THE COST OF PASTEURIZING MILK AND CEEAM. 



TEST NO. 1. 



Referring to test No. 1, the pasteurizing was done with hot water 

 which was heated by exhaust steam from five steam-driven turbine 

 separators and five reciprocating steam pumps. The arrangement 

 for utilizing the heat in the exhaust steam is illustrated diagrammati- 

 cally in figure 1 . As it was impracticable to put a back pressure on the 

 small steam turbines used for driving the separators, as would be done 

 if they were allowed to exhaust under water or into a milk heater, the 

 arrangement shown was resorted to. The exhaust from the separators 

 and pumps was piped into the box above the water level. The hot- 

 water circulating pump took the water from the box and forced it 

 through the internal tubular heater and back into the box. The 

 spray pipe, located in the top of the box, above the water level, was 



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Fig. 1.— Elementary diagram of hot water pasteurizing equipment. 



perforated with a large number of small holes through which the re- 

 turn water was sprayed. The heat contained in the exhaust steam 

 was taken up by the water, the equipment acting on the principle of 

 the jet condenser. There was a valve placed on the end of the spray 

 pipe for controlling the temperature of the water. By opening this 

 valve the return water was allowed to pour out into the box without 

 absorbing much heat from the steam, while, on the other hand, if the 

 valve was closed all of the return water was sprayed, thereby absorb- 

 ing the maximum amount of heat. The temperature of the water was 

 controlled very satisfactorily by this arrangement. There was an 

 overflow pipe placed in the box, as indicated, which kept the water 

 at a constant level by allowing the condensed steam to overflow into 

 the sewer. There was a vapor pipe on one end of the box which 



