Liquid Ring Vacuum Pumps are Vital to Industry
Liquid ring vacuum pumps are also commonly referred to as water seal vacuum pumps. These vacuum pumps utilize a rotating positive displacement pump to perform its main function. With a low friction design, the liquid ring pump has only one moving part: the rotor. Therefore, sliding friction only happens to the shaft seals. The function of a liquid ring vacuum pump is similar to a rotary vane vacuum pump. It is possible that the liquid ring pump most widely utilized vacuum pump in industry, the liquid ring vacuum pump provides a simple design that can safely manage combustible gases through isothermal compression.
Liquid ring pumps can also be used as a gas compressor. Water is utilized as an energy source to be used as a gas compressor. The vacuum in the pump initiates the pumping motion and compression process. An induction motor is what typically powers liquid ring vacuum pumps.
Liquid ring pump systems come in either single stage or multi-stage platforms. A typical multi-stage liquid ring pump will have no more than two compression stages on a single shaft. Single stage liquid rings can be used for continuous operation. Vapor pressure from the ring liquids puts a limit on the pressure reduction the vacuum service is able to achieve. The single stage design is able to operate under wet, corrosive process streams and is typically tolerant of particulates. Their simplistic design requires minimal maintenance, vibrations and noise.
Assuming that the ring liquid is water and it is pumped at 15°C or less, single stage liquid ring vacuum pumps can produce vacuum to 35 torr and multi-stage liquid ring vacuum pumps can produce vacuum to 25 torr. To generalize and universalize the manufacturing standard of liquid ring vacuum pumps, most manufacturers use dry air and sealant water at 15°C to test their standard performance curves.