JPH057850B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to a superconducting magnet used for example in a magnetic resonance diagnostic apparatus, in which a cryogenic liquid for cooling a superconducting coil is injected into a cryogenic container. This invention relates to a superconducting magnet with an improved arrangement of a detachable power lead and cryogenic liquid inlet port (hereinafter referred to as a service port).

(Prior Art) A conventional superconducting magnet used in a magnetic resonance diagnostic apparatus, for example, has an inner cylinder 1a as shown in FIG.
A vacuum container 1 is constructed in which both open ends of the outer cylinder 1b are closed to form a vacuum heat-insulated space 1c, and the inner diameter side of the inner cylinder 1a serves as a normal temperature effective space to which the subject is accessed. . In the vacuum insulation space 1c of the vacuum container 1, a cryogenic container 2 with a closed end between both open ends of a double cylinder is arranged. A superconducting coil 4 is immersed therein. The outer periphery of this ultra-low temperature container 2 is provided with a double cylindrical outer cylinder as a first shield 5a and an inner cylinder as a second shield 5b. A radiation shield 5 containing liquid nitrogen is arranged. On the other hand, a service port 6 that communicates with the cryogenic container 2 is provided above the axial center of the vacuum container 1, and a liquid helium 3
It is now possible to inject

By the way, in such a superconducting magnet, the service port 6 for injecting liquid helium 3 into the cryogenic container 2 is located at the axial center of the vacuum container 1, where the influence of thermal contraction is least, as can be seen from FIG. It is installed in the upper part. Therefore, when various operations are performed through this service port 6, not only is it troublesome to handle, but also a lot of effort and time is required to manufacture it.

(Problems to be Solved by the Invention) As described above, in the conventional superconducting magnet, the service port 6 is provided in the upper part of the axial center of the vacuum vessel 1. The problem was that the work was troublesome, and moreover, it took a lot of time and effort to manufacture.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a superconducting magnet that allows various operations to be performed through a service port and is also easy to manufacture.

(Means for Solving the Problems) In order to solve the above-mentioned objects, the present invention provides a vacuum container in which a vacuum insulation space is formed by closing the open ends of an inner cylinder and an outer cylinder, and the vacuum container. A cryogenic container arranged in the vacuum insulation space, with both open ends of a double cylinder closed and containing a cryogenic liquid therein, and a superconducting coil immersed in the cryogenic liquid in the cryogenic container. and a radiation shield arranged so as to surround the cryogenic container, the superconducting magnet comprising: a cryogenic liquid inlet port communicating with the cryogenic container and leading out to an outer cylindrical portion of the vacuum container; Provided on the upper side of one end in the axial direction of the vacuum container, and supporting the cryogenic liquid inlet port side in the axial direction of the vacuum container with the cryogenic liquid injection port side as a fixed support for the cryogenic container and the radiation shield. It is composed of

(Function) Therefore, in the case of a superconducting magnet having such a configuration, by supporting the cryogenic liquid inlet port side of the cryogenic container and the radiation shield in the axial direction of the vacuum container as fixed supports, the cryogenic temperature can be reduced. Even if the liquid inlet port is provided on the upper side of one axial end of the vacuum container, it is possible to reduce the influence of heat shrinkage of the cryogenic container and the radiation shield, and it is possible to The various operations to be carried out are facilitated, and the manufacture thereof is also simplified.

(Example) An example of the present invention will be described below with reference to the drawings.

1 and 2 show a configuration example of a superconducting magnet according to the present invention used, for example, in a magnetic resonance diagnostic apparatus, with FIG. 1 being a longitudinal cross-sectional view and FIG. 2 being a cross-sectional view. 1 and 2, reference numeral 11 denotes a vacuum container in which a vacuum insulation space 11c is formed by closing the opening ends of an inner cylinder 11a and an outer cylinder 11b, and the inner diameter of the inner cylinder 11a of this vacuum container 11 is The side is a normal temperature effective space to which the subject is accessed. Reference numeral 12 denotes a cryogenic container having a closed end between both open ends of a double cylinder. This cryogenic container 12 is arranged in the vacuum insulation space 11c of the vacuum container 11, and contains a cryogenic liquid, for example, liquid helium 13. At the same time, a superconducting coil 14 is immersed in this liquid helium 13. Further, 15 is a radiation shield in which the outer cylinder of the double cylinder is used as a first shield 15a and the inner cylinder is used as a second shield 15b, and both open ends thereof are closed.This radiation shield 15 surrounds the cryogenic container 12. A cooling medium, for example liquid nitrogen, is contained therein.
The cryogenic container 12 and the radiation shield 15 arranged in the vacuum insulation space 11c of the vacuum container 11 in this way
Both ends of the load support 16 as shown in FIG.
They are each supported so that they are suspended. On the other hand, reference numeral 17 denotes a refrigerator installed on the upper side of one end in the axial direction of the vacuum container 11;
is for cooling the liquid nitrogen in the radiation shield 15.

In a superconducting magnet with such a configuration,
In this embodiment, a service port 18 is provided on the upper side of the axial end of the vacuum vessel 11 on the opposite side from the refrigerator 17 so as to communicate with the cryogenic vessel 12, and the cryogenic vessel 12 and the radiation shield 15 The service port 18 side is fixedly supported, and the opposite side is elastically supported in the axial direction of the vacuum container 11 by support members 19a, 19b and elastic support members 20a, 20b, respectively. . That is, the support member 19a is connected to the radiation shield 15 on the service port 18 side of the cryogenic container 12.
The opposite side thereof is elastically supported in the axial direction by the elastic support member 20a on the radiation shield 15. Further, the service port 18 side of the radiation shield 15 is supported and fixed in the axial direction by a support member 19b on the inner surface of the outer cylinder 11a of the vacuum container 11,
The opposite side is elastically supported in the axial direction by an elastic support member 20b on the inner surface of the outer cylinder 11a of the vacuum container 11.

The service port 18 is a part for injecting liquid helium 13 into the cryogenic container 12, but is also used for discharging liquid helium vapor, drawing out the power lead of the superconducting coil 14, etc.

According to a superconducting magnet with such a configuration,
The service port 18 is connected to the refrigerator 17 of the vacuum container 11.
The support member 19 is provided at the upper part of the axial end opposite to the
By fixedly supporting the cryogenic container 12 and the radiation shield 15 in the axial direction by the elastic supporting parts 20a and 20b, the service port 18 can be fixedly supported in the axial direction by the elastic supporting parts 20a and 20b. It becomes possible to hold the position constant.
Therefore, even if the service port is located above the axial end of the vacuum vessel 11, the cryogenic vessel 12
In addition, since it is possible to reduce the effect of heat shrinkage of the radiation shield 15, various operations performed through the service port 18 are facilitated, and the manufacturing thereof is also simple and highly reliable. . In addition, since the service port 18 has a cooling capacity by the helium gas when the liquid helium 13 in the cryogenic container 12 evaporates, by providing the service port 18 on the opposite side of the vacuum container 11 from the refrigerator 17 side, The radiation shield 15 will be cooled by both the refrigerator 17 and the service port 18. This makes it possible to uniformly cool the radiation shield 15 as a whole, thereby reducing the amount of heat intrusion and reducing the amount of evaporation of liquid helium.

In the above embodiment, only the case where the service port 18 is made to reduce the influence of thermal contraction in the axial direction of the cryogenic container 12 and the radiation shield 15 has been described, but in addition, a bellows is inserted in the middle of the service port 18 to make the vacuum container If a configuration is added that absorbs positional deviation due to thermal contraction in a direction perpendicular to the axial direction of 11, the reliability can be further improved. It goes without saying that the present invention can be implemented in various other ways without changing the gist thereof.

[Effects of the Invention] As described above, according to the present invention, there is provided a vacuum container in which a vacuum insulation space is formed by closing the opening ends of an inner cylinder and an outer cylinder, and the vacuum insulation space of this vacuum container. a cryogenic container disposed in a double cylinder with both open ends thereof closed and a cryogenic liquid contained therein;
A superconducting magnet comprising a superconducting coil immersed in the cryogenic liquid of the cryogenic container and a radiation shield arranged to surround the cryogenic container, the superconducting magnet being in communication with the cryogenic container and connected to the vacuum container. A cryogenic liquid inlet port led out to the outer cylindrical part is provided on the upper side of one axial end of the vacuum container, and the cryogenic liquid inlet port side is connected to the cryogenic container and the radiation shield. is configured to support the vacuum container in the axial direction as a fixed support, so that even if the cryogenic liquid inlet port is provided at the upper side of one axial end of the vacuum container, the cryogenic liquid injection port and the radiation shield will not be connected to each other. It becomes possible to reduce the influence of thermal contraction, thereby facilitating various operations performed through the cryogenic liquid inlet port, and furthermore, it is possible to provide a superconducting magnet that can be manufactured easily.

[Brief explanation of the drawing]

1 and 2 are a longitudinal sectional view and a transverse sectional view showing an embodiment of a superconducting magnet according to the present invention, and FIG. 3 is a longitudinal sectional view showing an example of the structure of a conventional superconducting magnet. 11... Vacuum container, 12... Cryogenic container, 13
...Liquid helium, 14...Superconducting coil, 1
5...Radiation shield, 16...Load support, 1
7... Refrigerator, 18... Service port, 19
a, 19b...support member, 20a, 20b...elastic support member.

Claims (1)

[Scope of Claims] 1. A vacuum container in which a vacuum insulation space is formed by closing the openings of an inner cylinder and an outer cylinder, and both openings of a double cylinder body arranged in the vacuum insulation space of this vacuum container. A cryogenic container with closed ends and containing a cryogenic liquid, a superconducting coil immersed in the cryogenic liquid of the cryogenic container, and a radiation arranged so as to surround the cryogenic container. In the superconducting magnet equipped with a shield, a cryogenic liquid inlet port communicating with the cryogenic container and leading out to the outer cylindrical part of the vacuum container is provided on the upper side of one end in the axial direction of the vacuum container, A superconducting magnet characterized in that the cryogenic container and the radiation shield are supported in the axial direction of the vacuum container by using the cryogenic liquid injection port side as a fixed support. 2. The cryogenic liquid inlet port provided on the upper side of one axial end of the vacuum container is located on the side opposite to the refrigerator side of the radiation shield provided on the upper side of the axial end of the vacuum container. A superconducting magnet according to claim 1. 3. The cryogenic liquid inlet port has a bellows inserted in the middle thereof to absorb thermal contraction of the cryogenic liquid container and the radiation shield in a direction perpendicular to the axial direction of the vacuum container.Claim 1 The superconducting magnet according to item 1 or 2.