First, the classification of water ring vacuum pump 1, single-stage single-action water ring pump single-stage single-action water ring pump, single stage is only one impeller, single role refers to the impeller every one revolution, inhalation, exhaust once. The pump has a higher ultimate vacuum but lower pumping speed and efficiency. 2, single-stage double-acting water ring pump single-stage double-acting water ring pump, single stage is only one impeller, double role refers to the impeller every rotation, inhalation, exhaust twice. In the same pumping speed conditions, double-acting water ring pump than the single-action water ring pump greatly reduce the size and weight. Since the working chambers are symmetrically distributed on both sides of the pump hub, the load acting on the rotor is improved. Pump pumping speed larger, higher efficiency, but the lower limit of the vacuum. 3, two-stage water ring pump Two-stage water ring vacuum pump is mostly single-acting pump in series. Essentially two single-stage single-role water ring pump impeller shared a mandrel. Its main feature is still in a higher degree of vacuum, there is still a large pumping speed, and stable working conditions. 4, atmospheric water ring pump atmospheric water ring pump is actually a series of atmospheric ejector water ring pump unit. Water ring pumps in series in front of the pump is to increase the ultimate vacuum, expanding the use of the pump. Second, the advantages of water ring vacuum pump 1, the structure is simple, manufacturing precision is not demanding, easy processing. Simple operation, easy maintenance. 2, compact structure, the pump is generally directly connected with the motor, the higher the number of revolutions. With a smaller structure size, you can get a larger displacement. 3, there is no metal friction surface of the pump cavity, no need to lubricate the pump. Sealing between the rotating part and the fixing part can be completed by the water seal directly. 4, the pump chamber compressed gas process temperature changes is small, can be considered isothermal compression, it can be extracted flammable, explosive gas. 5, because there is no exhaust valve and friction surface, it can be removed with the gas dust, condensable gas and gas mixture. Third, the shortcomings of water ring vacuum pump 1, low efficiency, generally about 30%, better up to 50%. 2, low vacuum. This is not only due to the structural limitations, but more importantly, the saturated vapor pressure of the working fluid. Overall, the water ring vacuum pump has isothermal compression and water for sealing liquid, you can remove flammable, explosive and corrosive gases, but also can remove the dust and moisture containing gas and other outstanding advantages, so get a wide range of application.