Closed Cycle 1 K Refrigeration System

a closed cycle, cold-cycle technology, applied in the field of cryo-refrigerators, can solve the problems of increasing the cost of this irreplaceable natural resource, helium migration into space, and limited natural gas sources that also contain helium, so as to reduce the transfer of vibrations and reduce the design. low effect of vibration

US20140202174A1Inactive Publication Date: 2014-07-24CRYOMECH
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Patent Information

Authority / Receiving Office
US · United States
Current Assignee / Owner
Publication Date
2014-07-24
Estimated Expiration
Not applicable · inactive patent

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Abstract

A closed-cycle refrigerator provides cooling to extremely low temperatures, particularly in the range of 0.5 K to 2.0 K. A 4 K pulse-tube cryocooler cold head or G-M cryocooler cold head liquefies helium in a first cooling chamber at a pressure at approximately 1 atmosphere. Liquid helium flows from the first cooling chamber, through a Joule-Thomson valve, and into a second cooling chamber under a pressure differential created by a pump. Helium vapor extracted from the second cooling chamber by the pump is routed back to the first cooling chamber to be re-condensed. This closed-cycle design provides continuous cooling below 2 K. Cryocooler cold head cold sections have no physical contact with subsequent cooling elements, such as the first and second cooling chambers to reduce vibration transfer. In some embodiments the cryocooler cold head is connected to a vacuum chamber via a vibration damping coupler to further reduce vibration transfer.
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Description

REFERENCE TO RELATED APPLICATIONS

[0001] This application claims one or more inventions which were disclosed in Provisional Application No. 61 / 756211, filed Jan. 24, 2013, entitled “CLOSED CYCLE 1 K REFRIGERATION SYSTEM”. The benefit under 35 USC §119(e) of the United States provisional application is hereby claimed, and the aforementioned application is hereby incorporated herein by reference.BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention pertains to the field of cryorefrigeration. More particularly, the invention pertains to closed cycle cryorefrigerators for temperatures below about 4.2 Kelvin.

[0004] 2. Description of Related Art

[0005] Liquid helium has a boiling point at 1 atm (atmosphere of pressure) of 4.2 K, and is by-product of natural gas production. Helium is found in two isotopes, helium-3 (3He) and helium-4 (4He). Helium-4 is by far the most abundant isotope, and constitutes over 99.9% of the helium on Earth. As such, liquid helium makes an ide...

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Embodiment Construction

[0025]A closed-cycle refrigerator capable of producing temperatures down to 1 K or less, and doing so in an economic and reliable manner, has a number of practical applications. Integration of a 1 K closed-cycle refrigerator in a superconducting magnet allows for substantially 100% recovery and recycling of gaseous helium from the magnet cryostat. In other applications, the 1 K closed-cycle refrigerator can be used to cool a variety of detectors and low noise electronic circuitry. Further, when the working fluid is 4He (Helium-4, an abundant isotope of helium), temperatures below 2.17 K (at approximately 1 atm) cause the 4He to act as a superfluid. Superfluid 4H has a number of applications in basic quantum mechanical research (superfluid 4He is a Bose-Einstein condensate), and practical application in Superfluid Helium Droplet Spectroscopy (SHeDS) and construction of high accuracy gyroscopes, for example.

[0026]Referring now to FIG. 1 and FIG. 2, a schematic of a closed-cycle refrig...