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.

128 THE STEAM INJECTOR. (30) What methods are practicable for increasing the delivery pressure of an injector without altering its con- structional details? What are the limitations to such methods ? (31) Describe tlie reasons for and the precautions neces- sary in fitting up and using an exhaust steam injector. (32) Estimate the eoonomy of steani and water obtained (33) Describe a compound or double injector, and discuss by the use of an exhaust injector. its merits or demerits as compared with a simple injector having concentric lifting and forcing steani nozzles. (34) Describe a form of compound injector in which ex- haust steani is employed along with live steam, giving particulars of the approximate gradations of pressure and temperature of the deliverv jet as it passes through the appliance. (35) An injector using steani of 120 Ibs. per square inch absolute pressure, water at 1.00 deg. Fah., and having tlie overflow pressur© atmospheric, tlie delivery pressure 145 Ibs. per square inch absolute, and the delivery tem- perature 180 deg. Fali., draws 14,400 Ibs. of water per hour from the hot well. Ascertain approximatelv the throat area of the steam nozzle and the throat area of tlie delivery nozzle. (36) What is meant by tlie maximum velocity of efflux of steani from a vessel? Give a formula to determine this maximum. Is there such a thing as a maximum velocity of discharge (independent of the exaot exhaust pressure conditions) into an exhaust space? John Heywood Ltd., Excelsior Priuting and Bookbinding Works, Manchester.