JPH0656902B2 - Superconducting device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a superconducting device using a superconducting magnet or the like.

[Prior art and its problems]

Generally, the power lead used for excitation / demagnetization of the superconducting coil housed in the cryostat is introduced into the cryostat from the atmosphere side, so that heat is conducted into the cryostat by conducting this power lead. In order to reduce this heat intrusion as much as possible, the wire diameter of the power lead is made thin, and the power lead is cooled by helium gas in the cryostat so that the power lead is not burned out by the Joule heat generated from the power lead. Figure 1 shows a cryostat using power leads. Cryostat
Liquid helium (2) is stored in (1), and this liquid helium is stored.
Immerse the superconducting coil (3) in (2),
The power leads (4) and (5) used for excitation and demagnetization pass through the cooling tubes (6) and (7), respectively, and are guided to the atmosphere side.
Evaporated gas of liquid helium (2) in the cryostat (1) flows into these cooling pipes (6) and (7), and power leads (4) and (5)
Is cooled and is recovered from the gas recovery ports (8) and (9) provided on the atmosphere side of the cooling pipes (6) and (7). In addition, power lead
(4) and (5) are insulation materials (10) and (11), respectively, and cooling pipes (6) and (7).
It is fixed to.

In a configuration in which there are multiple cooling pipes (6), (7) led from the cryostat (1) to the atmosphere side, the helium gas is in a balanced state and the cooling pipes (6), (7) It is difficult to flow through the inside, and usually the balance is lost, and a large amount of helium gas flows into the cooling pipe that easily flows,
As a result, the cooling pipe with a large flow rate is further cooled and helium gas flows more easily, the flow rate of the helium gas in other cooling pipes decreases, and the power lead accommodated in this cooling pipe is insufficiently cooled. The power lead could be burned.

[Object of the Invention]

An object of the present invention is to eliminate the above-mentioned drawbacks, to provide a superconducting device which has a small amount of heat intrusion and is less likely to burn a power lead.

[Summary of the Invention] The present invention provides a cryostat, a superconducting coil immersed in a refrigerant stored in the cryostat, and a penetrating from the atmosphere side of the cryostat to the vicinity of the liquid surface of the refrigerant in the cryostat. In a superconducting device comprising a cooling pipe to be used and a plurality of power leads for energizing and demagnetizing the superconducting coil, the cooling pipe is made of an electrically insulating material, and The power leads and the cooling tubes are formed so that their respective cross-sectional shapes in a direction orthogonal to the long axis direction are in contact with the outer peripheral surface of the power leads and the inner wall surface of the cooling tube. A continuous substantially single flow in which the leads are not in contact with the inner wall surface of the cooling pipe and the evaporative gas of the refrigerant flows in the cooling pipe. Is characterized in adhesion fixed possible to ensure.

EFFECTS OF THE INVENTION By using the superconducting device according to the present invention, a plurality of power leads are cooled uniformly, so that the power leads are not burned even if the wire diameter of the power leads is minimized. Moreover, since the cross-sectional shape of each of the plurality of power leads and the cooling pipe in the direction orthogonal to the long axis direction is formed so that the outer peripheral surface of the power lead and the inner wall surface of the cooling pipe are in contact with each other, It is possible to take a large contact fixing effective area when fixing, and it is possible to satisfy both improvement of insulation performance and improvement of cooling efficiency.

Further, the cooling pipe is made of an electrically insulating material, and the plurality of power leads are electrically insulated and housed in the inner wall of the cooling pipe so as not to be in contact with each other, so that the cooling efficiency is improved with a simple structure. The power leads can be completely insulated from each other while maintaining. Furthermore, the wire diameter of the power lead can be minimized, and at the same time, since only one cooling pipe is provided, the amount of heat invading into the cryostat can be minimized.

[Embodiment of the Invention] Hereinafter, a representative embodiment of the present invention will be described with reference to Figs. 5 to 8, which is a prerequisite for the superconducting device of the present invention in order to facilitate understanding of the present invention. Reference examples are shown in FIGS. 2 to 4. It should be noted that the same parts as those in FIG. 1 are allotted with the same reference numerals to simplify the description. In Fig. 2, the power leads (4) and (5) that are excited and demagnetized in the superconducting coil (3) and partially immersed in the liquid helium (2) are liquid from the atmosphere side of the cryostat (1). Stored in the cooling pipe (12) so as not to partition the inside of the single cooling pipe (12) provided penetrating to the vicinity of the liquid level of helium (2) and not to interrupt the flow of evaporative gas Has been done. The vaporized gas of liquid helium (2) in the cryostat (1) flows into the gas inlet (13) provided on the liquid level side of the liquid helium (2) of the cooling pipe (12), and then the cooling pipe (12) The helium gas flowing inside is recovered by a recovery port (14) provided on the atmosphere side of the cooling pipe (12). Also, the cryostat of the power leads (4), (5)
The liquid helium (2) side in (1) is made of, for example, fiber reinforced plastic (FRP) as shown in FIG. 4, and holes (15a), (15b) penetrating the power leads (4), (5). And the atmosphere side of the power leads (4) and (5), which are plate-like insulating members (15) provided with gas flow holes (15c), are formed by, for example, FRP as shown in FIG. ), (5) through holes (16a), (1
Cooling pipe (12) by a plate-shaped insulating member (16) equipped with 6b)
It is insulated and fixed inside.

Next, the operation will be described. The vaporized gas of liquid helium (2) flows into the cooling pipe (12) through the gas inlet (13) of the cooling pipe (12) and the gas flow hole (15c) of the insulating member (15) and enters the cooling pipe (12). Since the flow in 1 is substantially divided into one flow path without being divided, the power leads (4) and (5) can be cooled uniformly. And this evaporated gas is the power lead
It is recovered from the recovery port (14) while cooling (4) and (5).

It should be noted that the withstand voltage of helium is 1 KV / cm even at room temperature (in the case of creeping discharge), and it becomes higher at low temperatures, so the withstand voltage does not pose a problem in this configuration.

Next, a superconducting device of the present invention, which is further improved in cooling efficiency and insulation performance of the power leads as compared with the configuration shown in the above reference example, will be described with reference to FIGS. 5 to 8. . Note that FIGS. 5 to 8 are enlarged views showing the improved essential parts of FIGS. 2 to 4 shown in the reference example, and the same parts are denoted by the same reference numerals and the description thereof will be omitted.

The power leads (4), (5) are formed in a semi-cylindrical shape as shown in FIG. 5 and have fins (17) extending radially in the center of the arc as shown in FIG. At the end on the atmosphere side, there are terminals (18), (19) used for connection with external equipment. The cylindrical cooling pipe is formed of an insulating material such as FRP, and has inner wall provided with protrusions (12a) and (12b) in the axial direction so as to insulate between the power leads (4) and (5). And this cooling pipe
As shown in Fig. 5, (12) is a power lead (4), (5) that is sandwiched between the protrusions (12a), (12b) and fixed along the inner wall with an adhesive or the like to seal and store it. ing. Furthermore, this cooling pipe (1
2) is a power lead at the end on the atmosphere side as shown in Fig. 7.
Projection plate (2) for insulation between terminals (18) and (19) of (4) and (5)
1a) and (21b), which are fixed to a cryostat (not shown) by a flange (20). Also, the power lead (4),
As shown in FIG. 6, a through hole (22) is formed in the center of the terminals (18) and (19) of (5) so that a cylindrical recovery port (14) made of an insulating material such as FRP can be inserted. ) Is provided and this through hole (22)
The recovery port (14) is installed with adhesive or the like.

Next, the operation will be described.

Liquid helium evaporative gas flows in from the lower end of the cooling pipe (12) and flows between the fins (17), so that power lead is generated.
While cooling (4) and (5), the temperature rises along the axial direction of the cooling pipe (12) and is recovered from the recovery port (14) to the atmosphere side.

In this way, change the cross-sectional shape of the power leads (4) and (5) to the cooling pipe.
By configuring so as to contact the inner wall surface of (12), the contact fixing effective surface area when contact fixing to the inner wall surface of the cooling pipe (12) and cooling compared to the conventional power lead having a general circular cross section. The cooling effective surface area provided for
Both the insulation performance and the cooling performance can be satisfied at the same time. Further, when the fins (17) are formed, the cooling area can be remarkably increased, so that the power leads (4) and (5) are cooled more effectively. Then, the cooling pipe (12) is made of an electrically insulating material, and the power lead (4) (5) and the cooling pipe (12) have respective cross-sectional shapes in a direction orthogonal to the longitudinal direction of the power lead (4) ( 5) is formed so that the outer peripheral surface and the inner wall surface of the cooling pipe (12) are in contact with each other, and the power leads (4) and (5) are closely fixed to the inner wall surface of the cooling pipe (12) in a non-contact manner. Therefore, the insulation performance can be significantly improved.

Although the embodiment shown in FIG. 5 shows an example in which two power leads (4) and (5) are housed in one cooling pipe (12),
In the case of independently exciting a plurality of superconducting coils, more power leads may be put in one cooling tube.

Further, the sectional structure of the power lead is not limited to that shown in FIG.
It is sufficient if the cooling area is large, the turbulent flow effect is promoted, and the pressure loss does not increase in the past.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a conventional superconducting device, FIG. 2 is a schematic sectional view showing a superconducting device of a reference example, and FIGS. 3 and 4 are front views showing insulating members used in the reference example. FIG. 5 is an enlarged perspective view showing an essential part of the superconducting device of the present invention, FIG. 6 is a perspective sectional view showing an essential part of the superconducting device of the present invention, and FIG. FIG. 8 is a perspective view showing a main part of the superconducting device, and FIG. 8 is a cross-sectional view showing an example of the shapes of the power lead and the cooling pipe used in the superconducting device of the present invention. (1) …… Cryostat, (2) …… Liquid helium (refrigerant), (3) …… Superconducting coil, (4), (5) …… Power lead, (12) …… Cooling tube.

Claims (2)

[Claims] 1. A cryostat, a superconducting coil immersed in a refrigerant stored in the cryostat, and a cooling pipe penetrating from the atmosphere side of the cryostat to near the liquid surface of the refrigerant in the cryostat. A superconducting device that is housed in the cooling pipe and has a plurality of power leads for performing demagnetization of the superconducting coil, wherein the cooling pipe is made of an electrically insulating material, and the plurality of power leads are provided. And each cross-sectional shape of the direction orthogonal to the long axis direction of the cooling pipe is formed so that the outer peripheral surface of the power lead and the inner wall surface of the cooling pipe are in contact, and the plurality of power leads are connected to each other. A continuous, substantially single flow path is provided so as to be in non-contact with the inner wall surface of the cooling pipe and to allow the evaporative gas of the refrigerant to flow in the cooling pipe. A superconducting device characterized in that it is closely fixed. 2. The superconducting device according to claim 1, wherein the power lead is formed with a fin protruding toward the inside of the cooling pipe.