Liquid Nitrogen Feedthroughs are used for the same cooling purposes as Water Feedthroughs but offer lower temperature (-200°C) capabilities and therefore greater cooling rates. Liquid Nitrogen Feedthroughs are designed so as to minimize heat transfer between coolant lines and vacuum mounts. Ice build up can be detrimental to the sealing characteristics of a vacuum mount.

Thermal insulation in liquid nitrogen lines is achieved through double wall coaxial construction. A .25 inch cooling line is inserted and welded to one end of a 1/2 inch support tube. The opposite end of the 1/2 inch support tube is welded to the vacuum mount which, when evacuated, creates a coaxial vacuum cavity between the two tubes. This cavity is an excellent thermal barrier, which prevents ice build up on the air side of the vacuum mount.

Both Water and Liquid Nitrogen Feedthroughs are available in one of three vacuum mount styles, Del-Seal CF, ISO NW Kwik-Flange and 1 inch Base Plate. In addition to these three mounts, ISI offers individual Liquid Feedthrough tube kits for direct welding into a customers chamber or custom flange. These kits are supplied in weld tube form only, without fittings.

Vacuum mount fitted, Water and Liquid Nitrogen Feedthroughs are constructed with .25 inch, type 304 stainless steel tubing with a choice of three industry standard fittings, Weld-tube (plain tubes without fittings), .25 inch Swagelok® compression fittings or .25 inch male VCR® metal gasket seal fittings. Mating VCR female nuts and metal copper gaskets must be purchased separately.