High vacuum pumps are used when the final absolute pressure required is very low.

These pumps may run continuously connected to closed containers to be emptied, and may not run continuously at length, at atmospheric pressure. The exhaust from these pumps is not filtered, thus, special purifiers are available for fumes.
The operating principle of the high vacuum pumps is like the lubricated rotary vane vacuum pumps one. However, in this case, the stator is immersed in the lubrification oil which has also the function of sealing the air loss. The pressure levels reached by this type of pumps are higher than any other rotary vane pump. These pumps are equipped with a gas ballast system to avoid the condensation of the water vapour.
The high vacuum pumps can be made of a single rotor-stator group (single stage) or they can be made of two rotor-stator groups connected in series, so the first group drain is connected to the second group intake system (double stage).

Main application fields