How to select liquid ring vacuum pump
How to choose liquid ring vacuum pump to meet our requirements?
In recent years, the industry has carried out a long-term exploration and research to solve the problem of anti-corrosion of vacuum pump products, in which liquid ring vacuum pump is favored by the market due to its advantages of energy saving and wide range of corrosion resistance.
It is reported that the liquid ring vacuum pump has the advantages of excellent corrosion resistance, compact structure, energy saving, high efficiency and reliable operation due to the small proportion, high strength and wide range of corrosion resistance of the materials used, which solves the disadvantages of the original vacuum pump products, and is suitable for pumping or compressing air, corrosive gas and slag water, organic and liquid without suspended particles or crystallization, which are widely used In chemical, pharmaceutical and other industrial fields, used in vacuum suction, vacuum filtration, vacuum drying, vacuum concentration, vacuum evaporation, vacuum distillation, vacuum crystallization and plastic molding.
It is pointed out in the industry that, especially for the by-product gases such as hydrogen chloride, which often appear in chemical and pharmaceutical enterprises, the use of corrosion-resistant liquid ring vacuum pump can effectively pump and compress these corrosive gases to form high concentration hydrochloric acid and other by-products, which not only meet the requirements of environmental protection, but also form a circular economy.
At present, there are many types of liquid ring vacuum pump in the market. Many customers report that they don’t know how to select. In this regard, the technical personnel of an enterprise gave four suggestions on the selection of liquid ring vacuum pump, hoping to provide reference for the industry.
Try to choose a lower speed specification
It is understood that at present, there are many rotating speeds for the same specification of liquid ring vacuum pump in China. Among them, the larger pump impeller diameter is large, so the speed is low, so on the premise of reaching the same air extraction, we should try to choose the vacuum pump with lower speed, so the specific power consumption is smaller and 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.
The influence of water temperature should be considered
It is reported that the performance curve and technical data on the technical documents of the liquid ring vacuum pump at home and abroad are obtained on the premise that the water inlet temperature is 15 ℃. Therefore, the influence of the actual water temperature on the gas volume should be fully considered when selecting the liquid ring vacuum pump.
According to the industry, the temperature of most users’ supplementary water in China is between 25 ℃ and 35 ℃. Therefore, when selecting the vacuum pump, the air volume should be increased properly compared with that in the technical documents.
Consider the effect of suction resistance
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, 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 the pipeline is arranged, the thicker suction pipe should be used to reduce the resistance loss and reduce the right angle elbow as far as possible To achieve the purpose of improving the inspiratory efficiency.
Selection of exhaust with micro positive pressure
It is reported that at present, some coal mines discharge the gas 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 vacuum pump cavity on the air extraction volume should be taken into account in the selection.
In addition, as the exhaust pressure increases, the shaft power of the vacuum 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.
