16 



MISC. PUBLICATION" 5 40, U. S. DEPT. OF AGRICULTURE 



series, the first running at a faster speed, help to maintain a continu- 

 ous line of trays for loading. If this system is used, tray scraping 

 and tray loading must be coordinated for efficient operation. 



Some operators have found it necessary, when using wooden trays, 

 to soak them before they are washed in order to obtain satisfactory 

 cleaning. Trays so washed must be dried under proper conditions 



Cross 

 Conveyor 



High-Pressure --Tray Cleaner 



Wot er. Spra y ^/ 



Car Being 

 Unloaded J 



-Tray Conveyor 



Figure 8. — Lay-out of tray line to avoid excessive handling of trays between 

 unloading and loading. 



to avoid damage from checking. It is desirable to dry the trays 

 before reloading so that the large amount of water carried in the wet 

 wood will not cause an increase in the drying time and a correspond- 

 ing decrease in quality of the vegetables being processed. 



Packaging Room 



The packaging room should be enclosed, thus excluding damp air 

 from the preparation room and dehydrator. Air-desiccating equip- 

 ment is advisable in many cases. If a refrigeration system already 

 is available, desiccation based upon refrigeration can be used. Where 

 no such equipment exists, nonrefrigerative types are generally in- 

 stalled. When a product is dried to an extremely low moisture con- 

 tent, desiccation of air is essential and will more than pay for itself 

 in improving the quality of the packaged material. 



Where a shaker-sieve is used to remove the fines from the dried 

 product, the economical use of these fines is a problem. If the quan- 

 tity is large, installation of grinding equipment may be advisable. 

 The necessity for grinding equipment also depends largely upon the 

 demand for soup stocks, purees, and seasonings. Onions, celery, and 

 garlic have been quite generally prepared in powder form, and pow- 

 dering equipment will probably continue to find its greatest use for 

 these vegetables. An extremely dry product and dry air are essen- 

 tial in any powdering operation. 



Plant and Equipment Costs 



The costs of the building and equipment vary considerably. The 

 construction of new buildings or the use or rental of old buildings, 

 the purchase of new or second-hand machinery, and the wide varia- 

 tion possible in the type and size of each item of equipment are fac- 

 tors that make an over-all estimate unreliable in many cases. As a 

 guide, however, tables 2 and 3 have been prepared. Table 2 pre- 

 sents rough cost estimates for the preparation, final inspection, and 

 packaging equipment indicated in figures 1 to 5. Table 3 gives the 

 approximate costs of constructing and equipping these same plants, 

 including all usual items. 



