Engineering Wonders of the World
Volume I

220 ENGINEERING WONDERS OF THE WORLD. himself in the discovery, but was struck down by a fatal illness before its importance had been proved. The inventor was enabled, however, by the help of Mr. James Riley of the Glasgow Iron Company, to put his idea into actual practice at the Wishaw Works, near Motherwell. The works were lighted successfully with, electricity generated by an engine built to use blast furnace gas—the first engine of the kind. The second was estab- lished by a Belgian firm at Seraing, and its good behaviour led the Germans to interest themselves also. Like many another inventor, Thwaite found himself a prophet without honour in his own country. The gas might burn well enough, folk said, but what about the dust with which it was so generously charged ? Rich Fig. 7.—FAN-TYPE DUST EXTRACTOR. men showed him their backs, but with commendable perseverance he continued to devise efficient “ scrubbers ” for ridding the gas of its noxious dust, the Cleaning harmful qualities of which were Blast . , mi Furnace °ny t0° aPParent The first Gas. scrubber used by Thwaite con- sisted of a wetted fan and a sawdust filter. The fan was one of the ordi- nary centrifugal type, into which the gas enters near the centre (Fig. 7). As it rotates, it whirls the gas violently round and flings it against the walls of the casing, whence it is washed, by water squirted from the side, into a trap, and so collected. A subsequent pas- sage through a sawdust filter removes the last traces of dust. At Ettingshall Works there are three such fans arranged “ tandem ” (See Fig. 17), through, which the gas travels suc- Fig. 8.-ANOTHER TYPE OF CLEANER. cessively. The water flowing from the first is black, that from the third a dirty milky colour, which means that very little, if any, dust has escaped the water. Other forms of scrubbers are shown in Figs. 8 and 9. Fig. 8 is perhaps the simplest type— a chamber with, a vertical partition which sud- denly changes the direction of the flow of the gas, and causes the heavier particles to be de- posited at the bottom. An- other kind of washer (Fig. 9) is used for lighter dust. It contains a number Various Types of Scrubbers.” Fig. 9.—REVOLVING DISC TYPE OF SCRUBBER. of metal discs attached to a horizontal shaft and enclosed in a cylindrical tank partly filled.