. The Street railway journal . low of thehot gases in the Heine boiler. Fig. 2 is a dia-gram showing the flow of the gases in otherleading types of water tube boiler. In the Heineboiler the gases pass from the grates to a com-bustion chamber—thence around the lower tierof fire brick into and through the nest of watertubes in a nearly horizontal direction—andfinally around the upper tier of fire brick, andback over the upper watsr tubes to the chimney. This movement of gases produces a strongser and far more uniform heating effecton the tubes than is found in the movementshown in Fig. 2. The lo
. The Street railway journal . low of thehot gases in the Heine boiler. Fig. 2 is a dia-gram showing the flow of the gases in otherleading types of water tube boiler. In the Heineboiler the gases pass from the grates to a com-bustion chamber—thence around the lower tierof fire brick into and through the nest of watertubes in a nearly horizontal direction—andfinally around the upper tier of fire brick, andback over the upper watsr tubes to the chimney. This movement of gases produces a strongser and far more uniform heating effecton the tubes than is found in the movementshown in Fig. 2. The longitudinal movementof the gases along the tubes has been shown bycareful experiments to be thirty per cent moreeffective for boiler purposes than when thegases meet the tubes at right angles. More-over, it is impossible to have perfect combustionin the type shown in Fig. 2, for the reason thatthe water tubes act as cooling surfaces to thehot gases coming direct from the grate andbring down the temperature of the uncombined. FIG. 2. carbon below the combustion point, so that alarge portion of the fuel is wasted. By the 138 STREET RAILWAY JOURNAL. [Vol. XII. No. lo. combustion chamber alone — a featurepeculiar to the Heine boiler—is this wasteof fuel avoided. A second and perhaps even more impor-tant advantage possessed by the Heine boiler, is
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
