60 CIRCULAR 740, U. S. DEPARTMENT OF AGRICULTURE 



ports requiring more air should be opened to full capacity in prefer- 

 ence to closing down dampers or openings at other points. When the 

 temperature of the delivery air is too low the ports should not be closed 

 down to prevent freezing : instead the temperature of the air should be 

 raised and as much volume as possible permitted to circulate through 

 the room. In many plants there is too little air circulation. This re- 

 sults in high temperatures in parts of the room, and sometimes an 

 attempt is made to correct this by lowering the delivery-air tempera- 

 ture. If this becomes too low for safety, closing down the openings to 

 prevent freezing aggravates the condition instead of improving it. 



FREEZING NEAR COILS 



In direct-expansion rooms the packages nearest the coils sometimes 

 become too cold even though other fruit in the room may be too warm. 

 This localized low temperature is caused by the radiation of heat di- 

 rectly from the packages to the coils, even though the air next to them 

 may be above the freezing point. In this case, increased air circulation 

 may keep the packages from getting too cold or it may be necessary to 

 put a shield between the boxes and the pipes. This shield is not for 

 deflecting the air but for preventing direct radiation, that is. to stop 

 the "shining."' or radiation, of heat from the boxes to the cold surface 

 of the pipes? This radiation takes place regardless of the temperature 

 of the air between boxes and pipes. 



LITERATURE CITED 



(1) Allen. F. W. 



1942. CARBON DIOXIDE STORAGE FOR YELLOW NEWTOWN APPLES. Amer. SOC. 



Hort. Sci. Proc. 40 : 193-200. 



(2) American Society of Heating and Ventilating Engineers. 



1945. heating, ventilating, air conditioning guide. 808 pp., illus. New 

 Tork. 



(3) American Society of Refrigerating Engineers. 



1942. refrigerating data book. Ed. 5, 518 pp., illus. New York. 



(4) Bowen. J. T. 



1932. REFRIGERATION IN THE HANDLING. PROCESSING. AND STORING OF MILK 



and milk products. U. S. Depi. Agr. Misc. Pub. 138, 59 pp., illus. 



(5) Britton. J. E.. Fisher. D. V.. and Palmer. R. C. 



1941. apple harvesting and storage in British Columbia. Canada Dept. 



Agr. Farmers' Bui. 105. 39 pp.. illus. 



(6) Brooks. C. Cooley. J. S.. and Fisher. D. F. 



1920. diseases of apples in storage. U. S. Dept. Agr. Farmers' Bui. 

 1160, 20 pp.. illus. (Revised 1935.) 



(7) Buffalo Forge Company. 



193S. fan engineering: an engineer's handbook on alr, its movement 



AND DISTRIBUTION IN ALR CONDITIONING ... Ed. 4. 739 pp., iilUS. 



Buffalo, N. Y. (Revised.) 

 (S) Fisher. D. F. 



1942. HANDLING APPLES FROM TREE TO TABLE, U. S. Dept. Agl*. Or. 659, 



39 pp., illus. 

 (9) Fisher. D. V. 



1940. storage of delicious apples in artificial atmosphere, Amer. Soc. 



Hort. Sci. Proc (1939) 37: 459-462. 



(10) Gerhardt, F.. and Ezell. B. D. 



1941. PHYSIOLOGICAL investigaiions on fall and winter pears in the 



pacific northwest. U. S. Dept Agr. Tech. Bui. 759. 67 pp.. illus. 



(11) Haller. M. H.. and aIagness. J. R. 



1944. picking maturity of apples. U. S. Dept. Agr. Cir. 711. 23 pp., illus. 



