Transactions . -value of the coal-mixture, about 4,900 h. u. Average steam-pressure 5 atm. Average steam temperature 270° C. Superheating 112° C. Water evaporated by 1 kg. coal kg. Corresponding heat utilized from 1 kg. coal in evaporation, 2,170 h. u. Efficiency of the boiler, about 44 per cent. 292 GENERATION OF STEAM BY WASTE HEAT FROM FURNACES. As the above figures show, the conditions of operation with thistype of boiler-construction were very favorable to a high the union of furnace- and boiler-masonry had a bad effect, caus-ing, in the latter, cracks, disloc
Transactions . -value of the coal-mixture, about 4,900 h. u. Average steam-pressure 5 atm. Average steam temperature 270° C. Superheating 112° C. Water evaporated by 1 kg. coal kg. Corresponding heat utilized from 1 kg. coal in evaporation, 2,170 h. u. Efficiency of the boiler, about 44 per cent. 292 GENERATION OF STEAM BY WASTE HEAT FROM FURNACES. As the above figures show, the conditions of operation with thistype of boiler-construction were very favorable to a high the union of furnace- and boiler-masonry had a bad effect, caus-ing, in the latter, cracks, dislocations and bulges, which increasedthe frequency of necessary repairs. Moreover, the longitudinal buck-stays of the furnace left much to be desired. Fig. 3 shows a Diirr boiler, with 120 sq. m. of boiler heating-sur-face, and 24 sq. m. of heating-surface in the superheater, the wholesupported, upon a separate frame of rolled iron, above a large ingot-heating furnace, the hearth-area of which is about 10 sq. Fig. 3.—Waste-Heat Boiler, Dure Type, OverLarge Ingot-Heating Furnace. These boilers, which have been running satisfactorily for about sixyears, produce per hour per square meter of heating-surface about11 kg. of steam at 280° C. The furnace-gases enter through twoopenings (a, a, Fig. 3) to the boiler, go in three passes over the water-tubes, and then escape into the atmosphere through a sheet-metal GENERATION OF STEAM BY WASTE HEAT FROM FURNACES. 293 pipe placed between two boilers and carried by the necessary shutting-off of boiler from furnace is made possible bya fire-proof chimney-flue under the floor of the works, with whichthe openings «, a, are connected, and which is ordinarily closed by aslide, so as to permit the normal circulation of the gases to the boiler.
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
