False temperature hole tube cold shrinkage compensation method for superconducting magnet cryostat

Abstract

The present application relates to superconducting magnet cryostat heat transfer technology field, particularly to a kind of for superconducting magnet cryostat's false temperature hole pipe cold contraction compensation method.This method includes: between outer Dewar end plate and cold screen end plate, set the length of bellows that can be extended, the outer side of false temperature hole pipe is movably sleeved with bellows;Left end of bellows is set as large hoop, large hoop is connected from right to left along the axial direction of false temperature hole pipe and outer Dewar end plate, along the intersection line of outer Dewar end plate and large hoop, the both are sealed and welded and form first weld;Right end of bellows is set as small hoop, along the intersection line of small hoop and false temperature hole pipe, the both are sealed and welded and form second weld;Wherein, false temperature hole pipe and bellows are made of stainless steel, set false temperature hole pipe to shrink by cold, false temperature hole pipe moves right relative to large hoop and drives small hoop to stretch the length of bellows to compensate the shrinkage deformation of false temperature hole pipe, avoid weld tear, ensure that there is stable vacuum state.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat transfer of superconducting magnet cryostat, in particular to a false temperature hole pipe cold shrinkage compensation method for a superconducting magnet cryostat. BACKGROUND

[0002] In an accelerator, quadrupole magnets have focusing or defocusing effect on the beam, and generally exist in a three-combination form, that is, three quadrupole magnets form a group, and opposite currents are loaded between each adjacent two magnets to form opposite magnetic fields to focus-defocus-focus or defocus-focus-defocus the beam in the radial direction.

[0003] For a three-combination form magnet, if a superconducting magnet is used, it needs to be placed in a cryostat to work normally. If three cryostats are provided for three superconducting magnets, that is, a separate cryostat is used for each superconducting magnet, the manufacturing cost is higher, and each cryostat needs to be configured with a corresponding low-temperature valve box, the overall heat leakage is larger, and the thermal load of the low-temperature system is increased. Therefore, one cryostat is considered for three superconducting magnets, which only needs to be equipped with one low-temperature valve box, and the heat leakage of the cryostat is lower than that of three separate cryostats, which can greatly reduce the overall thermal load of the low-temperature system and reduce the construction cost. However, the length of the three-combination magnet after connection is relatively long, generally 5-6m, and the manufacturing difficulty is relatively large.

[0004] During normal operation of the accelerator, the beam passes through the vacuum pipe inside the superconducting magnet, and the magnetic field radially confines the beam. For the beam vacuum pipe, there are generally two setting methods: one is to place the vacuum pipe in the warm hole pipe of the superconducting magnet cryostat, that is, the beam vacuum pipe and the warm hole pipe of the superconducting magnet cryostat are relatively independent, and the inside of the warm hole pipe of the cryostat is an atmospheric environment; the second method is to directly use the warm hole pipe of the superconducting magnet cryostat as the beam pipe.

[0005] For the same beam envelope constraint, that is, after the diameter of the beam vacuum pipe is determined, the first setting method will increase the inner diameter of the superconducting magnet, and accordingly the manufacturing difficulty and cost of the superconducting magnet will be increased, and even the magnetic field cannot meet the design requirements.

[0006] When the second setting mode is adopted, the inner diameter of the superconducting magnet can be reduced, and the difficulty and cost of manufacturing the superconducting magnet can be reduced. At this time, the outer side of the warm bore tube is a low-temperature thermostat sandwich vacuum, and the inner side is a beam current vacuum. The cold energy (temperature about 50K absolute temperature) of the cold screen center tube in the low-temperature thermostat is transmitted to the warm bore tube in the radial direction through radiation heat transfer and solid heat conduction of the support. The cold energy on the warm bore tube can only be conducted to the outside through the side wall thereof. Moreover, the warm bore tube is generally made of stainless steel. Stainless steel is a poor conductor of heat at low temperatures, and the cold energy transmitted to the warm bore tube from the cold screen center tube cannot be timely transmitted away in the form of heat conduction. Therefore, when the accelerator is running, the warm bore tube adopting the second setting mode will have an axial temperature gradient, and has characteristics different from those of the traditional warm bore tube. Therefore, the warm bore tube adopting the second setting mode is called a “pseudo warm bore tube”.

[0007] However, the two sides of the pseudo warm bore tube are generally connected through welding with the thermostat flanges. After local low temperature is generated in the center of the pseudo warm bore tube, cold shrinkage will occur, which causes the entire pseudo warm bore tube to cold shrink to the middle, thereby increasing the stress at the welding position of the pseudo warm bore tube and the flanges on both sides of the thermostat. For a common superconducting magnet cryostat (generally not longer than 3.5m) with a relatively short length, even if local low temperature is generated in the middle of the pseudo warm bore tube, the temperature gradient on the pseudo warm bore tube is not large due to the relatively short length, and although there is a certain cold shrinkage stress, the end weld can completely bear the stress. However, for the three-combination superconducting magnet cryostat described above, the maximum length is 6m, the axial temperature gradient of the pseudo warm bore tube is large, the cold shrinkage stress is large, and the overall stress will exceed the yield strength of the stainless steel of the pseudo warm bore tube. The end weld may be torn, resulting in loss of vacuum and causing serious consequences. SUMMARY

[0008] The present application aims to at least solve one of the technical problems existing in the related art. To this end, the present application provides a pseudo warm bore tube cold shrinkage compensation method for a superconducting magnet cryostat, to solve the problem that the warm bore tube of a three-combination superconducting magnet cryostat is easily torn when used as a beam tube due to cold shrinkage deformation, resulting in loss of vacuum.

[0009] The present application provides a pseudo warm bore tube cold shrinkage compensation method for a superconducting magnet cryostat, the cold shrinkage compensation method comprising:

[0010] Step S1, a length-expandable bellows is arranged between the outer Dewar end plate and the cold screen end plate, and the bellows is movably sleeved on the outer side of the pseudo warm bore tube;

[0011] Step S2, the left end of the bellows is arranged as a large hoop, the large hoop is threaded through the outer Dewar end plate along the axial direction of the pseudo warm bore tube from right to left, and the outer Dewar end plate and the large hoop are sealingly welded along the intersection line thereof and a first weld is formed;

[0012] Step S3, set the right end of the bellows as a small ring hoop, seal weld the small ring hoop and the false temperature hole tube along the joint line and form a second weld;

[0013] Wherein, the false temperature hole tube and the bellows are made of stainless steel, the false temperature hole tube is set to shrink under cold, the false temperature hole tube moves right relative to the large ring hoop and drives the small ring hoop to stretch the length of the bellows to compensate for the shrinkage deformation of the false temperature hole tube.

[0014] According to the present application, a false temperature hole tube cold shrinkage compensation method for a superconducting magnet cryostat is provided, and the large ring hoop is arranged to pass through the outer dewar end plate along the axial direction of the false temperature hole tube from right to left, which comprises:

[0015] After the large ring hoop passes through the outer dewar end plate, a positioning table protruding radially along the inner side of the large ring hoop is arranged, and the false temperature hole tube is arranged to abut against the positioning table, which is used to limit the left movement of the false temperature hole tube.

[0016] According to the present application, a false temperature hole tube cold shrinkage compensation method for a superconducting magnet cryostat is provided, and the false temperature hole tube is arranged to abut against the positioning table, which comprises:

[0017] A brass sleeve is arranged at the end of the false temperature hole tube, so that the brass sleeve is clamped between the large ring hoop and the false temperature hole tube, and the outer side of the brass sleeve is in sliding frictional contact with the large ring hoop.

[0018] According to the present application, a false temperature hole tube cold shrinkage compensation method for a superconducting magnet cryostat is provided, and the outer side of the brass sleeve is in sliding frictional contact with the large ring hoop, which comprises: the spacing between the positioning table and the left side end surface of the large ring hoop is less than or equal to the axial length of the brass sleeve.

[0019] According to the present application, a false temperature hole tube cold shrinkage compensation method for a superconducting magnet cryostat is provided, and the outer side of the brass sleeve is in sliding frictional contact with the large ring hoop, which comprises: the outer side of the brass sleeve is arranged to have a diameter greater than the outer side of the false temperature hole tube.

[0020] According to the present application, a false temperature hole tube cold shrinkage compensation method for a superconducting magnet cryostat is provided, and the false temperature hole tube is arranged to shrink under cold, which comprises:

[0021] The cryostat is cooled, and the absolute temperature of the helium tank is reduced to 4K, and the absolute temperature of the cold screen is reduced to about 50K; then, the gas in the false temperature hole tube is extracted to form a beam vacuum, a temperature gradient along the axial direction of the false temperature hole tube is formed on the false temperature hole tube through heat transfer between the cold screen center tube and the false temperature hole tube, local low temperature appears in the middle of the false temperature hole tube, the length of the false temperature hole tube along the axial direction is contracted to the middle, and the false temperature hole tube exerts a right pulling force on the small ring hoop through the second weld.

[0022] According to the application, a method for compensating cold shrinkage of a false thermal hole tube of a superconducting magnet cryostat is provided, a bellows is arranged on the false thermal hole tube, and the bellows has an initial compression amount when installed, which is greater than the shrinkage deformation amount of the false thermal hole tube caused by cooling, so as to avoid the weld seam from bearing additional stress.

[0023] According to the application, a method for compensating cold shrinkage of a false thermal hole tube of a superconducting magnet cryostat is provided, the false thermal hole tube is arranged to recover to an initial length, the end of the false thermal hole tube moves to the left relative to the large hoop, and drives the small hoop to compress the bellows, so as to recover the bellows to the initial compression amount.

[0024] According to the application, a method for compensating cold shrinkage of a false thermal hole tube of a superconducting magnet cryostat is provided, and the arrangement of the false thermal hole tube to recover to the initial length comprises:

[0025] Gas is filled into the hole of the false thermal hole tube to remove the beam vacuum, so that the false thermal hole tube is well affected by heat transfer, and the temperature gradient along the axial direction of the false thermal hole tube is removed.

[0026] Alternatively, the cryostat itself is arranged to recover to room temperature, so as to remove the temperature gradient along the axial direction of the false thermal hole tube.

[0027] According to the application, a method for compensating cold shrinkage of a false thermal hole tube of a superconducting magnet cryostat is provided, a second weld seam is arranged along the circumference of the false thermal hole tube, the second weld seam is closed at the head and tail to form a ring, and the second weld seam is used to limit the rotation of the false thermal hole tube in the circumferential direction.

[0028] The above one or more technical solutions in the application have at least one of the following technical effects:

[0029] By arranging the bellows with a telescopic length at the end of the false thermal hole tube, the false thermal hole tube of the cryostat can be compensated in length by the bellows when it shrinks due to cooling, so as to avoid the weld seam for connecting the false thermal hole tube from tearing, and further ensure that the hole of the false thermal hole tube and the interlayer of the cryostat can stably maintain a vacuum state, the false thermal hole tube can be used as a beam tube instead of a conventional vacuum pipeline, the diameter of the superconducting magnet is reduced, and the manufacturing cost of the superconducting magnet is reduced.

[0030] In addition to the technical problems solved by the application, the technical features of the technical solutions constituted by the application, and the advantages brought by the technical features, other technical features of the application and the advantages brought by the technical features will be further described with reference to the drawings or understood through the practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the following will briefly introduce the drawings needed to be used in the embodiments or the related art description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0032] Figure 1 The schematic diagram of the false temperature hole pipe cold shrinkage compensation method provided by the embodiment of the present application.

[0033] Figure 2 The assembly structure schematic diagram of the superconducting magnet cryostat and the superconducting magnet provided by the embodiment of the present application.

[0034] Figure 3 The Figure 2 The enlarged schematic diagram of the middle A partial view.

[0035] Reference signs:

[0036] 1, outer dewar end plate; 2, corrugated pipe; 3, cold screen end plate; 4, cold screen center pipe; 5, second weld; 6, false temperature hole pipe; 7, brass sleeve; 8, first weld; 9, positioning table; 10, large ring clamp; 11, small ring clamp; 12, cryostat; 13, superconducting magnet; 14, cryostat interlayer vacuum; 15, helium tank. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the present application more clear, the technical solutions in the present application will be described clearly below in combination with the drawings in the present application. Obviously, the described embodiments are some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0038] In the description of the embodiments of the present application, it should be noted that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application. In addition, the terms "first", "second", "third" are only for description purposes, and cannot be understood as indicating or implying relative importance.

[0039] In the description of the embodiments of the present application, it should be noted that unless specifically defined and limited otherwise, the terms "connected", "connected to", "connection" should be interpreted broadly, for example, can be fixed connection, can also be detachable connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0040] In the embodiments of the present application, unless specifically defined and limited otherwise, the first feature is "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only means that the first feature is higher in horizontal height than the second feature. The first feature "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or only means that the first feature is lower in horizontal height than the second feature.

[0041] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in the present application and the features of different embodiments or examples without contradiction.

[0042] In the present application, the beam envelope is a concept describing the boundary or profile of the particle beam in the particle accelerator, which refers to the spatial range occupied by the particle beam during transmission.

[0043] Beam vacuum refers to a very low pressure environment maintained in a particle accelerator, a storage ring or other equipment involving charged particle beam transmission in order to ensure efficient and stable transmission of the particle beam, which generally needs to be better than 5x10^-8Pa.

[0044] Interlayer vacuum refers to a closed interlayer space formed between a helium tank (a part containing a superconducting magnet) of a cryostat and an outer dewar of the cryostat. In order to ensure that less low-temperature cold energy is transmitted from the inside to a very low-pressure environment of the outer dewar, a pressure of better than 5*10^-4 Pa is generally required.

[0045] Absolute temperature refers to temperature measurement using Kelvin (K) as a unit. In embodiments of the present application, a cold shrinkage compensation method for a pseudo-temperature hole tube of a cryostat for a superconducting magnet is introduced.

[0046] As shown in Figure 2 , the cryostat 12 includes a pseudo-temperature hole tube 6, a helium tank 15 sleeved on the outer periphery of the pseudo-temperature hole tube 6, and outer dewar end plates 1 sleeved on both ends of the pseudo-temperature hole tube 6. The helium tank 15 includes a cold screen end plate 3 and a cold screen center tube 4. A superconducting magnet 13 is arranged in the helium tank 15. The cryostat interlayer vacuum 14 is formed between the cold screen end plate 3 and the outer dewar end plate 1.

[0047] As shown in Figure 1 , in order to use the pseudo-temperature hole tube 6 of the cryostat 12 as a beam tube, a structure capable of compensating for the length of the pseudo-temperature hole tube 6 when it shrinks due to cooling is arranged at the end of the pseudo-temperature hole tube 6, so as to avoid the situation of weld tearing and vacuum loss.

[0048] The cold shrinkage compensation method includes: step S1, a bellows 2 with a telescopic length is arranged between the outer dewar end plate 1 and the cold screen end plate 3, and the bellows 2 is movably sleeved on the outer side of the pseudo-temperature hole tube 6. Step S2, the left end of the bellows 2 is arranged as a large ring hoop 10, the large ring hoop 10 is connected to the outer dewar end plate 1 from right to left along the axial direction of the pseudo-temperature hole tube 6, and the outer dewar end plate 1 and the large ring hoop 10 are sealingly welded along the intersection line of the outer dewar end plate 1 and the large ring hoop 10 to form a first weld 8. That is, the large ring hoop 10 is connected to the outer dewar end plate 1 from right to left along the axial direction of the pseudo-temperature hole tube 6, and the intersection edge between the left side of the outer dewar end plate 1 and the outer periphery of the large ring hoop 10 is welded to fix the two, forming the first weld 8.

[0049] Step S3, the right end of the bellows 2 is arranged as a small ring hoop 11, and the small ring hoop 11 and the pseudo-temperature hole tube 6 are sealingly welded along the intersection line of the small ring hoop 11 and the pseudo-temperature hole tube 6 to form a second weld 5. That is, the small ring hoop 11 and the pseudo-temperature hole tube 6 are welded to fix the two around the intersection edge between the right end surface of the small ring hoop 11 and the outer periphery of the pseudo-temperature hole tube 6, forming the second weld 5.

[0050] Thus, the left end of the pseudo-temperature-hole pipe 6 is movably embedded in the large ring 10 and can move axially relative to the large ring 10. Moreover, the pseudo-temperature-hole pipe 6 and the bellows pipe 2 are both made of stainless steel and are poor conductors of heat at low temperatures. The cold energy radiated from the cold shield center pipe 4 to the pseudo-temperature-hole pipe 6 cannot be timely conducted away, and a temperature gradient is generated in the middle of the pseudo-temperature-hole pipe 6 during normal operation of the accelerator, which further causes the entire pseudo-temperature-hole pipe 6 to be cold-shrunk and deformed towards the middle.

[0051] The pseudo-temperature-hole pipe 6 is set to be cold-shrunk, and the pseudo-temperature-hole pipe 6 moves rightward relative to the large ring 10 and pulls the small ring 11 to stretch the length of the bellows pipe 2 to compensate for the shrinkage deformation of the pseudo-temperature-hole pipe 6.

[0052] Specifically, during normal operation of the accelerator, the interlayer vacuum 14 of the cryostat 12 is between the outer Dewar end plate 1 and the cold shield end plate 3. The inside of the pseudo-temperature-hole pipe 6 is a beam current vacuum. The cold energy from the cold shield center pipe 4 is conducted to the pseudo-temperature-hole pipe 6 in the radial direction through radiation heat transfer and solid support heat conduction, causing a local low temperature to be generated in the middle of the pseudo-temperature-hole pipe 6. The pseudo-temperature-hole pipe 6 is cold-shrunk towards the middle, and the second weld 5 pulls the bellows pipe 2 to move towards the middle. The bellows pipe 2 is provided with a certain pre-pressing amount during installation and can compensate for the length in the axial direction. The existence of the first weld 8 ensures the interlayer vacuum 14 of the cryostat 12 and ensures that, when the pseudo-temperature-hole pipe 6 is axially cold-shrunk and displaced, the entire pseudo-temperature-hole pipe 6 moves rightward, so that the bellows pipe 2 provides a compensation amount for the cold-shrunk displacement, rather than the entire bellows pipe 2 assembly being axially displaced.

[0053] Preferably, the second weld 5 extends along the circumference of the pseudo-temperature-hole pipe 6 to form a ring shape, so as to integrate the bellows pipe 2 and the pseudo-temperature-hole pipe 6 and limit the circumferential rotation of the pseudo-temperature-hole pipe 6.

[0054] In the embodiment, the length-expandable bellows pipe 2 is arranged at the end of the pseudo-temperature-hole pipe 6, so that the pseudo-temperature-hole pipe 6 of the cryostat 12 can be length-compensated by the bellows pipe 2 when it is cold-shrunk and deformed, the weld for connecting the pseudo-temperature-hole pipe 6 is prevented from being torn, the vacuum state in the pipe hole of the pseudo-temperature-hole pipe 6 can be stably maintained, the pseudo-temperature-hole pipe 6 can be used as a beam pipe to replace the vacuum pipe, the diameter of the superconducting magnet 13 is reduced, and the manufacturing difficulty and cost of the superconducting magnet 13 are reduced.

[0055] On the basis of the above embodiment, another embodiment of the present application introduces a pseudo-temperature-hole pipe cold-shrinking compensation method for a superconducting magnet cryostat.

[0056] The large ring 10 is arranged to be threaded through the outer Dewar end plate 1 in the axial direction of the pseudo-temperature-hole pipe 6 from right to left, including that, after the large ring 10 is threaded through the outer Dewar end plate 1, a positioning table 9 protruding in the radial direction of the large ring 10 is arranged on the inner side of the large ring 10, and the pseudo-temperature-hole pipe 6 is arranged to abut against the positioning table 9 and is used to limit the leftward movement of the pseudo-temperature-hole pipe 6.

[0057] Further, the abutting of the pseudo-temperature hole tube 6 and the positioning table 9 comprises: a brass sleeve 7 is arranged at the end of the pseudo-temperature hole tube 6, the brass sleeve 7 is clamped between the large ring 10 and the pseudo-temperature hole tube 6, and the outer side surface of the brass sleeve 7 is in sliding frictional contact with the large ring 10.

[0058] On the basis of the above-mentioned embodiment, another embodiment of the present application introduces a pseudo-temperature hole tube cold shrinkage compensation method for a superconducting magnet cryostat.

[0059] The sliding frictional contact of the outer side surface of the brass sleeve 7 and the large ring 10 comprises: the spacing between the positioning table 9 and the left side end surface of the large ring 10 is less than or equal to the axial length of the brass sleeve 7.

[0060] Alternatively, the outer side surface diameter of the brass sleeve 7 is greater than the outer side surface diameter of the pseudo-temperature hole tube 6. In this way, when the pseudo-temperature hole tube 6 moves to the right, the outer peripheral side of the end thereof is in contact with and slides against the brass sleeve 7, the brass has good wear resistance, and the hardness of the brass is lower than that of the stainless steel material, so that the pseudo-temperature hole tube 6 will not be damaged.

[0061] On the basis of the above-mentioned embodiment, another embodiment of the present application introduces a pseudo-temperature hole tube cold shrinkage compensation method for a superconducting magnet cryostat.

[0062] The cold shrinkage of the pseudo-temperature hole tube 6 comprises: the cryostat 12 is cooled, the absolute temperature of the helium tank 15 is reduced to 4K (Kelvin), and the absolute temperature of the cold shield end plate 3 and the cold shield center tube 4 is reduced to 50K (Kelvin); then, the gas in the pseudo-temperature hole tube 6 is extracted to form a beam current vacuum.

[0063] The temperature gradient along the axial direction of the pseudo-temperature hole tube 6 is formed on the pseudo-temperature hole tube 6 through the support heat conduction and radiation heat transfer between the cold shield center tube 4 and the pseudo-temperature hole tube 6.

[0064] The local low temperature appears in the middle of the pseudo-temperature hole tube 6, so that the pseudo-temperature hole tube 6 shrinks in length along the axial direction thereof, and the pseudo-temperature hole tube 6 exerts a rightward pulling force on the small ring 11 through the second weld 5. The bellows 2 are provided with a certain compression amount during installation, and the bellows 2 are stretched in length along the axial direction under the pulling of the pseudo-temperature hole tube 6, so as to provide length compensation to avoid weld cracking.

[0065] Further, the bellows 2 have an initial compression amount during installation. The initial compression amount is greater than the shrinkage deformation amount of the pseudo-temperature hole tube 6 caused by cold, and is used to avoid additional stress on the weld.

[0066] On the basis of the above-mentioned embodiment, another embodiment of the present application introduces a pseudo-temperature hole tube cold shrinkage compensation method for a superconducting magnet cryostat.

[0067] The dummy hole tube 6 is set to return to the initial length, the end of the dummy hole tube 6 moves to the left relative to the large ring 10 and drives the small ring 11 to compress the bellows 2, so that the bellows 2 returns to the initial compression amount.

[0068] Further, the setting of the dummy hole tube 6 to return to the initial length includes: filling the gas into the hole of the dummy hole tube 6 to remove the beam vacuum, so that the dummy hole tube 6 is well affected by the heat transfer and the temperature gradient along the axial direction of the dummy hole tube 6 is removed.

[0069] After the beam vacuum in the hole of the dummy hole tube 6 is removed, the cold contraction deformation of the dummy hole tube 6 gradually recovers, so that the end of the dummy hole tube 6 moves reversely along the axial direction to the initial position. Due to the existence of the positioning table 9, the dummy hole tube 6 returns to the position abutting against the positioning table 9, and the bellows 2 returns to the state with the initial compression amount.

[0070] Alternatively, the cryostat 12 itself returns to the normal temperature, that is, the helium tank 15, the superconducting magnet 13, the cold screen end plate 3 and the cold screen center tube 4 all return to the normal temperature, at this time, there is no temperature difference between the cold screen center tube 4 and the dummy hole tube 6, and the temperature gradient along the axial direction of the dummy hole tube 6 is removed.

[0071] And, since the brass sleeve 7 has good wear resistance, the damage of the dummy hole tube 6 can be avoided, so that the dummy hole tube 6 can repeatedly displace in the large ring 10 for many times, and the reliability of the cryostat 12 is improved.

[0072] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

[0073] The above only describes the preferred embodiments of the present application, and does not limit the present application; any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A pseudo-thermal hole tube cold contraction compensation method for a superconducting magnet cryostat, characterized in that, The application relates to a method for setting a length-adjustable bellows between an outer Dewar end plate and a cold shield end plate. Step S1: setting a length-adjustable bellows between the outer Dewar end plate and the cold shield end plate, and movably sleeving the bellows on the outer side of the pseudo-temperature hole pipe; Step S2: setting a large ring clamp at the left end of the bellows, penetrating the outer Dewar end plate along the axial direction of the pseudo-temperature hole pipe from right to left, and sealing welding the outer Dewar end plate and the large ring clamp along the intersection line of the two to form a first weld; Step S3: setting a small ring clamp at the right end of the bellows, and sealing welding the small ring clamp and the pseudo-temperature hole pipe along the intersection line of the two to form a second weld; The pseudo-temperature hole pipe and the bellows are both made of stainless steel, the pseudo-temperature hole pipe is set to be cold-shrunk, the pseudo-temperature hole pipe moves right relative to the large ring clamp and drives the small ring clamp to stretch the length of the bellows to compensate for the shrinkage deformation of the pseudo-temperature hole pipe.

2. The pseudo-thermal well tube cold contraction compensation method for a superconducting magnet cryostat of claim 1, characterized by, The method comprises the following steps: After the large ring clamp penetrates the outer Dewar end plate, a positioning table protruding radially on the inner side of the large ring clamp is arranged, and the pseudo-temperature hole pipe is arranged to abut against the positioning table to limit the left movement of the pseudo-temperature hole pipe.

3. The pseudo-thermal well tube cold contraction compensation method for a superconducting magnet cryostat of claim 2, characterized by, The method comprises the following steps: A brass sleeve is arranged at the end of the pseudo-temperature hole pipe, the brass sleeve is clamped between the large ring clamp and the pseudo-temperature hole pipe, and the outer side of the brass sleeve is in sliding frictional contact with the large ring clamp.

4. The pseudo-thermal well tube cold contraction compensation method for a superconducting magnet cryostat of claim 3, characterized by, The method comprises the following steps: The spacing between the positioning table and the left end surface of the large ring clamp is less than or equal to the axial length of the brass sleeve.

5. The pseudo-thermal well tube cold contraction compensation method for a superconducting magnet cryostat of claim 3, wherein, The method comprises the following steps: The outer side diameter of the brass sleeve is larger than the outer side diameter of the pseudo-temperature hole pipe.

6. A pseudo-thermal well tube cold contraction compensation method for a superconducting magnet cryostat according to any one of claims 1-5, characterized in that, The method comprises the following steps: The cryostat is cooled, the absolute temperature of the helium tank is reduced to 4K, and the absolute temperature of the cold shield is reduced to 50K; then, the gas in the pseudo-temperature hole pipe is extracted to form a beam vacuum, heat is transferred through the cold shield central pipe and the pseudo-temperature hole pipe to form a temperature gradient along the axial direction of the pseudo-temperature hole pipe on the pseudo-temperature hole pipe, local low temperature appears in the middle of the pseudo-temperature hole pipe, the pseudo-temperature hole pipe is shrunk in length along the axial direction thereof to the middle, and the pseudo-temperature hole pipe exerts a right pulling force on the small ring clamp through the second weld.

7. The pseudo-thermal well tube cold contraction compensation method for a superconducting magnet cryostat of claim 6, wherein, The bellows is set to have an initial compression amount when being installed, and the initial compression amount is greater than the shrinkage deformation caused by the cold of the pseudo-temperature hole pipe, so that the weld is prevented from bearing additional stress.

8. The pseudo-thermal well tube cold contraction compensation method for a superconducting magnet cryostat of claim 6, wherein, The pseudo-temperature hole pipe is set to return to the initial length, the end of the pseudo-temperature hole pipe moves left relative to the large ring clamp and drives the small ring clamp to compress the bellows, so that the bellows returns to the initial compression amount.

9. The pseudo-thermal well tube cold contraction compensation method for a superconducting magnet cryostat of claim 8, wherein, The method comprises the following steps: The gas in the pseudo-temperature hole pipe is filled to remove the beam vacuum, so that the pseudo-temperature hole pipe is well affected by heat transfer and the temperature gradient along the axial direction of the pseudo-temperature hole pipe is removed; Alternatively, the cryostat is set to return to normal temperature itself, and the temperature gradient along the axial direction of the pseudo-temperature hole pipe is removed.

10. A pseudo-thermal well tube cold contraction compensation method for a superconducting magnet cryostat according to any one of claims 1-5, characterized in that, The second weld is arranged along the circumferential direction of the pseudo-temperature hole pipe, the first and second ends of the second weld are closed to form a ring, and the circumferential rotation of the pseudo-temperature hole pipe is limited.

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