JPH0774019A - Cryogenic cooling system - Google Patents

Abstract

PURPOSE:To continue the stable cooling of a radiation shielding plate by a method wherein, separately from a refrigerator for an inner-tank cooling system, a refrigerator is installed also for a shield cooling system, a system is constituted so as to be small and lightweight as a whole and an evaporation coolant gas for the inner-tank cooling system is utilized even when the refrigerator for the shield cooling system is stopped abnormally. CONSTITUTION:Separately from a coolant tank 2 and a refrigerator 10 for an inner-tank cooling system which cools an inner-tank container 1 for a superconducting magnet device, a refrigerator 30 is installed also for a shield cooling system which cools a radiation shielding plate 3. A coolant gas is sent out to a shield-cooling-gas line 31 from the refrigerator 30, and the radiation shielding plate 3 is cooled. On the other hand, the shield-cooling-gas line 31 is connected to a coolant-gas collection pipe 7 for the inner-tank cooling system via a valve 34. When the refrigerator 30 for the shield cooling system is stopped abnormally, an evaporation coolant for the inner-tank cooling system is introduced into the shield-cooling-gas line 31 via the valve 34, and the radiation shielding plate 3 is cooled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryogenic cooling system for keeping cryogenic equipment such as a superconducting magnet device cold.

[0002]

2. Description of the Related Art Generally, in a superconducting magnet device (SCM), in order to maintain a superconducting state of a superconducting coil,
The superconducting coil is housed in the inner tank container, and the inner tank container is filled with a refrigerant liquid such as liquid helium (LHe) to cool the superconducting coil to a cryogenic state.

Further, in order to reduce the amount of heat invasion from the outside as much as possible, the inner tank container is housed and held in the outer tank container having a vacuum inside through a load supporting material having excellent heat insulating properties. , A radiation shield plate surrounding the outer circumference of the inner container is provided between the outer container and the inner container, and the radiation shield plate is kept at the temperature level of liquid nitrogen to prevent the radiant heat from entering from the outside. It has a structure.

For this purpose, as a cryogenic cooling system for a superconducting magnet device, first, as an inner tank cooling system, a refrigerant liquid such as liquid helium is supplied into an inner tank container containing a superconducting coil through a cryogenic pipe. A refrigerant tank, a refrigerator for liquefying the evaporated helium gas (GHe) in the refrigerant tank as a refrigerant gas, and a buffer tank for supplying the refrigerant gas are assembled.

When the heat load for cooling the radiation shield plate is 50 to 100 W or more, a separate shield cooling system other than the refrigerator is required, and a liquid nitrogen tank is usually provided, and this tank is used. Liquid nitrogen (LN ₂ ) is passed through a shield pipe attached to the radiation shield plate to cool the radiation shield plate.

The flow of such a cryogenic cooling system is shown in FIG. That is, the inner tank container 1 containing the superconducting coil
Is connected to a refrigerant tank 2 for introducing liquid helium through a cryogenic pipe, a radiation shield plate 3 is provided so as to surround the inner tank container 1 and the refrigerant tank 2, and a vacuum outside the outer circumference is provided. A tank container 4 is provided.
The outer tank container 4 is provided with an external connection port 5, from which a precooling / liquid injection pipe 6 and a gas recovery pipe 7 are connected to the inside of the refrigerant tank 2.

A refrigerating machine 10 for liquefying a refrigerant gas is provided so as to be partially incorporated in the outer tank container 4, and this refrigerating machine 10 has a refrigerant gas recovery pipe 11 and a frozen gas supply pipe 12 in the refrigerant tank 2. Connected through. Further, an evaporative refrigerant gas compressor 13 is connected to the refrigerator 10 by piping, and the high pressure refrigerant gas line 14a and the low pressure refrigerant gas return line 14b of the compressor 13 are provided with a high pressure control valve 15a and a low pressure valve. A buffer tank 16 for replenishing the refrigerant gas is connected via the control valve 15b.

On the other hand, the radiation shield plate 3 surrounding the inner vessel 2
Liquid nitrogen tank 1 as a shield cooling system for cooling
7 is installed and installed in the outer tank container 4, and the tank 17
A shield pipe 18 for passing liquid nitrogen (LN ₂ ) therein is attached along the radiation shield plate 3. The liquid nitrogen tank 17 is provided with a supply pipe 19 and a recovery pipe 20 for supplying liquid nitrogen from outside and recovering vapor gas, and an external connection port 21, while a shield pipe 18 is provided.
Is connected to the connection port 22 and from there is connected to the pumping or circulating device 23.

Thus, in the shield cooling system, the liquid nitrogen tank 17 is connected to the supply pipe 19 from the external connection port 21.
The liquid nitrogen is stored via the radiation pipe 3, and the liquid nitrogen passes through the shield pipe 18 by a self-pressure or pressure-feeding method.
Is cooled by heat exchange, and the nitrogen gas (GN
₂ ) is discharged or collected from the connection port 22 to the outside.

In the inner tank cooling system, helium gas is injected from the external connection port 5 through the precooling / injection pipe 6 to precool the inner tank container 1 to a predetermined temperature or less, and then the refrigerant tank 2 is cooled. Liquid helium is supplied to store the liquid, and the liquid helium is filled in the inner tank container 1. This liquid helium evaporates into helium gas due to the heat intrusion load from the outside, but it is condensed by the refrigerator 10 and reliquefied,
A predetermined amount is secured in the refrigerant tank 2.

The superconducting coil of the superconducting magnet device is cooled to a cryogenic state by controlling the refrigerator 10 of the inner tank cooling system and the liquid nitrogen pressure feeding or circulating device 23 of the shield cooling system separately provided. And maintain a stable superconducting state.

[0012]

By the way, in the cryogenic cooling system for keeping the cryogenic equipment such as the above-mentioned superconducting magnet device cool, if there is a structural limitation of the whole system, for example, in a car like a levitation railway, When it is necessary to take the form of a system, it is particularly necessary to reduce the size and weight.

In such a case, the capacities of the refrigerant tank 2 for the inner tank cooling system and the liquid nitrogen tank 17 for the shield cooling system are particularly limited. Therefore, assuming that the cooling heat load of the radiation shield plate 3 is 150 W and the capacity of the liquid nitrogen tank 17 is 50 l, it is necessary to supply liquid nitrogen to the tank 17 from the outside about twice a day. .

It is necessary to supply liquid nitrogen from the outside on a daily basis. In the case of the floating railway, the work of connecting / disconnecting the external pipe occurs each time. Furthermore, a large-scale liquid nitrogen supply device and a tank are required as ground equipment, resulting in a very high running cost of the entire system.

Therefore, it has been attempted to add a refrigerator for cooling the radiation shield plate 3 to the shield cooling system in addition to the refrigerator 10 for the inner tank cooling system. The liquid nitrogen tank 17 has to be further reduced in capacity or deleted.

Therefore, should the refrigerator of the shield cooling system stop abnormally, the temperature of the radiation shield plate 3 suddenly rises, and the amount of heat entering the refrigerator 10 of the inner tank cooling system and the superconducting magnet device is increased. There is a risk that the balance will suddenly be lost, the amount of liquid helium in the refrigerant tank 2 will begin to decrease, and it will be difficult to maintain the superconducting state of the superconducting magnet device.

The present invention has been made in view of the above circumstances, and a refrigerant tank and a refrigerator for liquefying a refrigerant gas are provided in an inner tank cooling system for cooling an inner tank container of a cryogenic device such as a superconducting magnet device with a refrigerant such as liquid helium. In addition to the provision of a refrigerator in the shield cooling system for cooling the radiation shield plate surrounding the inner vessel, the radiation shield plate is usually used in a cryogenic cooling system aiming at downsizing and weight reduction of the entire system configuration. Is cooled by the refrigerant gas discharged from the refrigerator of the shield cooling system, even if the refrigerator of the shield cooling system stops abnormally, the evaporated refrigerant gas of the inner tank cooling system is introduced into the shield cooling system, An object is to provide a cryogenic cooling system capable of continuing stable cooling of the radiation shield plate.

[0018]

In order to achieve the above object, the cryogenic cooling system of the present invention is an internal tank cooling for cooling an internal tank container of a cryogenic device such as a superconducting magnet device with a refrigerant such as liquid helium. The system is provided with a refrigerant tank and a refrigerator for liquefying refrigerant gas, and a refrigerator is also provided in a shield cooling system for cooling the radiation shield plate surrounding the inner tank container, and the shield cooling system is the refrigerator. From the cooling gas line to the cooling gas line to cool the radiation shield plate, and the cooling gas line is connected to the cooling gas line of the inner tank cooling system via a valve to protect the shield. When the refrigerator of the cooling system is abnormally stopped, the vaporized refrigerant gas of the inner tank cooling system is introduced into the shield cooling gas line through the valve to cool the radiation shield plate. To.

[0019]

[Operation] With the cryogenic cooling system having the above-mentioned configuration,
Normally, a refrigerant such as liquid helium is filled in the inner tank container of a cryogenic device such as a superconducting magnet device through a refrigerant tank of the inner tank cooling system, and the evaporated refrigerant gas is re-cooled by the refrigerator of the inner tank cooling system. It is liquefied and returned to the inside of the refrigerant tank to maintain the required amount of refrigerant liquid. This cools the inner tank container to an extremely low temperature. On the other hand, the radiation shield plate is cooled by the refrigerant gas such as helium gas discharged from the refrigerator of the shield cooling system to the shield refrigerant gas line.

If the refrigerator of the shield cooling system stops abnormally, the refrigerant gas line of the shield cooling system and the refrigerant gas line of the inner tank cooling system are connected via a valve so that the shield cooling system is In order to stably cool the radiation shield plate, the evaporated refrigerant gas is introduced into the refrigerant gas line of the shield cooling system corresponding to the increase in the amount of heat entering the refrigerant tank of the inner tank cooling system due to the stop of the refrigerator. become.

That is, for example, in a superconducting magnet device,
If the heat load on the radiation shield plate Q _S, the heat load on the inner tank container and the refrigerant tank was Q _L, the ability of the shield cooling system of the refrigerator capacity Q _SR and the inner tub cooling system of the refrigerator Q _LR Shall be designed in consideration of the system allowance (safety factor). Similarly, the refrigerant tank has a capacity that can maintain the required amount of, for example, liquid helium as a refrigerant for a certain predetermined time that does not hinder system operation even if the refrigerator or compressor of the inner tank cooling system stops abnormally. To design as. Now, normally, the refrigerators of the inner tank cooling system and the shield cooling system are operating normally, and under the condition of Q _SR > Q _S and Q _LR > Q _R , the inner tank container is filled with liquid helium and helium gas. And the radiation shield plate is cooled, and the superconducting magnet is kept at an extremely low temperature to stably maintain the superconducting state.

By the way, if the refrigerator of the shield cooling system stops abnormally for some reason, the supply of helium gas to the radiation shield plate also stops and the shield temperature rises. Accordingly, the heat load Q _L to the refrigerant tank inner tank cooling system also will be increased, if this state continues, the liquid helium of the refrigerant tank is rapidly decreased, finally the superconducting state of the superconducting magnet apparatus I can no longer hold it.

In order to prevent this, the shield cooling gas line of the shield cooling system and the refrigerant gas line of the inner tank cooling system are connected by switching valves or the like. As a result, the evaporated helium gas in the inner tank cooling system is introduced into the shield cooling gas line, and the temperature rise of the radiation shield plate is greatly reduced.

At this time, the capacity Q _LR of the refrigerator for the inner tank cooling system is increased by the heat load Q _LR increased by stopping the refrigerator for the shield cooling system.
_When there is a margin for _L , the amount of helium gas returned to the refrigerator in the internal tank cooling system is insufficient, but the amount of liquid helium in the refrigerant tank is replenished by replenishing that amount of helium gas from the buffer tank in the compressor line. The operation is performed while preventing the decrease of

When the heat load Q _L exceeds the capacity Q _LR of the refrigerator in the inner tank cooling system, the evaporated helium gas in the refrigerant tank increases by that amount, and the internal pressure of the refrigerant tank rises. Therefore, the amount of helium gas supplied to the refrigerant gas line of the shield cooling system increases.

[0026] Such in mind, so that the inner tub cooling system and the shield cooling system for cooling operation under balanced conditions set in advance, pre _{Q S, Q L, Q SR} , Q LR and coolant tank By designing the capacity and the like, highly reliable and stable cryogenic cooling of cryogenic equipment such as a superconducting magnet device becomes possible.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments of the cryogenic cooling system of the present invention will be described below with reference to FIGS. Here, a cryogenic cooling system in the superconducting magnet device is exemplified. Further, in the figure, the same reference numerals are given to those having the same configurations as those described in FIG. 4 to simplify the explanation.

First, FIG. 1 shows a first embodiment of a cryogenic cooling system according to the present invention, which is connected to the upper portion of an inner tank container 1 containing a superconducting coil through a cryogenic pipe as in the conventional case. A coolant tank 2 containing liquid helium as a coolant is provided, and a radiation shield plate 3 and a vacuum outer tank container 4 are provided for these.
A superconducting magnet device is surrounded by.

A precooling / liquid injection pipe 6 and a gas recovery pipe 7 are connected to the refrigerant tank 2 of the inner tank cooling system for cooling the inner tank container 1 from an external connection port 5 provided in the outer tank container 4. There is. Further, as an inner tank cooling system, a refrigerator (hereinafter referred to as a main refrigerator) 10 is connected to the refrigerant tank 2 via a refrigerant gas recovery pipe 11 and a frozen gas supply pipe 12. The main refrigerator 10 is a closed-loop refrigerator that condenses and reliquefies the helium gas evaporated in the refrigerant tank 2, and a refrigerant gas compressor 13 is connected to the refrigerant compressor 2 by piping, and the compressor 13 is also provided. A buffer tank 16 for replenishing the refrigerant gas is connected to the high pressure refrigerant gas line 14a and the low pressure refrigerant gas return line 14b via a high pressure control valve 15a and a low pressure control valve 15b. The main refrigerator 10 keeps the liquid helium in the refrigerant tank 2 constant and keeps the inner tank container 1 at the liquid helium temperature (about 4.2 K).

On the other hand, a refrigerator (hereinafter referred to as a shield refrigerator) 30 is provided in a shield cooling system for cooling the shield plate 3.
Is provided. This shield refrigerator 30 has a helium gas (about 80%) which is a low-temperature refrigerant gas generated in the system.
K) is discharged and circulated through the shield pipe 18 in the shield cooling gas line 31, so that the radiation shield plate 3 is cooled to about 80 K by heat exchange. Reference numeral 32 in the figure denotes a compressor for recondensing the refrigerant gas, which is connected to the shield refrigerator 30.

Further, the refrigerant tank 2 which is the refrigerant gas line of the inner tank cooling system and the portion (upstream) of the shield pipe 18 of the shield cooling gas line 31 of the shield cooling system.
The recovery pipe 7 is connected to the branch pipe 33 via the opening / closing valve 34. By this, in the unlikely event of abnormal shutdown of the shield refrigerator 30, the opening / closing valve 34 is opened, and the evaporated refrigerant gas of the inner tank cooling system is introduced into the shield cooling gas line 31 through the branch pipe 33 so that the radiation shield plate 3 is cooled. It is configured to be used for cooling.

Further, the return port pipe to the shield refrigerator 30 at the end side of the shield pipe 18 of the shield cooling gas line 31 is branched to form the external port 2 provided in the outer layer container 4.
2 and a pipe having an open valve 35 is connected to the external port 22 thereof.

When the heat load on the radiation shield plate 3 is Q _S and the heat load on the inner tank container 1 and the refrigerant tank 2 is Q _L , the capacity Q _SR of the shield refrigerator 30 of the shield cooling system is The capacity Q _LR of the main refrigerator 10 of the inner tank cooling system is designed in consideration of a margin (safety factor) appropriate for the system. Similarly, even if the main refrigerator 1 or the compressor 13 stops abnormally, the refrigerant tank 2 of the inner tank cooling system requires a required amount of liquid helium as a refrigerant for a certain predetermined time that does not hinder the system operation. Design as a capacity that can be maintained. As a result, normally, the main refrigerator 10 and the shield refrigerator 30 are normally operated under the conditions of Q _SR > Q _S and Q _LR > Q _R.

In the cryogenic cooling system having such a configuration, normally, the inner tank container 1 is filled with liquid helium as a refrigerant through the refrigerant tank 2 of the inner tank cooling system, and
The evaporated refrigerant gas is sent to the main refrigerator 19, condensed and returned by the compressor 13, and reliquefied to maintain a required refrigerant liquid amount in the refrigerant tank 2. This cools the inner tank container 1 to a cryogenic temperature of liquid helium (about 4.2 K).

On the other hand, the shield refrigerator 3 of the shield cooling system
Helium gas as a refrigerant gas discharged from 0 to the shield cooling gas line 31 flows into the shield pipe 18 to cool the radiation shield plate 3. During this normal state, the open / close valve 34 and the open valve 35 are closed, and the shield refrigerator 30 repeatedly recondenses with the compressor 32 while circulating the helium gas after heat exchange with the radiation shield plate 3. To the shield cooling gas line 31 to cool the radiation shield plate 3.

By the way, if the shield refrigerator 30 of the shield cooling system or its compressor 32 is stopped due to some abnormality, helium gas is not supplied to the shield pipe 8 and the temperature of the radiation shield plate 3 rises, With this, the heat load (heat penetration amount) to the inner tank container 1 and the refrigerant tank 2
Q _L is increased, the large that with the tank 2 internal pressure rises, if the heat load Q _L comes above the capacity Q _LR of the main refrigerating machine 10, the liquid helium in the refrigerant tank 2 starts to decrease rapidly Develops into a problem.

Therefore, in the present invention, when the shield cooling system has an abnormality, a sequence is set up in which the opening valve 34 and the opening valve 35 are automatically opened upon receipt of the abnormality occurrence signal, or manually. The valves 34, 35
open. As a result, first, the helium gas in the shield pipe 18 is once released or recovered to the outside via the open valve 35.

Next, as described above, the helium gas increased in the refrigerant tank 2 of the internal tank cooling system is pushed out by the increased pressure from the recovery pipe 7 through the opening / closing valve 34 and the shield cooling from the branch pipe 33. The helium gas introduced into the gas line 31 flows into the shield pipe 18 to heat-exchange and cool the radiation shield plate 3, and the open valve 3 as it is.
5 will be released or collected to the outside.

Now, the cooling temperature of the radiation shield plate 3 is normally about 80 to 90K, but in the case of the above abnormality,
As I mentioned earlier Q _S, Q _L, Nisato to keep the condition setting capacity of the Q _SR and Q _LR and the refrigerant tank 2, can be stopped to increase to about 120~150K level at most As a result, it is possible to prevent the liquid helium in the refrigerant tank 2 from rapidly decreasing, and to end the daytime running without causing any trouble to the system especially in daily operation such as a levitation railway. It will be possible.

Moreover, the excess / deficiency of helium gas in the refrigerant tank 2 of the inner tank cooling system or the compressor 13 is fixed by the buffer tank 16 connected from the compressor 13 via the high / low pressure control valves 15a and 15b. As a result, the liquid helium in the refrigerant tank 2 can be prevented from being rapidly reduced even in the above-mentioned abnormal state.

The external port 22 and the open valve 3 for releasing or recovering the refrigerant gas of the shield cooling system to the outside.
5 can be provided on the compressor 32 side of the shield cooling system.

Next, an embodiment of the shield of the cryogenic cooling system of the present invention will be described with reference to FIG. This basic configuration is similar to that of the embodiment of FIG. 1 described above, but here, the check valve 36 is provided in the middle of the branch pipe 33 branched from the recovery pipe 7 of the refrigerant tank 2 of the inner tank cooling system. And the adjustment valve 37 is provided near the discharge port of the shield refrigerator 30 of the shield cooling gas line 31 to which the branch pipe 33 is connected to maintain the helium gas pressure in the shield pipe 18 constant. .

Furthermore, the external port 22 provided in the outer layer container 4 by branching the return side pipe to the shield refrigerator 30 at the end side of the shield pipe 18 of the shield cooling gas line 31.
A recovery line 39 with a recovery valve 38 for recovering from the external port 22 to the low pressure refrigerant gas return line 14b of the refrigerant gas compressor 13 of the main refrigerator 10 is provided.

In the embodiment of this construction, the pressure in the refrigerant tank 2 of the inner tank cooling system usually depends on the saturation temperature of the helium gas and the characteristics of the main refrigerator 10 and the compressor 13, but is generally 0.1-. The discharge gas pressure of the shield refrigerator 30 of the shield cooling system is 0.4 4 kgf / cm ² G and the refrigerator 3
5 to 10 kgf / cm ² G due to the characteristics of the compressor 32 depending on the type
Although it is a degree, it is possible to set a predetermined pressure by the adjusting valve 37.

Therefore, when the shield refrigerator 30 and the compressor 32 of the shield cooling system are operating normally, the pressure difference between the shield pipe 18 of the shield cooling gas line 31 and the refrigerant tank 2 of the inner tank cooling system is Sufficiently, the evaporated helium gas in the inner tank cooling system does not flow into the shield cooling gas line 31 through the branch pipe 33, and at the same time, the check valve 36
Due to the effect, the helium gas discharged from the shield refrigerator 13 does not flow into the refrigerant tank 2 side of the inner tank cooling system through the branch pipe 33. With this, as in the above-described embodiment, the inner tank container 1 and the refrigerant tank 2 are cooled and held by the inner cooling system, and the radiation shield plate 3 is cooled and held by the shield cooling system at an extremely low temperature.

If the shield cooling system abnormally stops, the recovery signal 38 of the line 39 is opened in response to the abnormal signal, so that the helium gas in the shield pipe 18 becomes the inner tank cooling system. The low-pressure refrigerant gas return line 14b of the refrigerant gas compressor 13 collects the evaporated helium gas, and then the evaporated helium gas is collected by the refrigerant tank 2 due to the pressure increase accompanying the generation of the evaporated helium gas and the recovery capacity of the compressor 13. 2 from the recovery pipe 7 through the check valve 36 of the branch pipe 33 to the shield cooling gas line 31, and the helium gas flows into the shield pipe 18 to heat and cool the radiation shield plate 3, and the recovery line 39 as it is. The gas is recovered in the low pressure refrigerant gas return line 14b of the inner tank cooling system via the recovery valve 38 of FIG.

When the amount of evaporated helium gas from the refrigerant tank 2 becomes excessive, the recovery capacity is improved by increasing the operating frequency of the refrigerant gas compressor 13 or the like, and at the same time, the compressor 13 When the capacity is exceeded, it can be collected in the buffer tank 16 by the high pressure control valve 15a. Furthermore, it is possible to simplify the system by providing the opening valve 35 on the refrigerant gas compressor 13 side as in the case of the main embodiment.

In the embodiment of this shield,
It does not matter if the branch pipe 33 is used together with the check valve 36 and the opening / closing valve 34 provided in the main embodiment. Next, a third embodiment of the cryogenic cooling system of the present invention will be described with reference to FIG. This basic configuration is shown in FIG.
However, here, the branch pipe 33A for guiding the evaporated helium gas of the inner tank cooling system to the shield cooling gas line 31 via the check valve 36 when the shield cooling system is abnormal is connected to the refrigerant tank 2 With the configuration in which the refrigerant gas recovery pipe 11 from the to the main refrigerator 10 is branched, the same effect as described above can be obtained in this case as well.

In this embodiment, the discharge side of the refrigerator 30 of the shield cooling system and the precooling / liquid injection pipe 6 of the refrigerant tank 2 are connected via the branch pipe 33B with the switching valve 40. There is. Thus, at the initial stage of cooling, the helium gas is discharged to the shield cooling gas line 31 using the refrigerator 30 of the shield cooling system, and the gas is shielded by the shield pipe 1.
8 through which heat exchange cooling of the radiation shield plate 3 is carried out, and a part of the gas is pre-cooled / injected by the inner tank cooling system via the branch pipe 33B by opening the switching valve 40.
It is possible to carry out initial pre-cooling of the refrigerant tank 2 and the inner tank container 1 by sending the refrigerant tank 2 into the refrigerant tank 2.

In each of the above-described embodiments, the compressors 13 and 32 of the main refrigerator 10 of the inner tank cooling system and the shield refrigerator 30 of the shield cooling system have independent split configurations. A multi-configuration in which a part of the machines 13 and 32 is shared is also possible, and the same effect can be obtained.

Further, when the evaporated helium gas of the inner tank cooling system is introduced into the shield cooling gas line 31 when the shield cooling system is abnormal, in the embodiment of FIGS. 1 and 2, the recovery pipe 7 of the refrigerant tank 2 is introduced. From the refrigerant tank 2 to the main refrigerator 10 in the embodiment of FIG.
Although 3A is branched, the branch connection position of these branch pipes is not particularly limited, and it may be branched from any portion as long as it is the refrigerant gas line of the inner tank cooling system.

According to each of the embodiments described above, in the system of the cryogenic equipment in which the heat load on the radiation shield plate 3 surrounding the inner tank container 1 is relatively large, the refrigerant tank of the inner tank cooling system and the main refrigeration system. In addition to the machine 10, a shield refrigerator 30 of the shield cooling system is provided, and the radiation shield plate 3 is normally cooled by the reduced plum gas from the shield refrigerator 30. Even if it stops abnormally, its shield cooling gas line 31
Further, helium gas can be introduced from a vaporized refrigerant gas line such as a refrigerant tank of an internal tank cooling system through a valve to continue cooling the radiation shield plate, and a highly reliable and stable cryogenic cooling system can be obtained.

Therefore, for example, in the case of a cooling system for a vehicle-mounted superconducting magnet device such as a levitation railway, a liquid nitrogen tank for cooling the radiation shield plate and its circulation device are not required, and liquid nitrogen from outside is regularly supplied. Since it is not necessary to replenish the material, it is possible to reduce the running cost of the entire system without providing a large-scale supply device outside. Particularly in an in-vehicle system of a floating railway, in order to supply liquid nitrogen, an external pipe must be connected every time the vehicle leaves or leaves the vehicle, but according to the present invention, a closed cooling is achieved only by the in-vehicle system. The system configuration is eliminated and complicated work is unnecessary.

Further, since the refrigerant used for the cooling system is only the helium of the same kind, the system configuration is simple from this point as well, and in the case of the initial precooling of the superconducting magnet device, especially the refrigerator is operating. Even if it is not necessary, the refrigerant after cooling the inner tank container 1 from the pre-cooling / injection port can be flowed to the shield cooling gas line, so that the pre-cooling work of the superconducting magnet device can be carried out very easily. .

Further, when liquid nitrogen is used for cooling the radiation shield plate 3 as in the conventional case, the temperature of the refrigerant cannot be kept below 77K which is the boiling point of the liquid nitrogen, but by cooling with helium gas. , The capacity of the shield refrigerator 30 and the compressor 32 of the shield cooling system is improved.
Cooling below 7K is possible.

As a result, the temperature of the radiation shield plate 3 is further lowered, the amount of heat entering the inner vessel 1 at 4K level is further reduced, and there is a margin in the capacity of the main refrigerator 10 of the inner vessel cooling system. It will be. For example, it is particularly effective when there are two systems, such as a levitation railway, that operate at night and during daytime, and power supply is restricted.

That is, when the electric power at night is available, the radiation shield plate 3 can be cooled by temporarily improving the capacity of the refrigerator by increasing the operating frequency of the compressor. The radiation shield plate 3 has a certain amount of heat capacity and is provided with a heat storage function, so that even if the compressor is changed to the normal mode before starting the daytime operation, the radiation cooling plate 3 has Since the radiation shield plate 3 is cooled and the heat load to the superconducting magnet device is suppressed to a low level, even if the heat load is slightly increased for some reason during traveling, there is a margin in the capacity of the refrigerator. The stability of the superconducting magnet device system is maintained.

[0058]

The present invention has been made as described above. Therefore, the inner tank cooling system for cooling the inner tank container of the cryogenic equipment such as the electric superconducting magnet device by the refrigerant such as liquid helium is used for liquefying the refrigerant tank and the refrigerant gas. In a cryogenic cooling system aiming to reduce the size and weight of the entire system, a refrigerator is also provided in the shield cooling system for cooling the radiation shield plate surrounding the inner tank container. While the radiation shield plate is cooled by the refrigerant gas discharged from the refrigerator of the shield cooling system, even if the refrigerator of the shield cooling system stops abnormally, the evaporated refrigerant gas of the inner tank cooling system is cooled by the refrigerant of the shield cooling system. By introducing it into the gas line, the effect of being able to continue stable cooling of the radiation shield plate is obtained.

[Brief description of drawings]

FIG. 1 is a flowchart showing a first embodiment of a cryogenic cooling system of the present invention.

FIG. 2 is a flowchart showing a second embodiment of the cryogenic cooling system of the present invention.

FIG. 3 is a flow chart showing a second embodiment of the cryogenic cooling system of the present invention.

FIG. 4 is a flowchart showing a conventional cryogenic cooling system.

[Explanation of symbols]

1 ... Inner tank container, 2 ... Refrigerant tank, 3 ... Radiation shield plate,
4 ... Outer tank container, 6, 7, 11, 12, 14b ... Refrigerant gas line (pre-cooling / injection pipe, recovery pipe, 11 ... Aunt gas recovery pipe, 12 ... Refrigerant gas supply pipe, 14b ... Low pressure refrigerant gas return Piping), 10 ... Main refrigerator of inner tank cooling system,
13 ... Refrigerant gas compressor, 18 ... Shield piping, 30 ... Shield refrigerator of shield cooling system, 31 ... Shield cooling gas line, 32 ... Refrigerant gas compressor, 34, 36 ... Valve (34 ... Open / close valve, 36 ... Reverse) Stop valve), 35 ... open valve,
37 ... adjusting valve, 38 ... recovery valve, 39 ... recovery line, 40 ... switching valve.

Claims (10)

[Claims] 1. An inner tank cooling system for cooling an inner tank container of a cryogenic device such as a superconducting magnet device with a refrigerant such as liquid helium is provided with a refrigerant tank and a refrigerator for liquefying refrigerant gas,
In a cryogenic cooling system in which a refrigerator is also provided in a shield cooling system for cooling the radiation shield plate surrounding the inner vessel, the shield cooling system sends refrigerant gas from the refrigerator to the shield cooling gas line. A gas cooling structure for cooling the radiation shield plate, and the shield cooling gas line is connected to the refrigerant gas line of the inner tank cooling system via a valve, in the unlikely event of an abnormal stop of the refrigerator of the shield cooling system, A cryogenic cooling system, characterized in that a refrigerant gas evaporated in an inner tank cooling system is introduced into a shield cooling gas line via a valve to cool a radiation shield plate. 2. The cryogenic cooling system according to claim 1, wherein a valve that connects the shield cooling gas line of the shield cooling system and the refrigerant gas line of the inner tank cooling system is a check valve only or a check valve. The cryogenic cooling system according to claim 1, wherein the cryogenic cooling system is provided together with a valve. 3. The cryogenic cooling system according to claim 1, wherein the refrigerant gas is introduced from the refrigerant gas line of the inner tank cooling system into the shield cooling gas line of the shield cooling system via a valve to cool the radiation shield plate. When performing the above, a recovery line for recovering the refrigerant gas after the heat exchange with the radiation shield plate from the end of the shield cooling gas line to the outside or the refrigerant gas line of the inner tank cooling system is provided. Characteristic cryogenic cooling system. 4. The cryogenic cooling system according to claim 3, wherein the refrigerant gas that has undergone heat conversion with the radiation shield plate is recovered in the low pressure refrigerant gas return line of the refrigerant gas compressor of the refrigerator of the inner tank cooling system. A cryogenic cooling system characterized by having a recovery line. 5. The cryogenic cooling system according to claim 1, wherein the shield cooling gas line of the shield cooling system is connected to the refrigerant gas recovery line of the refrigerator of the inner tank cooling system via a valve. Cooling system. 6. The cryogenic cooling system according to claim 1, wherein the cooling of the radiation shield plate and the precooling of the refrigerant tank of the inner tank cooling system are performed at the same time, and the refrigerant gas discharge side of the refrigerator of the shield cooling system. And pre-cooling of the internal tank cooling system refrigerant tank
A cryogenic cooling system characterized in that it is connected to the liquid injection line via a switching valve. 7. The cryogenic cooling system according to claim 4, wherein when the refrigerant gas amount recovered in the low pressure refrigerant gas return line of the refrigerant gas compressor of the refrigerator of the inner tank cooling system becomes excessive, the compressor. Is a cryogenic cooling system characterized in that it operates at high speed to increase the amount of gas suctioned. 8. The cryogenic cooling system according to claim 1, wherein the operating frequency of the refrigerator of the shield cooling system or this refrigerant gas compressor is controlled.
A cryogenic cooling system characterized in that the cooling ultimate temperature of the radiation shield plate can be arbitrarily set. 9. The cryogenic cooling system according to claim 8, wherein the radiation shield plate is provided with a heat capacity to add a heat storage function, and the refrigerator of the shield cooling system or this refrigerant gas compressor is operated at high speed. A cryogenic cooling system, characterized in that by supercooling a radiation shield plate, the amount of heat entering the inner tank container can be reduced for a predetermined period of time to allow the refrigerator in the inner tank cooling system a margin. 10. The cryogenic cooling system according to claim 1, wherein the line of the refrigerant gas compressor of the inner tank cooling system and the line of the refrigerant gas compressor of the shield cooling system are partially shared to simplify the entire system. Cryogenic cooling system.