Check valves for gas recovery and vacuum applications

The use of gas recovery systems in cryogenics helps to save costs by carrying the evaporated fluid into a collection system. In order to prevent the gas from flowing back into the primary circuit, check valves with a very low response pressure should be used. Typical applications concerned are gases such as He, Ne, H2, N2 or Ar.

Valve characteristics

WEKA check valves of the ClpdV type are typically used for gases such as He, Ne, H2, N2 or Ar. They are designed for a nominal pressure PN of 4 bar and for a temperature range of -20 °C to 60 °C. Standard versions are the nominal diameters DN25, DN40 and DN50 with a vacuum KF flange connection. Larger nominal diameters or other connection versions, such as weld-on ends or thread connections, are also possible and are manufactured according to customer requirements.


Housing, insert, springs and screws: Grade 304 stainless steel

Sealing head: Aluminum

Sealing: Silicone

Opening pressure

Depending on the installation position, the opening pressure in flow direction is lower than 10 mbar and, as a result, allows the recovery of the gas at even the lowest differential pressures.

Larger opening pressures are also possible if necessary.


Each valve is subjected to a pressure test at 1.5*PN and integrally tested for tightness to the outside using helium. Tightness to the inside and opening properly in the flow direction are also tested and documented.


The typical case of application for check valves in cryogenics are cryostats, in which helium is used as a refrigerant and where the helium evaporates due to the heat dissipation of the process. The evaporated helium can be collected via evaporation lines. Check valves are installed in these and prevent the gas from flowing back into the cryostats or into the process. The valves operate at ambient temperature.

In general, however, the valves can be used in all cryogenics systems in which evaporation gases which are to be recovered are generated. ATEX certificates for the use of the valves in explosion-proof zones are also available.


For further information please contact us:

+41 43 833 43 43

Gas Recovery and Vacuum Applications

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