ZERO DELTA TEMPERATURE THERMAL LINK

Abstract

An apparatus for transferring cryogenic refrigeration includes a cryocooler interface, a housing, a working fluid, a heat exchanger, a flexible thermal link, and a remote cartridge cold head. The cryocooler interface is thermally connected to a cryocooler providing a source of refrigeration. The refrigeration is passed from the crycooler into the heat exchanger via the cryocooler interface. The remote cartridge cold head is attached to a remote location. Heat is drawn from the remote location through the remote cartridge cold head and into the heat exchanger via the working fluid within the flexible thermal link and housing. Within the heat exchanger, heat is transferred from the working fluid to the refrigeration source, such as a cryocooler; accordingly, the remote location is cooled.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of international patent application No. PCT/US2010/038328, entitled “ZERO DELTA TEMPERATURE THERMAL LINK,” filed on Jun. 11, 2010, which claims priority to U.S. provisional patent application No. 61/186,247, with the same title, filed on Jun. 11, 2009, the contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to cryogenic refrigeration. More specifically, it relates to the transfer of heat from a fixed location, such as a cryocooler, to a remote location, such as a superconducting magnet.

2. Description of the Prior Art

Applying refrigeration to remote locations in a cryostat typically involves constructing conduction paths from fixed copper links and using liquid cryogens provided by an open or closed loop. The fixed copper links create thermal and mechanical loads. Furthermore, the fixed copper links generate vibrations and are relatively complicated to install and use.

What is needed in the art is an apparatus to eliminate the thermal and mechanical loads created by the fixed copper links.

What is also needed is an apparatus to reduce the transfer of vibrations from the fixed copper links.

Yet another need in the art exists for an apparatus that facilitates use when compared with the maintenance of liquid cryogens in an open system.

Still another need in the art exists for an apparatus that facilitates installation in view of the installation of a complicate closed-loop cryogenic system.

However, in view of the prior art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the art how the limitations of the art could be overcome.

SUMMARY OF INVENTION

The long-standing but heretofore unfulfilled need for an improved apparatus for transferring heat from a fixed location to a remote location is now met by a new, useful, and nonobvious invention.

The novel apparatus transfers cryogenic refrigeration from a fixed location to a remote location. The apparatus generally includes a cryocooler interface, a housing having a self-contained volume of working fluid, a heat exchanger, a flexible thermal link, and a remote cartridge cold head. The cryocooler interface is disposed on the surface of the housing and in thermal communication with the heat exchanger. The heat exchanger is disposed within the housing and in thermal communication with the self-contained volume of working fluid. The flexible thermal link extends from, and is in thermal communication with, the housing. The remote cartridge cold head is in thermal communication with the flexible link and provides a heat transfer surface.

In operation, the cryocooler interface is thermally connected to a cryocooler providing refrigeration. The refrigeration is passed from the cryocooler into the heat exchanger via the cryocooler interface. The remote cartridge cold head is attached to a remote location. Heat is drawn from the remote location through the remote cartridge cold head and into the heat exchanger via the working fluid within the flexible thermal link and housing. Within the heat exchanger, heat is transferred from the working fluid to the cryocooler and is replaced by refrigeration from the cryocooler; accordingly, the remote location is cooled.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the invention, reference should be made to the following detailed description, taken in connection with the accompanying drawings, in which:

The FIGURE is an elevated, diagrammatic view of an embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is an apparatus for transferring cryogenic refrigeration from a fixed location, such as a cryocooler, to a remote location, such as a superconducting magnet. As depicted in the FIGURE, the apparatus generally includes cryocooler interface 10, housing 30, working fluid 25, heat exchanger 20, flexible thermal link 50, and remote cartridge cold head 60. Cryocooler interface 10 is disposed on the surface of housing 30 and in thermal communication with heat exchanger 20. Heat exchanger 20 is disposed within housing 30 and in thermal communication with the self-contained volume of working fluid 25. Flexible thermal link 50 extends from, and is in thermal communication with, housing 30. Remote cartridge cold head 60 is in thermal communication with flexible link 50 and provides a heat transfer surface.

The novel apparatus provides transfer of fixed position cold head refrigeration to remote locations from the cryocooler and other sources of refrigeration at various cryogenic temperatures. It also provides refrigeration at remote locations for both high-temperature and low-temperature superconducting magnets and devices as well as for other cryogenic components with zero or essentially zero temperature rise from the original source of refrigeration.

The apparatus uses a working fluid that is self-contained. This eliminates complicated liquid or gas handling operational requirements. No gas bottles or liquid cryogen handling is required to implement and operate this device.

The apparatus minimizes vibration transfer from the source of the refrigeration to the cryogenic component. It also minimizes thermal and other types of mechanical loads on the source of refrigeration. This reduces risk of damage dramatically in the case of thin-walled tubes in cryocoolers.

In the FIGURE, cryocooler 15 provides the fixed source of refrigeration. The apparatus, however, will work with other sources of refrigeration. Cryocooler interface 10 connects directly to cryocooler 15. The refrigeration from cryocooler 15 passes through cyrocooler interface 10 and into heat exchanger 20. Heat exchanger 20 facilitates the transfer of heat from working fluid 25 to the refrigeration. The heat transfer causes working fluid 25 to condense into the liquid phase. Housing 30 contains a self-contained volume of working fluid 25 so that an operator does not need to transfer cryogens. Charging nozzle 40 places the required mass of working fluid 25 into housing 30. Flexible thermal link 50 transfers working fluid 25 from housing 30 to a location remote of cryocooler 15. Remote cartridge cold head 60 provides a heat transfer surface at the remote location.

In operation, cryocooler interface 10 is thermally connected to cryocooler 15. Cryocooler 15 provides refrigeration. The refrigeration is passed from crycooler 15 into heat exchanger 20 via cryocooler interface 10. Remote cartridge cold head 60 is attached to a remote location. Heat is drawn from the remote location through remote cartridge cold head 60 and into heat exchanger 20 via working fluid 25 within flexible thermal link 50 and housing 30. Working fluid 25, containing heat from the remote location, travels up flexible thermal link 50 and housing 30 and into heat exchanger 20. Within heat exchanger 20, heat is transferred from working fluid 25 to cryocooler 15.

In a preferred embodiment, charging nozzle 40 is used only once during manufacturing and places the required mass of working fluid 25 into housing 30. Accordingly, working fluid 25 is a self-contained volume and an operator does not need to transfer or otherwise handle cryogens.

Working fluid 25 is preferably helium, hydrogen, methane, nitrogen, oxygen, neon or fluorine or a combination thereof.

Remote cartridge cold head 60 preferably includes at least one hole to facilitate heat transfer. Moreover, to further facilitate heat transfer, remote cartridge cold head 60 is formed from a high thermal conducting material. In the FIGURE, remote cartridge cold head 60 is depicted as a long cylinder but may be of any predetermined geometric shape.

It will be seen that the advantages set forth above, and those made apparent from the foregoing description, are efficiently attained and since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matters contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims

1. An apparatus for transferring cryogenic refrigeration, comprising:

an interface adapted to thermally connect to a source of refrigeration;

a housing having a self-contained volume of working fluid, said interface being disposed on a surface of said housing;

a heat exchanger in thermal communication with said interface and disposed within said housing, said heat exchanger transferring heat between said self-contained volume of working fluid and said source of refrigeration;

a flexible thermal link in thermal communication with, and extending from, said housing; and

a remote cartridge cold head in thermal communication with said flexible thermal link for providing a heat transfer surface at a location remote to said source of refrigeration.

2. An apparatus for transferring cryogenic refrigeration as in claim 1, further comprising:

a charging nozzle in mechanical communication with said heat exchanger housing.

3. An apparatus for transferring cryogenic refrigeration as in claim 1, wherein said source of refrigeration is a cryocooler.

4. An apparatus for transferring cryogenic refrigeration as in claim 1, wherein said flexible thermal link is a hollow tube.

5. An apparatus for transferring cryogenic refrigeration as in claim 1, wherein said remote cartridge cold head includes at least one hole.

6. An apparatus for transferring cryogenic refrigeration as in claim 1, wherein said remote cartridge cold head is an elongated cylinder or other predetermined geometry.

7. An apparatus for transferring cryogenic refrigeration as in claim 1, wherein said self-contained volume of working fluid is helium.

8. An apparatus for transferring cryogenic refrigeration as in claim 1, wherein said self-contained volume of working cryogenic fluid is hydrogen.

9. An apparatus for transferring cryogenic refrigeration as in claim 1, wherein said self-contained volume of working cryogenic fluid is methane.

10. An apparatus for transferring cryogenic refrigeration as in claim 1, wherein said self-contained volume of working cryogenic fluid is nitrogen.

11. An apparatus for transferring cryogenic refrigeration as in claim 1, wherein said self-contained volume of working cryogenic fluid is oxygen.

12. An apparatus for transferring cryogenic refrigeration as in claim 1, wherein said self-contained volume of working cryogenic fluid is neon.

13. An apparatus for transferring cryogenic refrigeration as in claim 1, wherein said self-contained volume of working cryogenic fluid is fluorine.

14. An apparatus for transferring cryogenic refrigeration as in claim 1, wherein said self-contained volume of working cryogenic fluid is a combination of helium, hydrogen, methane, nitrogen, oxygen, neon, or fluorine.