JPH064567Y2 - Cryogenic container - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention is directed to a superconducting device such as a superconducting magnet that exhibits a superconducting phenomenon at extremely low temperatures, and a refrigerant for cooling the same.
For example, it relates to a cryogenic container for storing liquid helium.

[Conventional technology]

Among well-known cryogenic containers, there is a forced cooling type container that also uses a refrigerator to reduce the evaporation amount of the refrigerant liquid in the inner container. For example, the one disclosed in Japanese Utility Model Laid-Open No. 63-75007 is also the forced cooling type, which improves the heat insulation performance of the cryogenic container by cooling the heat shield layer surrounding the inner container with a refrigerator. Therefore, the evaporation of the refrigerant liquid is suppressed thereby.

[Problems to be solved by the device]

Although the conventional cryogenic container as described above can reduce the heat entering from the outside, it is not possible to recondensate the vaporized gas positively, so the superconducting equipment and its accessories stored in the inner container There is a problem that the amount of evaporation of the refrigerant liquid increases when heat is generated.

This invention is intended to solve such a problem.

[Means for Solving the Problems]

In the cryogenic container of the present invention, the condenser part of the refrigerator is introduced into the inner container for containing the refrigerant liquid, and further, the periphery of the condenser part is surrounded by a heat conductor which is immersed in the refrigerant liquid. However, it is characterized.

[Action]

With the above configuration, the evaporated gas of the refrigerant liquid can be efficiently recondensed in the inner container.

That is, even if the condenser portion of the refrigerator is simply inserted into the internal unit, efficient recondensation of the evaporative gas cannot be expected even though the effect of suppressing the evaporation of the refrigerant liquid is enhanced. However, according to the present invention, the heat conductor surrounding the condenser portion prevents the temperature rise of the evaporative gas and keeps it at a temperature near the liquefaction temperature, so that even a refrigerator with a limited capacity can be efficiently recondensed. Will be possible.

To further explain this, for example, helium gas with a critical temperature of 5.22k cannot be liquefied at a temperature of 5.22k or higher, but the entire gas retention space in the inner container is limited to heat insulation performance.
Keeping below 22k is very difficult. Also, if it is 5.22k
Even if kept below, the liquefaction temperature of helium gas at atmospheric pressure = 4.2k, whereas the temperature of the condenser of the refrigerator used to cool it is generally 4.3k to 4.1k, so the actual gas temperature If the difference between the liquefaction temperature and the liquefaction temperature is large, most of the capacity of the refrigerator will be spent for cooling up to 4.2k, and liquefaction (recondensation)
Ability is greatly reduced. However, according to this invention,
Since the heat conductor immersed in liquid helium is cooled to 4.2k to prevent the temperature rise of the inner gas, the inner gas has a small difference with the liquefaction temperature under atmospheric pressure of 4.2 to 4.3k. It is retained, and therefore efficient recondensation takes place.

〔Example〕

 FIG. 1 shows an embodiment of this invention.

As shown in the figure, the cryogenic container 20 has a vacuum heat insulating layer 2, a liquid nitrogen shield tank 3, and a multilayer heat insulating layer 4 between an outer container 1 and an inner container 5 to form a heat insulating portion. 17 is an inlet of liquid nitrogen to the tank 3, and 18 is an outlet.

In the inner container 5, a superconducting magnet 14 that is energized from the outside through a power reed 8 and a lead wire 15 is provided.
It is hung from the upper lid 19 at 2. 6 is an inlet for supplying liquid helium to the inner container 5, 7 is an outlet for evaporated helium gas, and 9 is
Is a heat shield plate.

Reference numeral 10 is a refrigerator having a condenser 11 at its tip. Evaporated gas from the liquid surface 16 of liquid helium LHe is cooled and condensed by the condenser 11 inserted in the inner container, but cannot be condensed when the gas temperature exceeds 5.22k. Therefore, the cylindrical body 13 formed of a good electric heating material such as copper is provided so that the lower side is soaked in LHe and the upper side surrounds the condenser 11 from the outside.
The evaporative gas in this cylinder whose temperature rise is suppressed by cooling by the cylinder is recondensed by the cold heat from the condenser 11.

In this way, when the inner container inner diameter is 300 mm and the amount of heat penetration into the liquid helium is 5 w, the following difference in evaporation amount is obtained between the case with the device of the present invention and the case without the device of the present invention. That is,
Since liquid helium has an evaporation rate of about 1.4 / hr per 1w, about 7 / hr of evaporation occurs unless the device of the present invention is devised.
On the other hand, with the device of the present invention, the evaporation amount when using the 3w refrigerator was suppressed to 3.5 / hr. 3w
Since the refrigerator has a liquefaction capacity of 4.2 / hr, It means that recondensation was performed with high efficiency.

Although the cylindrical body 13 is supported by the magnet 14 in LHe in the drawing, it may be supported by the suspension rod 12 or the like.

〔effect〕

As described above, the cryogenic container of the present invention encloses the condenser part of the refrigerator inserted in the inner container with the lower part surrounded by the heat conductor immersed in the refrigerant liquid, so that the temperature rise is effectively prevented. Since the vaporized gas inside the conductor is efficiently recondensed, even if the superconducting equipment and its accessories generate heat, the amount of evaporation of the refrigerant liquid is reduced, and the operating cost of the device using this is reduced. There is an effect that the labor can be reduced by extending the supply time of the refrigerant liquid.

[Brief description of drawings]

 The attached drawing is a sectional view showing an embodiment of the present invention. 1 ... Outer container, 5 ... Inner container, 10 ... Refrigerator, 11 ... Condenser, 13 ... Cylindrical body, 14 ... Thermal superconducting magnet.

Claims (1)

[Scope of utility model registration request] 1. A condenser part of a refrigerator is inserted into an inner container for accommodating a refrigerant liquid, and the periphery of the condenser part is surrounded by a heat conductor immersed in the refrigerant liquid. A cryogenic container characterized in that the vaporized gas of 1. is re-condensed by cooling by the condenser section.