A vacuum-jacketed, cryogenic flex hose was designed with an integrated flange to be able to pass through a vacuum chamber wall. This design increases the quality of the cryogenic fluid at the exit of the hose (i.e., more liquid, less vapor) by extending the hose vacuum-jacket through the chamber wall, where usually a non-insulated fluid fitting would be required.

Cryogenic liquid was to be supplied to a heat exchanger inside a vacuum chamber for extended periods of time. In order to ensure the highest-quality fluid was being supplied, achieving the highest heat exchanger performance, the feed line needed to be vacuum-jacketed all the way from the source to the exchanger.

The new design integrates a flange to the hose outer vacuum-jacket so the line could be passed through the chamber wall, yet still form a vacuum seal. Commercial off-the-shelf (COTS) vacuum-jacketed flex hoses have standard, non-insulated, flared end terminations that require tube fittings to attach to the end item. These terminations allow unwanted heat into the cryogenic liquid, which results in lower-quality fluid at the test apparatus.

The flex-through consists of two main elements: a vacuum-jacketed, insulated flex hose and an integral vacuum flange operating at near ambient temperature. In this particular case, a 40-mm type KF vacuum flange was used for an 18-mm diameter flex hose. The parts make up a cryogenic supply system that is fully vacuum-insulated from the source, through the chamber wall, and to the test apparatus. The innovation provides a cost-effective way to increase the overall system thermal performance.

This work was done by Adam Swanger and James Fesmire of Kennedy Space Center. For more information, contact the Kennedy Space Center Technology Transfer Office at 321-867-7171. Refer to KSC-13933.


NASA Tech Briefs Magazine

This article first appeared in the April, 2016 issue of NASA Tech Briefs Magazine.

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