The Locomotive Of Today

The Boiler : Exhaust Injectors. 55 supplementary steam injector, which is specially designed, for dealing with hot water, and which delivers it into the boiler. In the case of Davies & Metcalfe’s injector, illustrated in Fig. 11, the steam is passed through a grease separator, which collects all oily impurities, water, &c., and allows the steam to pass along to the exhaust portion, where it meets the water; to assist the exhaust steam, a small jet of live steam is suppliedfrom the supplemental valve. As it is most important that there should be no air in the pipes between the biast pipe and injector, all joints must be carefully made to exclude it, and the overflow pipe is fitted with a flap valve; the reason for this care is that the exhaust steam passes along the pipe at so small a velocity that it can only induce a small amount of vacuum in the combining cone, and into this the water flows and condenses the steam, more steam then enters, this collects more water, and so the injector works. The combining cone is fitted with the flap nozzle, described earlier, for automatically reducing the pressure within, if it should become too great; a non- return valve is situated at the end of the exhaust injector, by which the heated water is passed at a temperature of about 2oo° F., and a pressure of 70 Ibs. As this is insufficient to enable it to enter the boiler against the high pressure now common on locomotives, the supplementary portion, worked entirely by live steam, then takes it and delivers it to the boiler, and in doing so heats it up to about 270° F. Thus the economy claimed is that the feed water is heated and delivered to the boiler almost entirely by means of waste steam, and a large quantity of water is used twice over; further, as it is not necessary to decrease the exhaust outlet, the steam drawn off by the injector reduces back-pressure in the cylinders. A wing- valve is placed in the exhaust steam pipe, just before the injector, and a branch from the injector is provided for the attachment of a pipe from a small valve 011 the boiler, so that when the engine is standing or running with regulator closed, and there is no exhaust steam, the wing valve may be closed, and a small quantity of live steam admitted clirect from the boiler to do its work. The exhaust portion must be placed below the level of water in the tank, and the quantity admitted to the injector is regulated by sliding the water cone, so as to decrease or enlarge the space around it, this being done by a wheel with an index fixed in the cab of the engine. The combustible most commonly employed on locomo- tives is coal, although wood and petroleum are extensively used in various districts. Of coal, many varieties are used, the particular grade burned by a certain railway depending chiefly on its geographical position, although the working of