138 MANAGEMENT OT DAIRY PLANTS 



Heating of feed water may be done by two methods — either 

 by exhaust steam or by chimney gasses. The heater used for 

 the latter is known as "Economizer." It is the former method 

 which will be most practical for the average creamery. There 

 are two objects for heating the feed water: First, there is a sav- 

 ing in heat when heating the feed water by exhaust steam, and 

 second, the water is heated to such a temperature so that it 

 will not injure the boiler as will water of a low temperature. 



When using water heaters, the best oil traps obtainable 

 should be used, as the oil, if entering the boiler, will mix with 

 the solids of the water and finally adhere to the sides of the 

 boiler, which will naturally lessen the efficiency of the boiler. 

 It is to be preferred that the steam pass through the heater 

 through a system of coils, thus eliminating the steam from the 

 water in the tank. Fig. 23 ' illustrates a plant with water 

 heating apparatus. 



2. Firing. — The method employed in firing the coal may 

 involve big losses. The ability of being able to obtain the 

 greatest amount of heat from the fuel burned lies in the abiUty 

 of the fireman to supply the right amount of air to the fuel under 

 the right conditions. Only such an amount of oxygen should be 

 supplied as is necessary to combine with the combustible por- 

 tions of the coal. The coal should be added in small quantities 

 at a time; it should be spread evenly over the grate. The fire 

 should have a thickness of from three inches to six inches; it 

 should be clean and should leave no burned-out places or holes. 



Proper installation of the boiler is of importance in order to 

 obtain the highest efiiciency. It is estimated that it will require 

 from one third to one half square foot of grate surface for each 

 horse power of a horizontal tubular boiler. Complete plans and 

 specifications for installation of the boiler and for building the 

 chimney are furnished by the manufacturer of the boiler and the 

 installation should be made and retained in accordance there- 

 with. 



3. Keeping Boiler Clean. — The efficiency of the boiler is 

 greatly reduced if the exterior of the tubes is covered with soot 



' Circular 209, B. A. I., 1913. 



