System and method for converting helium bath cooling system for a superconducting magnet of a magnetic resonance imaging system into a sealed cryogenic system

Patent metadata

Field	Value
Publication number	US-12406790-B2
Application number	US-202318484005-A
Country	US
Kind code	B2
Filing date	Oct 10, 2023
Priority date	Oct 10, 2023
Publication date	Sep 2, 2025
Grant date	Sep 2, 2025

Abstract

A superconducting magnet system includes a coil support structure having a body, a superconducting magnet having a plurality of coils disposed about the body, and a helium vessel encompassing the coil support structure and the superconducting magnet. The superconducting magnet system includes a cooling system that includes a network of tubes disposed within the helium vessel and configured to transport helium within, wherein the network of tubes is retroactively thermally coupled to the plurality of coils. The cooling system includes a liquid helium storage system located within the helium vessel and a helium recondenser located outside the helium vessel. The cooling system includes one or more tubes coupling the helium storage system to the helium recondenser, wherein where the one or more tubes pass through the helium vessel is retroactively vacuum sealed to make the helium vessel a sealed helium vessel.

First claim

The invention claimed is:

1. A superconducting magnet system for a magnetic resonance imaging system, comprising:
a coil support structure having a body; and
a superconducting magnet having a plurality of coils disposed about the body of the coil support structure; and
a helium vessel encompassing the coil support structure and the superconducting magnet; and
a cooling system comprising:
a network of tubes disposed within the helium vessel and configured to transport helium within, wherein the network of tubes is retroactively thermally coupled to the plurality of coils;
a liquid helium storage system located within the helium vessel;
a helium recondenser located outside the helium vessel to recondense vapor helium to liquid helium; and
one or more tubes coupling the helium storage system to the helium recondenser, wherein where the one or more tubes pass through the helium vessel is retroactively vacuum sealed to make the helium vessel a sealed helium vessel, wherein the cooling system is configured to keep a uniform temperature between the sealed helium vessel and the plurality of coils; and
wherein each coil of the plurality of coils is thermally coupled to a respective tube of the network of tubes via a thermocoupling assembly, wherein the thermocoupling assembly comprises a flat thermoconductive metal strap disposed on a respective coil, a thermoconductive metallic wire overwrap wound about both a portion of the flat thermoconductive metallic strap and the respective coil, and ends of the flat thermoconductive metal strap are coupled to a thermoconductive metallic plate coupled to the respective tube.

2. The superconducting magnet system of claim 1 , further comprising a respective bellows located where each respective tube of the one or more tubes pass through the helium vessel, wherein each respective bellows forms a vacuum seal and is coupled to the respective tube of the one or more tubes, and the one or more tubes are rigid.

3. The superconducting magnet system of claim 1 , further comprising a respective bi-metallic interface disposed about each tube of the one or more tubes where each respective tube of the one or more tubes passes through the helium vessel, wherein each respective bi-metallic interface forms a vacuum seal, and the one or more tubes are flexible.

4. The superconducting magnet system of claim 3 , wherein each respective bi-metallic interface comprises an inner metal layer that interfaces with the respective tube and an outer metal layer that interfaces with the helium vessel, and the inner metal layer is made of a different metallic material than the outer metal layer.

5. The superconducting magnet system of claim 1 , wherein the thermocoupling assembly comprises a thermoconductive metallic sheet wrapped around the respective tube, and the thermoconductive metallic plate is coupled to the thermoconductive metallic sheet.

6. The superconducting magnet system of claim 1 , further comprising a superconducting switch configured to operate at a temperature of 80 Kelvin or less, wherein the superconducting switch is both located within and thermally isolated from the helium vessel, the superconducting switch is configured to switch between a resistive mode and a superconducting mode, and the superconducting switch is thermally coupled to a respective tube of the network of tubes.

7. The superconducting magnet system of claim 6 , further comprising power leads coupled to the superconducting switch, wherein the power leads comprise a high temperature superconducting wire coupled to a heat sink located outside the helium vessel, wherein an end of the high temperature superconducting wire coupled to the heat sink is electrically isolated, and wherein the power leads comprise a low temperature superconducting wire having a first end coupled to the heat sink and a second end coupled to the superconducting switch, and the low temperature superconducting wire passes from outside the helium vessel through an electrically isolated feedthrough into the helium vessel.

8. The superconducting magnet system of claim 1 , wherein the body of the coil support structure is made of fiberglass composite.

9. A method for cooling a superconducting magnet for a magnetic resonance imaging system, comprising:
filling a sealed cryogenic vessel with liquid helium until a first desired temperature is reached for cooling the superconducting magnet having a plurality of coils disposed about a body of a coil support structure, wherein the superconducting magnet is disposed within the sealed cryogenic vessel;
ceasing filling the sealed cryogenic vessel with the liquid helium upon reaching the first desired temperature;
utilizing a roughing vacuum pump coupled to the sealed cryogenic vessel to evacuate excess helium gas after ceasing filling the sealed cryogenic vessel with the liquid helium; and
activating a sealed cryogenic system comprising a network of tubes disposed within the sealed cryogenic vessel by flowing a cryogen through the network of tubes to cool the superconducting magnet to a second desired temperature, wherein the second desired temperature is lower than the first desired temperature.

10. The method of claim 9 , wherein pressure in the sealed cryogenic vessel after evacuating the excess helium gas generates internal convection to ensure a uniform temperature distribution between the plurality of coils and the sealed cryogenic vessel.

11. The method of claim 9 , wherein each coil of the plurality of coils is retroactively thermally coupled to a respective tube of the network of tubes via a thermocoupling assembly, wherein the thermocoupling assembly comprises a flat thermoconductive metal strap disposed on a respective coil, a thermoconductive metallic wire overwrap wound about both a portion of the flat thermoconductive metallic strap and the respective coil, and ends of the flat thermoconductive metal strap are coupled to a thermoconductive metallic plate coupled to the respective tube.

12. The method of claim 9 , wherein the magnetic resonance imaging system comprises a cooling system for the superconducting magnet, wherein the cooling system comprises a liquid helium storage system located within the sealed cryogenic vessel, a helium recondenser located outside the cryogenic vessel to recondense vapor helium to liquid helium, and one or more tubes coupling the helium storage system to the helium recondenser, wherein where the one or more tubes pass through the sealed cryogenic vessel is retroactively vacuum sealed to a make a cryogenic vessel the sealed cryogenic vessel, and wherein the cooling system is configured to keep a uniform temperature between the sealed helium vessel and the plurality of coils.

13. The method of claim 12 , wherein the cooling system comprises a respective bi-metallic interface disposed about each tube of the one or more tubes where each respective tube of the one or more tubes passes through the sealed cryogenic vessel, wherein each respective bi-metallic interface forms a vacuum seal, and the one or more tubes are flexible.

14. The method of claim 9 , wherein the magnetic resonance imaging system comprises a cooling system for the superconducting magnet, wherein the cooling system comprises a superconducting switch configured to operate at a temperature of 80 Kelvin or less, wherein the superconducting switch is both located within and thermally isolated from the sealed cryogenic vessel, the superconducting switch is configured to switch between a resistive mode and a superconducting mode, and the superconducting switch is thermally coupled to a respective tube of the network of tubes.

Assignees

• Ge Prec Healthcare Llc

Inventors

• Celik Dogan
• Bhattarai Kabindra Ram
• Jiang Yuye
• Hackett Richard Thomas
• Yarborough Charles Dudley
• Feltham Stuart Paul
• Jiang Longzhi
• James Harold Monroe

Classifications

• G01R33/3804

  Additional hardware for cooling or heating of the magnet assembly, for housing a cooled or heated part of the magnet assembly or for temperature control of the magnet assembly · CPC title

• G01R33/3815

  with superconducting coils, e.g. power supply therefor · CPC title

• H01F6/06

  Coils, e.g. winding, insulating, terminating or casing arrangements therefor · CPC title

• G01R33/34023

  Superconducting RF coils · CPC title

• G01R33/3403

  Means for cooling of the RF coils, e.g. a refrigerator or a cooling vessel specially adapted for housing an RF coil · CPC title