Single stage liquid ring vacuum pump and double stage liquid ring vacuum pump

There are many vacuum pump equipment, vacuum pump products also have many, vacuum pump products are divided into single-stage vacuum pump and two-stage vacuum pump, today EVP vacuum pump manufacturers mainly talk about single-stage liquid ring vacuum pump and two-stage liquid ring vacuum pump. It is convenient for everyone to choose a suitable vacuum pump according to the process better.

The liquid ring vacuum pump is composed of pump body, eccentrically mounted impeller and end cover (with suction port and exhaust port).

Single stage liquid ring vacuum pump and double stage liquid ring vacuum pump

2BV Series Liquid Ring Vacuum Pump

Curve No. Model Max. suction capacity Ultimate vacuum
Motor power
Operating liquidflow rate
m3/min m3/h
60V 2BV2-060 0.45 27 33mbar
0.81 2840 2.5 62 37
61V 2BV2-061 0.86 52 1.45 2840 2.5 65 41
70V 2BV2-070 1.33 80 2.35 2860 3 66 66
71V 2BV2-071 1.83 110 3.85 2880 4.7 72 85
110V 2BV5-110 2.75 165 4 1440 7.2 63 120
111V 2BV5-111 3.83 230 5.5 1440 8.8 68 150
121V 2BV5-121 4.66 280 7.5 1440 11 69 210
131V 2BV5-131 6.66 400 11 1460 16 73 280
161V 2BV5-161 8.33 500 15 970 22 74 390
110V 2BV6-110 2.75 165 4 1440 67 63 150
111V 2BV6-111 3.83 230 5.5 1440 10 68 200
121V 2BV6-121 4.66 280 7.5 1440 12 69 230
131V 2BV6-131 6.66 400 11 1460 17 73 315
161V 2BV6-161 8.33 500 15 970 23 74 426


The principle of single stage liquid ring vacuum pump is that the pump body is equipped with appropriate amount of water as working fluid. When the impeller rotates in the direction indicated, 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 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 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 monthly conodont space is formed between the hub and the water ring of the impeller, which is divided into thousands of 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 increases from small to large at 180 degrees before the impeller rotates, and is connected with the suction port on the end face (i.e. the end cover) T. At this time, the gas is absorbed (attention should be paid to the termination position of the suction port to ensure the maximum volume of the small chamber). 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 from large, and the gas is compressed. When the small chamber is connected with the exhaust port, the gas is discharged out of the pump.

Single stage liquid ring vacuum pump and double stage liquid ring vacuum pump

2SK Liquid Ring Vacuum Pump

Model Suction capacity Ultimate vacuum Power speed Water supply Inlet/outlet diam Water inlet
m³/min MPa(G) KW r/min L/min DN(mm) (mm)
2SK1.5 1.35 -0.097 4 1440 10-15 40 G1/2”
2SK-3 2.7 -0.098 7.5/11 1440 15-20 40 G1/2”
2SK-6 5.4 -0.098 15 1460 25-35 65 G1/2”
2SK-12 10.8 -0.098 22/30 970 40-50 100 G1/2”
2SK-20 18 -0.098 45 740 60-80 125 G3/4”
2SK-30 27 -0.098 55/75 740 70-90 125 G3/4”


The working principle diagram of the double-stage liquid ring vacuum pump is that the pump chamber is double eccentric relative to the impeller, which is approximately elliptical. When the impeller rotates, the inner surface of the water ring and the hub form two symmetrical crescent-shaped spaces. There are two suction ports and two exhaust ports on the end surface. Therefore, each small cavity around the rotor rotates to suck and exhaust twice.

In summary, the liquid ring vacuum pump relies on the change of the volume of the pump chamber to achieve aspiration, compression and exhaust, so it belongs to the variable volume vacuum pump.

It is worth noting that the end position of suction port and the start position of exhaust port of liquid ring vacuum pump determine the compression ratio of the pump. Because the termination position of the suction port determines the volume of the suction chamber, and the starting position of the exhaust port determines the volume of the compressed gas in the exhaust. The compression ratio can be calculated for the water ring pump whose structure size has been determined. Similarly, given the compression ratio, the end position of the suction port and the start position of the exhaust port can also be determined.

In the liquid ring vacuum pump, the energy of the compressed gas in the water ring is transmitted in this way: water is driven by the impeller to form a water ring, then the impeller transfers energy to the water to increase its kinetic energy, so that the water can rotate in the pump chamber at a certain speed. For single-acting liquid ring vacuum pumps, on the suction side (front 180). When the water buried in the impeller is accelerated by the impeller, when the water is thrown out from the impeller chamber, the water has a velocity similar to the tangent velocity of the blade endpoint; in the first half of the week, due to the constant pressure of the inhaled gas, the velocity of each point is equal. In the second half of the week, the gas is compressed, and when the water ring re-enters the impeller chamber, the velocity decreases, and a part of its kinetic energy is converted into potential energy (pressure energy) to resist the gas expansion pressure. When no-load incompressible gas is used, the kinetic energy of water in the second half of the cycle will accelerate the rotation of the impeller.

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