According to the calculation, after the pumping speed of the vacuum pump is confirmed, the pump model must be carefully selected. For example, oil sealed mechanical pump with pumping speed of 150L / s, H-8 slide valve pump needs 17kw of driving power, while yz-150 cycloid pump only uses 13kw. If the latter is selected for long-term operation, it will save a lot of electric energy, and has small volume, light weight, small vibration and easy maintenance. At present, the transmission efficiency of the direct coupled pump is better than that of the V-belt drive.
Another example is oil diffusion pump, oil booster pump thermal efficiency is very low, long start-up time, will also consume a lot of energy and time, so can choose low evaporation latent heat oil as working fluid. In the heating system of the pump, the heat preservation measures should be strengthened to improve the oil return temperature. For example, the heating power of some pumps is reduced from 30kW to 20kW after the heat preservation measures are strengthened, and the pumping effect is the same. Then roots vacuum pump starts quickly, especially suitable for the system which starts frequently. If the oil booster pump or fault expansion pump is selected, the system will not stop the pump during the non working period, wasting energy in vain. The selection of maintenance pump is also a good way to save energy.
In the vacuum system of roots pump, the pressure difference between the outlet and the inlet of roots pump should not be too large, otherwise it will lead to excessive power consumption. The power consumption of the pump is proportional to the pressure difference. Usually, a small roots pump is always connected in series to greatly save power consumption.