Furnace Grate
An essential part of any coal-fired furnace is the metal grate on which the fuel is burned (Figure 13-12). The grate should be designed to allow sufficient primary air to pass upward through the fuel bed for the combustion process. The ashes will drop to the ashpit below through the same openings when the grate is shaken.
There should be a metal heat transfer surface (heat exchanger) of sufficient size above the fire to transfer the heat from the combustion process to the water or air in the heating system.
Coal Stoker
A coal stoker is a device used to feed coal to a coal-fired furnace or boiler automatically. See Chapter 3 of Volume 2, “Coal Firing Methods” for additional information about coal stokers.
Hand-Firing Methods
The method used to hand-fire a furnace will depend largely upon the type of solid fuel used in it. Coke and the various types of coals each have their own special hand-firing methods. Some of these firing methods are described in Chapter 3 of Volume 2, “Coal Firing Methods.”
Blower and Motor Assembly
The blowers used on coal furnaces are the same centrifugal types found on gas, oil, and electric forced-warm-air furnaces. The blowers are usually installed on either side of the furnace or at the back. The latter arrangement is especially recommended for wood-burning and multi-fuel furnaces. A detailed description of blowers and blower motors is included in Chapter 11, “Gas Furnaces.”
Blower Adjustment
Instructions for making blower adjustments can usually be obtained from the furnace manufacturer. A brief description of methods used to make blower adjustments is included in Chapter 11, “Gas Furnaces.”
Air Filter
The number, size, and type of air filter will be recommended by the furnace manufacturer in the specifications. See also Chapter 12, “Air Cleaners and Filters” in Volume 3.