CHAPTER XXII. 



ECONOMIC OPERATION OF CREAMERY. 



Inasmuch as it is impossible within the hmitcd space in this 

 work to talce up a detailed discussion of the various principles 

 and practices of operating boilers, engines, mechanical re- 

 frigerators, and other creamery machinery, only a few of the 

 chief factors common to creamery practice and effecting the 

 economic operation shall here be discussed. For more com- 

 plete information students are referred to works treating 

 specially of these phases. 



Firing the Boiler. — Much fuel can be wasted and saved ac- 

 cording to the completeness with which the combustion occurs. 

 This again depends upon the manner of firing, upon the regu- 

 lation of the draught, and upon the kind of boiler. The fire 

 on the grates should never be too thick nor should too much 

 coal be loaded on the fire at any one time. A thin, even fire 

 permits of a more complete combustion than when chnkers 

 and cinders are allowed to accumulate on bottom of fire, and 

 a heap of unburned coal on top. By this latter method of 

 firing, the grates are likely to be injured. 



To get the most heat from the coal the draught should be 

 regulated. The combustible part of the coal is of two kinds: 

 first, the fixed carbon, and second, the volatile matter. The 

 former is the coke or the part of coal which is seen on the grates 

 as a mass of glowing fire. The latter consists of the gases 

 which pass off when a certain temperature is reached, and which, 

 when mixed with a certain amount of air at a given tem- 

 perature, will burn. The heavy black trail of smoke seen rising 



329 



