JPS6223475B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention automatically controls the flow rate of refrigerant gas for cooling a superconducting device, particularly a power supply conductor connected to its superconducting coil, and a shield that prevents the intrusion of radiant heat. This invention relates to a control mechanism that can control the

[Conventional technology]

Generally, superconducting coils are kept cooled to an absolute temperature of nearly 4K, and are supplied with power via a power supply from an excitation power supply installed at room temperature. This type of device has conventionally had a configuration as shown in FIG.

That is, in the same figure, 1 is liquid helium 2
A helium container 3 is filled with helium, and 3 is a shield surrounding this container to prevent radiant heat from entering from the outside.
Reference numeral 4 denotes a vacuum container in which this shield 3 is further insulated, 5 a superconducting coil immersed in liquid helium 2 of the container 1, 6 a power supply conductor connected to this superconducting coil, and 7 surrounding this conductor 6. The conductor 6
A cooling conduit 8 extending upward to introduce helium gas for cooling the wafer is an excitation power source, and is connected to the conductor 6 via an external conductor 9. Note that 10 indicates an electrical insulator that seals the upper end of the cooling conduit 7 and supports the conductor 6 in an insulating manner.

11 is one external discharge conduit connected to the upper end of the cooling conduit 7 for discharging the helium gas after cooling the conductor 6, and 12 is a conduit for guiding the helium gas in the container 1 to cool the shield 3. A shield internal pipe is provided by surrounding the shield 3, and 13 is the other external discharge pipe connected to this internal pipe. Manual adjustment valves 14, 15, and cooling gas flow meter 1
6, 17 are provided, and each conduit 11, 1
The terminals of No. 3 are merged and connected to the recovery pipe 19. Note that 20 is a safety discharge pipe of the container 1, and 20a is a relief valve provided in this pipe.

According to the above configuration, the superconducting coil 5 is immersed in liquid helium 2 and cooled to 4.2K, and in this state, it is energized from the excitation power source 8 provided in the normal temperature section via the power supply conductor 6, and functions as a superconducting coil. runs a business. At this time, liquid helium 2 in container 1
is evaporated due to the Joule heat generation of the conductor 6 and the amount of heat entering from the outside. A good electrical conductor such as oxygen-free copper is used as the power supply conductor 6, but since its current heat generation is quite large, the evaporated helium gas is guided to the cooling conduit 7 to exchange heat with the conductor 6. Thereafter, it is led out to an external discharge conduit 11, and its flow rate is adjusted by a manual adjustment valve 14.
On the other hand, in order to counteract the amount of heat transferred from the outside to the container 1, the helium gas in the container 1 is guided to the shield 3 via the shield internal pipe 12 to cool it, and then to the other external discharge pipe 13. The flow rate is adjusted by a manual adjustment valve 15. Here, as a means of setting the helium gas flow rate introduced into the cooling conduit 7, the flow rate is manually adjusted while measuring the flow rate with the cooling gas flow meter 16 so that the heat generated by energization of the conductor 6 is about 1 m Watt per 1 A of current. Adjustment and setting operations are performed by means of the valve 14. On the other hand, the larger the helium gas flow rate guided to the shield 3, the more significantly the amount of heat entering from the outside can be reduced, but it is first of all important to ensure the required gas flow rate to cool the conductor 6. Only the subtracted flow rate obtained by subtracting the gas flow rate to the conductor 6 can be used for this, and the flow rate is confirmed by measuring the flow rate with the flow meter 17.

[Problem that the invention seeks to solve]

Since the conventional superconducting device is configured as described above, the gas flow rate of each external discharge conduit 11, 13 must be set by the flow rate adjustment valves 14, 15, and the respective gas flow rates are adjusted to It was necessary to maintain the flow rate within a predetermined range while measuring the gas flow meters 16 and 17. If the cooling gas flow rate on the cooling conduit 7 side is insufficient, there is a risk of burning out the conductor 6, and if the flow rate is too high than the set flow rate, the cooling gas flow rate on the shield 3 side will be insufficient, leading to an increase in the temperature of the shield 3. This increases the amount of heat entering the helium container 1. Moreover, the pressure inside the helium container 1 changes due to changes in the heat load, so even if the flow rate is set within the required range by the above-mentioned flow rate adjustment, the setting will not respond to changes in the pressure inside the helium container 1. If the opening degree of the flow rate regulating valve 14 is not increased when the internal pressure decreases, the conductor 6
The cooling gas flow rate is insufficient, eventually leading to a burnout accident. Furthermore, monitoring and inspection using the flow meter 16 is always required to prevent erroneous operation such as energizing the conductor 6 while the flow rate regulating valve 14 is in a fully closed state. Furthermore, when the regulating valves 14 and 15 are throttled too much, the internal pressure of the helium container 1 increases, and the relief valve 20a operates to release low-temperature gas to the outside, resulting in an increase in the temperature of the conductor 6 side and the shield system. There were drawbacks such as a significant drop in cooling efficiency.

The purpose of the present invention is to improve the defects of the conventional device as described above, and the present invention automatically controls the flow rate of cooling gas in the power supply conductor to direct the flow rate of refrigerant gas generated in the container to the conductor side. The object of the present invention is to provide a superconducting device in which the remaining amount is led out to the shield side after securing the amount, thereby preventing burnout of the conductor.

[Means for Solving the Problems] The superconducting device according to the present invention includes a temperature-sensitive type that opens and closes a flow path in response to the temperature of the discharged gas in the first external discharge conduit through which the refrigerant gas of the power supply conductor is discharged. By providing a flow control valve, or alternatively, in addition to the temperature-sensitive flow control valve, the second external discharge conduit on the shield side may also be provided with another valve that opens and closes in opposite directions to the temperature-sensitive flow control valve. It is equipped with a temperature-sensitive flow control valve.

[Effect]

In this invention, the temperature-sensitive flow control valve detects the temperature of the refrigerant gas after cooling the power supply conductor,
When this temperature becomes higher than the set value, the control valve is operated in the opening direction to increase the flow rate of the refrigerant gas on the power supply conductor side and lower the temperature, and conversely, when the temperature of the refrigerant gas becomes lower than the set value, the above control valve is operated in the opening direction. Operate the valve in the closing direction to reduce the flow rate and return the temperature to the appropriate value. Therefore, the refrigerant gas flow rate necessary for cooling the power supply conductor side is always ensured, and the remaining refrigerant gas flow rate is supplied to the shield side.

In the second aspect of the invention, since a pair of temperature-sensitive flow control valves that open and close in opposite directions are provided in both external discharge conduits, the response of the flow control is faster.

〔Example〕

Hereinafter, the present invention will be explained with reference to the illustrated embodiment. In FIG. 1, in which parts corresponding to those in FIG. 4 are denoted by the same symbols, 21 is a temperature-sensitive flow control valve;
A temperature sensing tube 21a provided in contact with one of the external discharge conduits 11 and a fluorocarbon gas (for example, R ₂₂ can be used) sealed in this temperature sensing tube are transferred to the pressure conduit 2.
The valve body 21d is comprised of a pressure-receiving operating mechanism 21c that responds to pressure changes guided through the temperature-sensitive tube 1b, and a valve body 21d on the downstream side of the temperature-sensitive cylinder, which is opened and closed by the pressure-receiving operating mechanism. 22 is a throttle passage connected in parallel with this valve body 21c, and 23 is the temperature sensing cylinder 21a.
and a heat insulating member covering the outlet side portion of the external discharge conduit 11.

According to the above configuration, a part of the helium gas in the container 1 is introduced into the cooling conduit 7 to cool the conductor 6 and is led to the external discharge conduit 11, similar to the one in FIG. needs to be sufficiently cooled when the rated current is passed through the superconducting coil 5, and the gas outlet temperature after cooling the conductor 6 is
It is desirable that it is 273K or less. Now, when the gas outlet temperature rises, the fluorocarbon gas pressure inside the temperature sensing cylinder 21a rises, and the pressure receiving actuation mechanism 21c is actuated by the gas pressure conducted through the pressure conduit 21b to control the opening degree of the valve body 21d. spread. Thus,
The gas flow rate for cooling the conductor 6 is automatically controlled based on a preset gas outlet temperature, so that there is no possibility of over-cooling or under-cooling. That is, when current is passed through the superconducting coil 5, the conductor 6 generates heat due to Joule heat, but the valve body 21d opens to ensure the flow rate of the cooling gas until the exit temperature of the cooling gas reaches a set value. Moreover, when the superconducting coil 5 is not energized,
Since the outlet temperature of the cooling gas decreases, the opening degree of the valve body 21d is closed by the function of the temperature-sensitive flow control valve 21 until the outlet temperature of the cooling gas reaches a set value.

By the way, as mentioned above, part of the helium gas vaporized in the container 1 is used for cooling the conductor 6, and the rest is used for cooling the shield 3.
Furthermore, since the amount of heat that enters the container 1 decreases as the temperature of the shield 3 decreases, it is desirable that the flow rate distributed to the shield internal piping 12 be as large as possible.

On the other hand, according to the present embodiment, as described above, the flow rate of the cooling gas of the conductor 6 can be automatically controlled according to its outlet temperature, so that the conductor 6 can be prevented from overheating. It is possible to prevent damage and maintain the temperature of the shield 3 by distributing the gas flow rate generated in the container 1 most effectively.

FIG. 2 is an enlarged view of the throttle passage 22 connected and installed in parallel with the valve body 21d in FIG. 1, and a throttle plate 22a is provided in the passage.
The hole diameter D of the throttle plate 22a is set so as to secure the minimum gas flow path necessary for cooling the conductor 6, and therefore, even when the valve opening of the flow control valve body 21d is fully closed. , the cooling gas of the conductor 6 can always flow, and there is no risk of burning out the conductor 6.

Note that the manual adjustment valve 15 is used to set the pipe resistance of the cooling gas flowing through the shield 3 to a predetermined value, and is used to measure the flow rate with a gas flow meter as in the conventional one shown in FIG. It is clear that it is not intended to adjust the flow rate according to the value.
Further, according to this embodiment, since the cooling gas flow rate is automatically controlled as described above, there is no risk of the relief valve 20a being activated due to erroneous operation and reducing the cooling efficiency, unlike in the conventional case. In the above embodiment, the temperature-sensitive tube 21a is provided adjacent to the external discharge conduit 11, but in order to respond quickly to changes in gas temperature, the temperature-sensitive tube 21a is inserted inside the external discharge conduit 11. You can also install it. Furthermore, although a throttle plate 22a is inserted as the throttle passage 22,
This can be replaced by a suitable thin tube, and if the valve body 21d is provided with a function that allows the minimum flow opening degree to be set in advance regardless of the temperature, the throttle passage 22 can be omitted. I can do it.

Next, FIG. 3 shows a specific example of the second invention, in which a temperature-sensitive flow rate control valve 24 is further installed in the other external discharge conduit 13 in the one shown in FIG. . That is, in Figure 3,
24a is another temperature sensing tube provided in contact with the one external discharge conduit 11, 24b is a pressure conduit that guides the pressure change of the fluorocarbon gas sealed in this temperature sensing tube, and 24c is a pressure receiving operating mechanism connected to this conduit. The other external discharge conduit 1 responds to the pressure change of the fluorocarbon gas.
The opening/closing operation of the valve body 24d provided at the valve body 24d provided in the valve body 24d is configured to operate in the opposite direction to that of the pressure receiving operating mechanism 21c on the one external discharge conduit 11 side. Note that 25 indicates a throttle passage provided in parallel with the valve body 24d.

Therefore, when the temperature of each temperature sensing tube 21a and 24a increases due to the energization of the superconducting coil 5,
First, the pressure receiving actuation mechanism 21c is activated in response to a change in the pressure of the fluorocarbon gas in the temperature sensing cylinder 21a, and the valve body 21d is activated.
At the same time, the pressure receiving mechanism 24c is actuated by the pressure change of the gas in the temperature sensing cylinder 24a to narrow the opening of the valve body 24d, thereby increasing the cooling gas flow rate of the conductor 6. Decrease flow rate. As a result, the flow rate of the cooling gas in the conductor 6 increases synergistically, allowing the conductor 6 to be rapidly cooled. Moreover, when the superconducting coil 5 is not energized,
Since the cooling gas outlet temperature of the conductor 6 decreases, the temperature-sensitive flow control valve 21 operates in the closing direction and the temperature-sensitive flow control valve 24 operates in the opening direction. Therefore, the flow rate of the cooling gas in the conductor 6 is synergistically reduced, and the flow rate of the cooling gas in the shield 3 is increased, resulting in extremely efficient cooling management.

〔Effect of the invention〕

As described above, according to the present invention, the flow rate of refrigerant gas in a superconducting device can be automatically controlled by a temperature-sensitive flow control valve. In addition to preventing burnout accidents, it also ensures the correct flow rate of refrigerant gas necessary for cooling the power supply conductor, and the remaining amount is led to the shield side to generate refrigerant gas such as helium in the container. can be effectively used to cool the shield, thereby lowering the temperature of the shield and reducing the amount of heat that enters the container.This has the effect of efficiently cooling the power supply conductor and the shield and providing a superconducting device with low thermal loss. .

Furthermore, in the second invention, each of the pair of temperature-sensitive flow control valves that open and close in opposite directions,
Since it is provided in both external discharge conduits, there is an effect that the control response of the refrigerant gas flow rate becomes faster.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a superconducting device in an embodiment of the first invention, FIG. 2 is an enlarged sectional view showing a throttle passage connected in parallel to the external discharge conduit in FIG. 1, and FIG. FIG. 4 is a schematic diagram showing a superconducting device according to an embodiment of the invention, and FIG. 4 is a schematic diagram showing a conventional superconducting device. In the figure,
1 is a helium container as a container, 2 is liquid helium as a refrigerant liquid, 3 is a shield, 5 is a superconducting coil, 6 is a power supply conductor, 11 and 13 are first and second external discharge conduits, 21, 24 is a temperature-sensitive flow control valve. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A container filled with a refrigerant liquid such as liquid helium;
It includes a shield that surrounds the container and prevents radiant heat from entering the container from the outside, a superconducting coil immersed in the refrigerant liquid, and a power supply conductor that supplies current to the superconducting coil from the outside. , the refrigerant gas in which the refrigerant liquid has been vaporized is guided to two paths, one of which is led out to the outside from a first external discharge conduit after cooling the power supply conductor, and the other is a second path after cooling the shield. In a device that is led out to the outside from an external discharge conduit, the temperature of the refrigerant gas after cooling the power supply conductor is detected and the refrigerant gas is opened and closed in response to the temperature to maintain the temperature within a certain range. A superconducting device characterized in that a temperature-sensitive flow control valve is provided in the first external discharge conduit. 2. Claim 1, characterized in that a throttle passage is connected to the temperature-sensitive flow control valve in parallel with the temperature-sensitive flow control valve.
Superconducting device described in Section 1. 3 A container filled with a refrigerant liquid such as liquid helium,
It includes a shield that surrounds the container and prevents radiant heat from entering the container from the outside, a superconducting coil immersed in the refrigerant liquid, and a power supply conductor that supplies current to the superconducting coil from the outside. , the refrigerant gas in which the refrigerant liquid has been vaporized is guided to two paths, one of which is led out to the outside from a first external discharge conduit after cooling the power supply conductor, and the other is a second path after cooling the shield. The refrigerant gas is discharged to the outside from an external discharge pipe, and the temperature of the refrigerant gas after cooling the power supply conductor is detected, and the refrigerant gas is refrigerated in opposite directions in response to the temperature to maintain the temperature within a certain range. A superconducting device characterized in that a pair of temperature-sensitive flow control valves that open and close are provided in the first and second external discharge conduits, respectively. 4. Claim 3, characterized in that a throttle passage is connected to the temperature-sensitive flow control valve in parallel with the temperature-sensitive flow control valve.
Superconducting device described in Section 1.