CN112815226A - High-vacuum maintained liquid helium dewar - Google Patents

High-vacuum maintained liquid helium dewar Download PDF

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Publication number
CN112815226A
CN112815226A CN202110158505.0A CN202110158505A CN112815226A CN 112815226 A CN112815226 A CN 112815226A CN 202110158505 A CN202110158505 A CN 202110158505A CN 112815226 A CN112815226 A CN 112815226A
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CN
China
Prior art keywords
vacuum
liquid helium
cavity
dewar
cold
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Pending
Application number
CN202110158505.0A
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Chinese (zh)
Inventor
杜希阳
艾青
梁志炜
冯苌春
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Hydrogen Technology Guangzhou Co ltd
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Hydrogen Technology Guangzhou Co ltd
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Application filed by Hydrogen Technology Guangzhou Co ltd filed Critical Hydrogen Technology Guangzhou Co ltd
Priority to CN202110158505.0A priority Critical patent/CN112815226A/en
Publication of CN112815226A publication Critical patent/CN112815226A/en
Pending legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C1/00—Pressure vessels, e.g. gas cylinder, gas tank, replaceable cartridge
    • F17C1/12—Pressure vessels, e.g. gas cylinder, gas tank, replaceable cartridge with provision for thermal insulation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C13/00—Details of vessels or of the filling or discharging of vessels
    • F17C13/001—Thermal insulation specially adapted for cryogenic vessels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/03—Thermal insulations
    • F17C2203/0391—Thermal insulations by vacuum
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/03—Thermal insulations
    • F17C2203/0391—Thermal insulations by vacuum
    • F17C2203/0395—Getter

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Thermal Insulation (AREA)

Abstract

The invention discloses a high-vacuum maintained liquid helium dewar, which comprises an outer vacuum cavity, a liquid helium cavity and a liquid helium diameter pipe; the outer surface of the vacuum outer cavity is provided with a vacuum electric connector and a vacuumizing port, the vacuum electric connector extends to the vacuum interlayer, and the vacuumizing port is communicated with the vacuum interlayer; the inner surface of the vacuum outer cavity is provided with at least one air suction device which is electrically connected with the vacuum electric connector; the outer surface of the liquid helium cavity is provided with at least one adsorption device, an adsorption medium is arranged in the adsorption device, the adsorption device is provided with a heating device, and the heating device is electrically connected with the vacuum electric connector. In the embodiment of the invention, the liquid helium dewar can maintain high vacuum degree for a long time, can achieve good heat insulation effect, can maintain low volatilization rate for a long time, and has good practicability.

Description

High-vacuum maintained liquid helium dewar
Technical Field
The invention relates to the technical field of liquid helium dewar structures, in particular to a high-vacuum maintained liquid helium dewar.
Background
The liquid helium dewar is usually applied to storage and transportation of liquid helium, and has the main function of ensuring that the dewar can keep extremely low liquid helium volatilization rate in the storage and transportation process, namely the volatilization rate per 24 hours is required to be less than 1 percent; therefore, the liquid helium dewar needs to have good heat insulation performance, and generally reduces heat leakage by reducing radiation heat transfer, reducing heat conduction, reducing convection heat transfer and the like, so that the liquid helium dewar meets the requirements.
In the liquid helium Dewar, a vacuum interlayer is arranged between a vacuum outer cavity and the liquid helium cavity, a cold shield, multiple layers of heat insulation, a heat connecting pipeline, a suspended part and the like are arranged in the vacuum interlayer, and the vacuum interlayer is assembled together in the form of assembly and/or welding and the like; the vacuum interlayer needs to be kept high, i.e. below 1.0 x 10e-3Pa, the purpose of heat insulation can be achieved; the higher the vacuum degree of the vacuum interlayer is, the better the corresponding heat insulation effect is, and the problems of vacuum degree reduction and volatilization rate increase can occur after some liquid helium dewars operate for a plurality of times, and the main reasons are as follows: the material in the vacuum interlayer is continuously deflated, helium and hydrogen can be slowly leaked to the interior of the vacuum interlayer from the external environment, and the gases cannot be condensed and adsorbed on the outer surface of the liquid helium cavity, so that a gas adsorber arranged in the vacuum interlayer is quickly saturated, and the vacuum is poor.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, and provides the high-vacuum-maintained liquid helium dewar which can maintain high vacuum degree for a long time, can achieve good heat insulation effect, can maintain low volatility for a long time, and has good practicability.
Correspondingly, the embodiment of the invention provides a high-vacuum maintained liquid helium dewar, which comprises an outer vacuum cavity, a liquid helium cavity and a liquid helium diameter pipe;
the liquid helium cavity is arranged inside the vacuum outer cavity, and a vacuum interlayer is arranged between the liquid helium cavity and the vacuum outer cavity;
one end of the liquid helium diameter pipe is communicated with the inside of the liquid helium cavity, and the other end of the liquid helium diameter pipe is communicated with the outside of the vacuum outer cavity;
a vacuum electric connector and a vacuumizing port are arranged on the outer surface of the vacuum outer cavity, the vacuum electric connector extends to the vacuum interlayer, and the vacuumizing port is communicated with the vacuum interlayer;
the inner surface of the vacuum outer cavity is provided with at least one air suction device, and the air suction device is electrically connected with the vacuum electric connector;
the outer surface of the liquid helium cavity is provided with at least one adsorption device, an adsorption medium is arranged in the adsorption device, the adsorption device is attached with a heating device, and the heating device is electrically connected with the vacuum electric connector.
In an alternative embodiment, the getter device is a non-evaporative getter having a non-evaporative getter built-in.
In an optional embodiment, the adsorption device is an activated carbon adsorber, and the adsorption medium is activated carbon adhered or placed inside the activated carbon adsorber.
In an optional embodiment, a vacuum pumping flange is disposed on an outer surface of the vacuum outer cavity, and the vacuum pumping port is disposed in the vacuum pumping flange.
In an alternative embodiment, the liquid helium dewar further comprises a sealing flange connected to the evacuation flange and sealing the evacuation port.
In an alternative embodiment, an O-ring seal is disposed between the sealing flange and the evacuation flange.
In an alternative embodiment, a plurality of cold shields surrounding the liquid helium chamber are disposed in the vacuum interlayer.
In an optional embodiment, the plurality of cold shields include a first cold shield, a second cold shield, and a third cold shield sequentially disposed between the liquid helium chamber and the vacuum outer chamber, wherein:
the first cold shield is a 30K cold shield;
the second cold shield is a 77K cold shield, and a plurality of layers of heat insulation are arranged on the 77K cold shield;
the third cold screen is a 200K cold screen, and the 200K cold screen is provided with a plurality of layers of heat insulation.
In an optional embodiment, the vacuum outer cavity is a 300K vacuum outer cavity.
In an alternative embodiment, the liquid helium chamber is a 4K liquid helium chamber.
The embodiment of the invention provides a high-vacuum maintained liquid helium dewar, in the liquid helium dewar, after the vacuum pumping of a vacuum interlayer is finished, a gas suction device can continuously absorb the gas of the vacuum interlayer, so that the vacuum degree of the vacuum interlayer is improved and the high vacuum degree is maintained for a long time; the adsorption medium in the adsorption device can adsorb the gas which is difficult to condense, such as hydrogen, helium and the like in the vacuum interlayer, the speed and the capacity of adsorbing the hydrogen and the helium in the liquid helium Dewar can be improved, the vacuum degree of the vacuum interlayer can be further improved, the time of adsorbing the adsorption device to saturation can be prolonged, and the high vacuum degree can be maintained for a long time; therefore, the liquid helium dewar can maintain high vacuum degree for a long time, can achieve good heat insulation effect, can maintain low volatilization rate for a long time, and has good practical use effect.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is an external structural view of a liquid helium Dewar in an embodiment of the present invention;
FIG. 2 is a view showing the internal structure of a liquid helium Dewar in the embodiment of the present invention;
FIG. 3 is a schematic view of a partial structure of a liquid helium Dewar in an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 1 is an external structural view of a liquid helium dewar in an embodiment of the present invention, and fig. 2 is an internal structural view of the liquid helium dewar in the embodiment of the present invention.
The embodiment of the invention provides a high-vacuum maintained liquid helium dewar, which comprises an outer vacuum cavity 1, a liquid helium cavity 2 and a liquid helium diameter pipe 3.
The liquid helium cavity 2 is arranged inside the vacuum outer cavity 1, and a vacuum interlayer is arranged between the liquid helium cavity 2 and the vacuum outer cavity 1.
In specific implementation, liquid helium can be conveyed into the liquid helium cavity 2 through the liquid helium radial pipe 3, and liquid helium can be extracted from the inside of the liquid helium cavity 2 through the liquid helium radial pipe 3.
The outer surface of the vacuum outer cavity 1 is provided with a vacuum electric connector 4 and a vacuum-pumping port 5.
The vacuum electric connector 4 extends to the vacuum interlayer, and the vacuum electric connector 4 is used for realizing the electric connection of the internal element and the external circuit.
The vacuum-pumping port 5 is communicated with the vacuum interlayer, in specific implementation, the vacuum-pumping port 5 is connected with a molecular pump or a low-temperature vacuum pump set, and the vacuum interlayer can be vacuumized through the vacuum-pumping port 5.
The vacuum outer cavity comprises a vacuum outer cavity body 1 and is characterized in that at least one air suction device 11 is arranged on the inner surface of the vacuum outer cavity body 1, the air suction device 11 is electrically connected with a vacuum electric connector 4, in the specific implementation, the air suction device 11 is electrically connected with the vacuum electric connector 4 through a lead, an external power supply is electrically connected with the vacuum electric connector 4 through an external circuit, after the vacuum interlayer is vacuumized, the external power supply controls the operation of the air suction device 11 through the vacuum electric connector 4, and the air suction device 11 absorbs gas in the vacuum interlayer, so that the vacuum degree of the vacuum interlayer is improved.
In specific implementation, the adsorption medium in the adsorption device 21 can adsorb the difficult-to-condense gas such as hydrogen gas and helium gas in the vacuum interlayer, and other gases are condensed on the outer surface of the liquid helium cavity 2, so that not only can the vacuum degree of the vacuum interlayer be further improved, but also the adsorption time of the air suction device 11 to saturation be prolonged, and the high vacuum degree is maintained for a long time; the heating device is electrically connected with the vacuum electric connector 4 through a wire, an external power supply is electrically connected with the vacuum electric connector 4 through an external circuit, when the vacuum interlayer is vacuumized, the external power supply controls the operation of the heating device through the vacuum electric connector 4, the heating device can integrally heat the liquid helium dewar, evaporate gas adsorbed by the adsorption medium, smoothly pump away the gas adsorbed by the adsorption medium, and enable the adsorption medium saturated in adsorption to recover the efficiency again.
Specifically, the getter device 11 is a non-evaporation getter, and a non-evaporation getter is built in the non-evaporation getter.
In specific implementation, after the vacuum interlayer is vacuumized, an external power supply controls the operation of the non-evaporation type getter through the vacuum electric connector 4, the non-evaporation type getter is discharged, gas in the vacuum interlayer is adsorbed, and the vacuum degree of 1-2 orders of magnitude can be improved.
In addition, the non-evaporable getter in the non-evaporable getter can work for a plurality of times, after the liquid helium dewar runs for a long time and the adsorption device 21 is adsorbed and saturated, the external power supply controls the operation of the non-evaporable getter again through the vacuum electric connector 4, the non-evaporable getter is discharged again, the gas in the vacuum interlayer is adsorbed again, the vacuum degree can be continuously improved, and the volatilization rate of the liquid helium can be reduced.
Specifically, the adsorption device 21 is an activated carbon adsorber, and the adsorption medium is activated carbon adhered or placed inside the activated carbon adsorber.
In specific implementation, after liquid helium is conveyed into the liquid helium cavity 2 through the liquid helium radial pipe 3, the adsorption capacity of the activated carbon is greatly enhanced, the activated carbon can adsorb gases which are difficult to condense, such as hydrogen gas, helium gas and the like in the vacuum interlayer, other gases are condensed on the outer surface of the liquid helium cavity 2, so that the vacuum degree of 1-2 orders of magnitude is improved, and finally 1.0 × 10e is achieved-6Pa or more.
In addition, when the vacuum interlayer is vacuumized, the heating device can integrally heat the liquid helium dewar to 45-120 ℃, heat the active carbon in the active carbon adsorber, evaporate the gas adsorbed by the active carbon, smoothly pump the gas adsorbed by the active carbon away, and recover the efficiency of the active carbon with saturated adsorption.
FIG. 3 is a schematic view of a partial structure of a liquid helium Dewar in an embodiment of the present invention.
Specifically, a vacuumizing flange 12 is arranged on the outer surface of the vacuum outer cavity 1, and the vacuumizing port 5 is arranged in the vacuumizing flange 12.
In addition, the liquid helium dewar further comprises a sealing flange 6, wherein the sealing flange 6 is connected with the vacuumizing flange 12 and seals the vacuumizing port 5.
In specific implementation, when the vacuum degree at the vacuum pumping port 5 reaches 1.0 × 10e-4After Pa or higher, the sealing flange 6 is connected to the vacuuming flange 12, and the vacuuming port 5 is sealed.
Particularly, an O-shaped sealing ring 61 is arranged between the sealing flange 6 and the vacuumizing flange 12, and the O-shaped sealing ring 61 can seal a connecting gap between the sealing flange 6 and the vacuumizing flange 12, so that a better sealing effect is achieved.
Specifically, a plurality of cold shields surrounding the liquid helium cavity 2 are arranged in the vacuum interlayer, and the plurality of cold shields have a heat insulation effect on the liquid helium cavity 2.
The plurality of cold shields comprise a first cold shield 71, a second cold shield 72 and a third cold shield 73 which are sequentially arranged between the liquid helium cavity 2 and the vacuum outer cavity 1.
Preferably, the first cold shield 71 is a 30K cold shield.
Preferably, the second cold shield 72 is a 77K cold shield, and the 77K cold shield is provided with a plurality of layers of thermal insulation.
Preferably, the third cold shield 73 is a 200K cold shield, and the 200K cold shield is provided with a plurality of layers of thermal insulation.
Preferably, the vacuum outer cavity 1 is a 300K vacuum outer cavity.
Preferably, the liquid helium chamber 2 is a 4K liquid helium chamber.
The embodiment of the invention provides a high-vacuum maintained liquid helium dewar, in the liquid helium dewar, after the vacuum pumping of the vacuum interlayer is finished, the getter device 11 can continuously absorb the gas of the vacuum interlayer, thereby improving the vacuum degree of the vacuum interlayer and maintaining the high vacuum degree for a long time; the adsorption medium in the adsorption device 21 can adsorb the gas difficult to condense, such as hydrogen gas and helium gas, in the vacuum interlayer, so that the speed and the capacity of adsorbing the hydrogen gas and the helium gas in the liquid helium dewar can be increased, the vacuum degree of the vacuum interlayer can be further increased, the time from adsorption to saturation of the gas suction device 11 can be prolonged, and the high vacuum degree can be maintained for a long time; therefore, the liquid helium dewar can maintain high vacuum degree for a long time, can achieve good heat insulation effect, can maintain low volatilization rate for a long time, and has good practical use effect.
In addition, the above detailed description of the high vacuum maintained liquid helium dewar provided by the embodiments of the present invention is provided, and the principle and the embodiments of the present invention shall be explained herein by using specific examples, and the above description of the embodiments is only used to help understanding the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims (10)

1. A high vacuum maintained liquid helium dewar is characterized in that the liquid helium dewar comprises a vacuum outer cavity, a liquid helium cavity and a liquid helium diameter pipe;
the liquid helium cavity is arranged inside the vacuum outer cavity, and a vacuum interlayer is arranged between the liquid helium cavity and the vacuum outer cavity;
one end of the liquid helium diameter pipe is communicated with the inside of the liquid helium cavity, and the other end of the liquid helium diameter pipe is communicated with the outside of the vacuum outer cavity;
a vacuum electric connector and a vacuumizing port are arranged on the outer surface of the vacuum outer cavity, the vacuum electric connector extends to the vacuum interlayer, and the vacuumizing port is communicated with the vacuum interlayer;
the inner surface of the vacuum outer cavity is provided with at least one air suction device, and the air suction device is electrically connected with the vacuum electric connector;
the outer surface of the liquid helium cavity is provided with at least one adsorption device, an adsorption medium is arranged in the adsorption device, the adsorption device is attached with a heating device, and the heating device is electrically connected with the vacuum electric connector.
2. The liquid helium dewar according to claim 1, wherein the getter device is a non-evaporative getter having a non-evaporative getter built-in.
3. The liquid helium dewar of claim 1, wherein the adsorption device is an activated carbon adsorber and the adsorption medium is activated carbon bonded or placed inside the activated carbon adsorber.
4. The liquid helium dewar according to claim 1, wherein an outer surface of the vacuum outer cavity is provided with a vacuuming flange, and the vacuuming port is provided in the vacuuming flange.
5. The liquid helium dewar of claim 4, further comprising a sealing flange connected with the evacuation flange and sealing the evacuation port.
6. The liquid helium dewar according to claim 5, wherein an O-ring seal is provided between the sealing flange and the evacuation flange.
7. The liquid helium dewar of claim 1, wherein a plurality of cold shields surrounding the liquid helium cavity are disposed in the vacuum interlayer.
8. The liquid helium dewar of claim 7, wherein the plurality of cold shields comprises a first cold shield, a second cold shield and a third cold shield disposed in sequence between the liquid helium chamber and the outer vacuum chamber, wherein:
the first cold shield is a 30K cold shield;
the second cold shield is a 77K cold shield, and a plurality of layers of heat insulation are arranged on the 77K cold shield;
the third cold screen is a 200K cold screen, and the 200K cold screen is provided with a plurality of layers of heat insulation.
9. The liquid helium dewar of claim 1, wherein the outer vacuum cavity is a 300K outer vacuum cavity.
10. The liquid helium dewar of claim 1, wherein the liquid helium chamber is a 4K liquid helium chamber.
CN202110158505.0A 2021-02-05 2021-02-05 High-vacuum maintained liquid helium dewar Pending CN112815226A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110158505.0A CN112815226A (en) 2021-02-05 2021-02-05 High-vacuum maintained liquid helium dewar

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110158505.0A CN112815226A (en) 2021-02-05 2021-02-05 High-vacuum maintained liquid helium dewar

Publications (1)

Publication Number Publication Date
CN112815226A true CN112815226A (en) 2021-05-18

Family

ID=75861608

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110158505.0A Pending CN112815226A (en) 2021-02-05 2021-02-05 High-vacuum maintained liquid helium dewar

Country Status (1)

Country Link
CN (1) CN112815226A (en)

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