1. choose the lower speed specifications:
At present, China’s liquid ring vacuum pump is the most widely used 2BE series, it is a single suction axial suction pump. There is a variety of speed options for the same specifications , when the inlet pressure at 200 hPa ~ 600 hPa, the exhaust pressure of 800 hPa ~ 1013 hPa, the linear velocity of the impeller outer circumference should be 14 ~ 17 m / s, the larger size of the pump impeller diameter with lower speed, in order to achieve the same exhaust volume under the premise,it will be better to choose low speed pump, large pump consumes less power, that is more efficient.
In addition, the larger liquid ring vacuum pump due to long blade( long flow path), small fluid curvature, the flow line is approximately linear, the flow of fluid close to the slow flow, fluid flow in the secondary vortex and the formation of the surface layer The energy loss is also small.
2. Consider the impact of water temperature:
As most liquid ring vacuum pump technical documents of performance curve and technical data are obtained under the premise of the inlet temperature is 15 ℃, the water temperature is below or above 15 ℃ has Influence on capacity.
Therefore, the election water ring vacuum pump should be given full consideration to the actual water temperature on the gas volume. Because most of our users to add water temperature is between 25 ℃ ~ 35 ℃. Therefore, the pump should be selected bigger when the gas volume on the appropriate increase in technical documents.
3. the impact of inspiratory resistance:
As the gas gas suction sites are often below the coal mine, far away from the liquid ring vacuum pump (some coal mines up to several kilometers), the suction line is too long, it should take full account of suction resistance loss can be used by the coal mining system Calculate the formula of suction resistance calculation, the layout of the pipeline should be used thick suction pipe to reduce the resistance loss, and minimize the right-angle elbow, in order to achieve the purpose of improving suction efficiency.
4.Select pump when exhaust with a slight positive selection:
At present, some coal mines discharge gas to farther places or compress to gas storage tanks, and the exhaust pressure is generally between 0.02 and 0.05 MPa.G. As liquid ring vacuum pump technical documents in the performance curve and technical data are based on one standard atmospheric pressure derived. So the exhaust pressure increases, the pump cavity reflux Large impact on the amount of exhaust should be taken into account .
In addition, with the exhaust pressure increasing, the pump shaft power increasing and with the drive power should also increasing. in this case, the manufacturer should provide test performance curve and the corresponding technical data selection to Fully meet the user’s requirements.
Edited by Nancy Zhang / EVP vacuum solution