ECONOMICAL USE OF FUEL IN CREAMERIES. 21 



air supply to the demand of the burning fuel. The leakage of air 

 through the walls of the boiler setting and through warped and 

 broken furnace doors is practically constant. 



The loss of heat due to the admission of an excessive supply of 

 air through or over the fuel bed is the greatest single loss in a boiler 

 plant. 



In good practice there is a loss of about 23 per cent in the stack, 

 due to heating aii\ This loss, however, is necessary in order to main- 

 tain draft through the furnace, and hence can not be avoided. 



In the average creamery the heat loss due to heating an excessive 

 amount of air is 40 or 45 per cent on account of air leaks in the 

 setting. At least half of the loss can be eliminated by stopping the 

 -cracks in the boiler setting. 



The tools necessary for firing should be provided and the floor 

 from which the coal is to be shoveled should be hard and smooth. If 

 the coal is shoveled directly from a wheelbarrow or specially de- 

 signed coal car, the inside surfaces should be made smooth by dressing 

 off all rivet heads or other obstructions against which the edge of 

 the shovel may strike. The coal should be placed near the furnace 

 door in such position that, it may be shoveled quickly and easily into 

 the furnace, thus making it necessary to keep the furnace doors open 

 onry a short time. Dampers should be provided in the uptake with 

 means for operating from the fireman's position in front or at the 

 side of the furnace doors. It is important that damper connections 

 be conveniently placed so that the dampers can be easily and accu- 

 rately adjusted; otherwise there will be a tendency to neglect their 

 use and, instead, control the draft by means of the ash-pit door. 

 Under no circumstances should the ash-pit. door be used to control 

 the draft in a furnace ; with the ash-pit door closed or partly closed 

 there is little or no air admitted through the grates and combustion 

 is incomplete, and valuable fuel in the form of combustible gases 

 which have been driven off from the green fuel is wasted by being 

 carried off unconsumed up the stack. 



Ordinarily the firing tools consist of a shovel, rake, hoe, and slice 

 bar, which should be of the proper size to suit the particular furnace 

 and should be kept in good condition. The front or cutting edge 

 of the shovel should be kept straight and never be allowed to become 

 bent or gapped. The tines of the rake and the blade of the hoe 

 should not be bent or otherwise distorted. The slice bar should be 

 bent to an angle suited to the particular furnace with which it is to 

 be used. 



The floor surrounding the boiler from which the coal is to be 

 shoveled should be of concrete, with a smooth and hard surface, or 

 better still, some form of car or truck should be used and the coal 



