=The Blower= consists of a small pipe attached to the steam dome or top
of the boiler with a globe or angle valve, and is situated near the
stack. This pipe enters the stack just above the boiler, the end being
bent up toward the top of stack and reduced to a very small opening.
When steam is turned on through this pipe, it displaces the air in the
stack, causes a partial vacuum in the smoke box, and the air rushes
through the grates, fuel and flues to replace that which is blown out
by the blower, and the draught can be increased as much as desired.