What is Oil rotary vacuum pumps？

Oil rotary vacuum pumps are positive displacement vacuum pumps that use oil to reduce the confidential and dead space between components such as the rotor, stator, and sliding vanes.

Features of Oil rotary vacuum pumps

This pump achieves high pumping performance by utilizing vacuum pump oil to smooth the movement of the rotating parts and to vacuum seal for the improvement of air tightness. It is the most efficient pump among the pumps that can operate effectively from atmospheric pressure to high vacuum. This pump is highly reliable and provides stable pumping performance in high vacuum.

Strength: low cost, compact, easy installation, and vacuum less than 10 pa can be easily obtained.
Weakness: The handling of vacuum pump oil is complicated.

Applications

Food, chucking, vacuum furnaces, leak systems, impregnation equipment, lasers, coatings, chemistry, medical treatment, central vacuum systems.

Mechanism of Oil rotary vacuum pumps

There are three types of oil rotary vacuum pumps.

1) Rotary vane type oil rotary vacuum pump.

The pump has two vanes on the rotor which is built inside the cylinder. This vane divides the inside of the cylinder into three spaces. The gas in the divided space is compressed as the rotor rotates, and is discharged to the atmosphere through the exhaust valve while changing periodically. Oil is used to lubricate and cool the bearings and to seal the vane and cylinder to enhance airtightness.

　Movie：Exhaust Principle

2) Cam type oil rotary vacuum pump.

An eccentric rotor is installed in the center of the cylindrical stator. The rotor rotates while part of the rotor contacts the stator. The blade (vane) which moves up and down to work as a seal for the intake and exhaust sides is installed. Vacuum pumping is performed by evacuating the space between the stator and rotor while the rotor makes one rotation.

3)Rocking Piston type oil rotary vacuum pumps.

The gas is transported by changing the volume of the space enclosed by the piston and cylinder. The volume of the space changes when the piston which slides on the guide oscillates up and down by the rotation of the eccentric rotor.