Vacunair’s Water Ring Vacuum Pump/Compressors

Bredel hose pumps from Watson-Marlow Fluid Technology Group (WMFTG) have replaced piston pumps on a series of prestigious €1.8 million concrete grouting projects performed in seas around the Chinese coastline.

The Bredel technology could overcome the leakage and wear problems, thus reducing costs through greater uptime and reduced maintenance and spare parts. In addition, a safer working environment would be created.

A balanced cylindrical rotor with hollow hub with series of curved blades running freely in eccentric casing. The sufficient sealing liquid, usually water, forms a solid ring on periphery of casing due to the centrifugal force. Since rotor is rotated in eccentric casing the blade creates working spaces whose volume increases as rotor rotates from lower to upper vertex and decreases as the rotor rotates from upper to lower vertex. The uniform distribution of working spaces on rotor periphery results in continuous suction and exhaust of gases.


  • Only one rotating part, a balanced rotor running with close clearances without any metallic contact with other parts.
  • No lubrication is required and air or gas handled is oil free.
  • The pump can handle hot and saturated vapours. Vapours are condensed by cool seal water.
  • Air is compressed by rotating water ring radially and since inlet and outlet are ports are radial, the pump can comfortably handle dust, fibers and foreign matter with seal water.
  • Can handle more seal water and hence for many of the applications receivers are not required.
  • Cylindrical control plates having ample area for inlet/outlet port fitted with close clearances to the rotor. Axial clearances are not to be maintained and so it is very easy while in maintenance. A fitter conversant with centrifugal pump can handle our Vacuum pump very conveniently. Surprisingly this pump maintenance is less than an electric motor.
  • Pressurised gland system ensures leakages of atmospheric air into the pump.
  • Unloaded valves are provided to throw out any foreign solid particles like any process fibers / pulp, thus increasing life of the pump and decreasing over all maintenance.
  • Low power and water consumption.
  • Control plate clearances are not affected by small variation in Axial length / Axial position of the rotor.
  • Ball / Roller bearings on both sides are floating and have small axial movement as in a Electric Motor.
  • Control Plate port angle selected on basis of specific operating condition which reduces over compression & power.
  • The foreign matter entering in to the pump is continuously removed while the pump is in working.
  • The pump gives non-pulsating vacuum because the air is pre-compressed before it leaves the pump.


For more details contact:

Vacunair Engineering Co. Pvt. Ltd., Ahmedabad

Tel: 22910771-2-3 Fax: 079-22910770