. The Street railway journal . the furnace with a blow-off,so there are practically two mud-drums providing for thedeposit and removal of sediment before the in-fliowing waterreaches the hot surfaces of the furnace and tubes, where scalewould be formed. It is found by experience in using impurewater that it is easy to keep the boiler clean by the regularuse of the blow-off cocks, and the usual washing out throughthe hand-holes at the front and back of the lower shell andthrough the manhole in the upper drum. In addition, there aretwo large hand-holes in the shell at the rear of the furnace for
. The Street railway journal . the furnace with a blow-off,so there are practically two mud-drums providing for thedeposit and removal of sediment before the in-fliowing waterreaches the hot surfaces of the furnace and tubes, where scalewould be formed. It is found by experience in using impurewater that it is easy to keep the boiler clean by the regularuse of the blow-off cocks, and the usual washing out throughthe hand-holes at the front and back of the lower shell andthrough the manhole in the upper drum. In addition, there aretwo large hand-holes in the shell at the rear of the furnace forcleaning between the tubes, the tubes being spaced in paralleldiagonal rows, so that a bar may be passed through every rowof tubes at the rear of the furnace, where scale will form, if atall. Owing to the rapid circulation of water around the upperpart of the furnace and tubes it is found scale will not formexcept at the lower part of the boiler. In cases where ex-ceptionally bad water is used the furnace and tubes are bolted. .SECTIOXS OF IXTERXALLY FIRED BOILER and as every part of the boiler is cylindrical except the tubesheets, no staying is required. The gases, after leaving thefurnace, pass through the tubes and return between the lowerand upper shells to the outlet at the front of the boiler. The furnace being of large diameter and highest at the back,with considerable space beyond the grate surface, is favorableto good combustion. The tubes are short, direct and pro-portioned to give the correct area, in order that they may allbe filled with hot gases. Most of the soot is carried throughthe tubes and deposited in the rear smoke box, so that all theheating surfaces, furnace, tubes and return flue between theupper and lower drum, are very effective. The circulation of water inside the boiler is around thefurnace and tubes, up the rear neck into the steam and waterdrum, where the steam is released, the water passing along theupper drum towards the front and down the front
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
