EJECTOR. An apparatus which moves air, liquids, and loose materials such as sand, cinders, gravel, liquid clay and chemicals, by the eductive force of steam or compressed air. Inlets are arranged for the steam and the suction, and the former rushing along at high speed draws the air or other element with it. A simple form of ejector and its mode of piping to force water out of a pit or tank are shown in the figure. The draining of wells, foundations, quarries, and the emptying of ships' bilges and ballast tanks lie within the scope of an ejector.
The vacuum brake is operated with the help of an ejector on the engine, steam being admitted around the cones and passing through the ejector barrel at great velocity; this action with draws the air from the train-pipe and cylinders. This type really combines two ejectors in the body, a small one that works con tinually to maintain the vacuum, and a large one for rapid pro duction of the vacuum. Another type, for securing economy in steam consumption against greatly varied working conditions of trains of different classes, has two small ejectors, one or both being used to keep the vacuum up, the large ejector still being employed for rapid working.
Other sorts of ejectors are those in which compressed air is applied to the surface of a liquid, as in the Shone apparatus (see AIRLIFT), and the air-ejector employed in connection with a condenser (q.v.) One type of condenser used in conjunction with steam engines is the ejector condenser. Sometimes water is fed in large volumes by the eductive action of a high-pressure jet of water. Mechanical ejectors include those in revolvers and guns which abstract the cartridge-case, and devices which push punched or stamped articles out of the dies in power-presses, when they cannot fall away by gravity. Air-ejection is adopted in some cases, a blast of compressed air blowing the work into a chute, and also cleaning the die of dirt and scale. (See also INJECTOR.)
