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.

96 THE STEAM INJECTOR. The amount of warer delivered by the injector comprises the water taken in at the feed, and also the water resulting from the condensation of the s team, that is C (B + 1) . i — pounds per second. The area of the nozzle (A,z) required to pass this quantity of water, having a density p and a velocity V,( feet per second, is given by the following forniula :— — C (B + 1) , -x Az, =------------. (xxxvi.) < l B x P x V(Z V ’ Application of Formulce.—Calculate from theoretical consiclerations the area of the steam and delivery nozzle throats of an injector taking 4 Ibs. of water per second from the hot well, the feed water temperature being 60 deg. Fah., the delivery temperature 140 deg. Fah., the steam or boiler pressure 90 Ibs. per square inch absolute, the water head 2 ft., and the vacuum at the steam nozzle mout-h or ouitlet 24 in. metrcury. The pressure at the steam nozzle throat is 90 x *58 Ibs. (52 approximately) per square inch absolute as maximum flow conditions exist. Taking the initial dryness fraction as unity, the dryness fraction at the nozzle throat is: T = -- L2 T„ 889 781 •452 - -415 915 744 = -956. The steam velocity at the nozzle throat is V = x 144 v n + 1