Advantages and disadvantages of water ring vacuum pump

Working principle of water ring pump: the pump body is filled with appropriate amount of water as working fluid When the impeller rotates clockwise according to the direction indicated in the figure, the water is thrown around by the impeller Due to the centrifugal force, the water forms a closed ring of approximately equal thickness, which is determined by the shape of the pump cavity The inner surface of the upper part of the water ring is just tangent to the impeller hub, and the inner surface of the lower part of the water ring is just in contact with the top of the blade (in fact, the blade has a certain insertion depth in the water ring) At this time, a crescent 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 upper 0 ° of the impeller is taken as the starting point, the volume of the small cavity will increase from small to large when the impeller is 180 ° before rotation, and it is connected with the suction port on the end face At this time, the gas will be inhaled, and when the suction is finished, the small cavity will be isolated from the suction port; when the impeller continues to rotate, the small cavity will change from large to small, so that the gas will be compressed; when the small cavity is connected with the exhaust port, the gas will be discharged out of the pump Advantages of water ring vacuum pump: 1 Simple structure, low manufacturing accuracy requirements, easy processing 2 Compact structure, high number of pump revolutions, generally can be directly connected with the motor, no reduction device Therefore, with a small structure size, a large exhaust volume can be obtained, and the floor area is also small 3 Compressed gas is basically isothermal, that is, the temperature change of compressed gas process is very small 4 Because there is no metal friction surface in the pump cavity, there is no need to lubricate the pump, and the wear is very small The seal between the rotating part and the fixed part can be directly completed by the water seal 5 The suction is even, the work is stable and reliable, the operation is simple, and the maintenance is convenient Disadvantages of water ring vacuum pump: 1 Low efficiency, generally around 30%, better up to 50% 2 The low vacuum degree is not only limited by the structure, but also by the saturated vapor pressure of working fluid When water is used as working fluid, the limit pressure can only reach 2000-4000pa Using oil as working fluid can reach 130pa