Four suggestions on the selection of liquid ring vacuum pump

1 The liquid ring vacuum pump should choose the specification with lower rotating speed as far as possible At present, the liquid ring vacuum pump is widely used in 2BV Series in China, which belongs to the axial suction and exhaust single action pump There are many rotating speeds for the same specification When the inlet pressure is 200 hPa ~ 600 HPA and the exhaust pressure is 800 HPA ~ 1013 HPA, the linear speed of the outer circle of the impeller blade should be 14 ~ 17 m / s Because of the large impeller diameter, the rotating speed of the larger pump is lower Therefore, on the premise of reaching the same pumping capacity, the pump with lower rotating speed should be selected as far as possible The specific power consumed by the larger pump is smaller, that is, the efficiency is higher In addition, the energy loss caused by the secondary vortex and boundary layer in the flow of fluid is also small 2 The influence of water temperature on liquid ring vacuum pump should be considered Because the performance curve and technical data on the technical documents of liquid ring vacuum pump at home and abroad are all obtained on the premise that the inlet water temperature is 15 ℃, the calculation formula of the influence coefficient of water temperature on gas volume when the water temperature is lower or higher than 15 ℃ has been introduced previously Therefore, the influence of the actual water temperature on the gas volume should be fully considered when selecting the liquid ring vacuum pump Because the temperature of most users' make-up water in our country is between 25 ℃ and 35 ℃ Therefore, the air volume in pump selection shall be increased properly compared with that in technical documents 3 Influence of suction resistance of liquid ring vacuum pump Because the gas suction place is often under the coal well, far away from the liquid ring vacuum pump (some coal mines are thousands of meters), and the suction pipeline is too long, so the suction resistance loss should be fully considered It can be calculated by the formula used in the coal mine system to calculate the suction resistance When arranging the pipeline, the thicker suction pipe should be used to reduce the resistance loss and reduce the right angle elbow as much as possible In order to improve the efficiency of inhalation 4 Type selection when there is micro positive pressure in the exhaust of liquid ring vacuum pump At present, some coal mines need to discharge the gas removed to a far place or compress it into the gas storage tank, and the exhaust pressure is generally between 0.02 and 0.05 MPa · G As the performance curve and technical data in the technical documents of liquid ring vacuum pump are obtained under the condition that the exhaust pressure is 1 standard atmospheric pressure, the influence of the increase of exhaust pressure and the increase of return flow inside the pump cavity on the pumping capacity should be considered in the selection In addition, as the exhaust pressure increases, the shaft power of the pump increases, and the power of the matched driving machine should also increase In this case, the manufacturer should provide the test performance curve and corresponding technical data during the selection, so as to fully meet the requirements of the user.