Page 10 



BETTER FRUIT 



April, 1920 



The Department of Agriculture Cold Storage Plant 



By Lon A. Hawkins, Plant Physiologist, Office of Horticultural and Pomological Investigation, Bureau of Plant Industry, 



United States Department of Agriculture 



THE ever increasing demand for 

 foodstuffs has led to the develop- 

 ment of various methods of pre- 

 serving and storing fruits and vege- 

 tables in season for use when fresh 

 products are not readily obtainable. 

 One of the most important of these 

 methods is that of cold storage, that 

 is, the storing of fruit and vegetables 

 at temperatures low enough to slow 

 down the life processes but not in- 

 hibit them. By such treatment the 

 life of a fruit or vegetable, which 

 might be only one or two weeks after 

 removal from the plant, may be length- 

 ened to several months, with only 

 slight deterioration in its food value 

 and attractiveness. 



The mechanical phases of cold stor- 

 age, that is, the means of producing 

 and regulating low temperatures, are 

 fairly well understood. Much less is 

 known, however, concerning the reac- 

 tion of the various kinds and varieties 

 of fruits and vegetables to low temper- 

 atures, though considerable experi- 

 mental work has, of necessity, been 

 done by commercial cold storages to 

 determine the best temperatures for 

 the keeping of produce. 



It was this dearth of information con- 

 cerning the effect of low storage temp- 

 eratures on fruits and vegetables that 

 led the office of Horticulture and 

 Pomology of the Bureau of Plant In- 

 dustry to plan and erect a cold storage 

 plant to be used for experimental work. 

 This plant was designed with rooms 

 large enough to give approximately 

 commercial conditions of storage but 

 not so large that the cost of operation 

 and equipment for experimental pur- 

 poses would be prohibitive. The plant 

 was designed by Mr. S. J. Dennis, a 

 refrigerating engineer formerly con- 

 nected with this office. 



The building is 100 ft. by 44 ft. on 

 the outside and is two stories high, 

 being 22 ft. from the top of the first 

 floor to the plate. The exterior of the 

 building is shown in figure 1. The 

 walls and floors are of monolithic con- 

 crete. The gable roof is frame covered 

 with fire proof shingles. The first 

 floor of the plant, figure 2, is divided 

 into engine room, storage space and 

 handling room. The engine room is 

 26x42 ft. 4 inches inside, with an office 

 about 10x12 ft. The ammonia compres- 

 sion system of refrigeration is used and 



large tank of calcium chloride brine 

 which is pumped through coils in the 

 refrigerating chambers by means of a 

 motor driven centrifugal pump. A 

 gasoline engine connected to a two and 

 a half kilowatt direct current generator 

 furnishes power to drive the brine 

 pump motor in case of interruption of 

 the electric service. 



The storage rooms are located next to 

 the engine room. They are arranged in 

 tv^-o rows of four rooms each (see figure 

 1) and open out into the insulated and 

 refrigerated corridors which run along 



KiGiiRE 1 — View of tlie experimental cold storage plant. 



the engine room is equipped with two 

 twelve-ton belt drive vertical ammonia 

 compressors run by 25 horse, slow 

 speed induction motors. A forty horse 

 power gasoline engine is provided for 

 auxiliary power in case of accident to 

 the electric equipment. Refrigeration 

 is by circulating brine. The ammonia 

 expansion coils are immersed in a 



both sides of the building. The rooms 

 are about 8x14 ft. by 11 ft. 7 in. high 

 over all, furnishing in round numbers 

 1300 ft. of space. The rooms are insu- 

 lated with insulation made up of flax 

 fiber, mineral wool and a binder. Four 

 inches of insulation were laid on the 

 outside corridor walls and the same on 



Continued on page 36. 



^y^i - mum 



F UTURE COLD STORAGE ROOM 



I HANDLING HCDM ! 



i 



^T^ ' r?^jy ' ir3 ^:i ^» ' mf ' V :Sf ^ i fW >zr^ ^^^.^j-^y ^^ ^jrJ - ^i r.ji Vfc.=-- ^gra>g prf 



1 



Figure 2— First floor plan of experimental cold storage plant, sho\\ ing engine room, refrigeration clianibers, unfinished refrigeralion space 



and handling room. 



