THE Spray PROCESS 311 
and escapes through the small orifice in the cap, forming a 
fine spray or mist. 
The small orifice through which the milk spray enters the 
desiccating chamber increases in size by usage due to wear, and 
necessitates the frequent replacing of the old caps or nozzles by 
new ones. When in operation, these spray nozzles at times be- 
come clogged and must be changed for cleaning. It is necessary, 
therefore, for the operator to supervise the process continually, 
making sure that all the spray nozzles function properly, so as to 
secure maximum efficiency and speed of desiccation. 
In order to facilitate the changing of spray nozzles while desic- 
cation is in progress, the nozzles are so placed as to connect with 
the milk pipe on the outside of the desiccating chamber, the nipples 
carrying the spray nozzles connecting with the milk supply pipe by 
means of Barco joints (loose joints), can be turned in all directions 
sufficiently to withdraw the nozzles from the desiccating chamber 
independently and at any time during the desiccating operation. 
Spray Pumps.—In order to maintain a uniform efficiency of 
desiccation and to secure a uniform fineness of spray, it is im- 
portant that the pressure of the milk should be uniform. To ac- 
complish this requires a special type of pump. The pumps best 
EY 
Fig. 107. High pressure pump for spraying milk 
Courtesy of Union Steam Pump Co. 
suited for this purpose are three cylinder pumps with large, heavy 
valves and with extra deep stuffing boxes that can be packed with 
one-half inch packing rings, and special, heavily bolted glands that 
can be readily adjusted when the pump is running. 
The triple cylinder arrangement insures a steady pressure 
