It condenses by means of the smallest possible quantity of cold water the largest possible quantity of exhaust steam and puts it into the boiler without the aid of any other power than the exhaust steam itself. It can be attached to any class of non-condensing engine, and its use increases the power both of the engine and boilers.
Figs. 534 and 535.
It is worked by waste steam, just as ordinary injectors are worked by live steam from the boiler.
The first cost and subsequent wear and tear of pumps are avoided. The power required to work pumps, of whatever construction, is saved: the exhaust injector doing the same work by the condensation of waste steam.
The waste steam, in passing through the injector, heats the feed-water to a temperature of about 190° F. The condensation in the injector of so large a quantity of waste steam reduces back pressure considerably, and necessarily increases the power of the engine.
It is not uncommon for these injectors to form a vacuum of a half-inch of mercury within the exhaust pipe, which of course helps the engine to that extent.
Fig. 536.—See page [260].
These injectors work with great success on stationary engines and boilers, also on steamers, tugs, dredges, etc., as their operation during the roughest weather is not affected by the motion of the vessel.