Water ring vacuum pumps have a high rotation speed, can be driven directly by a motor, and require no lubrication inside, right?

Water ring vacuum pumps have high rotational speeds; they can be driven directly by a motor, and no lubrication is required inside them

Yes. Driven directly by the motor, no lubrication is required.

Water ring vacuum pumps have a high rotation speed, can be driven directly by a motor, and require no lubrication inside, right? Answer: You are correct. Below are the advantages and disadvantages of rotary vacuum pumps for your reference: Compared with other types of mechanical vacuum pumps, water ring pumps have the following advantages: (1) Simple structure, low requirements for manufacturing precision, and easy to manufacture. (2) It has a compact structure, with a high rotational speed; it can generally be connected directly to the motor without the need for a reduction gear. Therefore, a small structural size can yield a large displacement, while also requiring less floor space. (3) Compressed gas is essentially isothermal, meaning that the temperature changes very little during the compression process. (4) Since there are no metal friction surfaces inside the pump chamber, no lubrication is required for the pump, and wear is minimal. The sealing between the rotating part and the fixed part can be achieved directly by a water seal. (5) Even air intake, stable and reliable operation, simple to use, and easy to maintain. Water ring pumps also have their disadvantages: (1) low efficiency, generally around 30%, with better ones reaching up to 50%. (2) The vacuum level is low, not only due to structural limitations but more importantly due to the saturated vapor pressure of the working fluid. Using water as the working fluid, the ultimate pressure can only reach 2000~4000 Pa. Using oil as the working fluid, a pressure of 130 Pa can be achieved. In short, since the gas compression in a water ring pump is isothermal, it is possible to pump out flammable and explosive gases. Due to the absence of exhaust valves and friction surfaces, it is possible to extract dusty gases, condensable gases, and gas-water mixtures. Thanks to these prominent features, it is still widely used despite its low efficiency.

A vacuum is created by water, which in turn provides sealing for the bearings