ECONOMICAL USE OF FUEL IN CREAMERIES. 
35 
SAVING IN FUEL THROUGH HEATING BOILER-FEED WATER BY EXHAUST STEAM. 
It is the common practice in creameries to feed the boiler with low- 
temperature water ; that is, water of the temperature at which it comes 
from the well or other source of supply. The temperature is gener- 
ally about 60° F., and in some instances, as when the water is drawn 
from a stream or from a storage tank, it is near the freezing point. 
The contraction strains which are set up in the boiler plates and 
seams, due to feeding cold water, are enormous and are liable to 
weaken the plates and open up the riveted joints. In addition to 
causing deterioration in the boiler itself, the feeding of cold water 
in large quantities reduces the temperature and consequent pressure 
inside the boiler and makes it difficult if not impossible to keep a 
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Fig. 9. — General arrangement for utilizing heat in exhaust gases and jacket 
water from internal-combustion engine. 
uniform pressure. It also reduces the output of the boiler, for it is 
obvious that the boiler must furnish the heat required to raise the 
temperature of the feed water from its initial temperature to that 
corresponding to the steam pressure carried in the boiler. 
It is advantageous to " preheat " the boiler-feed water, even though 
it is necessary to take live steam direct from the boiler to accomplish 
it, for by so doing the life of the boiler is prolonged, its output is 
increased, and there is a direct fuel saving due to the more even tem- 
perature maintained in the boiler. But by utilizing the heat in the 
exhaust steam which is otherwise wasted, not only are the contraction 
and expansion strains avoided to a great extent but there is a saving in 
fuel and the boiler output is materially increased. 
