Welke pomp kies je voor cryogene toepassingen?

Onderwerp

General laboratory equipment Dosing equipment/pumps Laboratory Technology

Pumping cryogenic gases is no easy task. To liquefy these types of substances, the temperature must be lowered and the system pressure increased. Cryogenic liquids therefore differ from “normal” liquids. Because they are processed at an extremely high system pressure, from 50 to 200 bar or more, and an extremely low temperature of up to –200 °C. The viscosity is also extremely low (> 0.1 mPas); about one-tenth of water. It is mainly the combination of these physical properties that makes it difficult.

For the pulsation-free pumping of cryogenic gases, depending on the desired differential pressure, both gear and turbine pumps are the perfect solution for these challenging applications.
The pump's (shaft) seal requires special attention. This is very difficult due to the extreme system pressure and temperature. A normal shaft seal (such as gasket, lip seal, mechanical seal, etc.) is virtually impossible, because it is blown out of the pump due to the extreme pressure difference inside and outside the pump.

Magnetically coupled pumps

The pumps we offer for this application are equipped with a magnetic coupling with seals that are suitable for system pressures up to 325 barg and extremely low temperatures down to –200 °C. Due to the use of a magnetic coupling, there is no shaft seal, only static seals. This means that the pump is hermetically closed and there is no risk of jamming due to ice build-up. The materials of the seals must especially be resistant to extremely low temperatures, such as PTFE (=TEFLON®), FFPM (=Kalrez®) or metal (e.g. silver).
To ensure that the process runs smoothly, the pump and pipes must be insulated to prevent ice build-up due to outside moisture.

Suurmond offers three types of pumps that have been used for cryogenic applications. Two types of gear pumps and a turbine pump. The choice is determined by, among other things, the desired differential pressure, the required system pressure and liquid temperature.