All About Engines

The Gas Engine 195 coke, could be used, and that the ammoniacal liquor from which a valuable fertiliser is made, could be recovered. The sale of this by-product reduced the cost of fuel in some cases to 3s. 6d. a ton, and it was evident that here was a source of power which rendered gas engines independent of the town supply. Engineers began at once to study the possibilities of large engines, and whereas engines of 100 horse-power had been the largest before they soon began to be made of 500 and 600 horse-power. But improvements in gas producers did not cease with Mond’s invention. In the earlier ones the air and steam were forced in, and the engine had to take what came, whether the load and its appetite were large or small. But in the modern producer the engine sucks gas just as fast as it requires it, like a baby with a bottle, and there is no fear of choking. In the sectional illustration of one of Messrs. Crossley Bros.’ suction gas producers (Fig. 114 on Plate 18) it will be seen to consist of three parts: the producer proper or gas generator a, the vaporiser or steam raiser b, and the scrubber or gas cleaner c. The gas generator is a steel casing lined with fire brick and having a hopper on the top through which the fuel is admitted. The vaporiser consists of a metal box containing a number of tubes which have “gills” in order to encourage the transfer of heat. The hot gases from the producer pass through the box, and as water flows through the tubes the steam which is necessary for the process is generated. The