JP3836171B2 - Cooling system - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a cooling device for a superconducting magnet of a forced cooling system in which a forced cooling conductor for cooling by flowing supercritical helium in a flow path is wound.
[0002]
[Prior art]
Forced cooling superconducting magnets are used in large-scale superconducting equipment such as fusion experimental devices (reactors) and energy storage devices that require high withstand voltage, high magnetic field, and high current density. The forced cooling superconducting magnet cooling device for a large superconducting device includes a superconducting magnet 1, a supercritical helium circulation pump 4 that circulates supercritical helium in the superconducting magnet 1, and a heat exchanger 5. A supercritical helium supply pipe 6a, a supercritical helium return pipe 6b, a remote control valve 18b, a supercritical helium circulation pump 4 and a heat exchanger, and supercritical helium containing liquid helium 2. The heat exchanger tank 3 constitutes a supercritical helium circulation system 6, and the supercritical helium circulation system 6 is accommodated in a heat insulating container 15. Outside the heat insulation container 15, a helium refrigerating and liquefying device 10, a liquid helium storage tank 7 for storing the purified liquid helium 2, a gas bag for recovering the evaporated helium gas, a recovery compressor, a purification A recovery / purification system 11 composed of an apparatus, a helium gas filling container 12, a helium compressor 13 and a valve 14, a recovery pipe 20, a pipe including a low-temperature high-pressure helium supply line 21, and the like are provided. The liquid helium 2 in the liquid helium storage tank 7 is transferred to the supercritical helium heat exchanger tank 3 by the liquid helium transfer pipe 9. The superconducting magnet 1 is excited from a power supply source (not shown) through a current lead 8 and a power supply cable 8a.
[0003]
Since the cooling device configured in this manner must be operated stably for a long period of time and with high reliability, it is necessary to improve the reliability of the main constituent devices and to make a dual configuration. In addition, even when the power supply to these main devices is stopped due to inconvenience such as a power failure, it is necessary to take measures such as an uninterruptible power supply so that the refrigerant can be circulated through the superconducting magnet.
[0004]
[Problems to be solved by the invention]
Since the conventional cooling device is configured as described above, it is prepared for an emergency such as a power failure, and is different for operation and control of the helium refrigeration device 10, the supercritical helium circulation pump 4, valves, and the like. It is desirable to provide a plurality of power supply sources. However, the helium refrigeration and liquefaction device 10 of these large superconducting devices requires a refrigeration capacity equivalent to several tens of kilowatts to one hundred kilowatts at a temperature of 4.5K, and the energy efficiency ((refrigeration capacity at 4.5K) / If (the actual electric power necessary at room temperature) is about 0.003, a plurality of enormous power supply sources are required. Moreover, it is not always used for driving and is provided for emergency use. For this reason, in general, there is only one power supply source for the helium refrigeration liquefaction apparatus 10, and a standby power supply such as an uninterruptible power supply is provided only for operation of the remote control valve 18b and the supercritical helium circulation pump 4 which are indispensable for safe operation. Will be provided.
[0005]
However, since the energy of these basically same forms (electricity) is used for operation, when trouble occurs not only in the main power supply but also in the standby power supply, the power supply source and the supercritical helium circulation pump When a power cable between the four power cables is disconnected, or when an equipment failure occurs in the refrigerant supply device such as the helium refrigerating / liquefying device 10 or the supercritical helium circulation pump 4, the supercritical helium is circulated. This makes it impossible to operate the superconducting magnet 1 without quenching (normal conducting transition), as well as to stop the operation. In general, when the superconducting magnet 1 is stopped, the exciting current is gradually lowered to suppress the release of large stored energy.
[0006]
Therefore, it is necessary to circulate the refrigerant even when the excitation current is decreasing. In addition, when the refrigerant is lost, the temperature of the superconducting magnet 1 rapidly rises. However, the rapid rise in temperature generates a large thermal stress, and the insulation of the superconducting magnet 1 and the soundness of the structure cannot be maintained. Driving may be impossible.
[0007]
Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to provide a highly reliable cooling device that can reliably circulate the refrigerant to the superconducting magnet even when the power supply is lost or the refrigerant supply device malfunctions. There is.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention of claim 1 of the present invention is a cooling device that circulates supercritical helium in a supercritical helium circulation system and cools the superconducting magnet in a heat insulating container containing the superconducting magnet. A liquid helium storage tank is provided, and an intermediate pressure vessel for filling supercritical helium inside the liquid helium storage tank is housed. The intermediate pressure vessel is constantly cooled to maintain a low temperature and intermediate pressure state, and the intermediate pressure vessel One end of the magnet was connected to the supercritical helium circulation system via a remote control valve, and the other end was connected to the superconducting magnet via a remote control valve, and when the refrigerant could not be circulated, it circulated in the superconducting magnet. releasing the recovery purification system through the recovery pipe for recovering the helium gas evaporating from the supercritical helium, and supplies a supercritical helium in the in vessel to the superconducting magnet And wherein the Rukoto.
[0009]
According to a second aspect of the present invention, there is provided a cooling device for cooling a superconducting magnet by circulating supercritical helium in a supercritical helium circulation system, and an intermediate pressure for filling the supercritical helium in a heat insulating container containing the superconducting magnet. A container is provided, and this medium pressure container is constantly cooled so as to maintain a low temperature and medium pressure state, and one end of the medium pressure container is connected to the supercritical helium circulation system via a remote control valve, and the other end is connected via a remote control valve. A superconducting magnet and a heat exchanger in the medium pressure vessel, and supercritical helium is allowed to flow through the heat exchanger from the supercritical helium circulation system so that the supercritical helium in the medium pressure vessel is passed through. and configured to cool, when the refrigerant circulation impossible occurs, the recovery and purification system from the supercritical helium to the superconducting magnet has been circulated through a recovery pipe for recovering the helium gas evaporating Out, and and supplying supercritical helium in the in vessel to the superconducting magnet.
[0010]
The invention of claim 3 constitutes a supercritical helium circulation system housed in a heat insulating container containing a superconducting magnet in a cooling device for cooling the superconducting magnet by circulating supercritical helium in the supercritical helium circulation system. An intermediate pressure vessel for filling supercritical helium is accommodated inside the supercritical helium heat exchanger tank, and this intermediate pressure vessel is constantly cooled to maintain a low temperature and intermediate pressure state, and one end of the intermediate pressure vessel is connected to the intermediate pressure vessel. Supercritical helium circulated in the superconducting magnet when the other end is connected to the superconducting helium circulation system via a remote control valve and the other end is connected to a superconducting magnet via a remote control valve. and wherein the release in recovery and purification system through the recovery arrangement for recovering helium gas evaporating and supplying supercritical helium in the in vessel to the superconducting magnet from That.
[0011]
According to a fourth aspect of the present invention, in the cooling device according to the first, second, or third aspect, a flow rate adjusting means for adjusting a flow rate of supercritical helium is mounted between the intermediate pressure vessel and the superconducting magnet. It is characterized by that.
[0015]
[Action]
In the cooling device corresponding to claim 1, when the refrigerant cannot be circulated due to loss of power supply or equipment failure of the refrigerant supply device, the cooling device is stored in an intermediate pressure vessel cooled by liquid helium stored in the liquid helium storage tank. Since some supercritical helium with a medium pressure of 10 atm or less can be supplied to the superconducting magnet by a pressure difference via a remote control valve, the refrigerant circulation of the superconducting magnet can be secured and stopped without quenching, and a sudden temperature rise It is possible to suppress the thermal stress generated in the superconducting magnet.
[0016]
In the cooling device corresponding to claim 2, medium pressure supercritical helium stored in the medium pressure vessel is 10 atm or less and the heat exchanger provided in the medium pressure vessel is operated with supercritical helium. The supercritical helium stored in the intermediate pressure vessel can be supplied to the superconducting magnet by a pressure difference via the remote control valve when the refrigerant is not circulating.
[0017]
In the refrigerant device corresponding to claim 3, when the refrigerant cannot be circulated, the medium pressure of 10 atm or less stored in the medium pressure vessel cooled by the liquid helium contained in the supercritical helium heat exchanger tank is stored. Supercritical helium can be supplied to the superconducting magnet with a pressure difference via a remote control valve.
[0018]
In the refrigerant device corresponding to claim 4, the supply flow rate (supply time) can be adjusted to an appropriate value by the flow rate adjusting means installed between the intermediate pressure vessel and the superconducting magnet. For this reason, when medium-pressure supercritical helium stored in the medium-pressure vessel is supplied to the superconducting magnet with a pressure difference, it can be supplied by controlling an appropriate flow rate or supply time, thereby further improving reliability.
[0023]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a system configuration diagram showing a first embodiment of the cooling apparatus of the present invention. This cooling device is connected to the superconducting magnet 1 on the discharge side of a supercritical helium circulation pump 4 that circulates supercritical helium, and exchanges heat in a supercritical helium heat exchanger tank 3 containing liquid helium 2. A supercritical helium return pipe 6b for connecting the vessel 5, the superconducting magnet 1 and the supercritical helium circulation pump 4 via a remote control valve 18b, and a remote control valve 18b for the superconducting magnet 1 and the heat exchanger 5. A supercritical helium circulation system 6 is constituted by the supercritical helium supply pipe 6a connected via the. The supercritical helium circulation system 6 is connected to a recovery pipe 20 for recovering evaporated helium gas and a low-temperature high-pressure helium supply pipe 21 for supplying low-temperature high-pressure helium.
Further, a liquid helium storage tank 7 is provided in the heat insulating container 15, and an intermediate pressure container 16 for storing supercritical helium is accommodated in the liquid helium storage tank 7, and the intermediate pressure container 16 includes a check valve 19 and a remote operation. The supercritical helium circulation system 6 is connected in parallel via the valve 18 a and the flow rate adjusting means 22.
The liquid helium 2 in the liquid helium storage tank 7 is transferred from the supercritical helium heat exchanger tank 3 by the transfer pipe 9a.
[0024]
Further, a temperature detecting means 27 for detecting the temperature of the outlet supercritical helium flowing through the superconducting magnet 1 or the supercritical helium return pipe 6b, and a controller 28 for controlling the opening area of the flow rate adjusting means 22 by a signal from the temperature detecting means. It has.
[0025]
Next, the function and effect of the first embodiment will be described. In a steady state in which the inability to circulate the refrigerant due to loss of power supply or equipment failure of the refrigerant supply device does not occur, the supercritical helium is boosted to a predetermined pressure by the supercritical helium circulation pump 4 and then the supercritical helium heat exchanger tank 3 The heat exchanger 5 installed in the inside is recooled to a predetermined temperature using the latent heat of vaporization of the liquid helium 2 and supplied to the superconducting magnet 1 via the remote control valve 18b and the supercritical helium supply pipe 6a. . The supercritical helium that has cooled the heat generated by the superconducting magnet 1 returns to the supercritical helium circulation pump 4 again via the supercritical helium return pipe 6b and the remote control valve 18b.
During the initial cooling or steady cooling of the superconducting magnet 1, supercritical helium is charged into the intermediate pressure vessel 16 through the cooling pipe 17b and the check valve 19 to a predetermined pressure. The intermediate pressure vessel 16 is constantly cooled by the liquid helium 2 in the liquid helium storage tank 7, and can maintain a low temperature and intermediate pressure state.
On the other hand, when the refrigerant cannot be circulated due to power loss or equipment failure, the remote control valve 18b is closed and the remote control valve 18a is opened. In addition, this operation is performed almost instantaneously in response to the refrigerant circulation impossibility signal. Although the supercritical helium circulating in the superconducting magnet 1 at a predetermined pressure and temperature is stopped by closing the remote control valve 18b, the helium gas evaporated from the supercritical helium does not pass through the line, and the line of the recovery pipe 20 is removed. To the recovery and purification system 11. Further, supercritical helium having a low temperature and intermediate pressure (approximately 10 atm) stored in the medium pressure vessel 16 is supplied to the superconducting magnet 1 through the low temperature helium pipe 17a through the opening of the remote control valve 18a.
In addition, since the supply amount of supercritical helium can be adjusted by installing a flow rate adjusting means 22 such as an orifice or a flow rate adjusting valve between the superconducting magnet 1 and the intermediate pressure vessel 16, it is stored in the intermediate pressure vessel 16. When supercritical helium having a certain medium pressure is supplied to the superconducting magnet 1 with a pressure difference, it can be supplied by controlling an appropriate flow rate or supply time. As a control method of the supply amount, the supply amount is calculated in advance from the relationship between the volume and pressure of the medium pressure vessel 16 and the supercritical helium circulation system 6 including the superconducting magnet 1, and the flow rate control such as the orifice and the flow control valve is performed. The method of setting the opening area of the means 22 and the temperature detecting means 27 detect the temperature of the superconducting magnet 1 or the supercritical helium on the outlet side from the superconducting magnet 1, and the controller 28 is controlled by the signal from the temperature detecting means 22. There is a method for controlling the opening area of the flow rate control means 22 such as a flow rate control valve.
[0026]
Thus, since the flow rate of the supercritical helium circulating through the superconducting magnet is adjusted by the flow rate adjusting means 22, the supercritical helium stored in the intermediate pressure vessel 16 can be used effectively.
Therefore, reliability is further improved.
[0027]
The helium gas evaporated from the supercritical helium that has cooled the superconducting magnet 1 is discharged to the recovery and purification system 11 through the supercritical helium return pipe 6b and the recovery pipe 20. With this operation, supercritical helium can be reliably supplied while the superconducting magnet 1 is demagnetized.
[0028]
Therefore, it is possible to stop the superconducting magnet without securing and quenching the refrigerant circulation of the superconducting magnet, and to suppress the rapid temperature rise and reduce the thermal stress generated in the superconducting magnet.
[0029]
Next, a second embodiment of the present invention will be described with reference to FIG. The difference from the first embodiment is the cooling method of the supercritical helium in the intermediate pressure vessel 16. In this embodiment, the supercritical helium in the intermediate pressure vessel 16 is cooled by flowing the supercritical helium used for cooling the superconducting magnet 1 through the heat exchanger 5 in the intermediate pressure vessel 16. The operation and effect during steady operation and when the refrigerant cannot be circulated are the same as in the first embodiment. Furthermore, according to the present embodiment, the liquid helium storage tank 7 is not required, the apparatus configuration can be made compact, and the liquid level control of the liquid helium 2 in the liquid helium storage tank 7 and the adjustment of the supply amount are unnecessary. Therefore, the control system of the cooling device is simplified.
[0030]
A third embodiment will be described with reference to FIG. In this embodiment, the intermediate pressure vessel 16 is accommodated in the supercritical helium heat exchanger tank 3, and the supercritical helium in the intermediate pressure vessel 16 is always cooled with liquid helium 2, which is the second embodiment. It has the same effect as the example.
[0031]
A fourth embodiment will be described with reference to FIG.
Although the main configuration is the same as in FIG. 1, a vacuum container 23 is provided in a heat insulating container 15 containing the superconducting magnet 1, and a decompression container 23 is provided under reduced pressure. One end of the decompression container 23 is connected to the superconducting magnet 1 via a remote control valve 18a. The other end of the vacuum exhaust pipe 24 is connected to the recovery pipe 20 via the check valve 19 and the exhaust pipe 25 is branched from the middle of the vacuum exhaust pipe 24 via the remote control valve 18b. Yes.
[0032]
Next, the function and effect of this embodiment will be described.
The decompression vessel 23 is always evacuated through the remote control valve 18 b and the vacuum exhaust pipe 24 by the exhaust device 25 installed outside the heat insulation vessel 15. On the other hand, when the refrigerant circulation is disabled due to power loss or equipment failure, the remote control valve 18b provided in front of the exhaust device 25 is closed and the remote control valve 18b provided at the same time is connected to the recovery pipe 20. By opening the operation valve 18 a, supercritical helium in the superconducting magnet 1 and the supercritical helium circulation system 6 is partially released to the recovery and purification system 11 through the recovery pipe 20. Next, the remote control valve 18 c interposed between the superconducting magnet 1 and the decompression vessel 23 is opened, and the remaining low-temperature helium gas is sucked into the decompression vessel 23 through the cooling pipe 17 connected to the decompression vessel 23. As a result, the superconducting magnet 1 can be cooled using the effect of a kind of Joule-Thompson adiabatic expansion, so that demagnetization can be achieved without quenching. Further, when the decompression vessel 23 is filled with low-temperature helium gas and the internal pressure rises to near atmospheric pressure, the check valve 19 is activated, and helium gas is released to the recovery and purification system 11 through the recovery pipe 20. The decompression vessel 23 is configured not to be abnormally filled with helium gas.
[0033]
A fifth embodiment will be described with reference to FIG.
The main configuration is the same as in FIGS. 1 to 4, but in this embodiment, instead of installing the intermediate pressure vessel 16 of the first to third embodiments and the decompression vessel 23 of the fourth embodiment. The heating means 26 is provided in the liquid helium 2 in the supercritical helium heat exchanger tank 3. The heating means 26 may be any means that can evaporate liquid helium, such as an electric heater or a heat exchanger that allows a room-temperature or high-temperature gas to flow therethrough.
[0034]
Next, the function and effect of this embodiment will be described.
When the refrigerant circulation becomes impossible due to power loss or equipment failure, the supercritical helium heat exchanger tank is heated by the heating means 28 provided in the supercritical helium heat exchanger tank 3 with the low-temperature helium gas supplied to the superconducting magnet 1. The liquid helium in 3 is evaporated to generate low-temperature helium gas. Since the pressure rise in the supercritical helium heat exchanger tank 3 generated when vaporized can be used, a simpler and more compact configuration is possible. Can supply low-temperature helium gas to the superconducting magnet.
[0035]
Instead of providing the heating means 28 in the supercritical helium heat exchanger tank 3, another liquid helium storage tank 7 may be provided in the heat insulating container 15, and the heating means 28 may be provided there.
[0036]
Furthermore, the present invention is not limited to the embodiments described above, by using a combination of each embodiment, it is possible to increase the supply amount of supercritical helium, or if the heat load of the superconducting magnet 1 is large, supercritical This is effective for extending the supply time of helium .
[0037]
Further, the flow rate adjusting means 22 described in the first embodiment, the temperature detecting means 27 for detecting the temperature of at least one of the superconducting magnet 1 or the supercritical helium on the outlet side from the superconducting magnet, and the temperature detecting means 27 The configuration in which the controller 28 for controlling the opening area of the flow rate adjusting means 22 by the signal and controlling the supply amount of supercritical helium to the superconducting magnet 1 can be applied to other embodiments.
[0038]
【The invention's effect】
As described above, according to the present invention, even when the power supply is lost or the equipment of the refrigerant supply device breaks down, the supercritical helium stored in the medium pressure vessel that is constantly cooled so as to maintain the low temperature and medium pressure state is maintained. The superconducting magnet can be supplied to the superconducting magnet with a pressure difference via a remote control valve, so that supercritical helium can be reliably supplied to the superconducting magnet, and the superconducting magnet can be safely stopped by avoiding quenching and excessive thermal stress. A reliable refrigerant device can be provided.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram showing a first embodiment of a cooling device of the present invention.
FIG. 2 is a system configuration diagram showing a second embodiment of the cooling device of the present invention.
FIG. 3 is a system configuration diagram showing a third embodiment of the cooling device of the present invention.
FIG. 4 is a system configuration diagram showing a fourth embodiment of the cooling device of the present invention.
FIG. 5 is a system configuration diagram showing a fifth embodiment of the cooling device of the present invention.
FIG. 6 is a system configuration diagram showing an example of a conventional cooling device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Superconducting magnet 2 ... Liquid helium 3 ... Supercritical helium heat exchanger tank 4 ... Supercritical helium circulation pump 5 ... Heat exchanger 6 ... Supercritical helium circulation system 6a ... Supercritical helium supply pipe 6b ... Supercritical helium return pipe 7 ... Liquid helium storage tank 8 ... Current lead 9 ... Liquid helium transfer pipe 10 ... Helium refrigerating and liquefying device 11 ... Recovery purification system 14 ... Valve 15 ... Thermal insulation container 16 ... Medium pressure vessels 17a, 17b, 17c ... Low temperature helium piping 18a, 18b , 18c ... Remote control valve 19 ... Check valve 20 ... Recovery pipe 21 ... Low temperature high pressure helium pipe 22 ... Flow rate adjusting means 23 ... Depressurized container 24 ... Vacuum exhaust pipe 25 ... Exhaust device 26 ... Heating means 27 ... Temperature detecting means 28 ... Controller

Claims (4)

In a cooling device that circulates supercritical helium in a supercritical helium circulation system and cools the superconducting magnet, a liquid helium storage tank is provided in a heat insulating container containing the superconducting magnet, and supercritical helium is placed inside the liquid helium storage tank. An intermediate-pressure vessel for filling is accommodated, and this intermediate-pressure vessel is constantly cooled so as to maintain a low-temperature and intermediate-pressure state, and one end of the intermediate-pressure vessel is connected to the supercritical helium circulation system via a remote control valve. The end is connected to a superconducting magnet via a remote control valve, and when the refrigerant cannot be circulated, it is recovered and purified via a recovery pipe that recovers helium gas that evaporates from supercritical helium circulating in the superconducting magnet. A cooling device which discharges into a system and supplies supercritical helium in the medium pressure vessel to the superconducting magnet. In a cooling device that circulates supercritical helium in a supercritical helium circulation system and cools the superconducting magnet, an intermediate pressure vessel for filling supercritical helium is installed in the heat insulating container containing the superconducting magnet. The vessel is constantly cooled to maintain a low temperature and intermediate pressure state, and one end of the intermediate pressure vessel is connected to the supercritical helium circulation system via a remote control valve, and the other end is connected to a superconducting magnet via a remote control valve. A heat exchanger is disposed in the intermediate pressure vessel, and supercritical helium is allowed to flow through the heat exchanger from the supercritical helium circulation system to cool the supercritical helium in the intermediate pressure vessel, when the refrigerant circulating impossible occurs, released into the recovery purification system from the supercritical helium to the superconducting magnet has been circulated through a recovery pipe for recovering the helium gas evaporating, and the in Cooling device and supplying the supercritical helium in the container to the superconducting magnet. A supercritical helium heat exchanger tank that constitutes a supercritical helium circulation system housed in a heat insulating container containing a superconducting magnet in a cooling device that circulates supercritical helium in the supercritical helium circulation system and cools the superconducting magnet. An intermediate pressure vessel for filling supercritical helium is housed inside, and this intermediate pressure vessel is constantly cooled so as to maintain a low temperature and intermediate pressure state, and one end of the intermediate pressure vessel is connected to the above-mentioned via a remote control valve. Connect the other end of the supercritical helium circulation system to a superconducting magnet via a remote control valve, and recover helium gas that evaporates from the supercritical helium circulating in the superconducting magnet when the refrigerant cannot be circulated. A cooling apparatus which discharges to a recovery and purification system through a recovery pipe and supplies supercritical helium in the intermediate pressure vessel to the superconducting magnet. 4. The cooling device according to claim 1, wherein a flow rate adjusting means for adjusting a flow rate of supercritical helium is mounted between the intermediate pressure vessel and the superconducting magnet.

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