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.

OVERFLOW ARRANGEMENTS. 63 the pressure is always below that of the boiler. The delivery passage, on the other hånd, is always at or above the boiler pressure when the injector is at work. The i'esult of this arrangement is that a large differential pres- Fig. 41. sure is ensured under all circumstances for the proper actuation of the shuttle valve. The action at starting is as follows : When the steam is turned on to the injector, the pressure whicli is imme- Fig. 42. diately set up in the passages v, v acts on the shuttle valve at s2, and the resulting moveni&nt of the shuttle in the direction s3 closes the ports h2 which communicate with the chamber c. In this condition no pressure is put upon the