REBCO non-insulation close-wound superconducting coil testing device

Abstract

The invention discloses an REBCO non-insulation close-wound superconducting coil testing device, and relates to the field of superconducting magnet utilization. Comprising a test box body, a box cover and a test clamping plate, the box cover is arranged at the top of the test box body, a plurality of limiting openings are correspondingly formed in the bottom wall of the test box body and the box cover, one end of the test clamping plate is arranged in the limiting opening of the test box body, and the other end of the test clamping plate penetrates through the limiting opening in the box cover and extends to the outer side of the test box body; an exhaust assembly is arranged on the box cover and comprises a base, a spring and a cover plate, the base is fixedly installed on the box cover, an exhaust port communicated with the interior of the test box body is formed in the center of the base, the cover plate is installed at the top of the base, the spring is connected between the base and the cover plate, and when the pressure of nitrogen in the test box body is larger than the tension of the spring, the nitrogen is exhausted through the exhaust port. Directional exhaust is realized through the exhaust port, so that the problem that the superconducting coil is frozen in the temperature returning process due to the fact that air enters the test box body and is in contact with water and water vapor to form hydrolysis is solved.

Description

Technical Field

[0001] The invention relates to the technical field of superconducting magnets, and in particular to a REBCO non-insulated densely wound superconducting coil testing device. Background Art

[0002] B R 2 Cu 3 O 7-б (REBCO) material is the most rapidly developed and widely used high-temperature superconducting material in recent years. The finished REBCO conductor is usually a strip with a total thickness of 40μm to 100μm. The strip is a multi-layer thin film structure, which mainly includes REBCO superconducting layer, Hastelloy base layer, buffer layer, silver protective layer, copper stabilization layer, etc. The REBCO superconducting layer is composed of a multi-layer texture, mainly composed of CuO 2 The plane produces superconductivity with strong anisotropy.

[0003] The Chinese patent with publication number CN118362951A, entitled A superconducting wire critical current testing device and testing method, specifically discloses that the monitoring device includes: a dewar, which is provided with a vacuum chamber and a liquid nitrogen chamber from the inside to the outside; a thermal insulation support assembly, which is located in the vacuum chamber, and temperature probes are evenly distributed on the thermal insulation support assembly, and the superconducting coil is located above the temperature probe; a superconducting current lead; a copper current lead, the superconducting current lead and the copper current lead are welded in parallel, and one end thereof penetrates into the vacuum chamber and is connected to the superconducting coil, and the other end thereof penetrates out of the liquid nitrogen chamber and is connected to an external power supply; a heating unit, which is installed on the thermal insulation support assembly and is used to heat the copper current lead.

[0004] The problem to be solved by the invention is to provide an adjustable background magnetic field, which can significantly reduce the amount of liquid helium used in superconducting wire testing, and can quickly obtain performance data, so as to solve the problems in the prior art of large amount of liquid helium used, high production costs of enterprises, and low efficiency of performance testing using direct cooling of superconducting wire samples, which is not suitable for batch superconducting wire performance testing. The invention can achieve beneficial effects in low-temperature superconducting magnet back field testing, but it cannot achieve rapid temperature recovery and one-time testing of multiple coils in the field of high-temperature superconducting coil testing.

[0005] Before magnet assembly, the REBCO closely wound coil needs to undergo multiple low-temperature critical performance tests in liquid nitrogen. During the repeated low-temperature test and warming-up process, it is easy to come into contact with air, freeze, liquefy and come into contact with the high-temperature superconducting tape in the low-temperature environment. The high-temperature superconducting tape will hydrolyze after multiple tests, causing the performance of the REBCO high-temperature superconducting tape to degrade, and the warming-up process from low temperature is very slow. Therefore, it is urgent to design a REBCO non-insulated closely wound superconducting coil test device that can quickly warm up in the liquid nitrogen temperature zone test environment without hydrolysis. Summary of the invention

[0006] The main purpose of the present invention is to provide a REBCO non-insulated densely wound superconducting coil testing device to overcome the problems existing in the prior art.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A REBCO non-insulated densely wound superconducting coil testing device comprises a test box, a box cover and a test clamp, wherein the box cover is arranged on the top of the test box, a plurality of limit openings are correspondingly arranged on the bottom wall of the test box and the box cover, one end of the test clamp is arranged in the limit opening of the test box, and the other end passes through the limit opening on the box cover and extends to the outside of the test box;

[0009] An exhaust assembly is provided on the box cover, and the exhaust assembly includes a base, a spring and a cover plate. The base is fixedly installed on the box cover, and an exhaust port connected to the interior of the test box is provided at the center of the base. The cover plate is installed on the top of the base, and the spring is connected between the base and the cover plate. When the nitrogen pressure in the test box is greater than the tension of the spring, the nitrogen is discharged through the exhaust port. When the nitrogen pressure in the test box is less than the tension of the spring, the cover plate is covered on the exhaust port to ensure that air does not enter the interior of the test box during the experiment and the rewarming process.

[0010] Furthermore, a vacuum interlayer is provided on the inner side of the test box, and a vacuum extraction port communicating with the vacuum interlayer is provided on the outer wall of the test box, and the vacuum extraction port is located at the upper part of the test box.

[0011] Furthermore, an insulating heating wire is provided on the outer wall of the test box, and the insulating heating wire is wound around the lower part of the test box. The insulating heating wire is used to heat the test box so that the interior of the test box can quickly return to temperature, and the heating temperature is not greater than 50°C.

[0012] Furthermore, the box cover is also provided with a liquid nitrogen low-temperature level gauge socket and a liquid injection port. During testing, liquid nitrogen is injected into the interior of the test box through the liquid injection port. During the temperature recovery process, normal temperature nitrogen is injected into the interior of the test box through the liquid injection port, and the speed of the normal temperature nitrogen inflow is adjusted by the pressure reducing valve.

[0013] Furthermore, the test clamp includes a bottom plate and an upper cover plate, the bottom plate is provided with a superconducting coil, and the upper cover plate is arranged on the outside of the superconducting coil.

[0014] Furthermore, a first vertical portion and a second vertical portion are respectively provided at the upper and lower ends of the bottom plate, the first vertical portion is installed in the limiting opening of the test box body, the second vertical portion passes through the limiting opening on the box cover, and an intermediate insulating block is provided on the second vertical portion, the two superconducting tapes of the superconducting coil are respectively connected to superconducting tape leads, the superconducting tape leads are connected to copper braided tapes, and the two copper braided tapes are respectively located on both sides of the intermediate insulating block and are led upward along the intermediate insulating block.

[0015] Furthermore, the superconducting coil and the base plate are fixed by limiting stud nuts and butterfly washers.

[0016] Furthermore, the number of the butterfly gaskets is one or more.

[0017] Furthermore, the surface of the copper braided belt is insulated by wrapping it with polyimide tape, and the second vertical portion passes through the limiting opening on the box cover and then a vacuum seal is used to fill the gap therebetween.

[0018] Furthermore, the elastic coefficient of the spring is 10N / m to 80N / m.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention arranges the exhaust assembly so that the exhaust port exhausts in a directional manner. When the nitrogen pressure in the test box is greater than the tension of the spring, the nitrogen can be discharged through the exhaust port. When the nitrogen pressure in the test box is less than the tension of the spring, the cover plate is arranged on the exhaust port to ensure that air does not enter the interior of the test box during the experiment and the temperature recovery process, thereby solving the problem that the superconducting coil freezes during the temperature recovery process due to air entering the test box and forms hydrolysis when in contact with water and water vapor;

[0021] (2) The bottom wall and the cover of the test box of the present invention are respectively provided with a plurality of limit openings, so that a plurality of test clamps can be placed, and a plurality of superconducting coils can be measured at one time, which saves time cost and liquid nitrogen resources, and the operation method is simpler and convenient to disassemble, and it is not easy to cause damage to the superconducting coil;

[0022] (3) The present invention arranges an insulating heating wire on the outer wall of the test box, and can heat up at a certain heating rate during the temperature recovery process, which not only controls the temperature uniformity in the test box, but also can complete the experimental temperature recovery in a shorter time, thereby speeding up the experimental efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the external structure of the present invention.

[0024] Figure 2 It is a schematic diagram of the internal structure of the present invention.

[0025] Figure 3 It is a cross-sectional view of the test box of the present invention.

[0026] Figure 4 It is a schematic diagram of the box cover structure of the present invention.

[0027] Figure 5 The present invention Figure 4 A partial enlarged view of point A in the middle.

[0028] Figure 6 It is a schematic diagram of the test splint structure of the present invention.

[0029] Description of the drawings: 1-test box body, 11-first limit port, 12-vacuum interlayer, 13-vacuum extraction port, 2-box cover, 21-second limit port, 22-liquid nitrogen low temperature level gauge socket, 23-liquid filling port, 3-test splint, 31-bottom plate, 4-exhaust assembly, 41-base, 42-spring, 43-cover plate, 5-insulated heating wire, 6-middle insulating block, 7-copper braided belt, 8-limiting stud nut. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0031] Combination Figures 1 to 6 The present embodiment provides a REBCO non-insulated densely wound superconducting coil test device, comprising a test box 1, a box cover 2 and a test clamp 3, wherein the box cover 2 is arranged on the top of the test box 1, and a plurality of limiting openings are correspondingly arranged on the bottom wall of the test box 1 and the box cover 2, and one end of the test clamp 3 is arranged in the limiting opening of the test box 1, and the other end passes through the limiting opening on the box cover 2 and extends to the outside of the test box 1;

[0032] An exhaust assembly 4 is provided on the box cover 2, and the exhaust assembly 4 includes a base 41, a spring 42 and a cover plate 43. The base 41 is fixedly installed on the box cover 2, and an exhaust port connected to the interior of the test box 1 is provided at the center of the base 41. The cover plate 43 is installed on the top of the base 41, and the spring 42 is connected between the base 41 and the cover plate 43. When the nitrogen pressure in the test box 1 is greater than the tension of the spring 42, the nitrogen is discharged through the exhaust port. When the nitrogen pressure in the test box 1 is less than the tension of the spring 42, the cover plate 43 is covered on the exhaust port to ensure that air does not enter the interior of the test box 1 during the experiment and the reheating process.

[0033] Specifically, the limiting opening in the test box body 1 is the first limiting opening 11 , and the limiting opening on the box cover 2 is the second limiting opening 12 .

[0034] Preferably, the elastic coefficient of the spring 42 is 10 N / m to 80 N / m.

[0035] In a further embodiment, a vacuum interlayer 12 is provided on the inner side of the test box 1, and a vacuum port 13 connected to the vacuum interlayer 12 is provided on the outer wall of the test box 1, and the vacuum port 13 is located at the upper part of the test box 1. An insulating heating wire 5 is provided on the outer wall of the test box 1, and the insulating heating wire 5 is wound around the lower part of the test box 1. The insulating heating wire 5 is used to heat the test box 1 so that the interior of the test box 1 can be quickly heated up, and the heating temperature is not greater than 50°C.

[0036] In a further embodiment, the box cover 2 is further provided with a liquid nitrogen low-temperature level gauge socket 22 and a liquid injection port 23. During testing, liquid nitrogen is injected into the interior of the test box 1 through the liquid injection port 23. During the temperature recovery process, normal temperature nitrogen is injected into the interior of the test box 1 through the liquid injection port 23, and the speed of the normal temperature nitrogen inflow is adjusted by the pressure reducing valve.

[0037] In a further embodiment, the test clamp 3 includes a base plate 31 and an upper cover plate 43, the base plate 31 is provided with a superconducting coil, and the upper cover plate 43 is arranged on the outside of the superconducting coil; the upper and lower ends of the base plate 31 are respectively provided with a first vertical portion and a second vertical portion, the first vertical portion is installed in the limiting opening of the test box 1, and the second vertical portion passes through the limiting opening on the box cover 2, and the second vertical portion is provided with an intermediate insulating block 6, the two superconducting tapes of the superconducting coil are respectively connected to superconducting tape leads, and the superconducting tape leads are connected to copper braided tapes 7, and the two copper braided tapes 7 are respectively located on both sides of the intermediate insulating block 6 and are led upward along the intermediate insulating block 6; the superconducting coil and the base plate 31 are fixed by limiting stud nuts 8 and butterfly gaskets.

[0038] Preferably, the number of the butterfly-shaped gaskets is one or more. By stacking the butterfly-shaped gaskets to apply pre-tightening force to the test clamp 3, deformation and damage of the superconducting densely wound coil due to thermal stress during the cooling and heating process can be prevented.

[0039] Preferably, the surface of the copper braided belt 7 is insulated by wrapping it with polyimide tape, and the second vertical portion passes through the limiting opening on the box cover 2 and a vacuum seal is used to fill the gap therebetween.

[0040] Example 1

[0041] In this embodiment, the heating temperature is 50°C. When the liquid nitrogen level gauge shows that the liquid nitrogen has completely volatilized, the insulating heating wire 5 continues to heat for 6 hours. The number of butterfly gaskets is 4. The preload force of 50N is applied to the test clamp 3 by stacking the butterfly gaskets. The elastic coefficient of the spring 42 is 10N / m.

[0042] During the specific operation, the tightly wound superconducting coil is placed on the bottom plate 31 of the test clamp 3, and the two are fixed by the limiting stud nut 8 and the butterfly gasket. The upper and lower superconducting tapes of the double-cake superconducting coil are respectively soldered to the superconducting tape lead wire, and the corresponding upper and lower copper braided tapes 7 are led upward along the middle insulating block 6. The fixed test clamp 3 is inserted into the limiting opening of the test box 1; then the box cover 2 is placed on the sealing gasket of the test box 1 and fixed by fixing the threaded hole. The sealing gasket can play a good sealing role; then the vacuum of the interlayer of the test box 1 is drawn by a mechanical pump through the vacuum extraction port 13 of the test box 1. When the vacuum degree reaches 1×10 -1 Pa, slowly inject liquid nitrogen through the liquid filling port 23 on the box cover 2, and judge the liquid level by the liquid nitrogen low-temperature liquid level gauge. When the liquid nitrogen submerges the top of the bottom plate 31, the copper braided belt 7 connected to the outside of the box cover 2 can be energized; after the test is completed, stop the mechanical pump to evacuate, break the interlayer vacuum, and start heating the insulating heating wire 5 wrapped around the test box 1. The heating temperature is 50°C, and the liquid nitrogen will evaporate into nitrogen. When the pressure exceeds the tension of the exhaust port spring 42, the exhaust port will discharge the nitrogen in the test box 1. When the pressure of the test box 1 is less than the tension of the spring 42, the cover plate 43 will press on the gasket of the base 41 to close the exhaust port, and no air will enter the box during the experiment and the warming process; when the liquid nitrogen low-temperature liquid level gauge shows that the liquid nitrogen has completely evaporated, the insulating heating wire 5 continues to heat for 6 hours, so that the superconducting coil is warmed up in a nitrogen environment.

[0043] The butterfly-shaped gaskets limited in the middle of the bottom plate 31 of the test clamp 3 are composed of 4. By stacking the butterfly gaskets, a pre-tightening force of 50N is applied to the test clamp 3, which can prevent the superconducting densely wound coil from being deformed and damaged due to thermal stress during the cooling and heating process. The surface of the copper braided belt 7 on the test clamp 3 is insulated by wrapping polyimide tape. The second vertical part of the test clamp 3 passes through the corresponding limiting opening on the box cover 2, and the gap is filled with vacuum sealant to ensure sealing.

[0044] Example 2

[0045] In this embodiment, the heating temperature is 40°C. When the liquid nitrogen level gauge shows that the liquid nitrogen has completely volatilized, the insulating heating wire 5 continues to heat for 7 hours. The number of butterfly gaskets is 6. The preload force of 100N is applied to the test clamp 3 by stacking the butterfly gaskets. The elastic coefficient of the spring 42 is 80N / m.

[0046] During the specific operation, the tightly wound superconducting coil is placed on the bottom plate 31 of the test clamp 3, and the two are fixed by limiting stud nuts 8 and butterfly gaskets. The upper and lower superconducting tapes of the double-cake superconducting coil are respectively soldered to the superconducting tape leads, and the corresponding upper and lower copper braided tapes 7 are led upward along the middle insulating block 6. The first vertical part of the fixed test clamp 3 is inserted into the limiting opening of the test box 1; then the box cover 2 is covered on the sealing gasket of the test box 1, and the screws are fixed by fixing the threaded holes at the corresponding positions of the box cover 2 and the test box 1; then the vacuum of the interlayer of the test box 1 is pumped by a mechanical pump through the vacuum extraction port 13 of the test box 1. When the vacuum degree reaches 1×10 -1 Pa, slowly inject liquid nitrogen through the liquid filling port 23 on the box cover 2, and judge the liquid level by the liquid nitrogen low-temperature liquid level gauge. When the liquid nitrogen submerges the top of the bottom plate 31, the copper braided belt 7 connected to the outside of the box cover 2 can be energized; after the test is completed, stop the mechanical pump to evacuate, break the interlayer vacuum, and start heating the insulating heating wire 5 wrapped around the test box 1. The heating temperature is 40°C, and the liquid nitrogen will evaporate into nitrogen. When the pressure exceeds the tension of the exhaust port spring 42, the exhaust port will discharge the nitrogen in the test box 1. When the pressure of the test box 1 is less than the tension of the spring 42, the cover plate 43 will press on the gasket of the base 41 to close the exhaust port. During the experiment and the warming process, no air will enter the test box 1; when the liquid nitrogen level gauge shows that the liquid nitrogen has completely evaporated, the insulating heating wire 5 continues to heat for 7 hours, so that the superconducting coil is warmed up in a nitrogen environment.

[0047] During the rewarming process, nitrogen at room temperature is connected through the liquid injection port 23, and the flow rate of nitrogen at room temperature is adjusted to 5L / min through the pressure reducing valve. The insulating heating wire 5 of the box body is continuously heated, which can quickly rewarm the box body without air entering.

[0048] The butterfly gaskets limited in the middle of the bottom plate 31 of the test clamp 3 are composed of 6 pieces. The pre-tightening force of 100N is applied to the test clamp 3 by stacking the butterfly gaskets to prevent the superconducting densely wound coil from being deformed and damaged due to thermal stress during the cooling and heating process.

[0049] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A REBCO non-insulated densely wound superconducting coil test device, characterized in that: The test box comprises a test box, a box cover and a test clamp, wherein the box cover is arranged on the top of the test box, a plurality of limit openings are arranged on the bottom wall of the test box and the box cover respectively, one end of the test clamp is arranged in the limit opening of the test box, and the other end passes through the limit opening on the box cover and extends to the outside of the test box; An exhaust assembly is provided on the box cover, and the exhaust assembly includes a base, a spring and a cover plate. The base is fixedly installed on the box cover, and an exhaust port connected to the interior of the test box is provided at the center of the base. The cover plate is installed on the top of the base, and the spring is connected between the base and the cover plate. When the nitrogen pressure in the test box is greater than the tension of the spring, the nitrogen is discharged through the exhaust port. When the nitrogen pressure in the test box is less than the tension of the spring, the cover plate is covered on the exhaust port to ensure that air does not enter the interior of the test box during the experiment and the rewarming process.

2. A REBCO non-insulated densely wound superconducting coil testing device as claimed in claim 1, characterized in that: A vacuum interlayer is arranged on the inner side of the test box, and a vacuum extraction port communicating with the vacuum interlayer is arranged on the outer wall of the test box. The vacuum extraction port is located at the upper part of the test box.

3. A REBCO non-insulated densely wound superconducting coil testing device as claimed in claim 1 or 2, characterized in that: An insulating heating wire is provided on the outer wall of the test box and is wound around the lower part of the test box. The insulating heating wire is used to heat the test box so that the interior of the test box can quickly return to temperature, and the heating temperature is no greater than 50°C.

4. A REBCO non-insulated densely wound superconducting coil testing device as claimed in claim 1, characterized in that: The box cover is also provided with a liquid nitrogen low-temperature level gauge socket and a liquid injection port. During testing, liquid nitrogen is injected into the interior of the test box through the liquid injection port. During the temperature recovery process, normal temperature nitrogen is injected into the interior of the test box through the liquid injection port, and the speed of the normal temperature nitrogen inflow is adjusted by the pressure reducing valve.

5. A REBCO non-insulated densely wound superconducting coil testing device as claimed in claim 1, characterized in that: The test clamp comprises a bottom plate and an upper cover plate, wherein a superconducting coil is arranged on the bottom plate, and the upper cover plate is arranged on the outer side of the superconducting coil.

6. A REBCO non-insulated densely wound superconducting coil testing device as claimed in claim 5, characterized in that: The upper and lower ends of the bottom plate are respectively provided with a first vertical portion and a second vertical portion, the first vertical portion is installed in the limiting opening of the test box body, the second vertical portion passes through the limiting opening on the box cover, and an intermediate insulating block is provided on the second vertical portion, the two superconducting tapes of the superconducting coil are respectively connected with superconducting tape leads, the superconducting tape leads are connected with copper braided tapes, and the two copper braided tapes are respectively located on both sides of the intermediate insulating block and are led upward along the intermediate insulating block.

7. A REBCO non-insulated densely wound superconducting coil testing device as claimed in claim 5, characterized in that: The superconducting coil and the bottom plate are fixed by limiting stud nuts and butterfly washers.

8. A REBCO non-insulated densely wound superconducting coil testing device as claimed in claim 7, characterized in that: The number of the butterfly gasket is one or more.

9. A REBCO non-insulated densely wound superconducting coil testing device as claimed in claim 6, characterized in that: The surface of the copper braided belt is insulated by wrapping it with polyimide tape, and the second vertical portion passes through the limiting opening on the box cover and then a vacuum seal is used to fill the gap therebetween.

10. A REBCO non-insulated densely wound superconducting coil testing device as claimed in claim 1, characterized in that: The elastic coefficient of the spring is 10N / m to 80N / m.

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