All About Engines

Raising Steam i°3 under the same pressure. These two principles are combined in the injector, in which a jet of steam draws up water from the well, which must not be more than 12 ft. deep and preferably less—and forces it into the boiler from which the steam is derived. There are a number of different makes, but the one illustrated (Fig. 58, Plate 6) is by Holden and Brooke, of Manchester. Steam enters at the top right-hand opening, which may be made larger or smaller or entirely closed by turning the lever at the top. The amount of the opening varies for different pressures, and the pointer on the right of the lever moves over a graduated circle which indicates the position for different pressures. The upper opening w on the left hand leads to the water tank, and the lower opening o allows for overflow. The pressure required is anything between 20 lb. and 180 lb. on the square inch. The diameter of the steam channel at its narrowest point in the smallest size is about inch, and in the largest t inch. The amount of water delivered depends upon the height from which it has to be lifted, the temperature, and the pressure of steam. With feed water at 115° Fahr, and a pressure of 160 lb. on the square inch the smallest size will deliver 141 gallons, and the largest 10,048 gallons per hour. That quan- tity is more than sufficient to satisfy the largest and most thirsty boiler that has ever been built, and the injector which will do it is as reliable as a pump, and it is lighter, cheaper, and more economical.