The design and operating principle of Roots vacuum pumps

A roots vacuum pump compresses and exhausts through rotation of a helical motor. The mechanical vacuum pump also known as the mechanical booster pumps increase the exhaust rate once mounted to oil sealed rotary front edge. The roots vacuum pump works alongside a vacuum pump that should compress up to stay in line with the atmospheric pressure. Such vacuum pumps include oil sealed rotary vacuum pump, dry vacuum pump or liquid ring vacuum pump.

- The design :

Rotor shaft bearing arrangements are in the side covers. The manufacturer designs them as fixed bearings on its one side and as movable on the other side to facilitate unequal thermal expansion between the rotor and the housing. The oil displaced to the gears and bearings by splash discs lubricate this pumps bearing.

In the standard versions, radial shaft seal rings immersed in sealing oil and made of FPM seals the drive-shaft feed through to the exterior. To ensure sufficient protection on the shaft, the manufacturers ensure that the sealing rings run on a protective sleeve ring that you can replace when worn out. A permanent pairing with a can also drives the pump if there is need of hermetic seal to the outside.

- The operating principle: 

The operating principle of roots vacuum pumps corresponds with that of multistage pumps. In these pumps, two synchronously pumps with counter-rotating rotors, rotates with no contact in housing. These rotors have an eight-figure configuration and separated from each other and from the stator by a narrower gap. A motor drives one of the shafts while pair of gear in the gear chamber synchronizes the other shaft.

The gear chamber and the two bearings have limited lubrication due to their sealing off from the suction chamber by labyrinth seals, which also bear compression rings. There is no friction in the suction chamber and therefore a root vacuum pump can operate at very high speeds which range between 1500 and 3000rpm. Since there are no reciprocating masses there is trouble free dynamic balancing. This means that the pumps do operate quietly despite their high speed.

Roots vacuum pumps are more suitable for applications in medium and lower vacuum. Therefore their usage is high in;

- Application :

Roots vacuum pumps are more suitable for applications in medium and lower vacuum. Therefore their usage is high in;

· Semiconducting and coating industries

· Research and development industries and

· Chemical and processing technologies

The manufacture may tailor the pumps to specific customer requirements. This may include specification of speeds or versions. Furthermore, roots vacuum pumps need a backing pump designed for gas stream and also suitable for the application.

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