Furnace

—In a steam boiler, that part designed for the burning of the fuel. The principal parts and appendages of a furnace are as follows: (1) The furnace proper or firebox, being the chamber in which the solid constituents of the fuel and the whole or part of its gaseous constituents are consumed, (2) the grate, which is composed of alternate bars and spaces, to support the fuel and to admit the air, (3) the dead plate, that part of the bottom of the furnace which consists simply of an iron plate, (4) the mouth piece, through which the fuel is introduced and often some air. The lower side of the mouth piece is the dead plate.