What is a liquid ring vacuum pump?

A liquid ring vacuum pump is a positive displacement pump that uses a liquid as a sealant.   The liquid, also referred to as operating fluid, is usually water.   Other fluids can also be used if required to suit the process conditions.

The housing of liquid ring vacuum pump is partially filled with operating fluid, and the blades of an eccentrically mounted impeller dip into it.   As the vacuum pump impeller rotates, a liquid ring is created due to the centrifugal force.   Chambers are formed between the vacuum pump impeller and the liquid ring, and the rotation of the impeller alters their volume.   The pumped medium is transported in these chambers, where it is compressed and expelled via the outlet.   Liquid ring vacuum pumps are available in single- and two-stage versions.   Compression is carried out once in single-stage versions.   Two-stage versions compress the pumped medium twice to achieve higher vacuum levels.

The operating fluid creates a barrier that prevents contamination from entering the vacuum pump.   Liquid ring vacuum pumps are often used in processes where a liquid is already present that can be used as the operating fluid.    Liquid ring vacuum pumps are particularly well suited for industries such as hospitals and healthcare facilities, vapor recovery, and biogas handling.