At a time when helium is in notoriously tight supply, Cryomech has developed a helium reliquefier for recovering and liquefying helium vapour for existing helium cryostat operations, reports Cold Facts magazine.

At present, a number of helium dewars and helium cryostats for dilution refrigerators are operating without cryo-refrigeration and have higher liquid helium boil-off rates as a result.

The helium reliquefier from Cryomech however, is designed to re-condense the boil-off from liquid helium dewars and cryostats and return it through the existing fill port, ensuring a closed cycle system and no escape of helium.

With the supply & demand equation for helium at something of an imbalance and a globally tight squeeze for supply, any gains that can be made through process efficiency are welcomed.

Employing a 4K pulse tube cryocooler, the reliquefier provides a liquefaction capacity of around 10 litres per day. Following exit of the cryostat through the vent, the helium vapour is warmed to room temperature and enters into the reliquefier where helium is pre-cooled and condensed.

This generates a strong natural convection for the vapour from the cryostat to the reliquefier, also called a thermo-siphon. The liquid helium is then funnelled into the liquid helium return line and drains back to the cryostat, therefore establishing a closed cycle of helium in the system.

US company Cryomech is a recognised leader in new cryorefrigerator, or cryocooler, design and manufacturing and provides an array of products and services.

Cold Facts is the magazine of the Cryogenic Society of America, Inc (CSA). As an internationally recognised and respected publication, Cold Facts magazine is published five times per year and delivered to every member of the CSA.