Design of a triaxial bayonet for connecting a helium liquefier cold box and receiver Dewar vessel

A transferline with a triaxial bayonet for connecting a helium liquefier cold box and Dewar has been conceived. Liquid helium (LHe) settles in the Dewar vessel and the remaining cold gaseous helium (GHe) returns to the cold-box as a part of the liquefier cycle. The two coaxial lines are enclosed in an outermost vacuum line. These three coaxial lines come out of the liquefier through a triaxial bayonet joint which facilitates assembly/disassembly of the system due to the absence of welded joints. The present paper discusses schematic, design, and working of such a triaxial bayonet. It is conceived such that reduction in overall length, ease of fabrication, reduction of thermal stresses due to flexibility of bellows and reduction in fabrication cost are achieved.