Heads, pressure vessels, cryostats and magnetic resonance imaging systems

Abstract

The application provides a head, a pressure container, a low-temperature holder and a magnetic resonance imaging system, the head is used for connecting an inner cylinder and an outer cylinder of a pressure container, the head comprises a head body and a reinforcing part, the reinforcing part is arranged at a predetermined position of the head body and comprises a joint body, the joint body is in contact with and connected to a surface of the head body. The application can achieve the purposes of improving stress distribution of the head and improving overall strength of the head by arranging the reinforcing part on the head body.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a head, a pressure vessel, a cryostat and a magnetic resonance imaging system. Background Art

[0002] The structure of superconducting magnets used in magnetic resonance systems is as follows: Figure 1 As shown, it includes multiple solenoid coils 1, which are wound in the wire slots of a bobbin 2 and enclosed in a cryostat. The cryostat is filled with a cryogenic medium, such as liquid helium, which immerses the solenoid coils 1 and maintains them in a low-temperature superconducting state. Thus, when the solenoid coils 1 are excited, they can generate a stable and strong magnetic field.

[0003] The cryostat is usually assembled from multiple layers of concentric cylindrical chambers. Figure 2 As shown, the cryostat generally includes an inner container 3, a heat shielding layer 4 and an outer vacuum container 5 arranged from the inside to the outside. Each cylindrical cavity includes an inner cylinder 6, an outer cylinder 7 and an annular head 8 for connecting and sealing the inner cylinder 6 and the outer cylinder 7. The annular head 8 is connected to the inner cylinder 6 and the outer cylinder 7 by welding or other processes.

[0004] The cryostat is made of metal materials such as stainless steel or aluminum alloy. For the inner container 3 and the outer vacuum container 5, both are subject to the internal pressure generated by the volatilization of the internal refrigerant and the external pressure generated by the atmosphere. Specifically, the inner container 3 is subject to internal pressure, and the outer vacuum container 5 is subject to external pressure. Therefore, the design and manufacture of the inner container and the outer vacuum container need to meet the corresponding pressure vessel standards. Generally, under the same stress conditions, when the annular head 8 is a spherical head or an elliptical head, the pressure distribution on it is relatively uniform and the thickness is relatively small. However, these two types of heads are limited by the length of the superconducting magnet, resulting in limited use. At present, most cryostat used to support superconducting magnets use a flat or approximately flat annular head. However, this type of head has large edge stress at the connection with the cylinder (inner cylinder and / or outer cylinder), and large bending stress in the center area of ​​the head. For this situation, the usual solution is to increase the thickness of the head or optimize the shape of the head. However, increasing the thickness of the head leads to an increase in the cost of the head, which in turn leads to an increase in the cost of the cryostat. Optimizing the shape of the head often results in complex processing technology, long processing cycles, and even the disadvantage of easy deformation of the head. Summary of the Invention

[0005] The purpose of the present invention is to provide a head, a pressure vessel, a cryostat and a magnetic resonance imaging system, aiming to improve the stress distribution of the head and enhance the overall strength of the head.

[0006] To achieve the above-mentioned objectives, the present invention provides a head for connecting the inner tube and outer tube of a pressure vessel, characterized in that the head includes a head body and a reinforcement part, the reinforcement part is arranged at a predetermined position of the head body and includes a coupling body, and the coupling body contacts and is connected to the surface of the head body.

[0007] Optionally, the reinforcement portion further includes a filling body, and at least a portion of the outer surface of the filling body is covered by the bonding body.

[0008] Optionally, the material of the bonding body is an adhesive or a welding material; the filling body is a sphere; and / or the filling body is a hollow structure; and / or a concave-convex structure is formed on the outer surface of the filling body.

[0009] Optionally, there are multiple filling bodies, and at least some of the filling bodies are mechanically connected to each other; and / or, at least some of the filling bodies are mechanically connected to the head body.

[0010] Optionally, the head body is an annular structure and includes a first annular area, a second annular area and a third annular area arranged radially from the inside to the outside; the predetermined position includes at least a part of the second annular area; and / or,

[0011] A reinforcement structure is formed on the second annular area, and the reinforcement portion is arranged inside the reinforcement structure.

[0012] Optionally, the head further includes a first connecting portion, which is connected to the inner edge of the first annular area and is used to connect to the inner cylinder; the predetermined position also includes at least a portion of the area where the first annular area and the first connecting portion meet; and / or,

[0013] The head also includes a second connecting portion, which is connected to the outer edge of the third annular area and is used to connect to the outer cylinder; the predetermined position also includes at least a partial area where the third annular area and the second connecting portion meet.

[0014] Optionally, the reinforcement portion corresponding to each annular area extends continuously along the circumference of the corresponding annular area; or, the reinforcement portion corresponding to each annular area includes a plurality of sub-reinforcements, which are arranged at intervals along the circumference of the corresponding annular area.

[0015] To achieve the above objectives, the present invention provides a pressure vessel comprising an inner tube, an outer tube and a head as described in any of the preceding items, wherein the head connects the inner tube and the outer tube and together with the inner tube and the outer tube form a closed inner cavity.

[0016] To achieve the above-mentioned objectives, the present invention provides a low-temperature holder, comprising a heat shielding layer and a pressure vessel as described above, wherein the number of the pressure vessels is two, one of the pressure vessels is arranged inside the heat shielding layer, and the other pressure vessel is mounted outside the heat shielding layer.

[0017] To achieve the above-mentioned object, the present invention provides a magnetic resonance imaging system, comprising the cryostat as described above and a superconducting magnet disposed in the cryostat.

[0018] Compared with the prior art, the head, pressure vessel, cryostat and magnetic resonance imaging system of the present invention have the following advantages:

[0019] The aforementioned head is used to connect the inner cylinder and the outer cylinder of the pressure vessel. The head includes a head body and a reinforcement part, and the reinforcement part is arranged at a predetermined position of the head body, and includes a coupling body, and the coupling body is in contact with and connected to the surface of the head body. When the head is actually used, the stress distribution of the head can be improved by arranging the reinforcement part, thereby improving the overall strength of the head. Preferably, the material of the coupling body can be resin glue or solder. In this way, when forming the reinforcement part, the fluid resin glue or solder can be solidified and formed on the surface of the head body, or the reinforcement part can be formed by a mold and then bonded or welded to the head body. There is no need to specially design the shape of the head body, and the head in the prior art can be directly used as the head body of the present invention, so that the molding difficulty will not be increased on the basis of the prior art.

[0020] Not only that, the reinforcement part also includes a filling body, which is dispersed in the joint body, and at least part of the outer surface of the filling body is covered by the joint body and connected to the joint body. In this way, the material of the joint body can be reduced and the cost can be reduced without reducing the reinforcement effect of the reinforcement part. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are provided for a better understanding of the present invention and are not intended to limit the present invention.

[0022] Figure 1 The figure shows a schematic diagram of the assembly structure of a superconducting magnet and a cryostat in the prior art;

[0023] Figure 2 Shown Figure 1 Axial cross-sectional view of

[0024] Figure 3 is a sectional perspective view of a head provided according to one embodiment of the present invention;

[0025] Figure 4 yes Figure 3 A schematic cross-sectional view of the head shown;

[0026] Figure 5 is a structural schematic diagram of a head provided according to another embodiment of the present invention;

[0027] Figure 6 is a structural schematic diagram of a head provided according to yet another embodiment of the present invention;

[0028] [Description of reference numerals is as follows]:

[0029] 100-head body, 110-first annular area, 120-second annular area, 121-recessed structure, 130-second annular area;

[0030] 200-reinforcement part, 210-joining body, 220-filling body;

[0031] 310-first connecting portion;

[0032] 320- second connecting portion;

[0033] 1-solenoid coil, 2-winding frame, 3-inner container, 4-heat shielding layer, 5-outer vacuum container, 6-inner cylinder, 7-outer cylinder, 8-head. DETAILED DESCRIPTION

[0034] The following describes the embodiments of the present invention through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner, and the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components during actual implementation. During actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0035] In addition, each embodiment described below has one or more technical features. However, this does not mean that users of the present invention must implement all technical features in any embodiment at the same time, or that they can only implement some or all technical features in different embodiments separately. In other words, as long as implementation is possible, those skilled in the art can, based on the disclosure of the present invention and depending on design specifications or implementation requirements, selectively implement some or all technical features in any embodiment, or selectively implement a combination of some or all technical features in multiple embodiments, thereby increasing the flexibility of the implementation of the present invention.

[0036] As used in this specification, the singular forms "a", "an", and "the" include plural objects, and the plural form "a plurality" includes more than two objects, unless the content clearly indicates otherwise. As used in this specification, the term "or" is generally used in a sense including "and / or", unless the content clearly indicates otherwise, and the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium, and it can be a connection between the internal parts of two elements or an interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0037] To make the objects, advantages, and features of the present invention more apparent, the present invention is further described below in detail with reference to the accompanying drawings. It should be noted that the drawings are greatly simplified and not to exact scale, and are intended solely to facilitate and clearly illustrate the embodiments of the present invention. The same or similar reference numerals in the drawings represent the same or similar components.

[0038] Figure 3 It shows a schematic structural diagram of a head provided by an embodiment of the present invention. Figure 4 A cross section of the head is shown.

[0039] Please refer to Figure 3 and Figure 4 , the head includes a head body 100 and a reinforcement portion 200 provided at a predetermined position on the head body 100. The head body 100 can be a rotating body with a certain axis as the axis, which can be used to connect to the ends of the inner cylinder and the outer cylinder of the pressure vessel, and together with the inner cylinder and the outer cylinder to form a chamber. The inner cylinder and the outer cylinder can be coaxially arranged. The reinforcement portion 200 includes at least a coupling body 210, and the coupling body 210 is in contact with and connected to the surface of the head body 100. By arranging the reinforcement portion 200 at a predetermined position on the surface of the head body 100, the stress distribution on the head can be improved, and its strength can be improved so that it can adapt to high-pressure use environments.

[0040] The material of the joint body 210 can be an adhesive or a welding material. In some implementations, the reinforcement portion 200 can be directly solidified on the head body 100 using a fluid resin glue or solder. In other embodiments, the reinforcement portion 200 can also be pre-molded using a mold and then connected to the head body 100 by bonding or welding according to the material of the joint body 210. In this way, the head body 100 in the embodiment of the present invention can be directly used as the head body 100 without changing the shape and processing of the head body 100, and the molding difficulty is not increased based on the existing technology. In particular, when the material of the joint body 210 is a polymer resin glue, the operation of forming the reinforcement portion 200 is simpler and more convenient, and the entire process does not require heat input, which will not cause deformation or performance degradation of the head body 100 (and the first connecting portion 310 and the second connecting portion 320 mentioned later). It should be noted that when the pressure vessel is used to load a superconducting magnet, the pressure vessel also needs to be filled with a low-temperature medium. Therefore, the resin glue or the solder should not generate magnetic interference and can maintain good strength and rigidity at low temperatures.

[0041] Furthermore, the predetermined position is determined according to the actual situation, and is usually an area with greater stress on the head body 100. Figure 3 and Figure 4The head body 100 includes a first annular area 110, a second annular area 120 and a third annular area 130 distributed radially from the inside to the outside. During actual use, there is a large bending stress in the second annular area 120, and the possibility of deformation is also the greatest. Therefore, the predetermined position may include at least a portion of the second annular area 120. Optionally, the head further includes a first connecting portion 310, which is connected to the inner edge of the first annular area 110 (that is, the edge of the first annular area 110 away from the second annular area 120) and is used to connect to the inner cylinder of the pressure vessel. The junction of the first annular area 110 and the first connecting portion 310 is a structural discontinuous area with a large edge stress. Therefore, it is preferred that the predetermined position also includes at least a portion of the junction of the first annular area 110 and the first connecting portion 310. Furthermore, the end cap may also include a second connecting portion 320, which is connected to the outer edge of the third annular region 130 (i.e., the edge of the third annular region 130 away from the second annular region 120) and is used to connect to the outer cylinder of the pressure vessel. The junction between the third annular region 130 and the second connecting portion 320 also has a large edge stress, so the predetermined position also includes at least a portion of the junction between the third annular region 130 and the second connecting portion 320.

[0042] In practice, the reinforcement portion 200 corresponding to any annular zone (for example, the reinforcement portion 200 arranged in the second annular zone 120) can extend continuously along the circumference of the corresponding annular zone and form a circle, or it can include multiple sub-reinforcement portions, and the multiple sub-reinforcement portions are arranged at intervals along the circumference of the corresponding annular zone.

[0043] The embodiment of the present invention does not particularly limit the shape of the reinforcement portion 200. Reinforcement portions 200 of various shapes can improve the stress distribution and strength of the head. In a preferred embodiment, the surface of the reinforcement portion 200 away from the head body 100 is smooth and can be smoothly connected to the head body 100, the surface of the first connecting portion 310, and the surface of the second connecting portion 320, so as to increase the force-bearing area of ​​the head and alleviate stress concentration. Furthermore, for some special shapes of the reinforcement portion 200, the effect of improving the performance of the head is even better.

[0044] For the reinforcement portion 200 provided on the second annular region 120, when the second annular region 120 is a flat plate structure, it is preferred that the surface of the reinforcement portion 200 away from the head body 100 is a curved surface, and along the radial direction (from inside to outside or from outside to inside), the distance from the surface of the reinforcement portion 200 away from the head 100 to the head body 100 first increases and then decreases (e.g. Figure 4 It should be noted that the reinforcement portion 200 provided in the second annular region 120 can be connected to the inner surface of the head body 100 (i.e., the surface of the head body 100 located inside the pressure vessel) or the outer surface of the head body 100 (i.e., the surface of the head body 100 located outside the pressure vessel).

[0045] Please refer back to Figure 4 The reinforcement portion 200 disposed at the junction of the first annular region 110 and the first connecting portion 310, and the reinforcement portion 200 disposed at the junction of the third annular region 130 and the second connecting portion 320, can be disposed on the inner surface of the head. Preferably, the surfaces of the reinforcement portions 200 in these two regions away from the head body 100 are curved, with the convex sides of these surfaces facing the head body 100 and / or the corresponding connecting portions. These surfaces are also smoothly connected to the inner surfaces of the head body 100 and the inner surfaces of the corresponding connecting portions to enhance the reinforcement effect. Figure 4 The surface of the reinforcement part 200 arranged at the junction of the first annular area 110 and the first connecting part 310, which is away from the head body 100, is a plane, while the plane of the reinforcement part 200 arranged at the junction of the third annular area 130 and the second connecting part 320, which is away from the head body 100, is a curved surface. Obviously, the reinforcement effect of the reinforcement part 200 corresponding to the third annular area 130 is better than the reinforcement effect of the reinforcement part 200 corresponding to the first annular area 110.

[0046] In addition, it should be noted that the second annular area 120 may also be a non-flat structure, and a reinforcement structure may be formed on the second annular area 120, and the reinforcement portion 200 may be provided inside the reinforcement structure. The reinforcement structure described here may be a recessed structure or a protruding structure that can enhance the local strength and rigidity of the head. Figure 6 As shown, when a recessed structure 121 is formed on the second annular area 120, the reinforcement portion 200 can be disposed in the recessed structure 121 (e.g., Figure 6As shown). Preferably, on the axial cross-section of the head, the bottom edge of the recessed structure 121 can be arc-shaped, so that the recessed structure 121 itself can improve the stress distribution of the head body 100 and increase the strength of the head body 100. It can be understood that the recessed structure 121 can be on the inner surface of the head 100 or on the outer surface of the head body 100, and the number of the recessed structures 121 can be multiple, and they are arranged at intervals along the circumference of the second annular area 120. In this case, each of the recessed structures 121 is actually provided with a sub-reinforcement portion, or the recessed structure is one and extends continuously along the circumference of the second annular area 120 (not shown in the figure). In addition, the junction of the first connecting portion 310 and the first annular area 110 can also form a chamfer or fillet, and the junction of the second connecting portion 320 and the third annular area 130 can also form a chamfer or fillet, so as to improve the overall strength of the head and improve the stress distribution.

[0047] Further, please refer to Figure 4 and Figure 6 The reinforcement portion 200 preferably further includes a filling body 220, at least a portion of the outer surface of the filling body 220 is covered by the joint body 210, and is also connected to the joint body 210. The filling body 220 can reduce the material usage of the joint body 210 and reduce production costs without reducing the performance of the reinforcement portion 200. It is understandable that the material of the filling body 220 does not generate magnetic interference and can maintain good rigidity and hardness at low temperatures. Specific optional materials include but are not limited to austenitic stainless steel, silicon glass, plastic, fiber-reinforced filler, etc. However, it is preferred that the density of the material of the filling body 220 is relatively low to reduce the mass of the head.

[0048] The number of the filler bodies 220 is generally multiple, and the multiple filler bodies 220 are dispersed within the bonding body 210 so that the filler bodies 220 are completely covered by the bonding body 210. It is understood that the multiple filler bodies 220 can be evenly dispersed within the bonding body 210, or unevenly dispersed, and adjacent filler bodies 220 can be in contact with each other or arranged at intervals. Alternatively, part of the surface of some of the filler bodies 220 can be exposed outside the bonding body 210, as long as the surface of the reinforcement portion 200 away from the head body 100 is smooth.

[0049] The embodiment of the present invention does not limit the shape of the filling body 220, which can be a sphere, an ellipsoid, a cylinder, a cube or an irregular polyhedron, etc. The filling body 220 can be a hollow structure or a solid structure. Preferably, the filling body 220 is a hollow sphere, because the hollow structure saves more raw materials, reduces costs, and can also reduce weight. In addition, a sphere is a better load-bearing shape. A hollow sphere can withstand a large pressure at a very small thickness. For example, a stainless steel sphere with a thickness of 1mm and a diameter of 100mm can withstand tens or even hundreds of atmospheres of pressure. When it is filled inside the joint 210, it can form a reinforcement part 200 with good rigidity and strength, thereby obtaining better pressure resistance. Moreover, compared with filling bodies of other shapes, the processing of a hollow sphere is also simpler and more convenient. The interior of the filling body 220 can also be filled with a fluid medium, such as helium or water.

[0050] The embodiment of the present invention does not limit the size of the filling body 220. In an exemplary implementation, the sizes of at least some of the filling bodies 220 are unequal, so that more filling bodies 220 can be filled inside the coupling body 210, further reducing the material usage of the coupling body 210, thereby reducing the cost of the head.

[0051] Preferably, the outer surface of the filler body 220 is formed with a concave-convex structure, so that the filler body 220 has a highly rough outer surface, thereby increasing the bonding area between the joint body 210 and the filler body 220 and improving the bonding strength. Furthermore, at least some of the filler bodies 220 can be mechanically connected to each other via screws or any other suitable means. Similarly, at least some of the filler bodies 220 can also be connected to the head body 100, the first connecting portion 310, and the second connecting portion 320 via screws or any other suitable means, further enhancing the strength and rigidity of the head.

[0052] The reinforcement portion provided in the embodiment of the present invention can not only be used for the head, but can also be arranged in areas with greater stress in other structural parts to improve the strength of the corresponding structural parts.

[0053] Furthermore, an embodiment of the present invention also provides a pressure vessel, comprising an inner tube, an outer tube and the aforementioned head, wherein the number of the heads is two, and they are respectively arranged at both ends of the inner and outer tubes to connect the inner and outer tubes, and together with the inner and outer tubes, form a chamber.

[0054] Furthermore, embodiments of the present invention provide a cryostat comprising a thermal shield and two pressure vessels, one of which serves as an inner container for accommodating a superconducting magnet and a cryogenic medium, and the other serves as an outer vacuum container. The thermal shield is disposed between the inner and outer vacuum containers. Specifically, the thermal shield is disposed outside one of the pressure vessels, while the other pressure vessel is disposed outside the thermal shield. Alternatively, the thermal shield may consist of one of the aforementioned pressure vessels.

[0055] Furthermore, an embodiment of the present invention also provides a magnetic resonance imaging system, comprising the fifth holding container and a superconducting magnet, wherein the superconducting magnet is accommodated in the inner vacuum container.

[0056] While the present invention is disclosed above, it is not limited thereto. Those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, the present invention is intended to encompass such modifications and variations as long as they fall within the scope of the claims and their equivalents.

Claims

1. A head for connecting the inner cylinder and outer cylinder of a pressure vessel, characterized in that: The head includes a head body and a reinforcement part, the reinforcement part is arranged at a predetermined position of the head body, and is used to improve the stress distribution at the predetermined position, the reinforcement part includes a coupling body and a filling body, the coupling body is in contact with and connected to the surface of the head body, and at least part of the outer surface of the filling body is covered by the coupling body.

2. The head according to claim 1, characterized in that: The material of the joint body is an adhesive or a welding material; the filling body is a sphere; and / or the filling body is a hollow structure; and / or a concave-convex structure is formed on the outer surface of the filling body.

3. The head according to claim 2, characterized in that: There are multiple filling bodies, and at least some of the filling bodies are mechanically connected to each other; and / or at least some of the filling bodies are mechanically connected to the head body.

4. The head according to claim 1, characterized in that: The head body is an annular structure and includes a first annular area, a second annular area and a third annular area arranged radially from the inside to the outside; the predetermined position includes at least a part of the second annular area; and / or, A reinforcement structure is formed on the second annular area, and the reinforcement portion is arranged inside the reinforcement structure.

5. The head according to claim 4, characterized in that: The head further includes a first connecting portion, which is connected to the inner edge of the first annular area and is used to connect to the inner cylinder; the predetermined position also includes at least a portion of the area where the first annular area and the first connecting portion meet; and / or, The head also includes a second connecting portion, which is connected to the outer edge of the third annular area and is used to connect to the outer cylinder; the predetermined position also includes at least a partial area where the third annular area and the second connecting portion meet.

6. The head according to claim 5, characterized in that: The reinforcement portion corresponding to each annular area extends continuously along the circumference of the corresponding annular area; or, the reinforcement portion corresponding to each annular area includes a plurality of sub-reinforcements, which are arranged at intervals along the circumference of the corresponding annular area.

7. A pressure vessel, characterized in that: It comprises an inner tube, an outer tube and a head as described in any one of claims 1 to 6, wherein the head connects the inner tube and the outer tube and together with the inner tube and the outer tube form a closed inner cavity.

8. A cryostat, characterized in that: It comprises a heat shielding layer and the pressure vessel as claimed in claim 7, wherein the number of the pressure vessels is two, one of the pressure vessels is arranged inside the heat shielding layer, and the other pressure vessel is sleeved outside the heat shielding layer.

9. A magnetic resonance imaging system, characterized in that: The cryostat comprises the cryostat according to claim 8 and a superconducting magnet disposed in the cryostat.

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