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.

102 THE STEAM INJECTOR. The losses in the delivery nozzle and connections may be taken as about 25 per cent, so that an approximation is: A» = ig (V25 A, - Po) Ad v v s / The velocity Vs is thai of the steam at the steam nozzle throat, as we are virtually comparing the momentum at the said throat with that at the delivery nozzle throat. Now, it is known that the velocity at the throat of & well-designed nozzle under maximum weight flo w con di- tions is equal to: ________________ ______ = 5-85 Jps vs when n — 1'135; then the formula becomes : _ 3 (1'25 pd — po) (xxxvii.) Ad ps Applying this formula to tlie problem previously worked out, and takirig the delivery pressure a-s 95 Ibs. and the overflow pressure as 15 Ibs., we get: A _ o (1-25 x 95 - 1.5) Td “ 90 = 3-125. If, in our previous calculations, we had not diacarded the valne Wi(, x Vw, the formula would have been : 2</ Ad (1-25 pd - Po) - W(„ x Vw (xxxviii) ’ “ 20-7874 These notes are more or less søhematic,- but are usetful as giving an insight into the problems surrounding the injector.