vacuum pump (vakuumpump)

A pump consisting of a chamber or barrel, a suction pipe with a valve to prevent return flow, a discharge-pipe which has a valve that is closed when the chamber is emptied, and a steam induction-pipe provided with a valve that is opened when the chamber is filled with water, and closed when the chamber is filled with steam. The chamber is placed at such a height above the water to be raised that the exterior atmospheric pre ure will cause the water to rise through the suction-pipe, and fill the partial vacuum caused by condensation of steam in the chamber. Steam being admitted to the chamber forces out the air, and fills the space. The induction-valve is then closed. The lo of heat from the surface of the cylinder, or the sudden injection of a water-spray, condenses the steam. Water then rises, and fills the chamber. Steam is then again admitted, forcing out the water through the discharge-pipe. As soon as the water is discharged and the chamber refilled with steam, the cycle of operations recommences, and it is repeated continuously as long as steam is supplied to the chamber. The opening and closing of the valves have been made automatic in this cla of pumps, but they are so wasteful of power that they are very little used. See cuts under monte - jus and pulsometer. Also called steam vacuum - pump.