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Science for beginners . Fig. 71.—Showing the feed cylinder tilted forward and filled withcoal. The apron closes the opening in the center of the grate throughwhich the coal is forced upward into the fire box. In the underfeed furnace, fresh coal is introduced at thebottom of the fire bed. Distillation of the volatile mattertakes place therefore at the bottom of the fire, where theoxygen supply may be more abundant than on top of the. Fig. 72. -Showing the fresh coal forced into the fire box and the burningcoal resting on the top of the fresh coal. fire, and hence it is more completely burned (
Science for beginners . Fig. 71.—Showing the feed cylinder tilted forward and filled withcoal. The apron closes the opening in the center of the grate throughwhich the coal is forced upward into the fire box. In the underfeed furnace, fresh coal is introduced at thebottom of the fire bed. Distillation of the volatile mattertakes place therefore at the bottom of the fire, where theoxygen supply may be more abundant than on top of the. Fig. 72. -Showing the fresh coal forced into the fire box and the burningcoal resting on the top of the fresh coal. fire, and hence it is more completely burned (Figs. 70, 71,and 72). Moreover, in passing through the glowing cokeabove, the volatile matter is sure to be heated to the kindlingtemperature. LIQUID FUELS 93 In steam boiler plants mechanical stokers are often em-ployed. With the mechanical stokers, the aim is to feed thefuel to the lire gradually by some device. In the stokershown (Fig. 73), which is a chain grate stoker, the coal is fedcontinually by being carried into the furnace on the the fresh coal approaches the zone of combustion, thevolatile matter is gradually distilled from the coal. There isalso provision for a supply of air ample to burn the volatilematter as well as the fixed carbon or coke.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectscience, bookyear1921