Method and device for low-temperature cooling/liquefaction

Patent metadata

Field	Value
Publication number	US-10690406-B2
Application number	US-201013515117-A
Country	US
Kind code	B2
Filing date	Nov 4, 2010
Priority date	Dec 11, 2009
Publication date	Jun 23, 2020
Grant date	Jun 23, 2020

Abstract

The invention relates to a method for low-temperature cooling/liquefaction of a working fluid, in particular a working fluid including helium or consisting of pure helium by means of a refrigerator/liquefier that includes a working circuit provided with a compressor station and a cold box. The refrigerator/liquefier subjects the working gas within the working circuit to a cycle that includes, in series: compressing the working fluid within the compressor station, cooling and decompressing the working fluid in the cold box, and heating the working fluid with a view to the return thereof to the compressor station. The compressor station includes one or more compression levels, each one using one or more compressors mounted on landings. The method is characterized in that the refrigerator includes a device for injecting a seal gas that is separate from the working fluid on at least one landing of the compressor(s) so as to form a gas seal that guides the working fluid leaks, coming from the working circuit, to an area for recirculating and returning the fluid into the working circuit.

First claim

What is claimed is:

1. A method for low-temperature cooling/liquefaction of a working fluid using a refrigerator/liquefier comprising a working circuit provided with a compression station and with a cold box, comprising the step of using the refrigerator/liquefier, subjecting the working gas in the working circuit to a cycle comprising in series:
a compression of the working fluid in the compression station, the compression station comprising one or several compression stages each using one or several compressors mounted on bearings, the working gas arriving at an inlet of the compression station at ambient temperature;
a cooling and an expansion of the working fluid in the cold box; a reheating of the working fluid so that the working fluid can be returned to the compression station, wherein the refrigerator/liquefier comprises a barrier gas injection device adapted to inject a barrier gas, that is distinct from the working fluid, into at least one bearing of the one or several compression stages to form a gaseous barrier guiding leaks of the working fluid originating from the working circuit towards a zone for recycling and returning the leaks to the working circuit; and returning at least part of the leaks to the working circuit.

2. The method of claim 1 , wherein the gaseous barrier prevents the leaks of working fluid from passing towards at least one contaminated zone of the compression station, the at least one contaminated zone being either an oil-containing mechanism of the compression station or not being sealed with respect to an atmosphere surrounding the at least one contaminated zone.

3. The method of claim 1 , wherein the barrier gas is injected into said at least one bearing at a pressure lower than a pressure of the working fluid in the working circuit at the compressor that is mounted on said bearing.

4. The method of claim 1 , wherein the barrier gas injection device comprises at least one barrier gas injection point and at least one outlet adapted to collect a mixture of the barrier gas and the leaks of the working fluid.

5. The method of claim 4 , wherein:
the refrigerator/liquefier comprises a gas purification member having an inlet adapted to receive gas that is to be purified and an outlet for purified gas, the outlet of the purification member being fluidically connected to the working circuit at an outlet of the compression station; and
at least part of the mixture of barrier gas and working fluid collected by the at least one outlet is reinjected into the inlet of the purification member so that the mixture can be purified and then reinjected into the working circuit at the outlet of the compression station.

6. The method of claim 5 , wherein the working circuit is open in that the inlet of the purification member is fed with gas by a gas that is distinct from the working fluid of the circuit.

7. The method of claim 4 , wherein at least part of the mixture of barrier gas and of working fluid collected by the at least one outlet of the barrier gas injection device is reinjected into the working circuit at a position selected from the group consisting of: an inlet of the compression station, an intermediate compression stage of the compression station, an outlet of the compression station, and combinations thereof.

8. The method of claim 7 , wherein the cycle is a closed cycle in that the cycle comprises a gas purification member having an inlet that is fed only with working gas originating from the working circuit and an outlet which feeds the cold box.

9. The method of claim 4 , wherein:
the refrigerator/liquefier comprises a gas purification member having an inlet for gas that is to be purified and an outlet for purified gas, the outlet of the purification member being fluidically connected to the working circuit at an inlet to the compression station; and
at least part of a mixture of barrier gas and of working fluid collected by the at least one outlet of the barrier gas injection device is reinjected into the inlet of the purification member so that the at least part of a mixture of barrier gas and working fluid can be purified and then reinjected into the working circuit at an inlet of the compression station.

10. The method of claim 4 , wherein;
the refrigerator/liquefier comprises a gas purification member having an inlet for gas that is to be purified and an outlet for purified gas, the outlet of the purification member being fluidically connected to the working circuit at an intermediate compression stage of the compression station and/or at an outlet of the compression station; and
at least part of a mixture of barrier gas and of working fluid collected by the at least one outlet of the barrier gas injection device is reinjected into the inlet of the purification member so that the at least part of a mixture of barrier gas and working fluid can be purified and then reinjected into the working circuit in or at an outlet of the compression station.

11. The method of claim 10 , wherein at least part of the mixture of barrier gas and of working fluid is compressed and fed to the inlet of the purification member after said compression.

12. The method of claim 1 , wherein the working fluid comprises helium.

13. The method of claim 1 , wherein the working fluid consists of pure helium.

14. The method of claim 1 , wherein the barrier gas comprises nitrogen.

15. The method of claim 1 , wherein the barrier gas consists of pure nitrogen.

Assignees

• Bernhardt Jean Marc
• Andrieu Frederic
• Delcayre Franck
• Durand Fabien
• Grabie Veronique
• Air Liquide

Inventors

• Bernhardt Jean-Marc
• Andrieu Frederic
• Delcayre Franck
• Durand Fabien
• Grabie Veronique

Classifications

• F25J1/0276

  Laboratory or other miniature devices · CPC title

• F25J2230/20

  Integrated compressor and process expander; Gear box arrangement; Multiple compressors on a common shaft · CPC title

• F25J1/0007

  Helium · CPC title

• F25J1/0065

  Helium · CPC title

• F25J2270/912

  Liquefaction cycle of a low-boiling (feed) gas in a cryocooler, i.e. in a closed-loop refrigerator · CPC title