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. 123 The operation of the compound exhaust injector illus- trated at fig. 69 may be briefly described as follows: The exhaust steam. at a temperature of 212 (leg. Fah. coming from the engine or other source of supply passes first through a grease separator, if such is required, and then enters the injector, meeting the feed water, which is under a head, and which is at a temperature' of, say, 50 deg. Fah. Condensation of the steam immediately takes place and a vacuum is formed. The small live steam nozzle b, known as the inducer, serves to increase the flow of exhaust steam to the injector. The combined jet of condensed steam and water rushes through the combin- ing nozzle into the delivery nozzle of the exhaust injector. In the latter nozzle the kinetic energy of the jet is con- verted into pressure energy, and the jet leaves the exhaust injector at a temperature of about 180 deg. Fah.; tlie temperature of the fee-d water has been raised 130 deg. Fah. in the exhaust portion of the injector. The delivery from the latter now passes to the supplementary live steam portion. Here it is acted on by a jet of live steam, which raises the temperatui’e of tlie water from 180 deg. Fali. to about 280 deg. Fah., and gives it sufficient pressure to overcome that in the boiler which is being fed. The very high final deliverery temperature will be noted. If a live steam injector only had been feeding the boiler under the same conditions as the compound exhaust injector, tlie delivery temperature- would have been about 1601 deg. Fah.