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. 57 steam and water are flowing thereto, a considei'able pressure may exist in the delivery chamber. Whilst makers generally employ the pressure in the delivery chamber of the injector to load the overflow valve or close the overflow apertures, thev adopt various means for neutralising the effect of the pressure existing in that chamber during the starting of the injector. Automatic loading of the overflow valve by means of the pressure in the delivery chamber is pro vided for in the injector illustrated at fig. 34, where the valve-like head b of the overflow valve c, is exposed to the delivery pressure. Fio. 34. No means are provided for neutralising the effect of said pressure upon the valve c when the injector is starting, consequently there is a throttling action upon the overflow which impairs the lifting and re-starting powers of the appliance. It will also be seen that all the overflow has to pass the valve c. The overflow from the compartment d, which has a free valve e thereon, is not independent of the overflow from the remainder of the overflow chamber, which it should be for most efficient working. In the arrangement illustrated at fig. 35 the overflow aperture a for the lifting steam nozzle b is placed in a