Water-ring vacuum pump is a kind of coarse vacuum pump. The ultimate vacuum it can obtain is limited by the structure and working environment, generally 3-50 kPa. Water ring vacuum pump mainly consists of impeller, pump body, disc (with suction port, exhaust port) and other parts. As shown in Fig. 1, the impeller is eccentrically installed in the pump body. When the impeller rotates, water is thrown to the pump body and forms a water ring concentric with the pump body. The water ring and the impeller form a one-month conodont space. As the impeller rotates, the cavity formed by the hub, blade and water ring of the impeller changes from small to large. It is sucked through the suction port, then from large to small, and exhausted through the exhaust port.
Water ring vacuum pump is a kind of energy conversion equipment which converts kinetic energy (mechanical energy) into potential energy (gas compression energy), rather than general energy transmission equipment (such as reducer). In the process of production and use of water-ring vacuum pump, more attention is paid to the gas flow and shaft power of the pump under a certain inlet pressure. The performance characterization of water-ring vacuum pump also refers to two curves of gas flow and shaft power relative to the inlet pressure. Therefore, the pumping capacity K Q of unit shaft power is used to express the energy efficiency of water-ring vacuum pump at a certain inlet pressure point, which is easy to calculate and use, and can directly reflect the performance of water-ring vacuum pump.