The difference between single-stage rotary vane pump and two-stage rotary vane pump
What is the difference between single-stage rotary vane pump and two-stage rotary vane pump? It doesn't matter who you don't know, so I'll introduce you.
Rotary vane vacuum pumps, vacuum coating available, the light bulb, thermos bottle, tube, medical, chemical, and laboratory and other vacuum operation, this pump can be used alone, also can be used as booster pump, diffusion pump, molecular pump backing pump.
There are some differences between the former pump and the latter pump. The pump cavity of the latter pump is larger than that of the former pump, because the pumping speed of the pump is mainly determined by the effective geometric volume of the latter pump. In addition, the front pump and the single-stage rotary vane pump, at any time oil into the pump chamber; Only a small amount of oil is available at the beginning of the pump.
After a period of work, no oil enters the pump cavity. After doing this will not affect the performance of the pump, because the extraction time grows, the pump inlet pressure drop greatly, and its export pressure are also small, import and export of the pressure difference is not big, the compressed gas gap reflux quantity few, at the same time, in the case of high vacuum degree, the flow resistance of aperture is bigger, although there is no oil seal, but the amount of gas reflux rarely.
On the contrary, it has the following advantages:
The partial pressure of the residual gas can be greatly reduced by avoiding the pump oil bringing the gas and steam into the rear air inlet. At the same time, because the light fraction of oil in the later stage pump is continuously pumped away by the former stage pump, the residual oil vapor pressure is also reduced, which makes the ultimate vacuum of the pump be increased. The partial pressure of the gas was also reduced, which increased the ultimate vacuum of the pump.