Grates. The grate is made up of a set of parallel bars at the bottom of the fire-box, which hold the fuel. These bars are commonly made of cast iron and constructed in sections of three or four bars each. They are supported at their ends by resting upon a frame and are connected by rods to a lever which can be moved back and forth to rack the bars and shake ashes and cinders out of the fire. A drawing of such a grate is illustrated in Fig. 46. When the grates occupy the full length of the fire-box they are divided into three sections, any one of which can be moved by itself. In the burning of anthracite coal, water grates are commonly used, a type of which is illustrated in Fig. 47 and Fig. 48. In Fig. 47, the grate is formed of a tube a expanded into the back sheets of the fire-box and inclined downward to the front in order to insure a circulation of water. Opposite the back opening, a plug is screwed into the outer sheet which affords a means whereby the tube may be cleaned and a new one inserted in position if a repair is needed. At the front end, the tube is usually screwed into the flue sheet. Water grates are rarely used alone but usually have spaced between them plain bars. These bars pass through tubes expanded into the sheets of the back water leg and by turning them, the fire may be shaken; and by withdrawing them, it may be dumped. Fig. 48 shows a cross-section of the arrangement usually employed. In this figure, A represents the water tube and B, the grate bars.

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This page last updated 9/6/99