Please update your browser.

It looks like you are using an old version of the Microsoft Edge browser. To get the best experience with the Busch website, please update your browser.

Contact Pump registration

Liquid Ring Vacuum Pumps and Compressors


The marketing-cookies have to be accepted to watch this video.

Allow all cookies


An eccentrically mounted impeller rotates in a housing partially filled with operating fluid. The impeller blades dip into the fluid, and the centrifugal force exerted by their rotation forms a so-called liquid ring within the housing.

The pumped medium is transported in the spaces between the blades and the liquid ring. The eccentric rotation of the impeller alters the volume of these spaces. Thereby, the gas is drawn in, compressed and expelled.

In single-stage versions, compression is carried out once. In two-stage versions, the pumped medium is compressed again to allow higher vacuum levels to be achieved.

The operating fluid is usually water, but other liquids may be used if required by the process conditions.

Liquid ring vacuum pumps can be operated as a simple continuous flow system, or as a partial or total recirculation system. Operation as a compressor is also possible.

Our Portfolio of Liquid Ring Vacuum Pumps and Compressors

DOLPHIN are the robust liquid ring vacuum pumps and compressors from Busch. This series encompasses decades of experience in the use and further development of liquid ring technology.

Discover our DOLPHIN product family

Our experience. Our success stories.

  • Liquid Ring Vacuum Pumps - Classic Vacuum Technology and yet Still State of the Art

    Liquid Ring Vacuum Pumps - Classic Vacuum Technology and yet Still State of the Art

    Learn more