JP2007035945A - Ultralow temperature container and its assembling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain both connection between an outer peripheral wall and end walls and the tension adjustment of connection members without allowing, especially, the structure of a vacuum container to be heavy. <P>SOLUTION: The outer peripheral wall 18 of the vacuum container 10 is connected with a body 12 to be cooled via the connection members 16. Before adjusting the tension, the end walls 26 of the vacuum container 10 are connected to the outer peripheral wall 18. Operation windows are arranged in the vacuum container. A tool, etc., is inserted from the outer side of the operation windows so as to operate the tension adjustment operation part 50 of the connection members 16. After the termination of the tension adjustment, the operation windows are sealed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cryogenic container for keeping an object to be cooled such as a superconducting magnet used for MRI or the like at a cryogenic temperature and an assembling method thereof.

  As such a cryogenic container, a so-called horizontal container as described in Patent Document 1, for example, is known. An example of the structure of such a horizontal container is shown in FIGS.

  The illustrated container includes, for example, a vacuum container 10 that has a through hole 11 on a central axis as shown in FIGS. 4 (a) and 4 (b) and is installed in a posture in which the central axis faces a substantially horizontal direction. A body to be cooled 12 such as a superconducting magnet and a heat shield member 14 (not shown in FIG. 4B) are accommodated in the vacuum container 10 at a position coaxial with the vacuum container, and the body to be cooled 12 and the vacuum The container 10 is connected via a connecting member 16 capable of adjusting the tension.

  Here, conventionally, the assembly of the container is performed in the following procedure, for example.

  1) A cylindrical outer peripheral wall (hereinafter referred to as a “vacuum container outer peripheral wall”) 18 of the vacuum vessel 10 is installed on the ground 2 via legs 4, and the shaft end is disposed inside the vacuum vessel outer peripheral wall 18. A body 12 to be cooled and a cylindrical outer peripheral wall (hereinafter referred to as “heat shield outer peripheral wall”) 20 of the heat shield member 14 are inserted from the opening, and the object to be cooled 12 and the heat shield outer peripheral wall 20 are connected to the vacuum container. Set at a position coaxial with the outer peripheral wall 18.

  2) The cooled object 12 and the vacuum vessel outer peripheral wall 18 are connected via a connecting member 16.

  The connecting member 16 includes a vacuum vessel side block 35 fixed to the vacuum vessel outer peripheral wall 18 side, a cooled body side block 36 fixed to the cooled body 12 side, and an intermediate block interposed between the blocks 35 and 36. 38, and connecting members 40 are interposed between the vacuum vessel side block 35 and the intermediate block 38 and between the cooled object side block 36 and the intermediate block 38, respectively. These connecting members 40 are formed of a material having a sufficiently low thermal conductivity as compared with a metal such as CFRP. A threaded rod 46 projects axially outward from the cooled body side block 36 and is inserted into a through hole of a seat plate 48 projecting from the end face of the cooled body 12. By attaching the nut 50, the connecting member 16 is fastened to the seat plate 48. Accordingly, when the tension adjusting nut 50 is turned, the screw rod 46 screwed into the nut 50 and the block to be cooled 46 connected to the screw rod 46 are displaced, and the tension of the entire connecting member 16 changes. It is like that.

  3) By inserting a tool or the like from the shaft end opening of the vacuum vessel outer peripheral wall 18 and operating the tension adjusting operation nut 50 of the connecting member 16, the tension of the connecting member 16 is increased to a predetermined target tension.

  4) After adjusting the tension, the inner peripheral wall 25 of the heat shield member 14 is inserted inside the outer peripheral wall 20 of the heat shield, and the doughnut-shaped end walls (the heat The end wall 24 of the shield member 14 is joined to the end surfaces of the peripheral walls 20 and 25. The end wall 24 is also joined to the intermediate block 38 of the connecting member 16 as necessary.

5) The cylindrical inner peripheral wall 28 of the vacuum vessel 10 is inserted inside the inner peripheral wall 25 of the heat shield member 14. Further, a donut-shaped end wall (end wall of the vacuum vessel 10) 26 that closes the shaft end opening between the inner peripheral wall 28 and the vacuum vessel outer peripheral wall 18 is joined to the peripheral walls 28 and 18.
U.S. Pat. No. 4,837,541

  The target tension of the connecting member 16 in the step 3) needs to be set high to such an extent that the to-be-cooled body 12 or the like can be effectively prevented from shaking during subsequent transportation. Further, when a material having a negative coefficient of thermal expansion (for example, CFRP) is selected as the material of the connecting member 16, the target tension is further increased by the amount that the connecting member 16 extends in a use state, that is, at a very low temperature. It needs to be set high.

  Such a high tension acts as an external force that applies a vertical strain ε as shown in FIG. 4B to the vacuum vessel outer peripheral wall 18. If such distortion is large, it becomes difficult to join the end wall 26 of the vacuum vessel 10 to the outer peripheral wall 18 thereafter. For example, in the case of a structure in which a bolt is inserted into a bolt insertion hole provided in the end wall 26 and screwed into a screw hole provided in an end portion of the vacuum vessel outer peripheral wall 18, the positions of the bolt insertion hole and the screw hole are shifted. There is a fear.

  For this reason, conventionally, in order to suppress the distortion of the vacuum vessel outer peripheral wall 18 against the tension, the thickness of the vacuum vessel outer peripheral wall 18 is set to be large and has a robust structure, which increases the size and weight of the entire vessel. This is an increase factor, which is a major obstacle to reducing production costs and transportation costs.

  As means for solving the above-mentioned problems, the present invention is a vacuum vessel installed with a posture in which the central axis is oriented substantially in the horizontal direction, and is accommodated in the vacuum vessel at a position coaxial with the vacuum vessel. A body to be cooled, and a connecting member that connects the body to be cooled and the vacuum vessel and has a tension adjusting operation unit for adjusting the tension, and the vacuum vessel has a diameter of the body to be cooled. A cylindrical outer peripheral wall that surrounds from the direction, and an end wall that is joined to the outer peripheral wall so as to close the axial end opening of the outer peripheral wall, and at least one of the outer peripheral wall and the end wall is external to the vacuum vessel. The cryogenic container is provided with an operation window at a position enabling the operation of the tension adjusting operation unit from the position.

  The present invention is also a method for assembling the cryogenic container, the step of inserting the object to be cooled from the axial end opening inside the outer peripheral wall of the vacuum container and setting it at a position coaxial with the vacuum container; A step of connecting the body to be cooled and the outer peripheral wall via the connecting member, a step of connecting the end wall to the outer peripheral wall so as to close the shaft end opening of the outer peripheral wall, and a joining of the end walls It includes a step of adjusting the tension of the connecting member by operating a tension adjusting operation portion of the connecting member later through the operation window of the vacuum vessel, and a step of sealing the operating window after the tension adjustment.

  According to the above configuration, the end wall is joined to the outer peripheral wall of the vacuum vessel before adjusting the tension of the connecting member, thereby avoiding the design of increasing the thickness of the outer peripheral wall and suppressing the distortion due to the tension adjustment. However, the joining is possible. Moreover, even after the joining, the tension can be adjusted by operating the tension adjusting operation portion of the connecting member through the operation window provided on the end wall or the outer peripheral wall, and then the operation window can be adjusted. By sealing with a lid member or the like, the inside of the vacuum container can be evacuated as in the conventional case.

  The cryogenic container may include a heat shield member disposed between the object to be cooled and the vacuum container. In this structure, when the tension adjusting operation portion of the connecting member is provided at a position on the inner side of the heat shield member, the operation window is also located at a position that substantially matches the operation window of the vacuum vessel on the heat shield member. The tension adjusting operation portion of the connecting member can be operated from the outside of the vacuum vessel through both operation windows.

  Such a cryogenic container includes a step of inserting the object to be cooled and the heat shield member from the opening of the shaft inside the outer peripheral wall of the vacuum container and setting the same at a position coaxial with the vacuum container; A step of connecting the cooling body and the outer peripheral wall of the vacuum vessel via the connecting member; and an end wall of the vacuum vessel on the outer peripheral wall of the vacuum vessel so as to close an axial end opening of the outer peripheral wall of the vacuum vessel. The step of joining, and the step of adjusting the tension of the connecting member by operating the tension adjusting operation part of the connecting member through the operation window of the vacuum vessel and the operation window of the heat shield member after joining the end walls; And the step of sealing the operation window after adjusting the tension.

  Further, it is more preferable that the end wall of the vacuum vessel has an outer peripheral wall fitting portion that is fitted to the inner side of the outer peripheral wall with almost no gap to suppress distortion of the outer peripheral wall. According to such a configuration, when the tension of the connecting member is adjusted after joining the end wall and the outer peripheral wall, the occurrence of distortion of the outer peripheral wall due to the tension can be more effectively suppressed.

  As described above, according to the present invention, the tension adjustment can be performed by operating the tension adjusting operation portion of the connecting member through the operation window after joining the outer peripheral wall and the end wall of the vacuum vessel. There is an effect that both the joining of the outer peripheral wall and the end wall and the tension adjustment of the connecting member can be adjusted without making the structure of the vacuum vessel heavy, and the production cost and the transportation cost can be reduced.

  Hereinafter, a method for assembling a cryogenic container according to a preferred embodiment of the present invention will be described in order with reference to FIGS. 1 to 3 in addition to FIG. The same components as those shown in FIG. 4 are given the same reference numerals as those in FIG.

  1) The same cylindrical heat shield outer peripheral wall 20 is inserted inside the outer peripheral wall 18 of the cylindrical vacuum vessel, and both are connected by an outer peripheral wall connecting material (not shown). Thereby, both the outer peripheral walls 18 and 20 hold | maintain the state arrange | positioned substantially concentrically.

  In the present invention, the heat shield member 14 can be omitted as appropriate according to the specifications. In this case, the step 1) may be omitted.

  2) Insert a body 12 to be cooled, such as a superconducting magnet, inside the outer peripheral wall 20 of the heat shield. Further, the position of the body 12 to be cooled is adjusted so as to be substantially concentric with the outer peripheral walls 18 and 20.

  3) The cooled object 12 is connected to the vacuum vessel outer peripheral wall 18 through the connecting member 16 shown in FIG. Here, conventionally, tension adjustment is performed to immediately increase the tension to the target tension when the connecting member 16 is connected to the cooled object 12 and the outer peripheral wall 18 of the vacuum vessel. The high tension is not applied yet, and the tension of the connecting member 16 is kept to a minimum necessary for holding the cooled object 12 in the concentric position.

  4) The cylindrical inner peripheral wall 25 constituting the heat shield member 14 is inserted inside the heat shield outer peripheral wall 20. Further, the end wall 24 of the heat shield member 14 is fixed to the end surfaces of the peripheral walls 20 and 25 and also to the intermediate block 38 of the connecting member 16.

  5) Insert the inner peripheral wall 28 of the vacuum vessel 10 further inside the inner peripheral wall 25 of the heat shield member 14, and close the shaft end opening between the inner peripheral wall 28 and the outer peripheral wall 18 of the vacuum vessel 10. As shown in FIGS. 1 and 2, a donut plate-like end wall (end wall of the vacuum vessel 10) 26 having a through hole 66 in the center is fixed to the end faces of the peripheral walls 28 and 18 by bolts 56.

  At this time, if an outer peripheral wall insertion portion 26a is projected in advance on the back surface of the end wall 26, the outer peripheral wall insertion portion 26a is inserted into the vacuum vessel outer peripheral wall 18 with almost no gap ( 1), the presence of the outer peripheral wall insertion portion 26a makes it possible to more effectively suppress the distortion of the vacuum container outer peripheral wall 18 (distortion that occurs during tension adjustment described later). It becomes possible to obtain.

  Further, when the end wall 26 is joined, an appropriate pressure is applied to the vacuum vessel outer peripheral wall 18 from a plurality of different positions in the circumferential direction toward the inside in the radial direction by using a jack or the like. If the distortion (particularly, the distortion in the direction of flattening in the vertical direction due to its own weight) is suppressed, the joining operation of the end wall 26 can be performed more smoothly.

  6) As a feature of the cryogenic container, the end wall 26 is provided with a plurality of operation windows 68 as shown in FIG. These operation windows 68 are formed at positions where the tension adjusting operation nuts 50 of the respective connecting members 16 are opened outward (forward or backward) in the axial direction. Further, in the case where each nut 50 is provided inside the heat shield member 14 as shown in the figure, an operation window 58 is provided at a position corresponding to the operation window 68 on the end wall 24 of the heat shield member 14. Provided, the operation windows 58 and 68 cooperate to open the tension adjusting operation nut 50 of each connecting member 16 to the outside in the axial direction of the end wall 24.

  By forming the operation windows 58 and 68 as described above, even after the end walls 26 are joined, a tool or the like is inserted into the container through the operation windows 58 and 68 to rotate the tension adjusting nut 50. The tension of each connecting member 16 can be adjusted by this rotation operation.

  If the tension of the connecting member 16 is adjusted after joining the end wall 26 to both the peripheral walls 18 and 28 in this manner, the end wall is caused by the vacuum vessel outer peripheral wall 18 being distorted due to the increased tension. It is possible to prevent the joining of the inner wall 26 from being impossible, and the joining of the end wall 26 can more effectively suppress the distortion of the outer peripheral wall 18 of the vacuum vessel. In particular, if the outer peripheral wall fitting portion 26a as described above is formed on the back surface of the end wall 26, the effect of suppressing the distortion becomes more remarkable.

  Therefore, the joint of the end wall 26 to both the peripheral walls 18 and 28 in the vacuum vessel 10 and the connection member 16 can be performed without designing the wall thickness of the outer peripheral wall 18 to be particularly large in order to suppress the distortion. It is possible to perform both tension adjustment, and as a result, the thickness of the vacuum vessel outer peripheral wall 18 can be suppressed and the weight and cost of the entire vessel can be reduced.

  In addition, after the tension adjustment, if the operation window 68 is closed by fixing a cover plate to the end wall 26 of the vacuum container 10, a vacuum is formed in the vacuum container 10 as in the conventional case. Is possible. Similarly, if a cover plate or the like is fixed to the end wall 24 of the heat shield member 14 so as to close the operation window 58, a higher heat shield effect can be secured.

  The positions and shapes of the operation windows 58 and 68 may be set as appropriate depending on the specific structure and arrangement of the connecting member 16.

  For example, when the tension adjusting operation nut 50 of the upper connecting member 16 is close to each other as shown in FIG. 3A, the operation window 69 common to both nuts 50 is used as shown in FIG. (And the operation window 59 on the heat shield member 14 side) may be formed. When the operation portion such as the tension adjusting nut 50 is outside the heat shield member 14, the operation windows 58 and 59 on the end wall 24 on the heat shield member 14 side are not necessary.

  Further, when the connecting member 16 connects the outer peripheral portion at a position away from the shaft end of the body 12 to be cooled and the vacuum vessel outer peripheral wall 18, the outer peripheral wall, not the end wall 26 of the vacuum vessel 10. 18 may be provided with the operation window 68.

It is a side view which shows the whole structure of the cryogenic container which concerns on embodiment of this invention. It is a front view of the end wall of the vacuum vessel in the cryogenic vessel. (A) is a front view which shows the modification of arrangement | positioning of the connection member in the said cryogenic container, (b) is a front view which shows the example of a shape of the operation window of the vacuum vessel end wall corresponding to the said arrangement | positioning. (A) is the cross-sectional side view which shows the example of the conventional cryogenic container, (b) is the front view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vacuum container 12 To-be-cooled body 14 Heat shield member 16 Connection member 18 Outer wall of vacuum container 20 Outer wall of heat shield member 24 End wall of heat shield member 26 End wall of vacuum container 26a Outer wall insertion part 50 For tension adjustment operation Nut 58 Heat shield member operation window 68 Vacuum vessel operation window

Claims (6)

  A vacuum vessel installed with a posture in which the central axis faces substantially in the horizontal direction, a cooled object accommodated in the vacuum vessel at a position coaxial with the vacuum vessel, and the cooled object and the vacuum vessel are connected to each other. And a connecting member having a tension adjusting operation unit for adjusting the tension, and the vacuum vessel includes a cylindrical outer peripheral wall that surrounds the object to be cooled from its radial direction, and an axial end opening of the outer peripheral wall. And an end wall joined to the outer peripheral wall so as to block the operation window, and at least one of the outer peripheral wall and the end wall is operated at a position that enables the operation of the tension adjusting operation unit from the outside of the vacuum vessel. A cryogenic container characterized in that is provided.   The cryogenic container according to claim 1, wherein the end wall has an outer peripheral wall fitting portion that is fitted into the outer peripheral wall with almost no gap to suppress distortion of the outer peripheral wall.   The cryogenic container according to claim 1 or 2, further comprising a heat shield member disposed between the object to be cooled and the vacuum container, and adjusting the tension of the connecting member at a position inside the heat shield member. An operation portion is provided, and an operation window is also provided at a position that substantially matches the operation window of the vacuum vessel in the heat shield member, and the tension adjustment operation portion of the connecting member is externally provided through the operation window. A cryogenic container configured to be operable.   3. A method for assembling a cryogenic vessel according to claim 1 or 2, wherein the object to be cooled is inserted into the outer peripheral wall of the vacuum vessel from its axial end opening and set at a position coaxial with the vacuum vessel. A step of connecting the body to be cooled and the outer peripheral wall via the connecting member, and a step of joining the end wall of the vacuum vessel to the outer peripheral wall so as to close the shaft end opening of the outer peripheral wall. And adjusting the tension of the connecting member by operating the tension adjusting operation portion of the connecting member through the operation window of the vacuum vessel after joining the end walls, and sealing the operating window after the tension adjustment. And a process for assembling the cryogenic container.   4. A method for assembling a cryogenic container according to claim 3, wherein the object to be cooled and the heat shield member are inserted into the outer peripheral wall of the vacuum container from the axial end opening thereof and are coaxial with the vacuum container. A step of setting the position, a step of connecting the object to be cooled and the outer peripheral wall of the vacuum vessel via the connecting member, and an outer periphery of the vacuum vessel so as to close the shaft end opening of the outer peripheral wall of the vacuum vessel Joining the end wall of the vacuum vessel to the wall and operating the tension adjusting operation portion of the connecting member through the operation window of the vacuum vessel and the operation window of the heat shield member after joining the end walls. A method for assembling a cryogenic container, comprising: adjusting a tension of a member; and sealing the operation window after adjusting the tension.   6. The method of assembling a cryogenic container according to claim 4 or 5, wherein the step of joining the end wall to the outer peripheral wall so as to close the shaft end opening of the outer peripheral wall differs in the circumferential direction with respect to the outer peripheral wall. A method of assembling a cryogenic container, wherein the end wall is joined to the outer peripheral wall while suppressing distortion of the outer peripheral wall by applying pressure from a plurality of positions.

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