grate room (gratrom)

In some forms of furnace, a compartment or chamber with a grate beneath it, separated from the rest of the furnace, in which the fire is made. These grate - rooms are sunk several feet below the level of the bed of the furnace, and are separated from each other by a portion of the bed, which is called the flag. Gla -making, p. 111. The area of grate-surface (grat'sér fās), n. any grate in a furnace. In steam-engineering the term is used in designating the extent of surface required in a grate to hold sufficient fuel to evaporate a given quantity of water, and thus indirectly to produce a certain amount of power. Thus, in a locomotive-boiler one square foot of grate-surface is a umed to suffice for the evaporation of eight cubic feet of water per hour. Ordi nary forms of boilers are much le effective; some do not evaporate per hour more than a single cubic foot per square foot of grate-surface.