A process equipment for superconducting switch testing

Abstract

The present invention discloses a process equipment for testing a superconducting switch, comprising a cryogenic sealed container, a plurality of current leads and a superconducting switch bracket; the superconducting switch bracket is located in the cryogenic sealed container; one or more superconducting switches are fixed on the superconducting switch bracket by a clamp; the current lead has an upper and a lower joint, the upper joint is located above the top cover of the cryogenic sealed container and connected to an external power supply, and the lower joint is located inside the cryogenic sealed container and connected to the superconducting switch to be tested; the heater of the superconducting switch is led out to the outside of the cryogenic sealed container by an insulated copper wire; the superconducting wires of the superconducting switch are closely arranged and fastened to the superconducting switch bracket by an insulating tape. The process equipment for testing a superconducting switch of the present invention can realize the testing of multiple superconducting switches without switching, directly carrying multiple superconducting switches, reducing the loss of liquid helium, reducing the switching time loss and low temperature loss, and reducing the probability of major damage to the hardware of the magnetic resonance superconducting magnet.

Description

Technical Field

[0001] The invention relates to a process equipment for superconducting switch testing, and is particularly suitable for superconducting switch testing of a magnetic resonance imaging superconducting magnet. Background Art

[0002] With the rapid development of related technologies such as superconducting technology, cryogenic technology, magnet technology, electronic and computer technology, superconducting magnetic resonance imaging system technology and magnet technology have developed rapidly and have been widely used in clinical practice, becoming an indispensable member in the field of medical imaging. Magnetic resonance imaging equipment usually consists of five parts: magnet system, radio frequency system, gradient system, computer system and other auxiliary equipment. The magnet system mainly provides a static magnetic field with high uniformity and high stability. At present, low-field magnetic resonance systems are mainly permanent magnets, and some low-field open magnetic resonance systems have also begun to use superconducting magnets, while high-field magnetic resonance is mainly superconducting magnets.

[0003] At present, the superconducting magnets used in magnetic resonance systems are mainly cooled by immersion in liquid helium. After the superconducting coils acquire superconducting properties under low temperature conditions, they need to be charged by an external power supply through the current leads and the cables inside the magnet to achieve the required magnetic field. If the magnetic field needs to be removed, the reasonable way is to discharge the superconducting coils through the external power supply through the current leads and the cables inside the magnet.

[0004] In the prior art, most magnetic resonance devices use superconducting magnet systems. Due to the need for long-term operation, such superconducting magnet systems are often designed to operate in a closed-loop mode, that is, to allow the superconducting current to flow continuously in a loop inside the liquid helium tank at a very small attenuation rate.

[0005] In order to achieve closed-loop operation, a superconducting switch branch (switch heater) needs to be connected in parallel between the positive and negative poles of the superconducting magnet coil and the excitation power supply.

[0006] Before excitation, voltage is applied to both ends of a heater that is close to or contained in a superconducting switch to heat the superconducting wire of the superconducting switch nearby, thereby causing the superconducting switch to switch from a closed operating mode (superconducting state) to an open operating mode (resistance state); then, the output current is gradually increased through the excitation power supply.

[0007] Since the branch of the superconducting switch is in a resistance state, most of the current will enter the branch where the superconducting magnet coil is located, thereby achieving the purpose of exciting the superconducting magnet coil; when the current in the magnet coil reaches the preset value, the output current of the excitation power supply stops rising, and the voltage applied to the two ends of the superconducting switch heater is removed. After the external heating disappears, as the temperature drops, the superconducting switch will enter the closed working mode (superconducting state) from the open working mode (resistance state).

[0008] At this time, the output current is gradually reduced through the excitation power supply. Since the superconducting switch branch is in a superconducting state and the superconducting switch usually has only a small inductance, as the output current of the excitation power supply decreases, the current on the superconducting switch will gradually increase, while the current flowing on the superconducting magnet coil with a larger inductance basically does not change; when the output current of the excitation power supply drops to zero, the superconducting switch and the superconducting magnet coil have the same current, forming a current closed loop. At this time, the connection between the excitation power supply and the positive and negative poles of the superconducting magnet can be disconnected.

[0009] It can be seen that after entering the closed-loop operation, the superconducting magnet can maintain a long-term continuous operation with nearly zero energy consumption. An important component of realizing the closed-loop mode operation is the switching of the superconducting switch between the two working modes of closed (superconducting state) and open (resistance state). In traditional and known technologies, this state switching is mostly achieved by switching heaters. At the same time, there are also some special technologies that achieve the switching between the open and closed states of the superconducting switch by applying an external magnetic field or external stress.

[0010] The good performance of superconducting switches plays a key role in the excitation and use process. A process equipment for superconducting switch testing plays a role in quality control and quality assurance of the good performance of superconducting switches. Summary of the invention

[0011] The purpose of the present invention is to overcome the defects of the prior art and provide a process equipment for superconducting switch testing, which can realize the testing of multiple superconducting switches without switching, thereby ensuring that the liquid helium loss of the magnetic resonance superconducting magnet can be reduced during the excitation and use process, reducing the switching time loss and low temperature loss, and reducing the probability of major damage to the hardware of the magnetic resonance superconducting magnet, thereby further reducing labor costs and quality costs.

[0012] The technical solution to achieve the above purpose is: a process equipment for superconducting switch testing, including a low-temperature sealed container, a plurality of current leads and a superconducting switch bracket, wherein:

[0013] A support plate is disposed transversely in the low-temperature sealed container;

[0014] The superconducting switch bracket is located in the low-temperature sealed container and is fixed on the upper and lower sides of the support plate;

[0015] One or more superconducting switches are fixed on the superconducting switch bracket via a clamp;

[0016] Each of the current leads has an upper connector and a lower connector, wherein the upper connector is located above the top cover of the cryogenic sealed container and is connected to an external power source, and the lower connector is located inside the cryogenic sealed container and is connected to a superconducting switch to be tested;

[0017] Among the multiple current leads, one is a positive current lead, and the rest are negative current leads;

[0018] The heater of the superconducting switch is led out to the outside of the low-temperature sealed container through an insulated copper wire;

[0019] Each superconducting switch has two superconducting wires, and the superconducting wires of all superconducting switches are closely arranged and fastened to the superconducting switch bracket by insulating tape; the lower connector of the positive current lead is connected to one superconducting wire of all superconducting switches; the lower connectors of all negative current leads are connected to the other superconducting wire of all superconducting switches one by one.

[0020] In the above-mentioned process equipment for testing a superconducting switch, the low-temperature sealed container adopts a Dewar sealed container, and the Dewar sealed container includes a Dewar and a Dewar cover sealed at the opening at the upper end thereof.

[0021] In the above-mentioned process equipment for testing a superconducting switch, the superconducting wire of the superconducting switch is fastened to the lower connector of the corresponding current lead by means of a tinned copper wire.

[0022] In the above-mentioned process equipment for testing a superconducting switch, the superconducting switch bracket comprises an outer frame and a switch mounting plate fixed in the outer frame, and the superconducting switch bracket is located on the central axis of the low-temperature sealed container.

[0023] In the above-mentioned process equipment for testing a superconducting switch, the top end of the superconducting switch bracket is connected to the support plate through a vertical rod.

[0024] In the above-mentioned process equipment for testing a superconducting switch, the current lead is laid in a current lead bushing.

[0025] In the above-mentioned process equipment for testing superconducting switches, the current lead bushing is a GFRP insulating bushing.

[0026] In the above-mentioned process equipment for testing a superconducting switch, the insulating tape is made of polyimide tape or glass cloth tape.

[0027] In the above-mentioned process equipment for testing a superconducting switch, the insulating material of the copper wire with insulating skin is an insulating material resistant to low temperature environment.

[0028] The process equipment for testing superconducting switches of the present invention respectively switches on the superconducting coils and current leads and thin-film heater leads inside the superconducting switch in a low-temperature magnetic field environment and tests the performance of the superconducting switch, thereby realizing direct testing of multiple superconducting switches without switching, thereby ensuring that the magnetic resonance superconducting magnet can reduce liquid helium loss during excitation and use, reduce switching time loss and low-temperature loss, and reduce the probability of major damage to the hardware of the magnetic resonance superconducting magnet, thereby further reducing labor costs and quality costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the process equipment for superconducting switch testing of the present invention. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solution of the present invention, the specific implementation methods thereof are described in detail below in conjunction with the accompanying drawings:

[0031] See also Figure 1 The best embodiment of the present invention is a process equipment for testing a superconducting switch, comprising a low-temperature sealed container, a plurality of current leads 2 and a superconducting switch bracket 3.

[0032] A support plate 4 is transversely arranged in the cryogenic sealed container 1; the cryogenic sealed container 1 adopts a Dewar sealed container, which includes a Dewar 11 and a Dewar cover 12 sealed at its upper end opening. The support plate 4 is transversely arranged in the Dewar 11.

[0033] The superconducting switch support 3 is located in the dewar tank 11 and fixed below the support plate 4; the superconducting switch support 3 includes an outer frame and a switch mounting plate fixed in the outer frame, and the superconducting switch support 3 is located on the central axis of the low-temperature sealed container 1. The top of the superconducting switch support 3 is connected to the support plate 4 through a vertical rod 5.

[0034] One or more superconducting switches 100 may be fixed on the switch mounting plate of the superconducting switch bracket 3 by means of a clamp; the superconducting switch 100 is located in the low-temperature sealed container 1 at the center of the magnetic field.

[0035] The current lead 2 is laid in the current lead sleeve. Each current lead 2 has two joints, an upper joint and a lower joint. The upper joint is located above the Dewar cover 12 (i.e., the top cover of the cryogenic sealed container) and is connected to an external power source. The lower joint is located inside the cryogenic sealed container 1 and is connected to the superconducting switch 100 to be tested. Among the multiple current leads, one is a positive current lead, and the rest are negative current leads.

[0036] The heater of the superconducting switch 100 is led out to the outside of the low-temperature sealed container 1 through an insulated copper wire; each superconducting switch 100 has two superconducting wires, and the superconducting wires of all superconducting switches 100 are closely arranged and fastened to the superconducting switch bracket 3 through insulating tape; the lower joint of the positive current lead is connected to a superconducting wire of the superconducting switch 100; the lower joints of all negative current leads are connected to the other superconducting wires of the left and right superconducting switches 100 one by one. The heater of the superconducting switch is led out to the outside of the low-temperature sealed container through an insulated copper wire;

[0037] The superconducting wire of the superconducting switch 100 is fastened to the lower connector of the corresponding current lead 2 by means of tinned copper wire and reinforced by soldering to ensure good contact.

[0038] The current lead casing adopts GFRP insulating casing. The insulating tape adopts polyimide tape or glass cloth tape. The insulating material of the copper wire with insulating skin adopts the insulating material resistant to low temperature environment.

[0039] The process equipment for testing superconducting switches of the present invention has the property of one positive and multiple negatives, and has multiple current leads, wherein the upper joint of the positive current lead is connected to the positive pole of an external power source, the lower joint of the positive current lead is connected to a superconducting wire of all superconducting switches, and the lower joints of all negative current leads are respectively connected to the remaining other superconducting wires of each superconducting switch, and the superconducting switch is fastened to the superconducting switch bracket 3 with a clamp, and is placed in a low-temperature sealed container 1 with a magnetic field by a crane, and is powered on for testing respectively, and the actual measured value reaches the standard design value.

[0040] In summary, the process equipment for testing superconducting switches of the present invention respectively switches on the superconducting coils and current leads and thin-film heater wires inside the superconducting switch and tests the performance of the superconducting switch in a low-temperature magnetic field environment, thereby realizing the direct carrying of multiple superconducting switch tests without switching, thereby ensuring that the magnetic resonance superconducting magnet can reduce liquid helium loss during excitation and use, reduce switching time loss and low-temperature loss, and reduce the probability of major damage to the hardware of the magnetic resonance superconducting magnet, thereby further reducing labor costs and quality costs.

[0041] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A process equipment for superconducting switch testing, characterized in that: It includes a cryogenic sealed container, a plurality of current leads and a superconducting switch bracket, wherein: A support plate is disposed transversely in the low-temperature sealed container; The superconducting switch bracket is located in the low-temperature sealed container and is fixed on the upper and lower sides of the support plate; One or more superconducting switches are fixed on the superconducting switch bracket via a clamp; Each of the current leads has an upper connector and a lower connector, wherein the upper connector is located above the top cover of the cryogenic sealed container and is connected to an external power source, and the lower connector is located inside the cryogenic sealed container and is connected to a superconducting switch to be tested; Among the multiple current leads, one is a positive current lead, and the rest are negative current leads; The heater of the superconducting switch is led out to the outside of the low-temperature sealed container through an insulated copper wire; Each superconducting switch has two superconducting wires, and the superconducting wires of all superconducting switches are closely arranged and fastened to the superconducting switch bracket by insulating tape; the lower connector of the positive current lead is connected to one superconducting wire of all superconducting switches; the lower connectors of all negative current leads are connected to the other superconducting wire of all superconducting switches one by one.

2. A superconducting switch testing process equipment according to claim 1, characterized in that: The low-temperature sealed container is a Dewar sealed container, and the Dewar sealed container includes a Dewar and a Dewar cover sealed at the upper end opening thereof.

3. The process equipment for superconducting switch testing according to claim 1, characterized in that: The superconducting wire of the superconducting switch is fastened to the lower connector of the corresponding current lead by means of tinned copper wire.

4. The process equipment for superconducting switch testing according to claim 1, characterized in that: The superconducting switch support comprises an outer frame and a switch mounting plate fixed in the outer frame, and the superconducting switch support is located on the central axis of the low-temperature sealed container.

5. A superconducting switch testing process equipment according to claim 4, characterized in that: The top end of the superconducting switch bracket is connected to the support plate through a vertical rod.

6. The process equipment for superconducting switch testing according to claim 1, characterized in that: The current lead is laid in a current lead bushing.

7. A superconducting switch testing process equipment according to claim 6, characterized in that: The current lead bushing is a GFRP insulating bushing.

8. The process equipment for superconducting switch testing according to claim 1, characterized in that: The insulating tape is polyimide tape or glass cloth tape.

9. The process equipment for superconducting switch testing according to claim 1, characterized in that: The insulating material of the copper wire with insulating skin is an insulating material resistant to low temperature environment.

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