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.

QUESTIONS. 127 minutefrom a boiler under a pressure of 219 Ibs. per square inch absolute into tlie atmosphere through an aperture of ‘006 square foot area. An approximate formula may be used for this calculation. What would be the difference in the discharge if the exhaust pressure, instead of being atmospheric, were («) 131 Ibs. per square inch absolute, and (&) 160 Ibs. per square inch absolute? (26 ) Compare the velocity, mass, momentum, and kinetic energies of two fluids of dift'erent clensities issuing through orifices of equal cross-sectional area from a vessel under pressure. What is the water velocity equivalent of 23 Ibs. pressure per square inch absolute, taking the density of water as 60 Ibs. per cubic foot? (27 ) An injector under test gives the following result: — Steani pressure, Feed-water Height Ibs. per temperature, of sq. inch deg. Fah. lift. absolute. 100 60 3 ft. Pressui-e at point where steani and water unite. 5 Ibs. per sq. in. abs Delivery Delivery pressure, temperature, Ibs. per deg. Fah. sq. inch absolute. 140 120 (</) Calculate the ratio of water to steam passing through the appliance (c) Calculate the theoretical velocity of inflow of the steani and water. (d) Calculate, neglecting aH consideration of losses, what the delivery pressure and temperature of said injector should have been under ideal conditions. (e) Calculate the heat units (contained in eacli 1 Ib. of steam used) lost from the injector by radiation, the heat units actually used to produce the cleli- verv and g’ive the number of heat units utilised- in heating the feed water. (f) Calculate the efficiency of the injector as a pump. (28) What are the quantities or valnes which affeet the ratio of water to steani passing through an injector? (29) Describe an exhaust injector, pointing out its limita- tions. What is the chief difference between an exhaust and a “ live ” steam injector? Can an exhaust injector lift its feed water ? If so, under what conditions ?