Roots Vacuum Pumps

Roots pumps are rotary plunger type pumps where two symmetrically shaped impellors rotate in opposite directions inside the pump housing. Due to insufficient friction in suction chamber the roots vacuum pump can be capable of operating at high speeds. The roots pumps operate at the high speeds completely quietly due to insufficient reciprocating mass which also provides reliable dynamic balancing. As fore vacuum pumps can be used rotary vane, rotary piston, screw and liquid ring pumps. This types of mixed pumps can be used in all fields where the rough, medium vacuum and high pumping speeds are required.

Roots pumps are dry-jogging vacuum pumps and may pump large volumes. In blower procedure you can reach vacuum to approx. 0.5 bar a (as a single aggregate). In the execution as a high-vacuum blower vacuums are reached up to 10-3 mbar a, but just in combination with a suitable pre-vacuum pump. As pre-vacuum pumps may be used, for example:

Single-stage essential oil lubricated rotary vane vacuum pumps (accessible final pressure approx. 10-2 mbar a)
Two-stage essential oil lubricated rotary vane vacuum pumps (accessible last pressure approx. 10-3 mbar a)
Liquid ring vacuum pumps, if necessary in combination with ejectors (accessible final pressure approx. 1 mbar a).
Roots pumps, in combination with suitable pre-vacuum pumps, are found in particular when in short evacuation occasions Air Vacuum Pump china closed volumes should be evacuated or constantly big quantity streams are to be charged. Where the suction home of the pre-vacuum pumps starts to drop (e.g., by single-stage essential oil lubricated rotary vane pumps with approx. 10 mbar), a roots pump can be started up as a 2. Stage. The suction house of the roots pump could be up to 10 instances bigger as the suction real estate of the pre-vacuum pump.

In a Roots vacuum pump, an inlet interface is located at a position n spaced by a positive displacement angle of 120° in one direction from a center of each rotational axis in accordance with an imaginary line m connecting rotor axes. An outlet slot is located at a position o opposite to the inlet port in accordance with the line. An air flow feed interface is formed at a posture t on a casing wall structure obtained by returning by 90° from the position o to the inlet port side to ensure that two closed areas are described by adjacent rotor lobes and a casing internal wall at both interface sides immediately after atmosphere suction respectively. The casing offers discharge grooves within an area of the inner wall structure so as to communicate with the wall plug port. The region ranges from the positioning o to a posture u obtained by returning by 45° from the positioning o to the inlet port side. The discharge grooves possess a total volume which range from 2% to 5% of a level of one of the closed spaces.