Stainless steel water ring pump for textile machinery
The water ring pump was initially used as a self-suction pump. It is composed of impeller, pump body, suction and exhaust disc, water ring, suction port, exhaust port and auxiliary exhaust valve formed by water in the inner wall of pump body.
In many industrial processes, such as vacuum filtration, vacuum water diversion, vacuum feeding, vacuum evaporation, vacuum concentration, vacuum moisture regain and vacuum degassing, water ring pumps are widely used. Due to the rapid development of vacuum application technology, the water ring pump has been attached great importance in obtaining rough vacuum. Because the gas compression in the water ring pump is isothermal, it can extract flammable and explosive gases, in addition, it can also extract dust and water containing gases. Therefore, the application of the water ring pump is increasing.
The pump body is equipped with appropriate amount of water as working fluid. When the impeller rotates clockwise in the figure, the water is thrown around by the impeller. Because of the centrifugal force, the water forms a closed ring which is approximately equal in thickness depending on the shape of the pump chamber. The inner surface of the lower part of the water ring is just tangent to the hub of the impeller, and the upper inner surface 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-shaped space is formed between the hub and the water ring of the impeller, which is divided into several small cavities equal to the number of blades by the impeller. If the lower part of the impeller is 0 degree as the starting point, the volume of the small chamber increases from small to large when the impeller rotates 180 degrees, and is connected with the suction port on the end surface. At this time, the gas is absorbed, and at the end of the suction, the small chamber is isolated from the suction port; when the impeller continues to rotate, the small chamber becomes smaller and compresses the gas; when the small chamber is connected with the exhaust port, the gas is discharged out of the pump.
In summary, the water ring pump relies on the volume change of the pump chamber to achieve aspiration, compression and exhaust, so it belongs to the variable-volume vacuum pump.
The impeller is eccentrically installed in the pump body. When the impeller rotates, the water entering the pump body is thrown around by the impeller. Because of the centrifugal force, the water forms a closed water ring with the same thickness as the shape of the pump chamber. The upper inner surface of the water ring is just tangent to the hub of the impeller, and the lower inner surface of the water ring is in contact with the top of the blade. At this time, a one-month conodont space is formed between the hub and the water ring of the impeller, which is divided into several small cavities equal to the number of blades by the impeller. If the starting point is 0 degrees above the impeller, the volume of the small chamber gradually increases from small to large and the pressure decreases continuously when the impeller rotates 180 degrees before rotation, and it is connected with the suction port on the suction and exhaust disc. When the pressure in the small chamber space is lower than the pressure in the sucked container, according to the principle of gas pressure balance, the sucked gas is continuously pumped into the small chamber, which is in the suction process. When the suction is completed, it is isolated from the suction port. From section II-II to section III-III, the volume of the small chamber is gradually decreasing, and the pressure is constantly increasing. At this time, it is in the process of compression. When the compressed gas reaches the exhaust pressure ahead of time, it is exhausted from the auxiliary exhaust valve ahead of time. From section III-III to I-I, the volume of the small chamber connected with the exhaust port further reduces the pressure and further increases. When the pressure of the gas is greater than the exhaust pressure, the compressed gas is discharged from the exhaust port. During the continuous operation of the pump, the process of suction, compression and exhaust is continuously carried out, so as to achieve the purpose of continuous exhaust.
The structure is simple, the manufacturing accuracy is not high, and it is easy to process.
Compact structure, high pump speed, generally can be directly connected with the motor, without the need for deceleration device. Therefore, with a small structure size, we can get a large amount of exhaust gas and occupy a small area.
Compressed gas is basically isothermal, that is, the temperature change of compressed gas is very small.
Because there is no metal friction surface in the pump chamber, there is no need to lubricate the pump, and the wear is very small. The sealing between the rotating part and the fixing part can be accomplished directly by the water seal.
Inhalation uniformity, stable and reliable work, simple operation, easy maintenance.
The efficiency is low, generally about 30%, better up to 50%.
The low vacuum degree is not only limited by the structure, but also by the saturated vapor pressure of the working fluid. Using water as working fluid, the limit pressure can only reach 2000-4000Pa. Oil can be used as working fluid up to 130 Pa.
In short, because the gas compression in the water ring pump is isothermal, it can extract flammable and explosive gases. Due to the absence of exhaust valves and friction surfaces, dust-laden gases, condensable gases and gas-water mixtures can be removed. With these outstanding characteristics, it has been widely used in spite of its low efficiency.
Because of its compact structure, reliable working balance and uniform flow rate, it is often used to transport or suck inflammable, explosive and corrosive gases in chemical production. Water ring vacuum pump has a low efficiency because of the large energy loss caused by the impeller mixing liquid.