted. They are left in this position throughout the entire processing period, thus permitting the essential circulation of steam throughout the retort and past the thermometer bulb. Processing time is counted as soon as the thermometer indicates the processing temperature desired and is in agreement with the gage pressure. (See table 8 for gage pressure corresponding to specified process temperatures at various altitudes.) Compute the time in which processing is to be done and record it on the retort or on a clock face or pad. A small square marked off on the retort with blackboard paint makes a very satisfactory place to record processing periods. Chalk may be used and erased with each processing. To avoid confusion when recording processing time on a pad or clock face, it is important that the retorts be numbered for identification and the appropriate number be recorded on the pad or clock face.
The correct temperature in the retort is maintained by regulating the bottom steam-inlet valve. Retorts should be watched carefully throughout the processing period. Fluctuations in temperature or pressure may result in underprocessing or overprocessing. Further- more, these fluctuations cause undue strain on the can seams. If the temperature or pressure is permitted to drop, it may be necessary to lengthen the processing time, or to reprocess, in order to prevent spoilage. (See p. 58.) The practice of depending on pressure- reducing valves as a control of the retort pressure should be discouraged as this is not a protection against a drop in boiler pressure. Furthermore, these valves may get out of adjustment or fail to operate. At the end of the processing period the steam supply line to the retort should be closed and the retort left to vent until the pressure gage reaches zero before the retort cover is removed. Too rapid venting at the end of the processing period may cause cans to buckle. When No. 3 cans are used, pressure should be released slowly, and the pet cock adjusted to about one-half open. When smaller cans are used, pressure may be released more rapidly. However, the pet cock should be opened gradually as the pressure goes down. When the gage-pressure reading is at zero, open the retort promptly and remove the cans for cooling.
Pressure cooling of cans in retorts of 106 No. 3 can capacity or larger (pressure maintained with steam)
Cans of larger diameters, such as No. 5 and No. 10, if processed under pressure, must be cooled under pres- sure. Otherwise, the ends of the cans may buckle when the steam pressure is permitted to drop after the cooking is completed. This buckling is caused by ex- cessive pressure inside the can as opposed to the lower atmospheric pressure outside the can. Such excessive pressure, in addition to disfiguring the can, may over- strain the double seam and cause spoilage owing to leakage. This pressure differential can be reduced only
by lowering the temperature of the can contents before the pressure in the retort is permitted to drop. If buckling has been experienced in cans of smaller diam- eter (such as No. 2, No. 2%, and No. 3), processed under pressure, they should also be cooled under pressure.
Pressure cooling may be accomplished by maintain- ing the pressure either with steam or compressed air. Where compressed air is available the use of this method is more desirable. However, since most com- munity canneries will of necessity be limited to the method in which the pressure is maintained with steam during part of the cooling period, instructions are given for that method.
Figure 12 illustrates a typical retort installation with minimum pipe connections to permit pressure cooling. The pressure is maintained with steam.
Retorts in which cans are to be pressure-cooled are operated according to the preceding instructions, with the following exceptions:
1. Before putting the crate in the retort, admit from 6 to 8 inches of water and turn on the steam to bring the water to the boiling point. This provides a cushion of water in the retort to prevent condensa- tion of the steam when water is admitted at the beginning of pressure cooling.
2. Before starting the venting process close the steam valve A in the steam supply line coming in at the top side of the retort.
3. When venting the retort, open the gate valve E in the overflow line and leave it open throughout the venting period. At the end of the venting period completely close this valve.
At the end of the processing period the following points should be observed for pressure cooling all large diameter cans, and small sizes where necessarv.
Open the steam valve B an additional quarter turn or more to build up the pressure slightly above oper- ating pressure. Give water inlet valve C about a quarter turn. Let stand a few minutes and repeat until a full flow of water comes into the retort. It is extremely important at all times that the water be admitted to the retort gradually, and particularly so where the water pressure at the retort is in excess of 50 pounds.
Continue admitting steam and water together until the layer of hot water has been increased by several inches in the retort. This will usually require 2 or 3 minutes.
As the layer of hot water builds up, turn off the lower steam valve B gradually until it is completely closed and cold water is being admitted under the layer of hot water. This layer of hot water pre- vents the steam in the top of the retort from condens- ing and thus makes it possible to maintain a pressure on the cans.
The pressure should be held at or above the normal operating pressure. This is accomplished by opening the top steam-inlet valve A as the bottom steam valve B is closed.
As the retort fills with water, there will be little use for steam to hold the pressure because it will be
18
VENT SAFETY VALVE PET COCK
C-ATE VALVE FOR OVER FLOW AKID^^C^y VENT
Figure 12. — Diagram of piping arrange- ment to single retort for processing and pressure cooling.
GATE VALVE STEAM MAIN
PRESSURE-REDUCING VALV PRESSURE GAGE
SAFETY VALVE THERMOMETER
RETORT
SUPPORTS FOR RETORT CRATE CROSS
l"DRAIN
a
CHECK VALVE,
63
^PERFORATED STEAM PIPE
DRAIN
maintained by the water pressure. However, con- tinued observation and adjustment of valve A will be necessary. When the water level reaches the pet- cock bleeder on the thermometer it should be closed and valve A, top steam inlet, should be closed. It will be noted that the mercury column of the ther- mometer drops rapidly. When the retort is about full the water will shoot out of the pet-cock bleeder or the vent valve on the retort lid. Close the bleeder or valve, and at once partially open the overflow valve E and cut back the flow of water by partially closing valve C. The retort pressure should be kept the same as, or slightly higher than, the processing pressure during these operations, care being taken so that the pressure never exceeds the processing pressure by more than 5 pounds. Adjust the water-inlet valve C and the overflow valve E so as to maintain the desired flow of water through the retort at the de- sired pressure. With practice one can soon learn the exact method of handling valves during this stage.
Great care must be exercised to prevent excessive pressure as the retort fills with water. The retort operator must make every effort to keep the pressure constant. Practice with an empty retort until de- tails are mastered. When the retort has filled with water it should be held at the normal operating pres- sure and the water allowed to run through the retort freely until the cans have been cooled, so that when the water pressure on the retort is relieved the cans will have no more internal pressure than is displayed by a springer. Because the top row of cans cool more slowly than the other rows, observation should be made of these and determinations set up for each product as a guide for cooling time required.
Products, such as peas, string beans, beets, and carrots, which heat by convection will cool rapidly and will require but very short holding periods under pressure after the retort is full of water. There will
be cold water circulating in through the bottom and hot water out through the overflow. When the water flowing out of the overflow pipe is cool enough so that the hand may be held on the pipe, the pressure may be dropped and the retort lid removed. This should be done gradually at the rate of 1 pound per minute until 0 gage pressure has been reached. This is accomplished by opening the overflow valve E until all the pressure is out of the retort. When this occurs the water inlet valve may be closed tightly and the lid removed. Cooling should be continued after the lid is removed by maintaining the above- mentioned circulation until the cans are just warm when placed to the cheek.
Other products which heat by conduction, such as pumpkin or cream-style corn, will require longer periods for cooling under pressure. This period may vary from 20 to 25 minutes. When such products are cooled the retort should be held at full pressure to within 10 minutes of the end of the cooling period and then the pressure should be dropped at the rate indicated. It is best to drain the retort before the cans are removed to prevent spilling water on the floor. In pressure-cooling the following rules should be observed:
1. Keep valves well oiled so that they work freely.
2. Fill retort full of water as rapidly as possible to prevent over- cooking top cans. Cut back the flow of water as soon as retort is sufficiently filled to coal cans in desired time.
3. Maintain a constant pressure in retort while it is being filled with water. Slowly reduce pressure thereafter.
4. To prevent buckling of cans and overstraining of seams do not relieve retort pressure too abruptly.
5. To prevent paneling at sides of cans do not cool too long under pressure.
6. Observe the top cans for the effects of too-short cooling under pressure and the bottom cans for the effects of too-long cooling or too much pressure during the later stages. Too great a differential between the results on top and bottom cans may indicate that the retort has been too slow in filling or that too small a flow of water has been going through while cooling.
19
Testing pressure gages
Since pressure gages sometimes get out of order they should be tested at the beginning of the canning season and at frequent intervals thereafter as long as the retorts or pressure canners are in use. This is particularly important where pressure gages are the only means provided for determining the temperature inside the vessel. Pressure gages are best tested by the use of dead-weight gage testers or manometers but since many canneries find their cost prohibitive an inspector's test gage is often used instead. Figure 13 illustrates the assembly necessary for using an inspector's test gage.
This method of testing gages is satisfactory pro- vided the inspector's test gage is checked periodically for accuracy against a dead-weight gage tester or a manometer. State colleges and railroad shops usually have these facilities.
If a test gage is to be used for testing pressure gages on retorts and pressure canners it should be of the following specifications:
1. Inspector's test gage.
2. Three-inch dial.
3. A pressure range of 0 to 30 pounds per square inch, with total scale graduations of not less than 270°.
4. The smallest graduation not greater than }i pound per square inch.
5. Accuracy guaranteed within one-half of 1 percent of maximum scale graduation.
6. One-fourth-inch bottom connections.
(See partial list of manufacturers (p. 83) for suppliers of test gages. The piping and fittings to make up the test-gage assembly may be purchased at any hardware store.)
Figures 14 through 25 illustrate the parts of an inspector's test-gage assembly and the method for testing pressure gages on pressure canners or retorts heated with a direct flame. Pressure gages on retorts heated with steam from a boiler are tested in the same manner except, of course, that it is not neces- sary to put water in the retort.
Steps in testing pressure gages are:
Step 1: Fill the vessel with 2 to 3 inches of water. Close the lid of the vessel and fasten into position. Remove the pressure gage with a bicycle wrench.
Step 2: Replace pressure gage with %-inch T (part 2, fig. 14) and screw canner gage into top of T. In screwing gage into T use two wrenches, as shown, to support the T properly.
Step 3: Remove the %-inch pipe plug (part 3, fig. 14) from the T. Screw the %-inch nipple with union connection (part 4, fig. 14) into T, using bicycle wrench and supporting gage with hand.
Step 4: Pour water into siphon (part 5, fig. 14) until it comes out at the bottom. Water in the siphon pre- vents the hot steam from entering the test gage. Keep siphon upright to prevent loss of water.
Step 5: Mount siphon in position in the %-inch union connection and tighten with wrench. Support siphon with hand so as not to place strain on the pipe connection into canner.
Step 6: Place inspector's test gage (part 6, fig. 14) in position and tighten union connection with wrench, supporting pipe assembly with hand.
Step 7: Apply heat to canner or retort, leaving the vent valve or pet-cock bleeder open until steam issues freely from the vessel. Close the vent or pet cock to permit pressure to build up in the vessel. As the pressure rises tap the pressure gages lightly at the center of the dial to correct any tendency of the pointers to stick.
Step 8: Test pressure-canner gage at 10 and 15 pounds per square inch by bringing the test gage to these pressures and observing the corresponding read- ing of the canner gage. Be sure the test-gage pointer is at the correct pressure at which the test is being made. If the test-gage pointer exceeds the correct value, open the vent valve to release pressure. Note carefully the reading of the canner gage at each test pressure (10 pounds and 15 pounds per square inch). When the test is completed, turn off the heat.
Step 9: Open vent valve wide to relieve pressure in vessel. Do not attempt to remove testing assembly until pressure has returned to 0. Remove test gage first, then siphon, and then union nipple, supporting piping assembly with hand at each step to prevent strain on connection in lid. Leave the %-inch T and gage assembled. By leaving this assembly in posi- tion future tests can be made without disturbing the pressure gage on pressure canner or retort.
INSPECTOR'S TEST GAGE.
4 STREET ELBOW-
4"PLU5-£JJ}
:lose NIPPLE 'COVER OF PRESSURE CANNER
Figure 1 3. — Inspector's test gage and piping assembly.
20
Figure 14. — Pressure canner and parts for gage tester: (1) Pressure canner with the pressure gage which is to be tested; (2) 1/4-inch T reduced to 1/8 inch at top and bottom,- (3) 1/^-inch pipe plug,- (4) V^-inch pipe nipple with V^-inch union connection,- (5) 1/4-inch siphon with "j/^-inch union connections,- (6) inspector's test gage with 1/4-inch union connection,- (7) 2 bicycle wrenches. (For details of parts listed above see figure 1 3.)
Figure 15. — Step 1, removing pressure gage.
Figure 16. — Step 2, assembling gage tester.
Step 10: Screw the %-inch plug into the %-inch T on which the pressure gage is mounted . Support pressure gage with hand as plug is tightened with wrench.
The pressures shown by the canner gage when the test gage was at 10 pounds and 15 pounds per square inch are the pressures which the canner gage should show to give 10 pounds and 15 pounds, respectively, inside the canner. For example, if a canner gage registered 11 pounds when the test gage showed 10
pounds and 16 pounds when the test gage showed 15 pounds, that canner gage must read 11 and 16 pounds, respectively, in order to have 10 pounds and 15 pounds per square inch inside the canner. The readings of the canner gage which the test showed to give 10 pounds and 15 pounds within the canner should be recorded on a linen tag and the tag attached to the gage. Pressure gages which are in error more than 2 pounds should be replaced.
689041° — 46-
21
Figure 17. — Step 3, assembling gage tester.
Figure 19. — Step 5, assembling gage tester.
Figure 20. — Step 6, assembling gage tester.
U_ i*.
Figure 18. — Step 4, assembling gage tester.
Figure 21. — Step 7, testing pressure gage.
22
Figure 22. — Step 8, testing pressure gage.
Figure 24. — Step 10, completing gage assembly on pressure vessel.
Figure 23. — Step 9, removing gage tester.
Figure 25. — Record and use of test results.
23
Open-process tanks
Although retorts may be used for processing acid products by the water-bath method, it is advisable to provide open-process tanks for this purpose. Greater flexibility in handling both acid and nonacid products during peak production periods is thus afforded. Each plant should have at least one open- process tank of the same size as the largest retort. By having them of the same size the inset crates of both vessels can be used interchangeably. At least two inset crates should be provided for each open- process tank. The tank, made of galvanized sheet metal, should be so constructed that the inset crate will rest on a perforated false bottom located slightly above the perforated steam pipe at the bottom of the tank. (See fig. 26.)
Such an arrangement permits the free circulation of water under the cans, necessary for the proper heat pen- etration, when processing. As with all open vessels fitted with standard-type pipe connections, steam is supplied to the open-process tank from the high- pressure line. A %-inch line is adequate and may be connected to a perforated steam pipe as shown in the drawing or to a closed-coil system. An overflow pipe line should be provided at the top of the tank to keep the water at the proper level and to prevent spilling over that might otherwise occur when the water is at the rolling boil. The tank should be installed in line with the retorts and be properly centered so that the crates may be removed with the overhead hoist. It should be supported on a frame of the proper height to permit the installation of the steam pipe and drain. Water is supplied to the tank through a faucet or hose arrangement conveniently located near the tank.
Open-process tanks and retorts used for processing acid products should be filled with sufficient water to cover the cans. It is important that the water be boiling when the cans to be processed are added and that the timing of the water-bath process is not begun until the water has returned to the boiling point. In using steam-heated process tanks, care must be taken not to mistake the agitation caused by the steam for the actual boiling of the water. The water must be kept boiling throughout the processing period as any
OVERFLOW-
U. — WATER 5UPPLY
VALVE-
PERFORATED STEAM PIPE
FALSE BOTTOM WITH 1"H0LE5 SPACED 4" ON CENTERS
FALSE-BOTTOM SUPPORT STEAM VALVE
STEAM SUPPLY
r— IjOVERFLOW ,
^ i Co
^TOP OPEN
.J "cold WATER-
r
SIDE ELEVATION
-I4 DRAIN
FRONT ELEVATION
Figure 27. — Detail of cooling tank.
drop in temperature will cause the processing time given in this publication to be insufficient. The time for processing should be recorded on a pad of clock face specifically used for that tank. At the end of the the processing period the steam is turned off and the cans are removed for cooling.
.ooling
tank
Figure 26. — Detail of open-process tank.
To make the most efficient use of retorts a cooling tank should be provided for cooling products in cans of a size that do not require cooling under pressure. Metal cooling tanks are preferable because they are easy to keep clean and may be readily moved if neces- sary. Cooling-tank capacity should be sufficient to accommodate one crate for every three retorts or open- process tanks. The tank should be provided with a cold-water inlet at the bottom and an overflow pipe slightly above the height of the crate to carry the heated water to the drain. The overflow pipe should be placed at the opposite end from the inlet and should be sufficiently large to carry away the water displaced by the crate of cans when it is placed in the tank. The drain at the bottom of the tank should be of the same size as the overflow pipe. The cooling tank should be installed near the retorts and open-process tanks and directly under the overhead track and hoist so that crates of cans to be cooled mav be conveniently handled. It should be mounted on a frame sufficiently high to permit the installation of a drain. The tank should be slightly elevated at the water-inlet end to facilitate drainage. (See fig. 27.)
The tank should be filled with cold water before the crate of cans is placed in it for cooling. Admit cold water to the cooling tank throughout the cooling period to assure the circulation of water necessary for rapid cooling. Remove the cans from the tank as soon as they are cooled to the proper temperature. (See p. 59.) The tank should be completely drained and thoroughly cleaned at the end of each day's operation and oftener if necessary.
Chain hoist and track
A differential geared-type chain hoist of %- to %-ton capacity attached to an overhead track is necessary for lifting crates in and out of retorts, open-process tanks, and the cooling tank. (See fig. 28.) A hoist of %-ton capacity should be used with the larger retorts in order
24
to provide the needed safety margin . The track should be centered directly over those vessels and should be extended over the areas where a hoist is needed to facilitate the handling of loaded crates. A heavy- duty garage-door track, hay track, I-beam, or a standard canner's rail and trolley may be used. The track should be installed high enough for the hoist to lift a basket clear of the vessels it is to serve. A sim- ilar hoist and track is recommended for those plants processing meats in order to facilitate the handling of carcasses.
Steam-jacketed kettles
One or more steam-jacketed kettles should be pro- vided in each plant for rendering lard, making fruit butters and soup stock, and preheating such products as corn, apples, and pumpkin. They should be of stainless steel or aluminum to permit their use for any product. Kettles of 10- to 40-gallon capacity are most practical for use in community canneries. Either a stationary type, such as that shown in figure 29, or a tilting or trunnion type may be used. Tbey should be located near the sealer since in most instances products heated in these kettles are filled directly into cans and sealed. They should be placed so that they are acces- sible from all sides. A pressure-reducing valve should be installed in the steam line leading to the kettle and should be set at the pressure recommended by the manufacturer of the vessel. A globe valve is provided between the pressure-reducing valve and the kettle for admitting steam to the kettle. In order to make the proper adjustment of the pressure-reducing valve and to know at all times the pressure of the steam that is being admitted to the kettle, a steam gage must be provided between the globe valve and the kettle. The pressure range of the gage should be such that it will measure the maximum operating pressure of the kettle.
A safety valve is usually provided on the kettle, as shown in figure 29. Where this provision has not been made, a safety valve must be installed in the
Figure 29. — Stationary-type steam-jacketed kettle.
TROLLEY
GEARED HOIST
CHAIN
HOOK
Figure 28. — Assembly of differential-geared hoisf.
steam line between the globe valve and the kettle. This valve should be set at a pressure slightly higher than that of the pressure-reducing valve and within the safety limits of the pressure at which the kettle can be operated.
Steam-cooking coil
One or more steam-cooking coils, often referred to as brine tank coils, should be provided in a community cannery to supplement the steam-jacketed kettles. (See fig. 30.) They should be of a size to fit into a stockpot or kettle for preheating quantities of prod- uce which are insufficient to warrant the use of a steam-jacketed kettle. They are convenient to use in that the inlet and outlet are over the side of the kettle and permanent attachments to the kettle are not required, thus making it easy to transfer them from one kettle to another. They should be supplied with
25
steam from a low-pressure line. It will be necessary to have a safety valve and a pressure gage between the pressure-reducing valve and the steam line leading to the cooking coils. In order to conserve the number of pressure-reducing valves required in the plant, this installation may be made in the low-pressure line leading to the steam-jacketed kettles.
For convenience in operation it is well to provide a low bench or table for the stockpots in which the cooking coils are used. An insulated mat should be provided under the kettle to protect the surface of the table or bench. Since these coils come in direct contact with the food and are usually made of copper tubing, they should be tinned. In some instances, particularly where large kettles are used, it may be desirable to have a coil with double loops in order to get more even heat throughout the product. By specifying the kind of produce to be heated, the size of the kettle to be used, the temperature to which the products are to be heated, and the amount of steam pressure available, manufacturers can determine the number of loops required in the coil and the type of coil that would be most satisfactory.
Sealers
A can sealer is a machine designed to form the double seam which attaches the cover to the can in such a manner as to effect a hermetic closure. Models
vary widely in design, speed of operation, and a number of other details but they all have in common the following units essential in forming and rolling a double seam.
The chuck is machined to fit snugly into the recessed cover or countersink of the can and serves the dual purpose of steadying the can and acting as an anvil against which the seam is formed. In some machines the chuck is slightly knurled for traction which enables it to rotate the can.
The seaming rolls are divided into two classes according to their purposes. The first-operation roll has a groove which is semicircular and serves the purpose of turning the edge of the cover over the top flange of the can, thereby putting the cover hook and the can hook, as they are known, in proper position for seal- ing. The finished seam made by the first operation roll has a rounded contour. (See figs. 31 and 32.)
The second-operation roll is very similar to the first in that it bears the same relationship to the chuck, and that it is activated by the same force which may be either manually or automatically controlled. Its purpose is to smooth down or flatten the loosely formed layers of tin plate of the rounded seam made by the first-operation roll. For this purpose the seaming groove in the second-operation roll has a shallower and flatter groove contour than the first- operation roll. (See fig. 33-)
4 CONDENSATE
k STEAM 5UPPY
NON CORROSIVE-METAL STOCKPOT
PLAN
VALVE
VALVf
• ",
CONDENSATE
{ STEAM SUPPLY
PIPE BRACE
TINNED COPPER PIPE LE
Figure 30. — Stockpot and steam cooking coil.
■^— HANDL
I0-0R 15-GALL0N N0NCORROSIVE METAL STOCKPOT
PIPE BRACE 1" TINNED COPPER COIL
L<>IN5ULATED MAT
-TABLE TOP
FRONT ELEVATION
26
FIRST -OPERATION ROLL
CAN BODY
5E.AMER CHUCK CAN COVER COUNTERSINK OF CAN COVER
Figure 31. — Position of can and cover in relation to sealer part before seaming.
The base plate is a base or platform on which the can is supported during the seaming operation. In most machines it is free running and has no effect on driving the can, its only purpose being to give the can the proper pressure when it is raised into position.
Each of these parts is so machined that it may be adjusted to assure a perfect seam.
The size and number of sealers needed are determined by the anticipated daily output of the plant and the sizes of cans that are to be used. It is false economy to provide other than well-constructed sealers . Heavy- duty bench-type motor-driven sealers, such as shown
FIRST-OPERATION ROLL
CAN BODY
SEAMER CHUCK
CAN COVER
COUNTERSINK OF CAN COVER
Figure 32. — Innermost position of first-operation roll in relation to chuck for forming first-operation seam.
SECOND -OPERATION ROLL
SEAMER CHUCK-
Figure 33.— Innermost position of second-operation roll in relation to chuck for forming second- operation seam.
CAN COVER
COUNTERSINK OF CAN COVER
CAN BODY
27
Figure 34. — Heavy-duty bench-type motor-driven sealers.
in figure 34, are recommended for use in community canneries. Such sealers are capable of sealing 5 or 6 cans per minute. At least 2 sealers of this type should be provided for plants having a capacity of from 1,000 to 2,000 cans per day. Plants having a capacity of from 2,000 to 3,000 cans per day should have 3 such sealers. Community canneries processing food in No. 10 cans for school-lunch purposes will require a heavy- duty sealer for sealing this size of can.
A bench-type motor-driven sealer is desirable for use in any size of plant. Hand-operated sealers may be used in very small plants but their limitations should be recognized. They are laborious to operate and even when operators are changed frequently, it is difficult to get capacity production from them. How- ever, one or more hand-operated sealers should be pro- vided in each plant for emergency use when the power is temporarily off or to replace motor-driven models that may have to be removed from service for repair or adjustment. Figure 35 illustrates a heavy-duty hand- operated sealer suitable for use in community canneries.
Can sealers should be located as near the exhaust box as possible, and they should be fastened securely to a sturdy table provided for that purpose. The table should be large enough to provide space for marking cans and should be of a height suitable for the type of sealer used. A table 34 inches high is needed for motor-driven sealers although a table 32 inches high is best for hand sealers. The table top should be of 2-inch lumber and should extend at least 2 inches from the frame of the table in order to provide space for securing the sealer.
Operation of sealers (double seamers)
The sealing of the can is the operation that safe- guards its contents, and the success of the entire canning project depends on this step. The directions for operating and adjusting sealers given in this pub- lication are based on those contained in a research report by Jarvis (#), of the United States Department
Figure 35. — Heavy-duty hand-operated sealer.
28
of the Interior, and on information contained in Baumgartner's Canned Foods (3).
Sealers should be operated in accordance with the manufacturer's instructions. They become worn by constant use and may get out of order, and their adjustment should be checked at least daily. This is best done at the beginning of the day by sealing several cans and examining the can seams. A careful visual examination of the contour of the double seam should be made first. Its outline should be free from sharp edges and it should not be beaded or rounded.
Rounded seams are usually the result of excessive rolling by the first-operation roll. In this instance, the strong curl that is formed resists the subsequent pressure of the second-operation roll. The top of the seam should be distinctly but not excessively flattened. Sharp edges at the top inside of the seam, known as "cut overs," are most frequently found on the cover where it coincides with the lock seam of the can body. They may be caused by a worn or chipped chuck, incorrectly set second-operation roll, or other mal- adjustments, and if cuts are deep enough to cut through the plate of the can, leakage may occur and spoilage result.
Spurs (or lips) may also cause leaker spoilage, and they are most frequently observed at the overlap, where the rolled seam coincides with the soldered side seam. They appear as protrusions at the base of the seam and usually result from failure of the seaming rolls to fold completely the cover hook under the can hook at one or more points. Among the causes of "spurring" the most common are: The first-operation roll being too tight; too much base plate pressure; maladjustment of rolls to the chuck; and irregular curl on can ends. There should not be any marked variation in the thickness of any given seam except for the normal increased thickness where the rolled seam coincides with the side seam. By comparing the seam made by the sealer with the factory-made seam of the can, noticeable differences can easily be detected.
Examination of the can sea
m
In order to confirm opinions formed as the result of the external examination of the can seam and to deter- mine the sealer adjustment necessary to correct seam- ing operations, a section of the can seam should be stripped and examined. Leakage may occur from the defective engagement of the can and cover hooks. The lack of proper engagement may be due to one or both hooks being short or the hooks may be of normal length but not flattened tightly together. Figures 36 to 40, inclusive, illustrate the steps involved in filing a can seam in order to separate the hooks for examina- tion and measurement. These steps are:
Step 1 . With the edge of a flat file held at a 45-degree angle cut a notch completely through the double seam about 1 inch from the body seam. Examine the notch with a magnifying lens and note whether there are pin-point holes at the top of the seam or at the bottom. The absence of a pin-point hole or dark speck in the
Figure 36. — Step 1, filing a can seam.
cross section of the seam at either of these points indi- cates that the base plate and the first-operation roll are properly adjusted. A noticeable pin-point hole near the bottom of the crosscut section indicates that the base plate pressure needs to be increased. A notice- able pin-point hole near the top of the crosscut section may indicate that the first-operation roll is too loose. A small hole at this point is of no importance. If the layers of tin are plainly visible in the crosscut section the second-operation roll is too loose.
Step 2. Starting at the notch, file away the top out- side edge of the double seam for a distance of 2 or 3 inches until the second layer of metal," the can hook," is reached. Care must be taken to avoid filing into the top of the can hook. The area filed should extend beyond the body seam of the can. Hold the file at a 30-degree angle.
Step 3. Starting at the filed notch, tap sharply with the flat face of the file on the cut edge of the seam to disengage the cover hook and leave the can hook ex- posed. The tenacity with which the cover hook is held in place is an indication of the tightness of the seam.
Step 4. Bend cover hook up, as shown, for observa- tion and measuring of both the can hook and the cover hook.
With a metal ruler, with a point %-inch wide and less than 0.010-inch thick, measure the can hook, cover hook, and the countersink at several points. The
Figure 37. — A, Correct seam. B, Incorrect seam.
689641° — 46-
29
Figure 40. — Step 4, filing a can seam.
Figure 38. — Step 2, filing a can seam.
Figure 39. — Step 3, filing a can seam.
length of the can hook should closely approximate that of the cover hook and should measure slightly over Kg inch. (See fig. 41.)
The hooks should be free from wrinkles or folds. These indicate seam looseness. On a properly flat- tened seam, all wrinkles should be ironed out fairly smooth by the second-operation roll. Figure 42 shows four degrees of wrinkles. A good seam will correspond to the 0 and 1 stages.
COUNTERSINK
SCALE
Figure 41. — Metal ruler and method of measuring can hook, cover hook, and countersink.
|
' |
||
|
teiii -^ Tt 0 I |
A 2 |
1 3 |
Figure 42. — Waves in cover hook.
30
The countersink should be slightly over }{ inch in depth. A deeper countersink usually indicates that the chuck has been set too low in relation to the rolls. This may be responsible for short cover hooks. A shallow countersink may result from a worn chuck flange.
The chief cause of can-hook shortness is lack of base-plate pressure. It may also occur if there is too much clearance between seaming rolls and chuck. Another cause is short plate that results when body blanks are cut too narrow or when the body flange is uneven. It should be noted than the can hook at the overlap of the side seam is sometimes slightly short, the upper flap of metal being shorter than the under flap at their lower edges. It is equally im- portant that hooks should not be too long. Exces- sive base-plate pressure, resulting in a long can hook, causes a corresponding decrease in the length of the cover hook and consequently affects the degree of engagement of the two hooks. It also induces "spur" formation.
When the cover hook is short, this is usually because of failure of the first-operation roll to tuck the cover far enough under the flange of the body. As it has to be bent round two thicknesses of metal at the side seam, the cover hook is invariably slightly short at this point. It seems highly probable chat many cases of leakage in which mechanical defects are not obvious arise through this "normal" short- ening of the hooks at the side-seam overlap.
To make sure than the seaming operations are uniform, it is well to inspect the seam occasionally around the entire circumference of the can. To do this, pull off the entire top of the can with a pair of pliers, starting at the point where it was originally filed, for checking a section of the seam. The entire cover hook and can hook may then be disengaged and further inspected.
Adjusting sealers
The test wire or gage provided with most bench- type sealers may be used for making the preliminary adjustments of the seaming rolls. Instructions for making these adjustments are provided with the sealer. The first-operation roll should be checked independently of the second-operation roll, and the machine should be manipulated by hand in each instance. The wire test on the first-operation roll should be made at the time the roll is at its innermost position. This is usually just before it is ready to recede. The chuck should be so alined that the top flange of the first-operation roll just slips over the edge of the chuck disk without rubbing. The chuck should turn freely and yet show no space between its upper edge and the roll flange. Depend- ing on the type of sealer, adjust the chuck up or down or adjust the seaming rolls so that the chuck and seaming rolls are in perfect alinement. For correctly adjusted first-operation roll, see figure 43, and for correct first-operation seam, see figure 44.
FIRST-ROLL. FLANGE JUST PASSES OVER EDGE OF CHUCK-
FIRST ROLL
SEAMER CHUCK
Figure 43. — Correctly adjusted first-operation rol
Figure 44. — Correct first-operation seam.
ROLL-FLANGE SET TOO HIGH ABOVE EDGE OF CHUCK RE5ULTS IN CUT-OVER SEAMS7
SEAMER CHUCK
CHUCK TOO HIGH ROLL-FLANGE EDGE
WEARS CHUCK AND ROLL FLANGE UNDULY?
SEAMER CHUCK
Figure 45. — Incorrectly adjusted first-operation roll: A, Roll- flange set too high; B, Chuck too high.
Figure 46. — First seam operation: A, Too loose,- B, Too tigbt.
If the roll is set too high the can top will be rolled slightly over the edge of the chuck. If the chuck should be set too high the roll flanges will rub the edges of the chuck severely and in a short time the rolls and chuck will have to be replaced.
Figure 45 illustrates incorrectly adjusted first- operation roll.
Figure 46 illustrates first-operation seams that result when the first-operation roll is too tight or too loose.
In setting the first-operation roll for the proper dis- tance of its groove from the chuck face, use the larger sized test wire provided for this purpose, inserting it between the roll groove and the chuck face. Set the roll so that a firm, steady pressure must be exerted to insert and withdraw the wire. Check the base-plate pressure by putting a can with cover in the machine
31
as for sealing. Adjust the base plate into position for sealing. While the can is still in position, run it through the sealer by hand to test the adjustments of the first-operation roll and the base plate. The metal of the cover should be tucked up closely against the can body, forming an almost round bead. It should not be so tightly rolled as to be almost solid or like a piece of wire.
If the first-operation roll is found satisfactory the second-operation roll may be set in seaming position. The procedure followed is practically the same as for the first-operation roll. The height of the chuck when set properly for the first roll should also be correct for the second roll. Turn the machine by hand until the second roll is at its closest point to the chuck. This occurs just before seaming is completed. Insert the smaller test wire between the roll groove and the chuck face, and adjust the second-operation roll until a firm, steady pressure must be exerted to insert and withdraw the wire. Repeat the test of putting an empty can with cover through the machine but in this instance complete the seaming process and care- fully note the appearance of the seam. Do not depend entirely on the test wires for final adjustment but test the finished seam by the filing method previously described.
Exhaust boxes
An exhaust box is used for heating the contents of the can to the recommended center temperature for sealing. It must be so designed and constructed as to heat products evenly and in a minimum of time. Exhaust boxes heated with steam may be either tunnel-conveyor or batch-type. However, for econ- omy and adaptability to handling varied products, a batch-type box, such as that illustrated in figure 47, is recommended for community canneries.
The steam is supplied from a high-pressure steam line. Water, filled into the box to a specified height, is heated by the steam passing through the closed pipes of the box. The pipe arrangement shown in figure 47 has proved an efficient means of getting even heat distribution throughout the box and is preferred to the U-coil arrangement sometimes used in com- munity canneries. The spreader line at the end of the box where the steam is admitted is installed above the water line. Steam condensation is thus retarded and the heating efficiency of the steam is enhanced. A sloped arrangement of the pipes, lead- ing to the condensation pick-up line outside the box, facilitates drainage of the condensate from the steam pipes.
The 3- by 4-foot box, shown in figure 47 will ac- commodate approximately 80 No. 3 cans. Two boxes of this size will exhaust sufficient products in 1 loading to fill 1 large retort or 4 small ones.
A batch-type exhaust box should be constructed of galvanized metal encased in wood, or provided with other insulation to protect workers. Such insulation will also prevent heat losses that would otherwise occur. To further prevent heat losses the box should be provided with a lid constructed so as to
prevent condensate from dripping into the cans of produce. The lid, if hinged at the center, as shown in figure 47, may be easily lifted by a rope attached to a pulley overhead. A false bottom made of heavy- mesh wire should be provided in the box to allow for circulation of the water underneath the cans. A drain should be provided in the center bottom of the box and should be fitted with a removable over- flow pipe to keep the water line approximately 2 inches below the tops of the cans. The end of the overflow pipe fitting into the drain should be so threaded that it may be adjusted up or down according to the size of the cans being used. This adjustment can be made easily by providing a handle on the top of the overflow pipe.
In order that patrons' produce may be kept separate it is recommended that can trays be used and properly identified with the patron's number. Several trays may be required for each patron's produce. In order that the cans may be heated in a minimum of time, the water in the box should be at the boiling tempera- ture when the can trays are placed in the box. Natu- rally the temperature will drop somewhat at this time. After the water returns to a boil the globe valve, re- gulating the steam supply to the box, should be ad- justed so that the water will not bubble over into the cans of produce. To assure the best quality of canned produce the exhausting period required for heating the cans to the recommended center-can closing tem- perature should be kept to a minimum. For fruits and vegetables canned in a liquid medium, this period should not exceed 10 minutes. Too-long exhausting periods will result in an overcooked product. If an exhaust box is incapable of producing the desired re- sults, it should be corrected so that the canning pro- cedure recommended can be followed. In no instance should canning procedures be adjusted to fit poor equipment.
Cans should be sealed promptly when the exhaust- ing process is completed. Remove one tray at a time and only as it can be handled at the sealer. After the center-can temperature is reached, the water in the box should be kept at the simmering point until all trays of cans are removed for sealing.
The exhaust box must be drained, thoroughly cleaned, and flushed at the end of each day's operation. The lid should be adjusted in an open position so that the box will dry and be thoroughly aired before the next day's run.
Wash sinks
Double-compartment sinks 2 feet wide, 4 feet long, and 18 inches deep are adequate for washing produce. They should be of metal for convenience in keeping them clean. A sink should be provided at the end of each preparation table and should he supported on a frame high enough to bring the top of the sink level writh the table top. Additional sinks will need to be provided near the preparation area, as shown in figure 2, so that a number of patrons can be accom- modated at one time and bottlenecks in preparation
32
SPREADER PIPE. ABOVE WATER LINE
FALSE BOTTOM 1 SQUARE OPEN-MESH NO.^-GAGE GALVANIZ1ED-WIRE WEAVE
-GATE VALVE
PLAN-WITH COVER REMOVED
^STRAINER
-THERMOSTATIC TRAP
t STEAM PIPES
DOUBLE-FLANGE WASHER-GASKET SEAL
NO. 18-GAGE GALVANIZED SHEET-STEEL TANK
SLOPED FLOW CONDENSATION PICKUP PIPE
5IDE ELEVATION
5ECTI0NAL END ELEVATION
Figure 47. — Batch-type exhaust box.
activities avoided. One such sink will be needed for washing pots and pans. Additional wash sinks or a hose in the rough-preparation area will cut down the demands on the sinks in the cannery proper. When washing produce, it is well to handle it in small quantities in order to assure thorough cleansing. Water should be changed frequently. All wash sinks should have adequate drains protected with strainers to prevent clogging. At the end of the day the sinks should be thoroughly drained and cleaned to prevent rusting. Where large quantities of produce are to be
handled, it may be well to purchase a rotary vegetable washer or to provide a large wash tank in the receiving area.
Blanch and scald tanks
Tanks of heavy galvanized metal, equipped with drains and closed-coil steam pipes for heating water, are essential for scalding and blanching operations. (See fig. 48.)
One tank should be provided at the end of each fill table adjacent to the cold-dip tank. It should be
33
supported on a frame sufficiently high to bring the top of the tank in line with the top of the fill table and supplied with steam from the high-pressure line. Tanks 22 inches square and 22 inches deep are adequate for blanching or scalding operations. A tank of this size is large enough to permit the introduction of the produce into the tank without changing the temper- ature of the water more than a few degrees. Blanch and scald tanks are used interchangeably, depending on the needs. Water used for blanching and scalding should be changed as often as is necessary to keep it clean and to avoid recontamination from the bacteria removed in the process. The tanks should be thor- oughly drained and flushed at the end of each day's operation. In those plants which process quantity lots of such produce as sweetpotatoes, peaches, and grapefruit it is well to provide a similar tank arrange- ment for lye-bath peeling. This tank should be convenient to the preparation tables.
Cold-dip tanks
A cold-dip tank of the same size and height as the blanch or scald tank should be installed adjacent to it at the end of each fill table. The cold-dip tank should be of galvanized metal and be equipped with a drain and a cold-water inlet. The water should be changed as often as necessary to keep it clean and cold. At the end of each day's operation the tanks should be drained, thoroughly washed, and steamed.
Tanks for the medium
A 15- to 25-gallon tank should be provided on each fill table, adjacent to the exhaust box, for the medium used in the cans of produce. Because the tank is used
for brines as well as for sirups and water, it should be of noncorrosive metal. The tank should be sup- ported on a frame sufficiently high to accommodate the tallest can under the spigot arrangement leading off from the bottom of the tank. (See fig. 49.)
-WATER SUPPLY
STEAM SUPPLY
DRAIN
pipe support condensate:
I STEAM SUPPLY STEAM VALVE
NO. 18-GAGE GALVANIZED SHEET-STEEL TANK
PIPE SUPPORT
§;" CONDENSATE VALVE
DRAIN VALVE
FRONT ELEVATION
Fisure 48. — Blanch or scald tank.
r-Jf CONDENSATE. WATE.R — — Jl VALVty / rVALVE
0=^ 4^| Irt" £ STEAM SUPPLY
FAUCET
15 TO 2.5 GALL0N5 CORROSION-RESISTANT TANK
CAN FILL VALVE
FILL-PIPE SUPPORT
n
PIPE BRACE TINNED COPPER PIPE
PIPE BRACE
l" TINNED COPPER PIPE COIL
CORROSION-RESISTANT PIPE Rgure 4o._Medium tank and steam coi
/CAN FILL VALVE.
3 FLAT-BAR LEGS
FILL TABLE
^J
34
The tank is heated by a steam coil such as is used in precooking foods in stockpots. It is supplied with steam from a low-pressure line. At the end of each day the tank should be emptied and thoroughly cleaned to avoid contamination and rusting. It should be rinsed with cold water before using.
Preparation and fill tables
Standard-sized tables, 4 feet wide, 10 feet long, and 34 inches high, should be provided for the preparation of the produce and the filling of the cans. (See fig. 50.)
A table of this size accommodates four persons at each side and is wide enough to permit the use of two preparation pans by each person. It is recommended that the table top be made of rough lumber covered with galvanized sheet steel. A rolled-edge around the sides of the table will help to keep the preparation area sanitary. Table tops may also be finished with masonite, or waterproofed plywood, or they may be made of tongue-and-groove flooring painted with a good grade of enamel or deck paint. Unpainted wooden table tops are difficult to keep clean and are therefore not recommended. Linoleum table tops may be used but they do not stand up under the treatment necessary to keep the table tops clean.
Meat-cutting tables
In those rural areas where a considerable amount of meat is canned it may be advisable to provide meat- cutting tables. However, hardwood meat boards placed on top of the preparation or fill tables are satisfactory for cutting and boning meat. It is best to have meat tables 32 inches high as this gives a good working leverage in handling and cutting meat. They should be 4 feet wide and from 6 to 10 feet long. They will need to be sturdily built. The top should be made of 2- by 4-inch hardwood. In order to assure a smooth surface free from cracks, it should be bolted at several points along the length of the table. The bolts should extend through the boards the entire width of the table. The bolts may be threaded on one or both ends and fitted with nuts and washers so that the table top may be tightened. The top may be made so that it can be reversed on the table frame. It need not be attached to the frame as the weight of the top is sufficient to hold it in place.
Other equipment
Cutting boards
Cutting boards of hardwood are needed for general use. They will conserve table tops and aid in handling produce in a sanitary manner.
Blanching baskets
Blanching baskets, approximately 16 inches in di- ameter and 18 inches deep, such as those illustrated in figure 51, should be provided for blanching or scalding
^
4"« 4"-
£- 10"
L
i^V
3
ROUGH LUMBER. TOP COVERED WITH OALV. 3HEET-STEEL WITH ROLLEO EOOES
u
FRONT ELEVATION
5IDE ELEVATION
Figure 50. — Detail of preparation or fill table
Figure 51. — Blanching baskets: (A), Perforated galvanized- metal bucket; (B), galvanized hardware-cloth basket; (C), gal- vanized hardware-cloth basket.
produce. Galvanized wire potato-picking baskets of one-half-bushel capacity and lined with No. 6 mesh hardware cloth also make excellent baskets.
Can trays
Trays made of wire are indispensable for carrying cans to the wash tank, fill table, and exhaust box and for keeping patrons' cans separated in the exhaust box. For ease in handling, trays should be only large enough to hold from 15 to 18 No. 3 cans.
Canning thermometers
Mercury-filled canning thermometers in metal car- rying cases, with temperature ranges of 0° to 220° F., are needed for checking center-can temperatures. (See fig. 52.) Every canning unit should have a minimum of two thermometers and two additional graduated glass tubes for replacements.
Dish
pans
Dishpans made of aluminum, tin, or enamel, of 12- to 16-quart size, should be provided for preparation of produce. The number of dishpans needed will be determined by the number of patrons that can be accommodated at preparation tables. An average of two dishpans should be allowed for each patron.
Figure 52. — Canning thermometer and metal carrying case.
35
Cutlery
Although most community canneries require that patrons provide their own cutlery for the preparation of produce, it is recommended that canneries purchase such equipment in order to standardize the type and size best suited for their use. All cutlery should be of high-quality carbon steel of an approved design.
Unpainted handles are preferred. Blades should be riveted to handles. Sharpening steels should be equipped with guards. Stainless-steel kitchen cutlery is not desirable since it does not retain a sharp edge under canning conditions. Accidents are reduced to a minimum when the proper cutting tool is used. Figure 53 illustrates cutlery of good design for the preparation of fruits, vegetables, and meats.
L
J
10
Figure 53. — Cutlery: 1 , Skinning knife, 6-inch blade; 2, scimitar steak knife, 1 0-inch blade; 3, scimitar boning knife, 6-inch blade,- 4, butcher knife, 6- to 12-inch blade,- 5, paring knife or chicken knife, 3J'j-inch blade,- 6, knee-action vegetable peeler,- 7, tomato- peeling knife- 8, pear-coring hook; 9, peeling and coring knife,- 1 0, fine-cut knife steel, 1 0 to 12 inches long,- 1 1 , meat saw, ^2-inch blade, 18 to 22 inches long.
36
Can-seam-inspection equipment
Gl
oves
Mill files of 10-inch length should be made available in canning units, for use in filing can seams. A small magnifying lens should also be provided for inspecting the seam. A metal ruler with a point }s-inch wide and less than 0.010-inch thick is needed for measuring the can hook, cover hook, and counter- sink. Metal files are usually available from can companies.
Can-straightening device
A can-straightening device should be provided in every cannery in order that those cans that have become misshapen or damaged in shipment may be straightened and used. Badly damaged cans should be discarded. This is particularly true where the soldered side seam has been damaged. Can-straight- ening devices are available from most suppliers of canning equipment.
|
3' |
-o" |
|||||||
|
(at^ |
\ (ftfr |
3) z. |
||||||
|
frh- |
T T-pi |
-0 |
||||||
|
\Qr- |
--4^ |
3 |
PLAN
Z"x4'
2"M"
[>clE^l U^\ E^l 15^1 F^l
4 SWIVtL CASTERS
SIDE ELEVATION
Figure 54. — Utility truck.
Rubber-covered canvas gloves are needed for han- dling hot cans at the sealer and for loading cans into re- tort crates. They should be loose fitting at the wrist so that they can be removed quickly in case of emergency. The use of gloves saves much time in handling hot containers. However, employees and patrons should be cautioned that continual use of gloves may cause hands to become tender and susceptible to infection.
Utility trucks
Utility trucks are necessary for moving produce, cans, and equipment. They may be of metal or wood and should have ball-bearing wheels to facilitate the movement of heavy loads. The frame should be substantial enough to support a retort crate filled with cans. (See fig. 54.)
Garbage cans
Enough refuse and trash containers should be pro- vided to give sufficient capacity for at least 1 day's accumulation of refuse. These should be of metal with close-fitting covers and should be watertight. Galvanized buckets are needed for general use, such as carrying out garbage.
Steam and water hose
Steam hose should be provided near the equipment that needs to be cleaned by steam. Steam hose may also be used for heating water. Water hose is needed for cleaning floors, tables, and similar equipment.
Fire extinguishers
If wood or coal is used as fuel and no oil, gas, or gasoline is used in the building, a soda-acid type of extinguisher will be adequate, or if a reliable source of water is available, a suitable pump or hose will be sufficient. If oil or gas is used as fuel, two or more 15-pound Dugas dry-powder-type hand fire extin- guishers should be installed in addition to the water extinguishers. Installation of any safety device should be checked by a safety engineer.
Tools for adjusting and repairing equipment
Tools for adjusting and repairing equipment should be kept in a definite place so they may be readily avail- able when needed. Loss of tools may mean loss of production hours. Tools required for adjusting and repairing equipment should include:
1 hammer 1 saw 1 square
1 pipe vise
2 18-inch pipe wrenches 1 set of bicycle wrenches
1 set of pipe-threading equip- ment 1 6-inch screw driver 1 12-inch screw driver 1 hack saw and blades
689641°— 46 6
37
Replacement parts
A supply of extra parts should be kept on hand at the cannery to replace or repair those parts that may break or wear out quickly under constant use. This will avoid delay in operation. The following items should be the minimum kept in stock:
For retorts
Wing nuts, 1 extra for each retorc.
Eye bolts, 1 extra for each retort.
Gaskets, 1 extra for each 2 retorts of same size.
Pressure gage, 1 extra for each 3 retorts.
Safety valve, 1 extra.
Thermometer, 1 extra.
For pressure canners Wing nuts, 1 extra for each canner used. Gasket, 1 extra for each canner. Safety valve, 1 extra. Pressure gage, 1 extra for each 5 canners. Safety plug, 1 extra.
For sealers
Seaming rolls, 1 set for each sealer. Sealer arms, 1 set.
Adjusting screws, springs, and hand washers or rubber pads as required for base plates.
Other items needed will depend on the type of sealer used. Sealers should be given periodic inspec- tion for worn parts.
For hollers 2 water-gage glasses and packing washers. 2 sets of hand plate gaskets. 1 fusible plug.
For plumbing
Valve seats for all types of replaceable seat valves. Pipe-thread compound. Thread-cutting oil.
Cleaning equipment
Cleaning equipment, consisting of brooms, mops, squeegees, scrub brushes, and cleaning cloths, should be provided. Such items should be kept together in a storeroom provided for that purpose.
Containers Generally Used
Size of cans
The number of can sizes used in a community can- nery should be limited because the processing time differs for the various sizes and because the time involved in changing the sealer may delay the canning
|
Table 2.— Size |
and description of cans common |
\y used |
|||
|
Dimensions |
Factory symbols |
Volume of cans |
Average |
||
|
Size of can |
Diam- eter |
Height |
net weight |
||
|
No. 2 No. 2)4 No. 3 No. 10 |
Inches 37l6 4>i6 4Me 6Mc |
Inches 4^6 4% 41Me 7 |
307 x 409 401 x 411 404 x 414 603 x 700 |
Cups 2y2 4 13 |
Ounces 20 28 38 110 |
operation. Sizes most commonly used for community and school-lunch or institution canning are given in figure 55 and in table 2.
Type of finish
Three types of finish in containers generally used for canning are: Plain tin; C-enamel; and R-enamel, also called Standard enamel. Enameled cans are not necessary to insure a wholesome product but are used to prevent discoloration which occurs with some products when plain tin is used. C-enamel cans are used to prevent discoloration of nonacid products containing sulfur. R-enamel cans are used to prevent the loss of color which occurs when highly colored fruits and beets are placed in plain tin.
Table 3 gives the recommended types of container most satisfactory for various products.
Table 3.
-Recommended type of container for products
specified
Product
Apples
Apricots
Asparagus
Beans, green and wax.
Beans, green lima
Beets
Berries
Carrots
Cherries, sour
Cherries, sweet
Corn
Fruit juices
Grapefruit
Meats
Mixed vegetables
Okra
Peaches
Pears
Peas
Pineapple
Plums
Pumpkin or squash
Sauerkraut
Summer squash
Sweetpotatoes
Tomatoes
First choice
Plain.
.do_
do—
do--.
C-enamel_ R-enamel. do__-
Plain
R-enamel_
Plain
C-enameL R-enamel_
Plain
do—
„do_ .do_ .do.
.do_ .do. .do_
R-enamel_
do___
do...
Plain.
.do. .do_
Second choice
Plain.
Plain.
Plain.
Purchase of cans
When a large production is expected and space is available for storage it is desirable from a standpoint of expense and convenience to purchase the season's supply of cans at one time. A carlot of No. 2 cans contains from 50,000 to 97,000 cans, and of No. 3 cans from 36,000 to 50,000, depending on the length of the car. Cans should be shipped in bags or cartons to minimize damage in shipment and storage and to keep cans clean until they are used.
Table 4 gives the approximate number of cans re- quired for a measured quantity of some of the more common fruits and vegetables.
38
Table 4. — Approximate number of cans required for meas- ured quantities of produce
Product
Apples
Beans, lima (in shell)
Beans, green and wax
Beets (without tops)
Berries i
Carrots
Cherries
Corn (green, sweet)
Greens
Peaches
Peas (green, in shell)
Plums
Squash
Sweetpotatoes (fresh har
vest)
Tomatoes
Weight
per bushel
Pounds 50 28 24 60 »40 50 56 35 12 50 30 60 40
52 56
No. 2
cans
required
Number 30 10 21 32 24 30 34 2 12 10 30 32 45 30
30 22
No. 3
cans
required
Number 20 8 16 24 18 20 25
7 20 24 30 20
20 15
No. 10
cans
required
Number 6 3 4 7 6 6 7
No. 2
No 2V2 Figure 55. — Relative can sizes.
1 24-quart crate.
2 Whole gram.
Small canning centers operated with gas burners
In those sections of the country where gas is avail- able at low cost, communities planning to set up small centers may find it advantageous to use gas burners to heat the various pieces of equipment needed to process foods. In planning this type of unit it is well to con- sider its disadvantages as well as its advantages. Chief among these disadvantages is the lack of a cen- tral source of heat to furnish adequate supplies of steam and hot water. Furthermore, the heat gener- ated by the numerous burners required for heating individual vessels presents ventilation problems in that the atmosphere in the room becomes most un-
45'
comfortable unless adequate means of ventilation are provided. It is recognized that this type of plant is less costly to install than a similar-sized plant set up to operate with steam generated from a gas-fired boiler.
Before deciding on the type of plant to be set up it is recommended that local authorities governing the installation of gas equipment be consulted because, in many municipalities, there are regulations which must be complied with. The advice of the local gas company should also be sought before selecting gas appliances since they generally can supply the names of high grade manufacturers of national reputation who are in a position to furnish equipment that is properly designed and engineered. The local gas com- pany can also furnish the necessary information which the manufacturers would need in order to supply a burner most suitable for the gas in the particular locality and advise on safety precautions. The same careful planning will need to be exercised in selecting the site and building for the multiple burner units as for steam-operated units. In addition, special con- sideration must be given to ventilation, as stated
**-
rC. I DRAIN PIPE EXTENDED TO GREASE TRAP
,DRAIN TRENCH
|
\l |
4' |
z |
|
0 H O >o z r *z |
\ |
T^?
OOOQ
RETORTS^
PRESS
8-6"
CPr
IV6"
u|re cookers>
18 NO. 3 CJANs CAPACITY EACH -DRAIN TRENCH
-MEDIUM TANK
It' r 4>IP ^BLANCH /SCALD iOII
r"
01
FILLING TABLE
10"
4'
PREPARATION TABLE
10"
PREPARATION TABLE
PREPARATION TABLE
C.I.DRAIN PIPE EXTENDED TO GREASE TRAP
DRAIN TRENCH
-I E
4 I-
DftAIM TBEMCH
Figure 56. — Plan of community canning plant, using gas service, with daily capacity of 500 to 800 No. 3 cans.
39
above, in order to avoid overheating of the plant and the accumulation of moisture and the products gen- erated by the fuel. Figure 56 illustrates the place- ment of the major items of equipment in a multiple- burner plant with a daily capacity of 500 to 800 cans. It is not considered feasible to operate a plant of greater capacity without a boiler as a central source of steam.
A list of the equipment required for a multiple gas burner plant similar to the one illustrated is given in table 5.
The blanch and scald tanks, the medium tank, and the exhaust box should be of a size for efficient opera- tion of the plant. The burners for these tanks and the box as well as for the retorts and pressure canners should be of a size and type to generate sufficient heat to bring the vessel up to operating temperature within the time required for efficient plant operation and to assure products of good quality. This is well illus- trated in the case of the blanch or scald tank. To heat these vessels the burner must be of sufficient capacity to assure quick recovery of boiling tempera- tures required for scalding and blanching the produce.
Unless this is provided, much time will be lost in waiting for the water to return to a boil and the produce will be partially cooked in the process. In the case of the medium tank a smaller burner may be used as it is only necessary to keep the brine or sirup at a boiling temperature. Any change made in the details of the drawings in the illustrations may change the burner requirements.
For those vessels heated with an open-flame gas burner it is essential that a skirt be provided around the base of the vessel to screen the flame from air drafts and to prevent injury to workers. It is also necessary when heating with gas burners to provide proper-sized flues or outlets to the outer air to assure the full effi- ciency of the burners and to carry away the products of combustion. Such flues should be equipped with a suitable draft diverter and should extend vertically from the appliance and exhaust the products either under a properly ventilated hood into a chimney or in an approved manner through the roof. The size of the flue varies with the size of the burner. The area of the flue should be at least 1 square inch for each 7,500 B. t. u. of burner capacity.
Table 5. — Canning equipment required for multiple gas burner plant of 500 to 800 No. S can capacity per 8-hour day
|
Item |
Description |
Number required |
Item |
Description |
Number required |
|
Gas burner _ _ |
85,000 B. t. u./hr. wheel- type for heating 33 can capacity retorts. 107,000 B. t. u./hr. wheel- type for heating 20" x 18" galvanized blanch and scald tank. 40,000 B. t. u./hr. ring-type for heating 17" x 15" medium tank. 30,000 B. t. u./hr. ring-type for heating 14 to 18 qt. pressure canners. 125,000 B. t. u./hr. immer- sion-type for heating 3' x 4' batch-type exhaust box. 33 No. 3 can capacity 14 to 18 No. 3 can capacity. _ Wash boiler heated over pressure-canner burners (blanch or scald tanks or retorts may also be used) . Heavy galvanized metal, 5 to 10 gallon size for pre- cooking of products such as corn, applesauce, etc. Bench-type, motor-driven, 5 or 6 cans per minute. Bench-type, heavy-duty, hand-operated, 3 or 4 cans per minute. 3' x 4' x 15" batch-type (covered). |
2 2 1 4 or 5 1 2 4 or 5 0) 2 to 4 1 1 1 |
Wash sink Wash sink Scald and blanch tank. Cold-dip tank Medium tank. Cooling tank Preparation table Fill table |
2' x 2' x 18" (for washing utensils). 4' x 2' x 18" double-com- partment (for washing produce). 18" diameter x 20" deep 18" diameter x 20" deep 15" diameter x 17" deep for brine, sirup, etc. (ap- proximately 10-gallon ca- pacity) . 4' x 3' x 2' (mounted at working height). 10' x 4' x 34" __ . . _ |
1 |
|
Gas burner _ |
2 |
||||
|
Gas burner. _ |
2 2 |
||||
|
Gas burner |
1 |
||||
|
Gas burner |
1 |
||||
|
3 |
|||||
|
10' x 4' x 34" ... . . . |
1 |
||||
|
Retort with inset crate. Pressure canner with inset rack. Open-process tank |
Sealer table Sealer table Blanching basket Can tray |
30" x 4' x 32" (for hand- operated sealer). 30" x 4' x 34" (for bench- type motor-driven seal- er). Wire mesh _ |
1 1 6 |
||
|
18 No. 3 can capacitv Hardwood 18" x 12" 12 to 16 quart |
24 |
||||
|
Cutting board Dishpan |
(3) |
||||
|
Thermometer Gage tester |
Canning |
2 |
|||
|
For testing pressure gages For lifting cans from ex- haust box. For handling cans at sealer. _ 10" for filing can seams Small, for inspecting can seams. Standard, for measuring body and cover hook of can seam. 20-gallon capacity with cover. |
1 |
||||
|
Can lifter. |
2 |
||||
|
Sealer |
Gloves _ . |
(4) |
|||
|
Mill file ..____ |
6 |
||||
|
Sealer |
Magnifying lens Metal ruler |
1 |
|||
|
1 or 2 |
|||||
|
Exhaust box . |
Garbage can |
2 or 3 |
1 One or more.
* Six pair.
2 Optional. ^Eighteen or more.
Note.— Other equipment needed will include fire extinguisher, marking equipment for cans, repair parts for equipment, tools for making repairs, and special equipment, such as sieves, meat grinder, small pea sheller, and small bean cutter. Paring knives, tomato-peeling knives, vegetable knives, and butcher knives should be provided by the cannery to standardize the types and sizes desirable. For suppliers of equipment for gas-burner units, see Partial List of Manu- facturers, page 83.
40
Flue requirements in particular should be reviewed with the authorities governing installation of equip- ment, as this is one point on which almost e very- municipality has regulations. All flues should be in- sulated to a height of 6 feet to protect the workers from coming in contact with the hot pipes. All floor, table, and wall surfaces exposed to the heat of the gas burners should be well insulated with noncombustible material to prevent fires. When gas burners are in- stalled a space of 3 to 6 inches should be left between the vessel and the burner to assure efficient heating. This will vary according to the characteristics of the gas. A competent gasman should be able to determine the proper height.
Installation drawings are shown of only those ves- sels which are heated with gas burners. Other items of equipment required, such as preparation tables, fill tables, cooling tank, and wash sinks, may be con- structed in accordance with specifications given for those items on pages 24 to 35 and in table 5- For information on the type of sealers to buy, see page 26.
The instructions, given in the preceding section of this publication, on operating the various items of equipment used in steam-operated plants apply also to the items of equipment used in small canning cen- ters operated with gas burners, with the exception of retorts and pressure canners. Instructions for their operation follow the sections on their installation.
The blanch and scald tanks are constructed of 18-gage galvanized sheet metal made in a cylindrical shape. To strengthen these tanks the top has a rolled wire-band edge smoothly finished to prevent any in- jury from contact when they are in use. These tanks ate supported on a separate base stand approximately 14 inches high so that the tank will be at a convenient working height. The base is made of angle-iron legs attached to a heavy-gage metal-band and seat arrange- ment. The tanks are removable from the base stand for cleaning. Cleaning and draining may be facili-
tated by fitting the tanks with adequate drain con» nections. The side skirt is made of light-gage metal extending down the angle-iron legs for a distance of 6 inches or more to bring it approximately 1 inch below the burner. The flue, also constructed of a light-gage metal, is insulated and extends vertically to a suitable outlet. The atmospheric wheel-type burner of approximately 107,000 B. t. u./hr. capacity with a Venturi mixing tube is recommended for heating these tanks. (See fig. 57.)
The medium tank used for heating water, brine, or sirup is placed on top of the fill table adjacent to the exhaust box at a height sufficient to clear the tallest can when filling the boiling liquid into the cans. The tank is constructed of heavy noncorrosive metal with a shallow funnel-type bottom to facilitate drain- ing and cleaning. It is supported by a separate base constructed of three angle-iron legs attached to a heavy-gage metal band-and-seat arrangement. The supply pipe fits into a threaded flange at the center bottom of the tank and extends through the center of the burner with a T arrangement below the burner. The pipes extending from the T are fitted with faucets which permit the filling of the medium into the cans from both sides of the fill table. A light-gage metal skirt of sufficient depth to come at least 1 inch below the burner is provided at the base of the tank. The flue, also of a light-gage metal, is attached to the skirt and extends vertically to a suitable outlet. An atmos- pheric ring-type burner of approximately 40,000 B. t. u./hr. capacity with a Venturi mixing tube is recom- mended for heating the tank. (See fig. 58.)
The exhaust box constructed of 18-gage galvanized sheet metal should be insulated on the sides and bot- tom and should be fitted with a tight cover of proper design. Such insulation and cover will largely eliminate both radiation- and evaporation-heat losses and will protect the worker from possible burns. The box should be fitted with a false bottom of heavy wire
P"1
-GAS VENT
Figure 57. — Blanch, or scald, tank with wheel-type burner.
CAPACITY 107,000 B.T.U/H R
IS DIAM.
BLANCH,0R SCALD, TANK
10
Hi J ^GAS BURNER tjj
'// / ! — \ W1
EE
PLAN OF GA5 BURNER
- — 1" DRAIN
SHEET-METAL SKIRT
14"
— SUPPORTS
-3 ANGLE-IRON LEGS
-^ ^ *—
^BURNER-SUPPORT STAND
389641° — 46-
41
V-WATE1R.
^
-NONC0RRO5IVE. METAL
Figure 58. — Medium tank with ring-type burner.
I5"0IAM.
MUDIUM TANK
it"
CAPACITY 40,000 BXU/HR.
^^
PLAN OF GAS BURNER AND MEDIUM PIPES
5heelt-mltal skirt
legs and burner supports •can-filler valves -5 angle: iron legs
=r~ FILL-PIPE SUPPORTS
TOP OF FILL TABLE, NO N C0MBU5 TIBLE MATERIAL
mesh and an overflow drain of the proper height and size to prevent water from getting into the produce being exhausted. The immersion-type burner has been found to be quite satisfactory for heating the batch-type exhaust box. It should be fitted with a Venturi tube and have a capacity of approximately 125,000 B.t.u./hr. This type of burner is enclosed in such a manner that the flame does not come in contact with anything except the interior of the coil unit which is immersed below the water level in the box. The immersion coil which extends around the sides of the box is equipped with the proper-sized flue and draft hood which extends vertically to a suitable outlet. The draft hood fitted near the top of the draft flue prevents down drafts and flash backs in the opera- tion of the immersion-type burner. (See fig. 59.)
Retorts of larger than 33 No. 3 can capacity should not be heated by gas burners. Specifications for retort equipment are given on page 13. A retort heated by a gas burner is supported on three heavy angle-iron legs at a height of approximately 14 inches from the floor. This places the retort at a convenient working height for loading and unloading by hand. The angle-iron legs which are set in a slightly slanting vertical posi- tion may be notched out at the top or angle-iron clips may be welded to the legs for the retort to rest on. Each leg is fitted with a }2-inch set screw to tighten against the retort body and hold it securely. Flat metal bars or round rods are welded to the legs below the burner in a triangular design to keep them in position. The skirt of light-gage metal fits around the base of the retort and extends down the legs to approximately 1 inch below the burner. It is fitted with a flue of the proper dimension which extends vertically to an adequate outlet. The burner, placed in central position under the retort, is supported by a pedestal which rests on the floor. An atmospheric wheel-type burner of approximately 85,000 B.t.u./hr. capacity is recommended for heating a 33 No. 3 can capacity retort. It should be fitted with a Venturi mixing tube. (See fig. 60.)
Operation of gas-heated retorts
Retorts heated with gas burners are operated in the same manner as those supplied with steam from a boiler, with the following exceptions:
1. Water provided in the retort is the source of steam. The water should be brought to the boiling point before the cans are placed in the retort. For a 33 No. 3 can capacity retort, 2J.9 gallons of water is used. This provides sufficient water to permit partial venting throughout a 30-minute processing period. If the processing period is longer, as in the case of meat, the amount of water should be increased. It is very important when operating retorts heated with a direct flame not to permit them to become dry.
2. A longer venting time is necessary in retorts which generate their own steam than in retorts connected to a pressure steam line. These self-heating retorts of 33 No. 3 can capacity should be vented for at least 25 minutes at 0 pound pressure (7).
The burner stand for a battery of pressure canners is made of heavy angle-iron and flat-metal rods of welded construction. It is recommended that the stand be made 18 inches high in order to facilitate the removal of the racks from the pressure canners with a minimum of effort. A ring-type burner of approxi- mately 30,000 B. t. u./hr. capacity fitted with a Ven- turi mixing tube is adequate for heating a pressure canner of 14 to 18 No. 3 can capacity, the smallest sizes recommended for use in this type of plant. The burners are supported on metal rods at a sufficient distance from the pressure canners to assure proper combustion. A light-metal hood fitted with the proper-sized flue which extends vertically at the cen- ter back of the hood to an adequate outlet is provided along the back of the burner stand to carry off the products of combustion. (See fig. 61.)
Operation of pressure canners
Pressure canners used for the processing of nonacid foods in tin containers are operated in the same manner as retorts heated with gas burners except that the pet-cock or vent valve is usually closed at the end of the venting period. This is done to conserve the water needed to generate steam in the canner. Approximately
42
Fl3ure 59. — Exhaust box with immersion- type burner.
WATER PIPE
STATIONARY
SWING COVERS
GAS-BURNER
CAPACITY
l£5,O00BTU/HR.
NSULATION FALSE. BOTTOM
NO. 18-GAGE GALV. SHEET-STEELTANK
BOX SUPPORTS
SECTIONAL ELEVATION
VENT SAFETY VALVE
PET COCK
GATE VALVE GAGE
CAPACITY 65,000 BT.U./HRj; H 40=? ^THERMOMETER
ET COCK
PLAN OF GAS BURNER "DRAIN
t! /«3AS BURNER ^
I i •* n\ "\\\
I I ,__ ■ .\ \\^sheeT-METAL SKIRT
/// / ?ij ' yr
| / im<^ Qp- SUPPORTS
Figure 60. — Retort with wheel-type burner and stand.
\
3 ANGLE-IRON LEGS
BURNER-SUPPORT STAND
43
.RATE
PART PLAN
ANGLE-IRON FRAME. s- GRATE ■
GAS VE.NT-
Figure 61. — Burner stand for battery of pressure canners.
fcr
(©) zga5 burner^ (©^burner 30,000 b.t.u./hr..each » support
-|"gas
c
=7^
(©) ^VENT DUCT
"X
G AS SUPPLY
PART FRONT F_LF_VATI0N
4 inches of water should be put in the canner and brought to a boil before the cans are placed in the can- ner. To permit the full circulation of steam through- out the canner, cans should be stacked in the canner rack in the manner recommended for stacking cans in retort baskets. To remove all air from the canner it must be vented for at least 10 minutes ((5), counting the venting time when steam escapes freely from the open vent or pet cock with an audible sound. This venting time applies to canners of the size recom- mended in this publication for use in community canneries.
To vent the pressure canner, open wide the pet-cock bleeder. At the end of the venting period close the pet-cock bleeder or vent and allow the pressure to come up as quickly as possible to the pressure desired for processing. As soon as this pressure has been reached, record the time and adjust the flame so that the pressure will be maintained at the point desired as uniformly as possible. It is well to have the patron whose food is being processed watch the pressure canner to avoid fluctuations in pressure. At the end of the processing period turn off the flame and open the pet cock gradually to release the pressure. When the pressure has returned to 0 open the canner prompt- ly. Tilt the lid so that the steam emerges away from the operator. Remove the cans for cooling.
Care of pressure canners
Wash the pressure canners every day and more often if needed. Keep the surfaces that form the closure between the pot and the cover clean. This will reduce the tendency of the cover to stick. Take care not to dent or roughen these surfaces. Do not use an abrasive on them. New pressure canners sometimes leak steam slightly at this juncture but after being heated several times, the surfaces should adjust to each other to make the closure tight.
As pressure gages are usually the only instrument provided on pressure canners for determining the temperature inside the canner it is particularly im- portant that the gages be accurate. (See p. 20, Testing Pressure Gages.) It is also important that the safety valve be dismantled and cleaned periodically as gumlike substances sometimes form in the valve and interfere with its normal operation. When a pressure canner is not in use for any period of time the mechanism inside the safety valve should be cleaned and then oiled lightly with a light tasteless mineral oil. Do not submerge pressure-canner covers in water when cleaning them. If that is done, the water may enter the pressure gage and corrode and finally destroy the gage mechanism. Keep the canner lid upright and in position on the canner when not in use.
44
Care of idle equipment
During the periods equipment is not in use it should be given special care to prevent rusting and corroding. The boiler should be thoroughly flushed out and refilled and % gallon of lubricating oil added to the top of the water. When the boiler is then drained the oil will coat the inside surfaces and keep them from rusting.
Remove gages, pet cocks, and thermometers from retorts and steam pipes, wrap them in heavy paper, and label them carefully to indicate the part and loca- tion. Clean thoroughly such equipment as retorts, exhaust boxes, pressure canners, and mechanical equipment; dry and treat all surfaces that are likely to rust with a heavy grease such as that used on an automobile chassis. Parts of equipment that need to be removed should be wrapped and placed with the equipment. Carefully inspect equipment for wear and make note of needed repairs. Steam-jacketed kettles and blanching baskets made of noncorrosive material may be covered with heavy paper for protec- tion from dust when they have been thoroughly cleaned. Check sealers for repair and replacement, oil where needed, and grease the external parts to prevent rusting. It is well to store sealers in their original shipping boxes, keeping all attachments together in a small sack, labeled, and stored in the box with the sealer. Small equipment, such as peeling knives and sharpening tools, also need to be thoroughly cleaned, wrapped in paper, and labeled before storing. Check belting and hose for wear and replacement and store in a cool dry place. Make an inventory of all equipment at the close of the season as well as at stated intervals during the operation period.
Sanitation
In those States that have regulations governing food-processing plants such regulations should be obtained and posted at the canning center. A high degree of sanitation is necessary if good results in canning are to be realized. Items of equipment, such as scald and blanch tanks, medium tanks, exhaust boxes, and sealers, will need to be thoroughly cleaned at the end of the working day. All equipment and utensils which come in contact with food should be treated with a germicidal compound after each day's use. Cutting boards and table tops need special treatment to keep bacteria under control. Scrape them, scrub with hot, soapy water, and rinse with boiling water or apply steam. Then disinfect them, using a hypochlorite solution or a chloride of lime bleaching fluid diluted according to directions on the can. Let the solution stay on for about half an hour, then wash off with scalding water and treat with steam. Linoleum-surfaced table tops are not satis- factory for preparing meat as they cannot be scalded or disinfected without injury to the surface. Such items as peelers, pulpers, grinders, and the exhaust box are left dismantled for airing and thorough cooling
and should be flushed with cold water before they are used again. Other important points in maintaining plant sanitation are as follows :
1. Make provisions for the regular disposal of garbage. Wash and, if possible, steam all garbage cans every day. Leave them open until time for use again.
2. Scrub and dry floors at least once a day. Flushing floors during shut-down periods or at meal time is frequently necessary. A squeegee or broom is used for removing excess water from the floor.
3. Keep walls, woodwork, and windows clean. Keep screens free from dust. Do not use window curtains as they catch and scatter dust in the cannery.
4. Clean toilets and lavatories and treat daily with a disinfecting solution.
5. Provide sanitary drinking fountains or individual paper cups for employees and patrons.
6. Sprinkle the area around the cannery with oil or cover with calcium chloride to keep dust down.
7. It is desirable that employees wear clean uniforms each day. Uniforms or towels should not be laundered in the cannery.
Safety
The importance of making the community cannery a safe place to work cannot be overemphasized. The supervisor should inform herself of all safety regula- tions applicable in the area in which the cannery is located. In addition to the safety precautions mentioned in connection with the installation and operation of equipment the following are also im- portant:
1. See that stairways and entries are well lighted.
2. Equip platforms and stairs on which patrons walk or work with handrails that are securely fastened at a height for convenient use.
3. Provide the ladders used in the plant with pads or points to prevent their slipping.
4. Keep floors clean and free of excess water and accumulated refuse.
5. See that stools, tables, and other wooden equipment are of solid construction and free from rough edges or splinters.
6. Do not repair machinery while it is in operation.
7. Protect exposed gears, belts, sprockets, chains, and shaftings, with secure guards to avoid the entangling of any clothing or object.
8. Protect and ground electrical equipment in accordance with existing codes. When pull-chain sockets are used they should be insulated.
9. Do not attempt to repair boiler lines or steam fittings while the steam system is under pressure, as this may result in serious injury to persons or cause property damage.
10. Place fire extinguishers at convenient locations in the plant and check them regularly to see that they are properly charged.
11. Where gasoline stoves are used, place them in large, shallow boxes of sand. Keep additional sand in buckets or provide a foam- type extinguisher to be used if fire should result from use of such stoves. Make no attempt to fill gasoline stoves while there are other stoves in operation or flames burning nearby. Such stoves should not be refueled inside the building.
12. Check retort crates, bails, and hoisting equipment at frequent intervals for defects.
13. Teach patrons the proper method of handling tools.
14. Advise patrons and employees to wear low-heeled, comfortable shoes to avoid slipping on floors.
15. Keep first-aid cabinets well stocked at all times. Give train- ing in first aid to employees.
16. Provide salt tablets during hot weather to prevent heat exhaustion.
17. Provide aprons, boots, and gloves of rubber or acid-resistant material to protect the worker where caustic alkali is used.
45
Management
Personnel — employed and volunteer
In getting ready for plant operation the supervisor and cannery committee must decide on the number of employees needed to operate the plant and how they will be selected. In a community cannery, patrons usually prepare their own produce, fill it into the cans, and mark the cans. Patrons also assume responsibility for cleaning the equipment and the space they have used in preparing their products, and for disposing of any refuse from their products. In small canneries it may be necessary for patrons to assume other jobs, but in most instances it is best to employ regular per- sonnel for such jobs as operating the retorts and sealer. In all instances an experienced boiler operator should be employed. In some States boiler operators must be licensed. The boiler operator should give full attention to boiler operation and the maintenance of the steam lines in a plant. He should not be required to do other tasks that will take him away from the boiler for any length of time.
During processing periods, if a person is not hired to spend full time with the retorts, a responsible patron should be assigned to this job. Other jobs that may be performed near the retorts include loading of filled cans into the retort crates, and cooling and unloading of the processed cans. In units where pres- sure canners are used each patron should be made re- sponsible for his own canner. Gages should have faces sufficiently large so that the floor supervisor can note at a glance the pressure indicated and, if the pressure is not correct, call the fact to the attention of the patron responsible.
The sealer operator, if one is employed, and the supervisor should be trained to test can seams and to make the necessary sealer adjustments. They, as well as all other employees, should be responsible for the daily upkeep and care of the equipment which they operate.
In large plants it is usually advisable to employ an assistant to the supervisor to help in receiving prod- uce, training patrons, and general supervision of the work of the plant. Such a person will need to be as capable and as well trained as the supervisor in operat- ing the cannery and in teaching or directing others.
Other employees might include: A clerk, to be responsible for making appointments, maintaining records, receiving money from patrons, and releasing canned goods; a janitor for general cleaning and refuse removal; an additional key employee who can be trained to replace anyone in the plant. Such an employee could relieve the retort operator and sealer operator during rest and lunch periods, or replace either one in an emergency, so that plant operations will not need to be curtailed in their absence. Other jobs that might be assumed by this person would include brine and sirup making and the issuing of cans to patrons.
Some communities have found it advantageous to use volunteer workers in their canning centers. Such workers usually assume the responsibility of instruct-
ing patrons in the preparation of their produce. Volunteer workers should not operate boilers, sealers, retorts, or other pressure equip7nent unless they are fully qualified to do so. When such workers are so used it is important to select those who can be depended on for a definite period of time.
Protection for employees and patrons
It is always wise in a community venture, such as a canning center, to insure employees and patrons against accidents that may occur.
Many canneries carry Workmen's Compensation Insurance which pays wages to employees in case of disability. Some canneries also carry a public liabil- ity policy and a boiler insurance policy for protection of patrons as well as employees in case of personal injury due to an accident at the cannery. The latter policy usually covers damage to property as well as personal injury.
If a cannery is operated under the supervision of a school which carries a public liability policy, the cannery usually can be included in this policy at a lower premium rate than would be charged for an independent policy.
Getting information to the public
Newspapers, local merchants, women's clubs, garden clubs, schools and radio stations can give valuable help in publicizing the community can- nery and its program if the information is made available to them by the cannery committee and the supervisor. To be effective, this information should follow a general pattern commencing with the organ- ization of the cannery. Throughout the canning season some member of the committee should be responsible for compiling and releasing pertinent information at stated intervals.
Newspapers and radio stations especially should be furnished with: Copies of agreements between the cannery and patrons; advance information on when the cannery will open; when and where people may make appointments for using the cannery's facilities; and what produce may be canned. They also should be given the names of the cannery committee members and their work.
Gas and electric-light companies may be willing to cooperate with the program to the extent of mailing informational circulars with their monthly bills.
If certain days are to be set aside for canning a particular product the notice should appear in the newspapers in advance. This allows patrons time to make their appointments with the cannery. Local stores that carry produce for canning may want to include notices of canning dates in their regular advertisements.
Items of public interest, such as outstanding ac- complishments of the cannery, should be reported both to radio stations and to newspapers as they occur. Newspapers may also be interested in well- illustrated articles on the cannery program for use in their Sunday issues.
46
Education and training for patrons
If the community cannery is to operate successfully and become a permanent facility in the community, all groups of people using the cannery must become increasingly skilled in its use and operation and be willing to support it.
In order that the cannery may operate effectively' an educational program should be conducted on: (1) Planning, (2) producing, and (3) conserving the fam- ily food supply. The program should begin before the planting season of the products which are to be conserved.
Individuals enrolled in any part of this educational program should be organized into groups of teachable size, based on : (l) Size of the cannery, (2) equipment available, (3) products to be processed, (4) previous experience in using canning equipment, (5) area from which patrons come, (6) time best suited to them, and (7) number to be trained. A seasonal sequence of instruction should be followed in all phases of this training. The training program will be most effective when taught just prior to or in connection with activi- ties carried on by the groups or individuals in proc- essing their own products.
In order to carry out this educational program, it will be necessary to use the existing educational agen- cies or other services available in the community. One of the responsibilities of the local advisory com- mittee will be to designate qualified persons to serve
as instructors for the training program, especially as it pertains to planning, producing, and conserving food. An educational program of this kind has been handled successfully in local communities by teachers of vocational agriculture and home economics, county Extension Service agents, county Farm Security Ad- ministration supervisors, garden-club leaders, and other trained or qualified individuals and groups. Experience has shown that greater quantities of more desirable food will be conserved by each family if the homemaker is given systematic instruction and train- ing on planning the food needs, food production, and food-processing practices. The educational program will provide the supervisor with definite information regarding the number of patrons planning to use the cannery and the amount of produce that will be processed in the cannery during the season.
Planning food for the family
To get the greatest benefit from the community cannery, a family should be given training in develop- ing a food budget. This is done by listing the kinds and quantities of food that will be needed by the fam- ily during the year. The food budget includes all foods that are produced in family gardens as well as those purchased from local markets or producers. The quantities of fruits and vegetables in the food budget should include those to be eaten fresh as well as those to be conserved for later use, by storing fresh or by canning, freezing, brining, and dehydrating.
Table 6. — Family food plan at moderate cost
Family members
Children under 12 years:
9-1 2 months
1—3 years
4-6 years
7-9 years
10-12 years
Girls:
13-15 years
16-20 years
Women:
Moderately active. _
Very active
Sedentary
Pregnant
Nursing
Boys:
13-15 years
16-20 years
Men:
Moderately active. _
Very active
Sedentary
Kinds and quantities of food for a week
Milk '
Qt.
7 5 5 5 6
4J4
51/2
4y2
7
10K2
6 6
5 6 5
Potatoes, sweet- potatoes
Lb. Oz.
0 8
1 0
1 8
2 8
3 0
3 8
3 0
4 0
5 0
4 0
7 0
3 0
Dry beans
and peas,
nuts
Lb. Oz.
0 2 0 2 0 2
0 4 0 4
0 6 0 12 0 4 0 6 0 6
0 8 0 12
0 12
1 0 0 6
Citrus
fruit,
tomatoes
Lb. Oz.
2 0
1 12
1 8
1 8
1 8
1 12
1 12
1 12 1 12
1 8 1 8 1 8
Green,
yellow
vegetables
Lb. Oz.
1 8
1 8
1 8
1 8
1 8
1 8
1 8
2 0
2 0
1 8
1 8
1 8
Other vegetables and fruit
Lb. Oz.
0 8
1 0
1 8
2 8 2 8
2 8
2 8
2 8
2 8
2 8
2 8
3 8
3 0
3 0
2 8
2 8
2 8
Eggs
No.
Meat,
poultry,
fish
Lb. Oz.
0 2
0 8
1 0
1 8
2 0
2 0
2 0
2 0
2 0
2 0
2 0
2 0
Flour.2 cereals
Lb Oz.
0 8
1 8
2 0
2 8
3 4
4 0 3 8
3 8
4 12 2 8
4 12 9 0 3 8
Fats and oils
Lb. Oz.
0 1
0 4
0 6
0 10
0 12
0 14
0 12
0 12
1 0 0 12 0 12 0 12
1 0 1 10 0 12
Sugar,
sirups,
preserves
Lh.
Oz. 1
2
(l 0
0 8 0 8 0 10
0 10 0 10
0 12 0 12 0 12 0 10 0 10
0 12 0 12
0 12 0 12 0 12
1 Or its equivalent in cheese, evaporated milk, or dry milk.
2 Count 1]4 pounds of bread as 1 pound of flour.
Bureau of Human Nutrition and Home Economics, XJ. S. Department of Agriculture (10).
47
Nutritional requirements of trie family
To meet the nutritional requirements of the family, the food budget should be based on the Basic 7 food groups as outlined by the Bureau of Human Nutrition and Home Economics (10~). The family food plan at moderate cost shown in that publication and repro- duced herein as table 6, can serve as a basis for deter- mining the quantities of food needed to meet the nutritional requirements of the average family on a weekly, monthly, and yearly basis.
Quantity of each food to be canned
The quantity of food to be preserved by canning would depend on other methods of preservation
available and on the length of the season when canned foods, rather than fresh products, are to be used. Food-preservation budgets, such as the one shown in table 7, are available in most States and may be used as a pattern in determining the amounts and varieties of food to be preserved by any one family. Although this budget was set up for rural families it may be adapted to the use of urban families. When setting up an individual family budget it is important to keep in mind the variation of produce even within a State and to have the budget include foods that are available on the local markets as well as those that are home-produced. Families should be taught how to plan individual food budgets that are adapted to their own needs.
Table 7. — Family food-preservation budget
|
Product |
Amount to can ' |
Product |
Amount to store, dry, brine, and cure |
||
|
For 1 person |
For my family |
For 1 person |
For my family |
||
|
Tomatoes and tomato juice |
30 qt 20 qt |
|
Potatoes |
3bu |
|
|
Green and yellow vegetables |
2-3 bu. (Irish) |
||||
|
5—7 qt. greens: |
1 bu. sweetpotatoes |
||||
|
Wild greens |
Cabbage and Chinese cabbage (about 10 heads). Yellow vegetables |
1 bu |
|||
|
Spinach |
1 bu |
||||
|
Mustard |
|||||
|
Chard |
}i bu. carrots |
||||
|
Turnip greens, etc _ |
}i bu. Hubbard squash |
||||
|
10-15 qt. other green vegetables: |
Sweetpotatoes (as above) |
||||
|
Young green beans |
Other vegetables and fruit |
4bu. |
|||
|
Peas |
1-3 bu. vegetables: Turnips |
||||
|
Asparagus, green |
|||||
|
1—2 qt. vellow vegetables: |
Beets |
||||
|
Carrots |
Onions |
||||
|
Sweetpotatoes |
Parsnips |
||||
|
Other vegetables and fruit |
50 qt |
Salsifv |
|||
|
10-20 qt. of vegetables: |
Rutabagas |
||||
|
Vegetable soup mixture |
Squash and pumpkin |
||||
|
1-3 bu. fruits: Apples |
|||||
|
Babv beets |
|||||
|
Corn |
Pears |
||||
|
Sauerkraut, |
Dried vegetables and fruits 2-3 gal. vegetables: Corn, beans, peas, soybeans |
4 gal |
|||
|
30-40 qt. fruits: Apples |
|||||
|
Peaches |
1-2 gal. fruits: Apples, peaches, pears |
||||
|
Pears |
|||||
|
Rhubarb |
Meat : Cured pork |
20 1b |
|||
|
Plums _ |
|||||
|
Grapes |
Cured bacon |
101b |
|||
|
Cherries |
Lard |
1 gal |
|||
|
Berries |
Sorghum and honev Sauerkraut (cabbage and turnip) Nuts (in shell) : Peanuts, hickory, wal- nuts, hazel, pecans Whole wheat for cereal and other dishes Popcorn, on cob |
2 gaL _ |
|||
|
Apricots |
1 gal |
||||
|
Apple, peach, pear, rhubarb, plum, grape, cherry, and berry juices |
1 bu |
||||
|
1 gal |
|||||
|
8-12 pts. pickles, relishes, catsup, etc_ 8-12 pt. jams, jellies, preserves, etc._ Meat |
5 qt |
||||
|
5 qt - |
2 a;al |
||||
|
20 qt _ |
|||||
|
8-12 pt. pork. |
|||||
|
8-22 pt. beef . |
|||||
|
8—12 pt. chicken and other meats |
|||||
1 If a freezer locker is used, reduce the number of quarts canned according to the amount placed in the locker. From Missouri Agricultural Extension Service (5, p. 8).
48
Food-production possibilities
In making out the family food budget the foods that can be produced at home will need to be considered. One large planting for canning will save time and transportation for patrons. Plantings for canning purposes should be made at the season most favorable for producing those fruits and vegetables adapted to any given area. This will not be as difficult for those people living on farms as for the urban dweller who will have to decide which products to plant in order to get the most value from the available garden space.
After the food budget for the family has been decided on, systematic instruction and study should be undertaken with respect to: (1) Determining size of garden; (2) selecting site for garden; (3) determining amount of seed needed; (4) selecting and obtaining kinds and amounts of fertilizers; and (5) other activi- ties which are needed in connection with planning for the family food supply.
Producins food for family use
Where families have their own gardens several group meetings should be held just before and during the growing season to study the methods used by success- ful growers in the community and the recommenda- tions of State experiment stations. These studies include: (1) Preparing the seedbed; (2) selecting varieties best adapted to the local area and for canning; (3) succession planting of crops to avoid overcrowding of the cannery; (4) starting plants in hotbeds or cold frames; (5) pruning; (6) spraying; (7) cultivating; and (8) harvesting.
Prior to the time when the fruits or vegetables are ready to be harvested or purchased for canning, a few group meetings should be held to discuss such problems as: (l) The stage of maturity of the produce that will insure a high-quality finished product; (2) the proper type of containers for harvesting and transporting produce to the cannery; (3) the quantity of produce to be harvested for processing during any one day; (4) time of day best suited for harvesting; {5) holding certain produce for processing by using temporary storage; and (6) preparatory steps to be taken before the produce is brought to the cannery.
This systematic instruction on providing the family food should be supplemented by posters, postal-card folders, news articles, circular letters, or other devices that will inform the patrons of planning, producing, and processing activities.
Instructing families in canning practices
Specific instructions should be given the patrons on preparation practices and canning techniques to be followed in the various steps of the canning operation. The individuals responsible tor the training program may be able to obtain the services of experienced patrons or volunteer workers to assist in the training of inexperienced patrons in the preparation of produce and the techniques of canning food. Instruction also must be given on the operation and use of equipment.
The use of trained employees to operate, maintain, and adjust the intricate pieces of canning equipment, such as boilers and retorts, will: (1) Increase the amount of food processed; (2) aid in more efficient operation of the plant; and (3) insure a high-quality canned product. The supervisor of the community canning plant will need to train employees or other persons to operate the equipment.
If the person responsible for the training program has had teaching experience that includes job analysis, little difficulty should be experienced in training the employees and patrons in canning procedures and operations.
In order that the instructor may make a job analysis it will be necessary to decide first, what specific job is to be taught. No attempt should be made to teach all the activities that take place in the operation of a cannery at one time. Instead, it is considered desir- able to teach a person only one operation at a time.
The instructor should list all the important steps in the order in which they must be done. Each step listed should be accurate, brief, and clear. This is important because, quite often, the instructor may know how to do the job so well that he does some step automatically and may not teach that step to the learner.
The instructor should list the key points in each step. A key point is anything in a step that might make or ruin the job, injure the worker, or make the work easier to do. The key points to be listed are the techniques -which are to be emphasized at each step of the operation if a thorough job of instruction is to be accomplished.
Before using the teaching plan with individuals or groups, the instructor shoulcf do the job according to the plan developed and check to see that all steps and key points have been included.
A break-down of all jobs connected with the prepa- ration and processing of the produce and the operation of each piece of equipment should be outlined and training given the individuals who are to do these jobs.
The direct or lecture method of teaching gives indi- viduals information about a canning technique but does not train the individual to acquire skill in per- forming the task. Similarly, a demonstration without explanation will show the individual how to perform a task but does not give information about the job or practical experience in performing it skillfully. The teacher who uses a combination of both methods of instruction plus the technique of having the patron "learn through doing" will carry on the most effec- tive training program. In using this procedure the instructor should outline the important steps in doing each job and the essential points to observe in per- forming each step. The correct equipment and all necessary materials and supplies should be available and correctly arranged for doing the particular job to be taught. The following procedure has been found effective in training inexperienced persons to do canning:
Step 1. — The instructor should state clearly the specific job to be done and stress the importance of
49
performing each operation correctly. Persons having previous canning experience may demonstrate their skill and if proficient, proceed with the work.
Step 2. — The instructor should explain and demon- strate the job in clearly defined steps, stressing the points which will result in success or failure. Charts, pictures, films, and other illustrations may be used to emphasize these points. It may be necessary to explain and demonstrate some steps several times in order to teach clearly the skills to individuals.
Step 3. — Each trainee should do the job under close supervision, the instructor attempting to prevent errors. It is a good practice to have the trainee point out the essential steps he has performed in doing the job. Questions may be raised as to what, how, and why he has carried out each operation. Have each trainee repeat the job under supervision until he understands and can perform each operation.
Step 4. — The training will be more effective if the person does the job immediately in connection with processing his own produce or operating the piece of equipment to which he has been assigned. If certain points are not clear, questions should be en- couraged to clear up these points. At first the in- structor should check frequently the work being done. Less supervision will be required as the per- son acquires skill. The instructor should designate some person to assist in giving information to patrons on canning operations or in operating canning equipment.
The use of wall charts (fig. 62), approximately 3 by 4 feet in size, on which are listed the several steps that need to be followed in processing each of the more common commodities is a good teaching device and will aid the patron to follow the recommended processing practices of the instructor.
|
CANNING TOMATOES |
||
|
1. |
Sorting: For size. Ripeness. Soundness. |
|
|
2. |
Washing. |
|
|
3. 4. 5. |
Scalding. Cold dipping. Peeling. |
|
|
6. |
Washing cans. |
|
|
7. |
Seasoning: No. 3 cans, 1 teaspoon salt. No. 2 cans, }i teaspoon salt. |
|
|
8. |
Pack tomatoes to }i inch of the top of can. |
|
|
9. 10. |
Exhausting to 140° F., center Sealing cans. |
can temperature. |
|
11. |
Marking cans. |
|
|
12. |
Processing: No. 2 cans, 45 minutes. No. 3 cans, 55 minutes. |
|
|
13. |
Cooling to 100° F. |
|
|
14. |
Cleaning utensils. |
|
|
15. |
Checking out. |
Figure 62. — A sample chart on canning tomatoes. Similar wall charts will aid in teaching the following: Processing times and temperatures; number of cans required for measured quantities of produce,- recommended type of container for each produce- instructions for making sirup and brine,- and the use of salt tablets.
Patron's agreement
An agreement outlining policies and regulations that have been adopted by the cannery committee is usually presented to patrons the first time they come to the cannery. Before operations begin, patrons are required to sign this agreement indicating that they fully understand its terms and are willing to comply.
Such an agreement might include the following :
1. The standards of operation and techniques of canning adopted by the canning center.
2. Divisions of labor; namely, the work the patron will do at the cannery and what services the cannery will supply.
3. Cost per can the patron will be expected to pav.
4. A list of materials and supplies to be furnished by the cannery and those the patron must furnish.
5. A statement of plant policy on spoilage of products.
6. Regulations on registration and scheduling.
7. Rules on cancellation of appointments, either by patron or by cannerv supervisor.
8. The types of produce that may be canned.
Appointments and scheduling
If the cannery is to operate with any degree of suc- cess, patrons must make appointments with the super- visor for the use of it. Such appointments should be made several days in advance of the day the canning is to be done so that a plan of work may be set up and operating needs determined. Produce of like types should be grouped in the quantities and sequence necessary to insure a smooth flow of work and the maximum use of the equipment.
During the peak production season it would be well to have special days for canning produce in abundance, such as peach day or corn day. Where it is necessarv to can several kinds of produce in one day the number should be kept to a minimum. Care should be taken not to schedule produce that will compete for the same equipment. Tomatoes, which are processed in the water bath, can be scheduled for canning at the same time as vegetables processed under pressure, such as snap beans or peas. When the quantity of produce of any one kind is not sufficient to till the retort or open- process tanks, those products requiring the same proc- essing time and temperature should be scheduled together, if possible. In that way the full capacity of each processing vessel can be utilized and the maximum production for each day assured. Table 4, on page 39, which gives the approximate number of cans required for measured quantities of produce, will be helpful in figuring the number of cans to be proc- essed.
When scheduling vegetables and fruits, preference should be given to the more perishable ones. The harvest of root crops may easily be delayed if neces- sary, so that perishable items, such as corn or peas at the right stage of maturity for canning, can be cared for promptly. Small fruits and berries need immediate care if waste from spoilage is to be avoided.
A standard form, such as the one shown in figure 63, will serve as an appointment schedule, production record, and receipt for the amount paid by the patron. It should be made out in duplicate so that both the plant and the patron will have the same record.
50
Name...
Address.
Date
Time a. m__ Patron's No. Telephone
p. m_
Produce
Amount to be .canned
Size of can
Number of cans
Cost per can
Total cost
Remarks
Total number of cans. Amount paid
Supervisor
Figure 63. — Patron's appointment record and receipt.
At the time the appointment is made the patrons should be advised of the hour and day on which they are to report to the cannery and how many helpers to bring to assist with the job. This will vary with the produce to be canned and the experience of the worker. Where patrons are required to bring sup-
plies, such as sugar, they should be advised of the amount needed. This will vary with the produce and the way in which it is to be canned.
The supervisor should have a daily operating schedule, using a form such as the one shown in figure 64.
|
Month Day Year |
|||||
|
Time |
Patron's name |
Patron's number |
Produce |
Amount |
Size of cans |
Figure 64. — Daily operating schedule.
If such a schedule is made up as appointments are made, the supervisor can more effectively regulate the amount and kind of produce to be canned as well as the number of patrons who will use the cannery on any one day. To get the maximum use of equipment it is well to schedule the largest group of patrons for early in the day. If the cannery is to close at the end of a normal working day, patrons should not be scheduled for appointments later than 3 p. m. This will allow the time necessary to complete canning operations and the cleaning of the plant by closing time. During peak periods of production it may be necessary to schedule appointments over a longer operating day.
A review of the schedule in advance of the day of operation makes it possible to adjust appointments if changes need to be made. This advance check will also allow time for making a plan of work so that employees and volunteer workers can be in- formed of their responsibilities and given necessary training.
The number, size, and type of containers and corre- sponding lids needed should be ascertained and checked to see that they are on hand. Other supplies that may be needed should also be determined and made available. All facilities should be checked and equip- ment should be adjusted for operation. Such fore-
51
thought will net improved efficiency in the clay's operation.
Staggered lunch periods for regular employees should be planned to insure continuous operation of the plant throughout the day. Schedule one person to relieve, as necessary, those in key positions. Each employee should report to work as the day's schedule requires his services. The boiler operator, for example, should come early enough to have steam up when operations begin. The sealer and retort opera- tor need not report until later. Others are scheduled according to their respective duties. Rest periods for each employee should be allowed both during the morning and afternoon.
Canning procedure
du(
Receiving produce
As patrons arrive with their produce it is checked in and recorded on the individual patron's appoint- ment record and receipt card. (See fig. 63-) The patron is issued a number, which is also recorded on the card. Canneries vary their methods of assigning numbers. Some assign new numbers each day, some each week, whereas others have their patrons use the the same number for the entire canning season. Where new numbers are assigned each day, or each week, it is necessary to stamp the date on each can in order to avoid confusion in identification of patrons'