24 



MASS. EXPERIMENT STATION BULLETIN 360 



rooms the wall coils are supplemented by similar coils hung in alle\s running 

 lengthwise of the room. In another arrangement pipes are assembled in groups 

 or bunkers extending the full length of the room and hung near the ceiling. In 

 all cases drip pans must be provided to catch the drip from the coils. The cold 

 air drops to the floor underneath the coils, spreads out over the floor and, as it is 

 warmed, rises in the spaces between the boxes. This system is quite satisfactory 

 provided boxes are piled so as to leave a small space — one to two inches — 

 between alternate rows. Naturally, bo.xes near the floor will cool off more rapidly 

 than those at the top of the stack. 



MDst new storages are equipped with blowers, sometimes called "diffusers." 

 In large rooms, 4000-bushel capacity or more, floor-type blowers are used, while 

 in the smaller rooms the blowers are suspended from the ceiling. The floor-type 

 blower consists of the evaporating coil enclosed in a sheet-iron casing. A fan 

 mounted at the top of the case draws air from the floor up through the coils and 

 discharges the cooled air at high velocity near the ceiling. The small blowers are 

 similar in general design to an automobile radiator, the air being drawn or forced 

 across the cooling coils horizontally. 



Figure 14. Floor-type Diffus 



Blower with Wooden Flues 



Blowers have an advantage over wall or ceiling coils in that a positive air circu- 

 lation is set up, which insures more uniform temperature throughout the storage; 

 and with a relatively high air velocit\' over the fruit the heat is removed more 

 rapidly. When blowers were first introduced, it was thought that this rapid air 

 circulation would dry out the fruit and cause shriveling. Extensive observations 

 made on fruit cooled by blowers indicate that this does not happen if a relative 

 humidity of not less than 80 percent is maintained. 



Where the blower cools a single room, the air is driven across the top of the 

 stack of bo.xes, filters down, and is drawn through the stack of fruit to the inlet 

 at the base of the blower. Where two rooms are cooled by a single blower (Fig. 15), 

 the air leaving the blower is divided between the two rooms, D and Do, the return 



