Cooling system for magnet, magnet and superconducting magnetic resonance imaging equipment

Abstract

The utility model relates to a cooling system for a magnet, the magnet and superconducting magnetic resonance imaging equipment. The cooling system comprises a first-stage cold head and a cold head sleeve which is arranged around the first-stage cold head and is thermally connected with the thermal shielding cover, and comprises a switching device for thermally connecting or disconnecting the first-stage cold head with the cold head sleeve, and the switching device comprises a fixed block which is attached to the first-stage cold head; a moving block arranged to be movable relative to the fixed block; and the telescopic piece is connected between the fixed block and the movable block. The telescopic piece can enable the moving block to move between a first position and a second position, in the first position, the moving block enables the first-stage cold head and the cold head sleeve to be in hot connection, and in the second position, the moving block enables the first-stage cold head and the cold head sleeve to be separated from hot connection. According to the embodiment of the invention, the hot connection between the first-stage cold head and the cold head sleeve can be disconnected as required, so that the evaporation loss of a coolant caused by the transfer of a large amount of heat to the coolant container through the cold head is avoided.

Description

Technical Field

[0001] The present disclosure relates to the technical field of medical devices, and in particular to a cooling system for a magnet, a magnet, and a magnetic resonance imaging device. Background Art

[0002] Magnetic resonance equipment uses the principle of nuclear magnetic resonance to obtain the position and type of the atomic nucleus of the substance based on the different attenuation of the released energy in the internal structure environment of different substances and the detection of the emitted electromagnetic waves through an external gradient magnetic field.

[0003] The superconducting magnet is the core component of the magnetic resonance device, which uses a superconducting coil made of superconducting material to generate a magnetic field with high field strength and high stability. The superconducting coil needs to be immersed in a coolant container filled with coolant (for example, liquid helium) so that the superconducting coil reaches the superconducting temperature and maintains the superconducting state. Among them, the coolant, such as liquid helium, absorbs the heat load of the magnet during operation and then evaporates to form a small amount of helium. When the helium rises to the cold head, it will recondense into liquid helium. Thereafter, the liquid helium flows back to the coolant container under the action of gravity, thereby realizing the circulation of liquid helium. It can be seen that the superconducting coil and the cooling system are important guarantees for the normal operation of the magnetic resonance device. However, the cold head in the cooling system may not work during transportation or during power outages, resulting in a large amount of liquid helium loss. This may cause the cooling effect of the cooling system to be reduced or the cooling system to be completely scrapped, which seriously affects the normal use of the magnetic resonance device.

[0004] The methods described in this section are not necessarily methods that have been previously conceived or employed. Unless otherwise indicated, it should not be assumed that any method described in this section is considered to be related art simply because it is included in this section. Similarly, unless otherwise indicated, the issues mentioned in this section should not be considered to have been recognized in any related art. Utility Model Content

[0005] According to a first aspect of the present disclosure, a cooling system for a magnet is proposed, the magnet comprising a heat shielding cover, the cooling system comprising a first-stage cold head, and a cold head cover arranged around the first-stage cold head and thermally connected to the heat shielding cover, and the cooling system comprising a switching device for thermally connecting or disconnecting the first-stage cold head from the cold head cover, the switching device comprising: a fixed block attached to the first-stage cold head; a moving block, the moving block being arranged to be movable relative to the fixed block; and a retractable member connected between the fixed block and the moving block, wherein the retractable member is capable of moving the moving block between a first position and a second position, wherein in the first position, the moving block thermally connects the first-stage cold head to the cold head cover, and in the second position, the moving block thermally disconnects the first-stage cold head from the cold head cover.

[0006] According to a second aspect of the present disclosure, a magnet is provided, comprising: a heat shield; and a cooling system according to the present disclosure.

[0007] According to a third aspect of the present disclosure, a magnetic resonance imaging device is provided, comprising: a magnet according to the present disclosure.

[0008] According to one or more embodiments of the present disclosure, by providing a switch device including a fixed block, a movable block, and a retractable member, it can be achieved that in the first position, the first-stage cold head is thermally connected to the cold head cover through the movable block, and in the second position, the first-stage cold head is thermally disconnected from the cold head cover. In this way, on the one hand, the thermal connection between the first-stage cold head and the cold head cover can be disconnected when necessary (for example, when the cold head stops working), thereby avoiding a large amount of heat from being transferred through the cold head to the heat shielding cover connected to the cold head cover and then to the coolant container, resulting in additional evaporation loss of the coolant. On the other hand, the switch device with the above structure basically does not affect the existing cold head assembly process, and there is no requirement for the torque of the bolts fixing the cold head. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can better understand the above and other features and advantages of the present disclosure. In the accompanying drawings:

[0010] Figure 1 A schematic diagram of a magnet of the related art;

[0011] Figure 2 is a schematic diagram of a magnet including a cooling system according to some exemplary embodiments of the present disclosure, wherein a retractable member of the cooling system is in an extended state;

[0012] Figure 3 To include Figure 2Schematic diagram of a magnet of a cooling system in which a retractable member of the cooling system is in a compressed state;

[0013] Figure 4 is a schematic diagram of a magnet including a cooling system according to some other exemplary embodiments of the present disclosure, wherein a retractable member of the cooling system is in an extended state; and

[0014] Figure 5 To include Figure 4 Schematic diagram of a magnet of a cooling system in which the retractable part of the cooling system is in a compressed state.

[0015] Figure 6a and Figure 6b They are shown respectively Figure 4 The initial state of the heat conducting sheet of the cooling system and the state after installation.

[0016] Description of Reference Numerals

[0017] Magnet 1000, 2000, 4000; coil 1110, 2110, 4110; coolant 1120, 2120; coolant container 1130, 2130; first stage cold head 1140, 2140, 4140; second stage cold head 1150, 2150; cold head cover 1160, 2160, 4160; heat shield 1170, 270; cold head flange 2180, 4180;

[0018] Cooling system 200, 400; switch device 201, 401;

[0019] Fixed blocks 210, 410; movable blocks 220, 420; retractable parts 230, 430; heat conducting wire 240; inflatable components 250, 450; inflatable ports 251, 451; inflatable tubes 252, 452; pluggable connector 253; heat conducting sheet 460; through hole 461; bolt 462. DETAILED DESCRIPTION

[0020] In order to have a clearer understanding of the technical features, purposes and effects of the present disclosure, specific embodiments of the present disclosure are now described with reference to the accompanying drawings, in which the same reference numerals represent the same parts.

[0021] In this document, “exemplary” means “serving as an example, instance or illustration”, and any diagram or implementation described in this document as “exemplary” should not be interpreted as a more preferred or more advantageous technical solution.

[0022] In order to simplify the drawings, only the parts related to the present disclosure are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked.

[0023] In this article, "one" not only means "only one", but also means "more than one". In this article, "first", "second", etc. are only used to distinguish each other, rather than to indicate their importance and order, or the premise of each other's existence.

[0024] like Figure 1 As shown, the superconducting coil 1110 in the magnet 100 is cooled by immersing in a coolant container 1130 filled with a coolant 1120 (e.g., liquid helium). The coolant 1120, such as liquid helium, absorbs the heat load of the coil 1110 during the operation of the magnet 100 and then evaporates to form a gas. When the gas rises to the first-stage cold head 1140 and the second-stage cold head 1150, it will recondense into a liquid coolant and flow back to the coolant container under the action of gravity, thereby realizing the circulation of the coolant.

[0025] In the related art, the first-stage cold head 1140 is in direct contact with the cold head cover 1160 by applying pressure. The cold capacity of the first-stage cold head 1140 is directly transferred to the heat shield 1170 surrounding the coolant container 1130 and used to reduce the radiant heat of the coil through a thermal connection. After the heat shield 1170 is cooled to about 50K, the thermal balance of the heat shield is maintained. Such a structure makes it possible that once the cold head stops working and the temperature of the cold head rises rapidly, a large amount of heat load will be transferred from the cold head to the heat shield, causing the temperature of the heat shield to rise rapidly, thereby increasing the radiant heat inside the heat shield. This will cause a large amount of coolant inside the heat shield, i.e., in the coolant container, to evaporate. At this time, since the cold head is not working, a large amount of evaporated coolant gas can no longer be condensed, and the pressure in the coolant container increases accordingly. Finally, the pressure relief channel opens, causing the coolant to be lost.

[0026] In view of this, the present disclosure provides a cooling system for a magnet, which has a switch device to disconnect the thermal contact between the first-stage cold head and the cold head cover when necessary, thereby preventing the loss of coolant caused by the non-operation of the cold head. In the present disclosure, a switch device including a fixed block, a movable block and a retractable member is provided, wherein, in a first position, the first-stage cold head is thermally connected to the cold head cover through the movable block, and in a second position, the first-stage cold head is thermally disconnected from the cold head cover. In this way, it is possible to disconnect the thermal connection between the first-stage cold head and the cold head cover when necessary (for example, when the cold head stops working), thereby avoiding a large amount of heat from being transferred through the cold head to the heat shield connected to the cold head cover and then to the coolant container, resulting in additional evaporation loss of the coolant. On the other hand, the cooling system with the above structure basically does not affect the existing cold head assembly process, and there is no requirement for the torque of the bolts fixing the cold head.

[0027] Exemplary embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0028] Figure 2 is a schematic diagram of a magnet 2000 including a cooling system 200 according to some exemplary embodiments of the present disclosure, wherein a retractable member 230 of the cooling system 200 is in an extended state; Figure 3 To include Figure 2 Schematic diagram of a magnet 2000 of a cooling system 200 in FIG. 1 , wherein the retractable member 230 of the cooling system 200 is in a compressed state. Figure 2 and Figure 3 As shown, the magnet 2000 may include a heat shield 2170 and a cooling system 200. Additionally, the magnet 2000 may also include a coil 2110 and a coolant container 2130 filled with a coolant 2120 (e.g., liquid helium) for the coil 2110 to be immersed. The heat shield 2170 surrounds the coolant container 2130 to reduce the heat radiation of the coil 2110. The cooling system 200 may include a first-stage cold head 2140, and a cold head cover 2160 arranged around the first-stage cold head 2140 and thermally connected to the heat shield 2170. The cold head cover 2160 is used to place the cold head. Additionally, the cooling system 200 may also include a second-stage cold head 2150, which is attached to the first side of the first-stage cold head 2140 and is close to the coolant container 2130. Additionally, the cooling system 200 may further include: a cold head flange 2180 , and the first-stage cold head 2140 is disposed (specifically, connected) between the cold head flange 2180 and the second-stage cold head 2150 .

[0029] The cooling system 200 may further include a switch device 201 for thermally connecting or disconnecting the first-stage cold head 2140 from the cold head cover 2160. Figure 2 and Figure 3As shown, the switch device 201 may include: a fixed block 210 , a movable block 220 and a retractable member 230 .

[0030] The fixed block 210 is attached to the first stage cold head 2140. The moving block 220 is arranged to be movable relative to the fixed block. The retractable member 230 is connected between the fixed block 210 and the moving block 220. The retractable member 230 can move the moving block 220 between a first position and a second position, wherein in the first position, the moving block 220 thermally connects the first stage cold head 2140 to the cold head cover 2160 (such as Figure 3 In the second position, the moving block 220 disconnects the first-stage cold head 2140 from the cold head cover 2160 (as shown in FIG. Figure 2 shown).

[0031] In this article, "thermal connection" means that two components are in contact or connected through an intermediate component (e.g., a heat conductive component) so that a large amount of heat can be transferred between the two components. "Disconnected from thermal connection" means that the two components are not in contact (i.e., there is a certain gap) and are not connected so that a large amount of heat cannot be transferred between the two components.

[0032] On the one hand, the above-mentioned switch device can disconnect the thermal connection between the first-stage cold head and the cold head sleeve when necessary (for example, when the cold head stops working), thereby avoiding additional evaporation loss of the coolant. Furthermore, the above-mentioned switch device can automatically disconnect the thermal contact between the first-stage cold head and the cooling sleeve without manual or instrument monitoring. On the other hand, the switch device with the above-mentioned structure basically does not affect the existing cold head assembly process, and there is no requirement for the torque of the bolts fixing the cold head. In other words, the components of the added switch device are fixed on the cold head in advance, which will not affect the original cold head assembly process. In addition, when installing the cold head, it is no longer necessary to apply a pre-tightening force to ensure that the first-stage cold head and the cooling sleeve are in pressure contact for better heat conduction, so the switch device disclosed in the present invention has no torque requirements for the bolts fixing the cold head.

[0033] The cooling system of the present disclosure can reduce the coolant loss in the magnet, thereby improving the stability of the magnetic field. This makes the product safer and reduces the pressure on after-sales maintenance personnel. In addition, the vacuum and low-temperature environment of the magnet can last longer, so there is no need to frequently refill the coolant, which also makes the maintenance process easier and reduces the maintenance cost after the cold head is turned off. According to some embodiments of the present disclosure, the fixed block 210 and the moving block 220 can be structures made of metals with high thermal conductivity, such as copper blocks, aluminum blocks, etc., to facilitate heat conduction.

[0034] According to some embodiments of the present disclosure, the retractable member 230 can be compressed and extended, and in its compressed state, the moving block 220 is thermally connected to the first-stage cold head 2140 and the cold head cover 2160 (eg, Figure 3), and in its extended state the mobile block 220 is configured to be thermally disconnected from the cold head cover 2160 (as shown Figure 2 As shown). Alternatively, the retractable member may also be configured as other mechanisms capable of moving up and down.

[0035] According to some embodiments of the present disclosure, the fixed block 210 and the movable block 220 may be, for example, annular, so as to facilitate installation through the second-stage cold head 2150 (and / or the first-stage cold head 2140) without affecting the original cold head assembly process. Additionally, the retractable member 230 may also be annular, so as to facilitate installation through the second-stage cold head 2150 and the first-stage cold head 2140. In some other examples, the fixed block 210 and the movable block 220 may also be a structure composed of multiple rectangular blocks arranged in a preset shape, etc.

[0036] According to some embodiments of the present disclosure, the fixed block 210 is attached to a first side of the first stage cold head 2140. The moving block 220 is arranged near a second side of the first stage cold head 2140 opposite to the first side. The retractable member 230 is connected between the fixed block 210 and the moving block 220 and is arranged between the cold head cover 2160 and the first stage cold head 2140. That is, the fixed block and the moving block are arranged on both sides of the first stage cold head 2140, respectively.

[0037] According to some embodiments of the present disclosure, Figure 2 and Figure 3 As shown, the first side to which the fixed block 210 is attached is the side facing the coolant container 2130, and the second side to which the moving block 220 is close is the side facing away from the coolant container 2130 (that is, the fixed block 210 is arranged at the lower part of the first-stage cold head 2140, and the moving block 220 is arranged at the upper part of the first-stage cold head 2140). Alternatively, the first side to which the fixed block is attached is the side facing away from the cooler container, and the second side to which the moving block is close is the side facing the coolant container.

[0038] According to some embodiments of the present disclosure, the second-stage cold head 2150 is attached to the first side surface of the first-stage cold head 2140 (specifically, for example, Figure 2 and Figure 3In the case where the second-stage cold head 2150 is arranged below the first-stage cold head 2140), the inner diameter of at least one (e.g., each) of the retractable member 230 and the moving block 220 is greater than the outer diameter of each of the first-stage cold head 2140 and the second-stage cold head 2150, and the inner diameter of the fixed block 210 is greater than the outer diameter of the second-stage cold head 2140. Usually, the outer diameter of the second-stage cold head is smaller than the outer diameter of the first-stage cold head. In this way, when installing the cooling system, the fixed block 210 can be passed from bottom to top through the second-stage cold head 2150 and attached to the second side of the first-stage cold head 2140. Before this, the moving block 220 and the retractable member 230 can be passed through the second-stage cold head 2150 and the first-stage cold head 2140 from bottom to top in sequence to be arranged close to the second side of the first-stage cold head 2140 and set at the second side of the first-stage cold head 2140. In this way, the disassembly and assembly of the cooling system can be achieved without affecting the original cold head assembly process.

[0039] According to some embodiments of the present disclosure, the fixing block 210 is detachably connected to the first-stage cold head 2140 (specifically, the first side), for example, by a detachable connection with bolts. Figure 2 and Figure 3 As shown, the fixing block 210 is fixed from bottom to top on the first side surface of the first-stage cold head 2140 by bolts. Thus, the fixing block and even the cooling system can be disassembled and assembled without affecting the original cold head assembly process.

[0040] According to some embodiments of the present disclosure, in the first position, the moving block and the cold head cover are thermally connected by contact, and in the second position, the moving block and the cold head cover are thermally disconnected by separation. Figure 3 As shown, the retractable member 230 in a compressed state makes the moving block 220 contact with the cold head cover 2160 (may include direct contact or contact through a heat conduction component) to conduct heat between the two. Figure 2 As shown, the retractable member 230 separates the moving block 220 from the cold head cover 2160 in the extended state so that the two are out of thermal connection.

[0041] According to some embodiments of the present disclosure, a heat conduction component (eg, a heat conduction component made of a material such as indium) may be provided on the side of the cold head cover for contacting the moving block to improve heat conduction between the cold head cover and the moving block.

[0042] Additionally, if Figure 2 and Figure 3As shown, the moving block 220 is always connected to the first-stage cold head 2140 through at least one heat-conducting tape 240 (for example, a structure made of a metal with high thermal conductivity such as copper, aluminum, or a belt-shaped structure made of a metal with high thermal conductivity such as copper, aluminum, etc., such as a copper braid). At this time, in the first position, the moving block is thermally connected to the cold head cover by contact and is thermally connected to the first-stage cold head through the heat-conducting tape, and in the second position, the moving block is thermally disconnected from the cold head cover by separation. The heat-conducting wire can facilitate the smooth up and down movement of the moving block while transferring heat between the moving block and the first-stage cold head. Alternatively, as Figure 4 and Figure 5 As shown, in the first position, the moving block may also contact the second side surface of the first-stage cold head for heat conduction (that is, the moving block and the second side surface of the first-stage cold head conduct heat by contact), without providing a heat transfer belt. At this time, in the first position, the moving block is thermally connected to the first-stage cold head and the cold head cover by contact, and in the second position, the moving block is thermally disconnected from the first-stage cold head and the cold head cover by separation.

[0043] According to some embodiments of the present disclosure, the retractable member 230 may be connected to the fixed block 210 and the movable block 220 by welding, bonding, or the like.

[0044] According to some embodiments of the present disclosure, the retractable member 230 is configured to place the moving block in the first position when the first-stage cold head 2140 is cooling (i.e., working), and to place the moving block in the second position when the first-stage cold head 2140 stops cooling. Thus, it is possible to disconnect the thermal connection between the first-stage cold head and the cold head cover when the first-stage cold head is not working to avoid coolant evaporation loss, and to connect the first-stage cold head and the cold head cover when the first-stage cold head is working, so as to directly transfer the cold capacity of the first-stage cold head to the heat shield 2170 through the thermal connection to maintain the thermal balance of the heat shield.

[0045] According to some embodiments, the retractable member 230 has a cavity, in which a gas, such as a gas having a boiling point greater than 50K (e.g., nitrogen) can be filled. At this time, the retractable state of the retractable member can be changed by utilizing the change in the state of the gas. In addition, the pressure of the gas filled in the retractable member is greater than the gas pressure in the magnet. At this time, the operation of the cooling system 200, for example, is as follows: when the first-stage cold head 2140 stops working, the heat load is first transferred to the retractable member 230 via the fixed block 210 through the first-stage cold head 2140, and is absorbed by the liquid nitrogen or solid nitrogen in the cavity of the retractable member 230. The temperature of the liquid nitrogen or solid nitrogen rises rapidly and eventually turns into nitrogen. The high-pressure nitrogen lifts the moving block 220 again, thereby disconnecting the thermal contact between the moving block and the cold head cover, so that the heat load conducted by the cold head will not be able to heat the cold head cover and the heat shield; when the first-stage cold head 2140 is turned on (i.e., refrigeration), the nitrogen in the cavity of the retractable member 230 will be cooled to a liquid or solid state. The pressure in the retractable member 230 is much lower than the pressure in the magnet, so that the retractable member 230 is compressed, and the moving block 220 moves downward to form a good thermal contact with the cold head cover 2160. Thus, the above-mentioned cooling system can realize the pressure change in the retractable member automatically caused by the change of the on / off state of the cold head, so that the first-stage cold head (more specifically, the moving block) is connected or disconnected from the cold head cover. It should be noted here that the fixed block fixed on the first-stage cold head can promote the heat of the non-working first-stage cold head to be transferred to the retractable member, so that the liquid nitrogen or solid nitrogen in the cavity of the retractable member is heated and evaporated into a gaseous state, so as to promote the expansion of the retractable member to disconnect the thermal connection between the first-stage cold head and the cold head cover.

[0046] According to some embodiments of the present disclosure, the cooling system 200 may further include a cold head flange 2180, and the first-stage cold head 2140 is arranged between the cold head flange 2180 and the second-stage cold head 2150. At this time, the cooling system 200 may also include: an inflatable component 250. The inflatable component 250 includes: an inflatable port 251 and an inflatable tube 252. The inflatable port 251 is arranged on the cold head flange 2180 (specifically, for example, the fourth side of the cold head flange away from the first-stage cold head). One end of the inflatable tube 252 is connected to the inflatable port 251, and the other end of the inflatable tube 252 is connected to the cavity of the telescopic member 230. Among them, the inflatable tube can be, for example, an inflatable bellows or other inflatable pipelines. The inflatable port and the inflatable tube constitute a channel for filling the telescopic member with gas. In some examples, the inflatable tube can be, for example, welded on the moving block, and, for example, communicated with the internal space fluid of the cavity of the telescopic member through a hole arranged on the moving block. In some examples, the gas filling port can be welded on the cold head flange, for example. The gas filling port can be designed as any interface for filling gas.

[0047] According to some embodiments of the present disclosure, the inflation assembly 250 may further include: a pluggable connector 253. The pluggable connector is disposed on the cold head flange 2180 (specifically, for example, the third side of the cold head flange facing the first-stage cold head), and is connected to one end of the inflation tube 252, so that the inflation tube 252 is connected to the inflation port 251 through the pluggable connector 253. The pluggable connector can be any connector that is convenient for the inflation tube to be connected, for example, an NW16 flange or a pluggable vacuum connector. Thus, it is convenient to make the switch device a detachable component, and the structural impact on the cold head is minimized.

[0048] Figure 4 is a schematic diagram of a magnet 4000 including a cooling system 400 according to some other exemplary embodiments of the present disclosure, wherein a retractable member 430 of the cooling system 400 is in an extended state; and Figure 5 To include Figure 4 Schematic diagram of a magnet 4000 of a cooling system 400 in FIG. 4 , wherein the retractable member 430 of the cooling system 400 is in a compressed state. Figure 4 and Figure 5 The magnet 4000 and the cooling system 400 and the switch device 401 therein are characterized and Figure 2 and Figure 3 The features of the magnet 2000 and the cooling system 200 and the switch device 201 therein are basically the same, except that no heat conducting wire is arranged between the connecting block 420 and the first-stage cold head 4140 and no pluggable connector is arranged in the inflatable component 450.

[0049] According to some embodiments of the present disclosure, a heat conductive sheet 460 extending from the first-stage cold head toward the retractable member 430 is provided on the first-stage cold head 4140, and the movable block 420 is in contact with the heat conductive sheet 460 in the first position. In this way, heat conduction between the movable block and the first-stage cold head can be achieved. By providing the heat conductive sheet, the influence of the size of the movable block can be avoided, so that the cooling system can be adapted to cold heads of various sizes. In other words, regardless of the size of the cold head, the movable block can transfer heat with the first-stage cold head in the descending state. In some examples, the heat conductive sheet can be made of a metal with high thermal conductivity, such as copper or aluminum. Figure 6a and Figure 6b As shown, the heat conducting sheet 460 may be a sheet structure with a through hole 461 on the surface. Bolts 462 may pass through the through hole 461 to fix the heat conducting sheet 460 on the second side of the first stage cold head 4140, and after installation, the heat conducting sheet 460 may be pulled out of the second side by a preset distance (such as 400 mm) according to the distance between the first stage cold head 4140 and the moving block 420. Figure 6b), so that the moving block can contact the heat conducting sheet when it is lowered. In some other examples, the size of the heat conducting sheet can also be set according to the distance between the first-stage cold head and the connecting block, so that the heat conducting sheet can contact the moving block after it is installed on the first-stage cold head and after the moving block is lowered.

[0050] According to some embodiments of the present disclosure, Figure 4 and Figure 5 As shown, the inflation port 451 of the inflation assembly 450 can be directly connected to the inflation tube 452 without providing a pluggable connector. In other words, one end of the inflation tube 452 is fixed to the cold head flange 4180.

[0051] It should be understood here that Figure 4 and Figure 5 Other features of the cooling system 400 (e.g., the moving block 420, the fixed block 410, the retractable member 430, etc.) and Figure 2 and Figure 3 The corresponding features of the cooling system 200 (eg, the moving block 220, the fixed block 210, the retractable member 230, etc.) are the same and will not be described in detail herein for the sake of brevity.

[0052] Similarly, in the cooling system 400, when the first-stage cold head 4140 is working (i.e., refrigeration), the nitrogen filled in the cavity of the telescopic member 430 will quickly cool to a liquid or even solid state, which causes the pressure in the telescopic member to drop to a pressure lower than that in the magnet. At this time, the telescopic member 430 is in a compressed state, and drives the moving block 420 to move downward until it contacts the cold head cover 4160 and the first-stage cold head 4140, thereby realizing the thermal connection between the cold head cover and the first-stage cold head. When the first-stage cold head 4140 stops working, the heat load is first absorbed by the liquid nitrogen or solid nitrogen in the telescopic member 430 through the first-stage cold head 4140, thereby converting it into nitrogen. The high-pressure nitrogen will lift the moving block 420, thereby disconnecting the thermal connection between the cold head cover and the first-stage cold head.

[0053] According to yet another aspect of the present disclosure, there is provided a magnet (eg, the magnet 2000 or 4000 ) including: a heat shield; and a cooling system (eg, the cooling system 200 or 400 ).

[0054] According to yet another aspect of the present disclosure, a magnetic resonance imaging apparatus is provided, including: a magnet (eg, the magnet 2000 or 4000 ).

[0055] The above are merely embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A cooling system for a magnet, characterized in that: The magnet comprises a heat shield, the cooling system comprises a first-stage cold head and a cold head cover arranged around the first-stage cold head and thermally connected to the heat shield, wherein: comprising a switch device for thermally connecting or disconnecting the first-stage cold head from the cold head sleeve, The switch device comprises: a fixing block, the fixing block being attached to the first-stage cold head; a moving block arranged to be movable relative to the fixed block; and a retractable member, the retractable member being connected between the fixed block and the movable block, Wherein, the retractable part can move the moving block between a first position and a second position, wherein in the first position, the moving block thermally connects the first-stage cold head with the cold head cover, and in the second position, the moving block disconnects the first-stage cold head from the cold head cover.

2. The cooling system for a magnet according to claim 1, characterized in that: The telescopic member has a cavity filled with gas, and the telescopic state of the telescopic member is changed by utilizing the state change of the gas.

3. The cooling system for a magnet according to claim 2, characterized in that: The cooling system further comprises a cold head flange, the first-stage cold head is arranged between the cold head flange and the second-stage cold head, and the switch device further comprises: An inflatable component, the inflatable component comprising: an air filling port, the air filling port being arranged on the cold head flange; and An air filling tube, one end of which is connected to the air filling port, and the other end of which is connected to the cavity.

4. The cooling system for a magnet according to claim 3, characterized in that: The inflatable component also includes: A pluggable connector is arranged on the cold head flange and connected to the one end of the inflation tube, so that the inflation tube is connected to the inflation port through the pluggable connector.

5. The cooling system for a magnet according to claim 1, characterized in that: In the first position, the moving block is thermally connected to the first-stage cold head and the cold head cover by contact, and in the second position, the moving block is thermally disconnected from the first-stage cold head and the cold head cover by separation.

6. The cooling system for a magnet according to claim 1, characterized in that: The moving block is always connected to the first-stage cold head through a heat-conducting belt, and in the first position, the moving block is thermally connected to the cold head cover through contact and is thermally connected to the first-stage cold head through the heat-conducting belt, and in the second position, the moving block is thermally disconnected from the cold head cover through separation.

7. The cooling system for a magnet according to claim 5, characterized in that: When the moving block is thermally connected with the first-stage cold head and the cold head cover by contact, a heat conductive sheet extending from the first-stage cold head toward the retractable member is provided on the first-stage cold head, and the moving block contacts the heat conductive sheet at the first position.

8. A cooling system for a magnet according to any one of claims 1 to 7, characterized in that: The fixed block is attached to a first side of the first-stage cold head, the movable block is located at a second side of the first-stage cold head opposite to the first side, the cooling system also includes a second-stage cold head attached to the first side, the inner diameter of each of the retractable part and the movable block is larger than the outer diameter of each of the first-stage cold head and the second-stage cold head, and the inner diameter of the fixed block is larger than the outer diameter of the second-stage cold head.

9. The cooling system for a magnet according to claim 1, characterized in that: The fixing block is detachably connected to the first-stage cold head.

10. The cooling system for a magnet according to any one of claims 1 to 7, characterized in that: The retractable member is configured to place the moving block in the first position when the first-stage cold head is cooling, and to place the moving block in the second position when the first-stage cold head stops cooling.

11. A magnet, characterized in that: include: Heat shield; as well as A cooling system for a magnet according to any one of claims 1 to 10.

12. A superconducting magnetic resonance imaging device, characterized in that: include: A cooling system for a magnet according to any one of claims 1 to 10.

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