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.

62 THE STEAM INJECTOR. access until the pressure in the chamber exceeds a certain amount. An arrangement in which the delivery chamber forms an overflow chamber when the injector is starting is illus- trated at fig. 43. The only overflow aperture from the combining nozzle is at a. When the injector is starting, the steam escaping therethrough forces open tlie valve 6. The latter then abuts against and opens the valve c, per- mitting free escape from the delivery chamber cl. The valve b is of greater area tlian the valve c. When the correct proportions of steam and water are passing through the combining nozzle, a vacuum is created at tlie aperture a, and the valve b is forcecl on to its seat. The valve c is then returned to its seat by the delivery pressure, and d Fin. 40. delivery takes pla.ce past the valve e. Fig. 44 is a view showing an injector of tlie type illustrated at fig. 43, but without the steam valve. In the overflow valve control arrangements illustrated at figs. 44 to 48, a shuttle valve s is provided in a sleeve h, its function being to control the admission of steam to the chamber c, into which the piunger o1 of the ovei’flow valve o projects. It is by this admission of steam that pressure is put upon the overflow valve and the injector thus trans- formed into the “ hot water ” type. The shuttle valve is arranged to be acted on at one end by the pressure in the delivery chamber through the pas- sages p, and at the other end by steam derived through the passages v, v from the throat of the steam nozzle, wbere