Liquid ring vacuum pump is the most common type of vacuum pump. The liquid ring vacuum pump is a multi-blade rotor eccentrically mounted in the pump housing. When it rotates, the liquid is thrown into the pump shell and a liquid ring concentric with the pump shell is formed. The liquid ring and the rotor blade form a rotating variable volume vacuum pump with periodic volume change. When working liquid is water, it is called liquid ring vacuum pump.
The liquid ring vacuum pump is mainly used in the process of rough vacuum and large pumping capacity. It has been widely used in chemical industry, petroleum, light industry, medicine and food industry, such as vacuum filtration, vacuum feeding, vacuum concentration, vacuum degassing, etc.
The limit pressure of single-stage liquid-ring vacuum pump can reach 8-2*103Pa, the limit pressure of double-stage liquid-ring vacuum pump can reach 1*102 Pa, and the exhaust capacity is 0.25-500 m3/h.
How does the liquid ring vacuum pump work:
When the working wheel of the liquid ring vacuum pump rotates in the pump body, a water ring and a working chamber are formed. Water ring and working wheel form crescent space. The right half-moon-shaped volume changes from small to large, forming an inspiratory chamber. The volume of the left half-moon shape changes from large to small, forming a compression process (equivalent to the exhaust chamber). The exhausted gas enters the suction chamber through the intake pipe and the intake port. The rotor rotates further so that the gas is compressed and discharged through the exhaust port and exhaust pipe 7. The discharged gas and water droplets enter the water tank through the exhaust pipeline. At this time, the gas is separated from the water. The gas is discharged into the atmosphere through the pipeline. The water is discharged into the pump from the water tank or into the drainage equipment through the pipeline.
The compression ratio of the liquid ring vacuum pump is determined by the end position of the suction port and the beginning position of the exhaust port. Because the end position of the suction port determines the volume of the suction chamber, and the beginning position of the exhaust port determines the volume of the compressed gas when the exhaust is exhausted. The compression ratio can be calculated for the liquid ring vacuum pump whose structure size has been determined.
liquid ring vacuum pumps types :
(1) Single-stage single-acting liquid ring vacuum pump: single-stage refers to only one impeller, single-acting refers to the impeller every rotating week, suction and exhaust once. This kind of pump has higher limit vacuum, but lower pumping speed and efficiency.
(2) Single-stage double-acting liquid ring vacuum pump: single-stage refers to only one impeller, double-acting refers to the impeller every rotation of a week, suction, exhaust twice. Under the same pumping speed, the size and weight of double-acting liquid-ring vacuum pump are much smaller than that of single-acting liquid-ring vacuum pump. Because the working chamber is symmetrically distributed on both sides of the pump hub, the load acting on the rotor is improved. The pumping speed and efficiency of this kind of pump are higher, but the limit vacuum is lower.
(3) Two-stage liquid-ring vacuum pump: Most of the two-stage liquid-ring vacuum pumps are single-acting pumps in series. Essentially, the impellers of two single-stage single-acting liquid ring vacuum pumps are joined together by a common spindle. Its main characteristic is that it still has a large pumping speed at a higher vacuum, and its working condition is stable.
(4) Atmospheric liquid ring vacuum pump: Atmospheric liquid ring vacuum pump is actually a set of air ejector series liquid ring vacuum pump. The air pump in series in front of the liquid ring vacuum pump is designed to improve the limit vacuum and expand the scope of use of the pump.
liquid ring vacuum pump advantages:
(1) The structure is simple, the manufacturing accuracy is not high, and it is easy to process. Simple operation and convenient maintenance.
(2) Compact structure, the pump is usually directly connected with the motor, and the speed is high. With smaller structure size, larger exhaust volume can be obtained.
(3) There is no metal friction surface in the pump chamber, so there is no need to lubricate the pump. The sealing between the rotating part and the fixing part can be accomplished directly by the water seal.
(4) The temperature change of the compressed gas in the pump chamber is very small, which can be regarded as isothermal compression. Therefore, flammable and explosive gases can be removed.
(5) Because there is no exhaust valve and friction surface, dust-laden gas, condensable gas and gas-water mixture can be removed.
The liquid ring vacuum pump has the outstanding advantages of isothermal compression and water sealing. It can extract flammable, explosive and corrosive gases. It can also extract gases containing dust and water, so it has been widely used.