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 suppty. 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 



Fig. 9. — General arrangement for utiljzin 



water from internal-combustion engine. 



heat in exhaust gases and jacket 



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 necessaiy 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. 



