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.

66 THE STEAM INJECTOR. can then pass through the passages v, v up the centre of the shuttle valve to the belt s1, thence through the holes h2, to the annular chamber h, and so through the passages j to the chamber c, where it acts on the piunger o and closes the overflow valve with the requisite pressure. By turning the screws Z, Z the passages p, p and v, v can be closed; this puts the shuttle out of action and cuts off the supply of steam to the chamber c. The sleeve and shuttle valve can then, if desired, be withdrawn complete, while the injector will continue to work in the ordinary way with a t'ree overflow valve. A general view of the injector is given in fig-. 48. That the construction of “hot water” injectors has been brought to a great state of efficiency will be realised from the following table showing typical results guaran- teed by some of the leading makers. Table VI.—Showing Maximum Temperature of Feed Water for Injector supplying the Bon,er from WHICH IT 18 RKCEIVING STRAM. Boiler and delivery pressure Lbs. per sq. in. absolute. Heiglit of lift In feet. Feed-water temperature. Deg. Fah. 225 6 120 225 2J 125 215 6 125 205 24 130 195 140 190 6 130 75 2Å 3 40 Under special conditions better results ar©, of course, obtainable, but the above are typical of ordinary practice. The temperatures are the maximum for automatic re- sta rting. The total overflow area should in a lifting injector be in excess of the total steam inlet area. If there are a plurality of overflow apertures in the combining nozzle