Water ring vacuum pump overview

Overview Vacuum pumps are used in many processes that modern industry produces, such as vacuum filtration, vacuum diversion, vacuum feeding, vacuum evaporation, vacuum concentration, vacuum rejuvenation, and vacuum degassing. Water ring vacuum pump has always been paid attention as a simple structure, low manufacturing precision, environmental protection, and the use environment is not harsh. With the rapid development and application of vacuum application technology and the improvement of technology, the application of water ring vacuum pumps will surely increase. The water ring vacuum pump is a rough vacuum pump. Since people usually use water as a working medium, it is often referred to as a water ring pump. The water ring pump moves the water (liquid) to the stator wall by means of an eccentric rotor that fixes the blades inside. The water (liquid) forms a liquid ring that is concentric with the stator. The liquid ring and the rotor blade together constitute a variable volume rotary volumetric vacuum. The device, which can achieve the ultimate vacuum of 2000 ~ 4000Pa, tandem atmospheric ejector up to 270 ~ 670Pa. Water ring vacuum pumps can also be used as compressors, known as water ring compressors, which are low pressure compressors with a pressure range of 0.1 to 0.2 MPa gauge pressure. The water ring vacuum pump was originally used as a self-priming pump and gradually used in many industrial sectors such as petroleum, chemicals, machinery, mining, light industry, medicine and food.

The principle starts with a suitable amount of water as a working fluid in the pump body. When the impeller rotates clockwise in the direction indicated in the figure, the water is thrown around by the impeller. Due to the effect of centrifugal force, the water forms a closed loop of approximately equal thickness depending on the shape of the pump chamber. The inner surface of the upper part of the water ring is just tangent to the impeller hub, and the lower inner surface of the water ring is just in contact with the tip of the blade (in fact, the blade has a certain depth of insertion in the water ring). At this time, a crescent-shaped space is formed between the impeller hub and the water ring, and this space is divided into several small cavities with equal number of blades by the impeller. If the starting point of the upper part of the impeller is 0°, then the volume of the small cavity will increase from small to large when the impeller rotates 180°, and it will communicate with the suction port on the end face. At this time, the gas is sucked in. When the suction is finished, the small cavity It is isolated from the suction port; when the impeller continues to rotate, the small cavity changes from large to small and the gas is compressed; when the small cavity communicates with the exhaust port, the gas is discharged from the pump.

Features Advantages: Simple structure, low manufacturing precision, easy to process, compact structure, high number of rotations of the pump, generally can be directly connected with the motor, no need of deceleration device; the compressed gas is basically isothermal, that is, the temperature of the compressed gas process changes Very small; Because there is no metal friction surface in the pump cavity, it is not necessary to lubricate the pump, and the wear is very small; the seal between the rotating part and the fixing part can be directly completed by the water seal; the suction is even and the operation is stable and reliable. It is simple and easy to maintain; because the gas compression in the water ring vacuum pump is isothermal, it can extract flammable and explosive gas; because there is no exhaust valve and friction surface, it can remove dusty gas, condensable Gas and gas water mixture.

Disadvantages: low efficiency, generally about 30%, better up to 50%; low vacuum, not only because of the structural restrictions, but more important is the saturated vapor pressure of the working fluid. With water as the working fluid, the ultimate pressure can only reach 2000~4000Pa. With oil as working fluid, up to 130Pa.