Roots Vacuum Pumps

Roots pumps are rotary plunger type pumps where two symmetrically shaped impellors rotate in contrary directions in the pump housing. Because of insufficient friction in suction chamber the roots vacuum pump is usually capable of operating at high speeds. The roots pumps operate at the high Air Vacuum Pump china speeds certainly quietly due to insufficient reciprocating mass which also provides reliable powerful balancing. As fore vacuum pumps can be used rotary vane, rotary piston, screw and liquid band pumps. This types of combined pumps can be utilized in all areas where the rough, moderate vacuum and high pumping speeds are needed.

Roots pumps are dry-jogging vacuum pumps and will pump great volumes. In blower procedure you can reach vacuum to approx. 0.5 bar a (as an individual aggregate). In the execution as a high-vacuum blower vacuums are reached up to 10-3 mbar a, but only in combination with the right pre-vacuum pump. As pre-vacuum pumps can 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 mixture with ejectors (accessible final pressure approx. 1 mbar a).
Roots pumps, in mixture with suitable pre-vacuum pumps, are found in particular when in a nutshell evacuation times closed volumes are to be evacuated or constantly big volume streams should be charged. Where the suction house 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 could be started up as a 2. Stage. The suction house of this roots pump could be up to 10 moments larger as the suction property of the pre-vacuum pump.

In a Roots vacuum pump, an inlet port is located at a posture 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 port is located at a position o opposing to the inlet interface relative to the line. An surroundings feed interface is formed at a posture t on a casing wall structure obtained by returning by 90° from the positioning o to the inlet port side to ensure that two closed areas are defined by adjacent rotor lobes and a casing internal wall at both port sides immediately after air suction respectively. The casing offers discharge grooves in an section of the inner wall so as to talk to the store port. The area ranges from the positioning o to a posture u obtained by returning by 45° from the positioning o to the inlet port part. The discharge grooves possess a total volume ranging from 2% to 5% of a level of among the closed spaces.