Miniature Joule-Thomson cryocooler operating at liquid helium temperatures

Patent metadata

Field	Value
Publication number	US-12078400-B2
Application number	US-202117412620-A
Country	US
Kind code	B2
Filing date	Aug 26, 2021
Priority date	Nov 29, 2020
Publication date	Sep 3, 2024
Grant date	Sep 3, 2024

Abstract

A miniature Joule-Thomson cryocooler operating at liquid helium temperatures includes an integral structure formed by welding at least three base plates sequentially superposed, an outermost base plate in the at least three base plates is configured as a cover plate and configured to seal the rest of the at least three base plates, the rest of the at least three base plates is configured as a first-stage cooling circulator, a second-stage cooling circulator and a third-stage cooling circulator respectively, the first-stage cooling circulator, the second-stage cooling circulator and the third-stage cooling circulator have a first-stage working fluid, a second-stage working fluid and a third-stage working fluid respectively, the first-stage cooling circulator is configured to precool the second-stage working fluid and the third-stage working fluid through the first-stage working fluid, and the second-stage cooling circulator is configured to precool the third-stage working fluid through the second-stage working fluid.

First claim

What is claimed is:

1. A miniature Joule-Thomson cryocooler operating at liquid helium temperatures, comprising an integral structure formed by welding at least three base plates sequentially superposed, wherein an outermost base plate in the at least three base plates is configured as a cover plate and configured to seal the rest of the at least three base plates, the rest of the at least three base plates is configured as a first-stage cooling circulator, a second-stage cooling circulator and a third-stage cooling circulator respectively, the first-stage cooling circulator, the second-stage cooling circulator and the third-stage cooling circulator have a first-stage working fluid, a second-stage working fluid and a third-stage working fluid respectively, the first-stage cooling circulator is configured to precool the second-stage working fluid and the third-stage working fluid through the first-stage working fluid, and the second-stage cooling circulator is configured to precool the third-stage working fluid through the second-stage working fluid; and wherein:
the integral structure is formed by welding seven base plates sequentially superposed; in the seven base plates, a first base plate serves as the cover plate, a second base plate and a third base plate form the first-stage cooling circulator, a fourth base plate and a fifth base plate form the second-stage cooling circulator, and a sixth base plate and a seventh base plate form the third-stage cooling circulator;
a top end of the first base plate is provided with six through holes serving as a first-stage working fluid inlet, a second-stage working fluid inlet, a third-stage working fluid inlet, a first-stage working fluid outlet, a second-stage working fluid outlet and a third-stage working fluid outlet respectively; a top end of the second base plate is provided with five through holes serving as a first-stage working fluid inlet, a second-stage working fluid inlet, a third-stage working fluid inlet, a second-stage working fluid outlet and a third-stage working fluid outlet respectively; a top end of the third base plate is provided with four through holes serving as a second-stage working fluid inlet, a third-stage working fluid inlet, a second-stage working fluid outlet and a third-stage working fluid outlet respectively; a top end of the fourth base plate is provided with three through holes serving as a second-stage working fluid inlet, a third-stage working fluid inlet and a third-stage working fluid outlet respectively; a top end of the fifth base plate is provided with two through holes serving as a third-stage working fluid inlet and a third-stage working fluid outlet respectively; a top end of the sixth base plate is provided with one through hole serving as a third-stage working fluid inlet; the working fluid outlets and the working fluid inlets of the same type are arranged at same positions on the corresponding base plates;
each of the third base plate, the fifth base plate and the seventh base plate is provided with a high-pressure side passage, a throttle valve and a buffer chamber in sequential communication, and an inlet end of each high-pressure side passage is in communication with the working fluid inlet of a corresponding stage; and
each of the second base plate, the fourth base plate and the sixth base plate is provided with a low-pressure side passage, and each low-pressure side passage has an inlet end in communication with the buffer chamber of a corresponding stage, and an outlet end in communication with the working fluid outlet of a corresponding stage; and the low-pressure side passages on the second base plate and the fourth base plate have functions of a heat exchanger, a precooler and an evaporator, and the low-pressure side passage on the sixth base plate has functions of a heat exchanger and an evaporator.

2. The miniature Joule-Thomson cryocooler operating at liquid helium temperatures according to claim 1 , wherein the first-stage cooling circulator and the second-stage cooling circulator are located between the first base plate and the third-stage cooling circulator, and the first-stage cooling circulator and the second-stage cooling circulator have interchangeable positions.

3. The miniature Joule-Thomson cryocooler operating at liquid helium temperatures according to claim 1 , wherein each buffer chamber has a width slightly greater than a width of a strip-shaped through hole in a corresponding base plate.

4. The miniature Joule-Thomson cryocooler operating at liquid helium temperatures according to claim 1 , wherein each of the first base plate, the second base plate and the third base plate is provided with a through hole serving as an additional first-stage working fluid inlet;
the second base plate is further provided with an additional first-stage low-pressure side passage, and the additional first-stage low-pressure side passage has an outlet end in communication with the inlet end of the low-pressure side passage on the second base plate; and
the third base plate is further provided with an additional first-stage high-pressure side passage, an additional first-stage throttle valve and an additional first-stage buffer chamber in communication, the additional first-stage high-pressure side passage has a top end in communication with each additional first-stage working fluid inlet through an upward extending passage, and the additional first-stage buffer chamber is in communication with an inlet end of the additional first-stage low-pressure side passage on the second base plate.

5. The miniature Joule-Thomson cryocooler operating at liquid helium temperatures according to claim 1 , wherein in the cooling circulator of each stage, when the low-pressure side passage is located above the high-pressure side passage, the buffer chamber is in communication with the inlet end of the low-pressure side passage through a strip-shaped through hole formed in a bottom end of the low-pressure side passage; when the low-pressure side passage is located below the high-pressure side passage, a through hole directly facing to the inlet end of the low-pressure side passage is formed in the buffer chamber, and the low-pressure side passage completely covers a region where the buffer chamber is located.

6. The miniature Joule-Thomson cryocooler operating at liquid helium temperatures according to claim 1 , wherein the first-stage working fluid is a working fluid capable of achieving a Joule-Thomson cooling effect without a precooling operation; the second-stage working fluid is neon or hydrogen; and the third-stage working fluid is helium.

7. The miniature Joule-Thomson cryocooler operating at liquid helium temperatures according to claim 1 , wherein a fin structure is provided in each low-pressure side passage, each high-pressure side passage and each buffer chamber.

8. The miniature Joule-Thomson cryocooler operating at liquid helium temperatures according to claim 7 , wherein a cross section of the fin structure has a shape of a rectangle, a circle, an ellipse, a diamond or a hydrofoil, and a size between several micrometers and tens of micrometers.

Assignees

• Univ Tsinghua

Inventors

• Cao Haishan

Classifications

• F25B2309/022

  characterised by the expansion element · CPC title

• F28D2021/0033

  for cryogenic applications · CPC title

• F28D9/0093

  Multi-circuit heat-exchangers, e.g. integrating different heat exchange sections in the same unit or heat-exchangers for more than two fluids · CPC title

• F25B2309/02

  using the Joule-Thompson effect · CPC title

• F25B2400/15

  Microelectro-mechanical devices · CPC title