The Steam Injector
A theoretical and practical treatise on the design and operation of injectors and on the flow of fluids through and the design of nozzles.

COMPOUND INJECTORS. 121 with the exhaust steam nozzle, and a supplementary live steam injector receiving the delivery from the exhaust injector and forcing it into the boiler being fed. A typical example of this class of injector is illustrated at fig. 69. In this, a indicates the exhaust steam intet nozzle, b the small live- steam nozzle of the exhaust portion, c the water inlet, and d the live steam nozzle of the supple- mentary live steam portion. The delivery from the exhaust portion passes by way of the pipe e to the supple- Steam SUCTIO" Fig. 68. mentary live steam portion. As the temperature of the final delivery water is well above boiling point, there is, even during normal working, a pressure above atmospheric in tlie overflow cliamber f of the supplementa ry live steam portion. The overflow valve g of such cliamber has there- fore to be loaded. In the illustrated case this is effected by the pressure in the delivery cliamber of the supplemen- tary injector through tlæ piunger h and lever i. When exhaust steam is not available for working the exhaust portion of the injector, live steam throttlecl clown to atmo- spheric pressure is supplied to the nozzle a.