How Do Rotary Vane Pumps Work?

What's The Working Principle for Rotary Vane Pumps and Compressors?

Rotary vane pumps are types of positive displacement pumps. In a cylindrical housing, the rotor is positioned eccentrically on the shaft so the rotor is positioned near the top of the cylinder. Rotor blades are positioned into numerous rotor slots. When the rotor starts turning, centrifugal force causes the blades to be thrown out and slide against the internal surface of the cylinder. A cell is formed between two blades with a volume that changes constantly during rotation. Air enters from the inlet port into a cell until the rear blade reaches the inlet port, at this point the cell has achieved its maximum air volume.

As the air cell then moves away from the port, its volume becomes smaller and smaller. The air is compressed and the pressure rises. This continues until the pressure in the cell exceeds that in the pressure chamber. The air then exits through the outlet port.

Some models are fitted with exhaust valves that stop the backflow of this discharged air if the maximum pressure has been reached. In a rotary vane vacuum pump, the process is similar, but the air cell gives decreasing pressure and the chamber is at atmospheric pressure.

Rotary vane pumps - working principle

The cylindrical pump head has a rotor with slots for pump blades. The pump uses centrifugal force to push and slide the vanes against the head's wall, creating a gap between the two vanes and the cylinder. As the rotor turns, it moves the gap and compresses the volume of the gas, increasing the pressure and creating a vacuum.

Gain more technical insights on rotary vane pumps in the knowledge hub. 

What Are Rotary Vane Pumps Used For?

Rotary vane pumps and compressors are used for a broad range of applications. Thomas miniature rotary vane pumps are used in compression therapy, electrocardiogram, gas sampling, gas detection, water analysis, medical diagnostics, inkjet printing, and vacuum pick and place.

The larger pumps and compressors from the PICOLINO series are used for vacuum handling, air and gas sampling & analyzers, lab instrumentation and automation, food & beverage packing, medical devices.

What Are The Benefits of Rotary Vane Pumps and Compressors?

  • Suitable for pressure or vacuum
  • Wetted parts made from gray cast iron, carbon, stainless steel, and plastic
  • Self-lubricating and self-adjusting vanes
  • Good controllability
  • Nearly pulsation-free
  • Compact design
  • DC Models available– Some with the reversible operation
  • Good controllability
  • Low pulsation
  • Thomas rotary vane pumps provide flow rates up to 7 cfm (200 l/min), pressure up to 14.5 psi (1 bar), and vacuum up to 25.0 in.Hg (-850 mbar)

Browse Thomas Rotary Vane Pumps and Compressors

Select Flow Rate (l/min

up to 1 LPM
1-5 LPM
5-10 LPM
10-20 LPM
20-30 LPM
30-50 LPM
50-100 LPM
above 150 LPM

Select Max. Vacuum

Up to 300mbar / 9 in.Hg
300-500 mbar / 9-14.75 in.Hg
500-800 mbar / 14.75-23.6 in.Hg
800-900 mbar / 23.6-26.6 in.Hg
Above 900 mbar / 26.6 in.Hg

Select Max. Pressure Level

Up to 1 bar/14.5 psi
1-2 bar/14.5-29 psi
2-5 bar/29-72.52 psi
5-7 bar/72.52-101.53 psi
7-10 bar/101.53-145 psi
above 10 bar/145 psi

Select Flow Rate (cfm)

up to 0.035 cfm
0.035-0.176 cfm
1-2 cfm
2-3 cfm
3-4 cfm
4-5 cfm
above 5 cfm

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