How Does A Roots Vacuum Pump Work?

The roots vacuum pumps are positive displacement pumps is without contraction. Depending on the different working pressure range of roots vacuum pumps,  it can be divided into two stages: Multistage roots vacuum pumps and Single-stage root vacuum pumps.

The single-stage roots vacuum pump is worked as a booster pump for several types of fore pumps to help them improve the final pressure and pumping speed.

On the other hand, the multi-stage roots vacuum pumps are used in a high, low, medium and ultra-high vacuum system to produce the dry state.

When multistage roots vacuum pumps are working, no fore pump is needed and they can function from atmospheric pressure. Where a dry atmosphere is essential, roots vacuum pumps are required.

Working Principle Of Roots Vacuum Pumps:

In the simplest form of root vacuum pumps, it applies two counter-rotating interlinked “lobed’ rotor units which are rotating within a chamber. Gas enters through an air input placed perpendicular to the

Cylinders and rotators, and then isolated between rotating rotors, which are spinning in the opposite direction. Then the compressed gas expelled through the air discharge port.

Using this model of a roots vacuum pump, a multi-stage roots vacuum pumps apply several sets of rotors. The shape of the rotors creates compression and each stage of a pump produces gradually higher pressure.

Like this, the result of a lower stage is the supplier of gas for the next higher stage, but without interlinking valves.

Advantages and Disadvantages of Roots Vacuum Pumps:

Multistage roots vacuum pumps have many advantages over the other vacuum pumps and a few disadvantages.

Multistage roots vacuum pumps are very compact and calm, enjoy a long-lasting service life, have no connection between moving parts.

However, Multistage roots vacuum pumps have some disadvantages like comparatively high atmospheric pressure. In addition, they can only achieve a slight pressure difference, which is the reason they are employed in a multistage structure where each progressive stage can build upon the pressure enhance achieve from the compression of the previous stage.


  • Compact design
  • Robust
  • Long service intervals and economical
  • Lower noise level
  • Safe and Reliable
  • No connection between moving parts
  • Clean pumping


  • Higher service cost
  • Not suitable for pumping liquids


To know more about the Roots Vacuum Pumps get in touch China Vacuum Pump.

Call us on 0086-571-87870085.