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. 49 ture of the water in the jet and in the density of the jet, and to the lessened cross-sectional area of the combining nozzle. The temperature» of the jet at a (fig. 24) under ordinary working conditions, be equal to, above, or below 212 cleg. Fah., and the pressure there, therefore, equal to above or below atmospheric; but at 6 the pressure is always considerably below atmospheric. The injector may therefore create a vaeuum in the overflow chamber, and if said chamber communicates freely with the atmo- sphere draw in air through the overflow pipe. The valve c (®g’- 24) prevents such. inflow. Inflow of air to the Fig. 25. combining nozzle, due to leaky overflow valves or other causes, is a very serious hindrance to the proper working of the appliance, and also results in the presence of excessive quantities of air in the exhaust steam of the engine worked from the boiler fed by the injector. Such air impairs the action of the condensing plant, and reduces the vaeuum in the exhaust pipe. Fig. 25 illustrates in diagram form, the variations in pressure in the combining nozzle of an exhaust injector. If the pressure conditions at the various overflow aper- tures are not considered when deciding upon the nature 5 si