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 air 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 
only 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 
