Cryogenic gas circulation and heat exchanger

Abstract

A cryogenic system includes a housing of a cryogenic chamber, a cold source in the cryogenic chamber, and a gas circulation loop for circulating cryogenic gas between the cold source and material to be cooled in the cryogenic chamber. The circulation loop includes a gas pump, and a counter-flow heat exchanger connecting the gas pump to the cold source for cooling an in-flow of the cryogenic gas from the gas pump to the cold source with an out-flow of the cryogenic gas from the material to be cooled to the gas pump. In a preferred construction, the heat exchanger includes an outer tube and an inner tube nested within the outer tube, and a pair of three-port connector fittings attached to respective ends of the tubes.

Description

RELATED APPLICATIONS[0001]The present application claims the benefit of Nick Strickland and Stuart Wimbush U.S. Provisional Application Ser. 61 / 980,337 filed Apr. 16, 2014, incorporated herein by reference.TECHNICAL FIELD[0002]This disclosure relates to circulation of cryogenic gas in a cryogenic system, and a heat exchanger especially adapted for use in such a cryogenic system.BACKGROUND[0003]A cryogenic system often includes material to be cooled to a cryogenic temperature, a cryocooler for cooling the material to the cryogenic temperature, and a means for transporting heat from the material to the cryocooler. The means for transporting heat from the material to the cryocooler may include a gas circulation loop. For example, the material to be cooled to cryogenic temperature is a sample of material under analysis while properties of the material are measured as a function of temperature. In another example, the material to be kept at cryogenic temperature is a superconducting comp...

AI Technical Summary

Benefits of technology

[0012]This disclosure also provides a counter-flow heat exchanger especially adapted for circulating cryogenic gas between a room-temperature environment and a cryogenic environment in a cryogenic chamber. The heat exchanger includes an outer tube and an inner tube nested within the outer tube, and a pair of three-port connector fittings attached to respective ends of the tubes. The three-port connector fittings provide a sealed environment with independent access to a first flow of fluid and a second flow of fluid through the heat exchanger, while preventing mixing of the first flow of fluid and the second flow of fluid. The first flow of fluid flows between the three-port connector fittings inside the outer tube and outside the inner tube, and the second flow of fluid flows between the three-port connector fittings inside the inner tube. In a preferred embodiment, the tubes are wound into a helix for compactness.

Problems solved by technology

This particular placement may not be convenient or possible in all applications and also may not provide the flow rate required.

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