THE COST OF PASTEURIZING MILK AND CREAM. 
7 
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- 
calfy 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 
o 
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 
