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.

54 THE STEAM INJECTOB. Another sliding nozzle injector is shown at fig. 31 with- out the control fittings of the combination type. In this injector a is the sliding combining nozzle and 6 the steam- inlet nozzle. A modificatioii of the sliding-nozzle arrangement is shown at fig. 32. In this a collar or ring a slides upon tlie exteriör of the combining nozzle, and opens or closes the outlet from the chamber b, containing an overflow gap, according to whether the injector is starting or is working normally. An external view of this type of injector is given in fig. 33. With the arrangement illustrated at figs. 26 to 33 the action of the injector becomes automatic; that is to say, Fig. 31. the injector can automatically start or re-start after a stoppage, for the opening and closing of the overflow apertures is automatic. The injector can therefore rapidly clear itself of steam when starting (without the steam supply being reduced), and allow of the production of a vacuum in the feed-water pipe to draw in the feed water. With the advent of what are known as “hot-water” injectors, or injectors intended for dealing with hot feed water and high-pressure steam, it has become necessary to provide for the closing not only of the overflow passage near to the inlet end of the combining nozzle, but also of