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May 31, 2020

Transfer Line Couplings: Multiline 4k

Multi-coaxial transfer line couplings for helium or other cryogenic fluids
In cryogenics, transfer line couplings are used in all cases in which separable connections, e.g. between a Dewar vessel and a line connected to the Dewar vessel, are required. With a multi-coaxial coupling, it is possible to also collect and feed back the generated boil-off gas in addition to the cryogenic fluid.

Coupling characteristics

The TLK-MS consists of two main components, i.e. the coupling housing and the coupling insert. A union nut allows easily coupling and decoupling the insert from the housing. WEKA couplings for cryogenics have an optimised design in order to prevent heat from having an impact on the cryogenic fluid as far as possible.

In addition to the inner conductor for the liquid medium, multi-coaxial couplings have an additional outer conductor in which the boil-off gas can be collected and fed back. The two conductors are not insulated from each other, but the outer conductor for the boil-off gas is surrounded by vacuum insulation. Due to the 2-conductor system, the housing has two welding ends that can be welded to the pipelines in the coldbox in addition to the welding flange.

Housing, insert, dummy inserts or dummy plugs are available as individual parts and can be purchased separately at all times.

Multi-coaxial couplings with more than two conductors or with vacuum insulation below the conductors can also be realised. Please contact us if you have detailed requests.


Housing, insert: Grade 316L stainless steel

Union nut: Brass

Sealing: NBR

Nominal sizes

WEKA TLK-MS couplings are available as standard in the sizes 5/11 (inner conductor / outer conductor), 11/28 and 15/28 and are designed for a nominal pressure of 25 bar.

Larger nominal diameters or even nominal pressures are also possible on request.


Each coupling is subjected to a pressure test at 1.5*PN and integrally tested for tightness to the outside using helium.

Further Information