CN217213104U - High-field superconducting magnet low-temperature vertical test system - Google Patents

Abstract

The utility model discloses a low-temperature vertical testing system for a high-field superconducting magnet, which is characterized in that it comprises a vertical testing Dewar, and the vertical testing Dewar is provided with a pressure sensor, a liquid level gauge and a safety device for rapid pressure relief. Valve, bursting disc for blasting the top; one end of the return gas vaporizer is connected to the vertical test Dewar through the low temperature pipeline, and the other end is connected to the helium recovery airbag through the first normal temperature pipeline; the first normal temperature pipeline is provided with a safety relief valve The second normal temperature pipeline is a current lead return line, one end is connected to the air outlet at the end of the current lead, and the other end is connected to the air outlet of the return gas vaporizer, and a current lead flow controller is arranged on it to control the flow of cold helium gas of the cooling current lead , so that the temperature of the current lead reaches the working temperature area, and the helium gas in the first and second normal temperature pipelines is returned to the helium gas recovery airbag; the vertical test Dewar is provided with a liquid injection port, an emptying port and a heater. The utility model has the characteristics of simple operation and high safety.

Description

A low-temperature vertical test system for high-field superconducting magnets

technical field

The utility model relates to the field of low-temperature engineering, in particular to a low-temperature vertical test system for a high-field superconducting magnet.

Background technique

Superconductors have zero resistance characteristics and complete diamagnetism below the critical temperature and critical magnetic field. In order to test the performance of superconductors, its temperature needs to be lowered below the critical temperature. During the test, the superconducting magnet to be tested is immersed in liquid helium. Due to the low temperature system of liquid helium involved, it is particularly important to test the amount of liquid helium in the Dewar vertically, pressure stability and other factors. The static heat leakage of the vertical test system, the leakage heat of the current leads, and the quench during the magnet power-on test will consume the liquid helium of the vertical test Dewar, which requires stable replenishment of liquid helium to achieve continuous testing.

The quench of the high-field superconducting magnet during the power-on test will consume the liquid helium in the vertical test Dewar. When the liquid helium level is lower than the required level, the low-temperature vertical test cannot continue, and liquid helium needs to be replenished. In the past, liquid helium was replenished by moving the liquid helium Dewar. The intermediate time interval would cause the temperature of the infusion tube to rise, causing liquid helium loss when liquid helium was replenished again. At the same time, the liquid helium replenishment time was too long, which reduced the test efficiency.

The previous vertical test system has high requirements for technicians, so it is necessary to provide a set of simple, safe and reliable low-temperature vertical test system for high-field superconducting magnets.

Utility model content

In view of the above analysis, the present invention aims to propose a uniquely designed low-temperature vertical testing system for high-field superconducting magnets, which is used to solve the problems introduced in the above background technology.

The technical scheme of the present utility model is:

A low-temperature vertical test system for high-field superconducting magnets, comprising:

The vertical test Dewar 001 is used to store the liquid helium for the vertical test of the high-field superconducting magnet, and a radiation protection screen 002 is set above the liquid helium surface. The radiation protection screen 002 is used to reduce the liquid helium and the vertical test. Heat transfer between the top flanges of tile 001;

The vertical test Dewar 001 is provided with a pressure sensor 003 for monitoring the internal pressure of the vertical test Dewar 001, and a liquid level gauge 014 for monitoring the internal liquid level of the vertical test Dewar 001;

The vertical test Dewar 001 is provided with a safety valve 004 for taking off when the pressure in the vertical test Dewar 001 reaches the take-off pressure threshold;

The vertical test Dewar 001 is provided with a bursting disc 006 for blasting the top of the vertical test Dewar 001 when the pressure in the vertical test Dewar 001 reaches the set burst pressure threshold;

The vertical test Dewar 001 is provided with a gas return vaporizer 007, one end of which is connected to the vertical test Dewar 001 through a cryogenic pipeline, and the other end is connected to the helium recovery airbag 010 through a first normal temperature pipeline for the The low-temperature helium in the vertical test Dewar 001 is recovered and heated to room temperature and then input to the helium recovery airbag 010; the first normal temperature pipeline includes two parallel branches, and the first branch is provided with a safety relief valve 009 , used for rapid pressure relief; the second branch is provided with a pressure control valve 008 for controlling the pressure of liquid helium in the vertical test Dewar 001;

The second normal temperature pipeline is a current lead return gas pipeline, one end of which is connected to the gas outlet of the current lead end of the high-field superconducting magnet, and the other end is connected to the gas outlet of the gas return vaporizer, and the second normal temperature pipeline is provided with a current lead flow controller 013, the current lead flow controller is used to control the cold helium flow of the cooling current lead, so that the current lead temperature reaches the working temperature zone, and the helium of the second normal temperature pipeline and the helium of the first normal temperature pipeline are at the outlet of the gas return vaporizer 007 Confluence, return to the helium recovery airbag 010; the vertical test Dewar 001 is provided with a liquid injection port 005 for injecting liquid nitrogen or liquid helium into the vertical test Dewar 001;

The vertical test Dewar 001 is provided with an evacuation port 011 and a heater 015 for discharging nitrogen or connecting normal temperature nitrogen through the evacuation port 011 to discharge liquid nitrogen from the liquid injection port 005 in reverse.

Further, the top flange of the vertical test Dewar 001 is used to suspend the high-field superconducting magnet to be measured, so that it is immersed in liquid helium.

Further, the take-off pressure threshold is 1.5 bara; the burst pressure threshold is 2 bara; when the pressure reaches 1.3 bar, the safety relief valve 009 is fully opened.

Further, the pressure control range of the pressure control valve 008 is 1 bar-1.3 bara.

Further, the anti-radiation screen 002 includes 7 layers of copper screens distributed vertically.

Further, when the safety relief valve 009 is opened, the liquid injection port 005 injects liquid helium into the vertical test Dewar 001, and the safety relief valve 009 is closed after the liquid injection is stopped.

The low-temperature vertical testing system for high-field superconducting magnets of the present utility model includes vertical testing Dewar 001, Dewar inner radiation shield 002, pressure sensor 003, safety valve 004, liquid injection port 005, bursting disc 006, return gas vaporizer 007 , Pressure Control Valve 008, Safety Relief Valve 009, Helium Recovery Airbag 010, Evacuation Port 011, Current Lead Flow Controller 013, Valve 012, Liquid Level Gauge 014, Dewar Helium Heater 015, etc., Valve 012 The opening degree is automatically controlled according to the flow rate set by the current lead flow controller 13 .

In a preferred embodiment of the present invention, the pressure 003 in the vertical test Dewar is controlled by the pressure control valve 008, and the pressure range can be precisely controlled to be 1 bara-1.3 bara according to the test requirements, and the pressure is the saturated vapor pressure of liquid helium , the lower the pressure, the lower the temperature, which is beneficial to the magnet test, but if the pressure is too low, the flow of cold helium gas in the cooling current lead will be reduced, and then the cooling effect will be lost and the temperature will rise. Helium pressure.

In a preferred embodiment of the present invention, the cold helium return gas is heated to room temperature through an external vaporizer 007 and returned to the helium recovery airbag 010. The vaporizers are connected in parallel to reduce pressure loss and facilitate vertical testing of the pressure in the Dewar. Emissions when elevated under abnormal conditions.

In a preferred embodiment of the present invention, a safety relief valve 009 is provided, and its set pressure is 1.3 bara, which is greater than the pressure or the valve of the safety relief valve 009 is opened when the pressure is greater than the pressure or the magnet quench interlock is triggered. Larger for quick pressure relief. At the same time, it has a manual function, which can be manually turned on during system debugging.

In a preferred embodiment of the present invention, a mechanical safety valve 004 and a bursting disc 006 are provided to protect the vertical test Dewar under extreme conditions.

In a preferred embodiment of the present utility model, a superconducting liquid level gauge 014 is installed in the vertical test Dewar to observe the liquid helium level inside the vertical test Dewar. After the liquid level reaches a certain height, the liquid helium level exceeds Magnet suspension height before power-up test can be performed.

In a preferred embodiment of the present utility model, the liquid helium storage dewar of the liquid helium refrigerator is connected to the liquid helium refrigerator through the liquid injection port 005, and the vertical test Dewar is provided, the liquid injection is stopped during the test, and the liquid injection valve maintains a small opening to prevent the infusion pipe. When the temperature rises, when the liquid helium level decreases and liquid helium needs to be replenished, open the opening of the liquid injection valve to fill the vertical test Dewar with liquid to the required liquid level.

In a preferred embodiment of the present invention, a layer of liquid nitrogen cold shield is arranged in the vacuum interlayer around the vertical test Dewar, and liquid nitrogen is introduced before the vertical test Dewar is cooled, so that the cooling of the liquid nitrogen is maintained at the level of the liquid nitrogen. temperature zone to reduce the heat leakage of liquid helium inside the vertical test Dewar to room temperature.

In a preferred embodiment of the present invention, due to the large cold mass of the high-field superconducting magnet, the consumption of liquid helium by simply cooling with liquid helium is very large. After the liquid is accumulated, high-pressure normal temperature nitrogen gas is introduced, and the liquid nitrogen is discharged from the infusion pipe extending into the bottom of the vertical test dewar until the temperature sensor at the bottom rises above the saturated liquid nitrogen temperature zone, completing the magnet from normal temperature to near the liquid nitrogen temperature zone. Cool down.

In a preferred embodiment of the present utility model, temperature sensors are arranged on the pendant near the bottom of the vertical test Dewar, the superconducting section of the current lead and the normal temperature end.

Compared with the prior art, the high-field superconducting magnet low-temperature vertical test system provided by the present invention has the following advantages:

First, the pressure control valve 008 is set up to test the pressure control of the liquid helium in the Dewar vertically, which realizes the precise control of the pressure, and the pressure control precision is high;

Second, set up a large-diameter safety relief valve 009, which is used for pressure relief after rapid pressure rise or quench during magnet test, so as to achieve the purpose of safe operation;

Third, set the return gas vaporizer 007 to heat the cold helium gas discharged from the vertical test dewar to normal temperature to prevent the main return gas pipeline from freezing and frosting along the way;

Fourth, the return gas is connected to the helium recovery device, and is recycled after being purified by the purification system.

Description of drawings

FIG. 1 is a schematic diagram of a low-temperature vertical testing system for high-field superconducting magnets.

Detailed ways

In order to explain the technical solutions of the present invention more clearly, the embodiments of the present invention will be further described below with reference to the accompanying drawings. Obviously, the embodiments in the following drawings are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

Referring to FIG. 1, the first embodiment of the present utility model provides a low-temperature vertical test system 000 for high-field superconducting magnets, including a vertical test Dewar 001, a Dewar inner radiation shield 002 is suspended at its inner top, and a liquid level gauge tooling is used Hang the liquid level gauge 014, and place the liquid helium heater 015 at the bottom. There is an end cover flange on the top of the vertical test Dewar 001, and holes are opened on the flange. Install the pressure sensor 003, safety valve 004, liquid injection port 005, blasting Auxiliary components such as sheet 006 and exhaust port 011. The main return gas pipeline, that is, the low temperature pipeline return gas enters the helium recovery air bag 010 through the return gas vaporizer 007, the parallel pressure control valve 008 and the safety relief valve 009, and the helium gas return gas of the cooling current lead enters through the current lead flow controller 013 Helium Recovery Bag 010. In this embodiment, the high-field superconducting magnet to be tested is immersed in liquid helium at a temperature of 4.2K for power-on testing, and liquid helium is added through the liquid injection port 005, and the liquid helium is stored in the vertical test test Dewar 001 Inside, pressure sensor 003 and liquid level gauge 014 are used to monitor the pressure and liquid level in the vertical test dewar. The pressure control valve 008 controls the pressure in the vertical test dewar according to the pressure setting, and opens the valve when the pressure rises. , otherwise close the opening.

In this embodiment, the set pressure of the safety relief valve 009 is 1.3 bara, and the valve is opened when the pressure is greater than this pressure or the magnet quench interlock is triggered for rapid pressure relief. Same as the pressure control valve, the helium gas flowing through the valve is first heated to room temperature through the vaporizer 007, and then enters the helium gas recovery bag after flowing through the valve. In addition, there is safety valve 004 with a take-off pressure of 1.5bara. After the safety valve 004 takes off, it will release the pressure to ensure that the pressure in the vertical test Dewar does not continue to rise. Interlocking; when the high-field superconducting magnet is tested, the pressure is greater than 1.3bara, and the safety relief valve 009 cannot be released after opening. When the pressure reaches 1.5bara, the safety valve 004 is opened. If it continues to rise to 2bara, the bursting disc 006 Blast, the helium is vented to atmosphere to keep the vertical test dewar safe.

In this embodiment, during the use of the high-field superconducting magnet low-temperature vertical test system, the liquid nitrogen cold shield must be cooled first. After the nitrogen temperature is reached, the liquid injection is stopped. After full soaking, the liquid nitrogen is discharged with high-pressure normal temperature nitrogen gas until the bottom temperature sensor is greater than the liquid nitrogen temperature zone to ensure that the liquid nitrogen is completely discharged. In the present application, liquid nitrogen is used for pre-cooling to reduce the consumption of liquid helium.

In the embodiment, after the liquid nitrogen is completely discharged, the vertical test Dewar is replaced with helium by a vacuum pump through the emptying port 011, and the safety relief valve 009 is manually opened after the full replacement, so that the vertical test Dewar and the helium recovery airbag 010 are used. Unicom, add liquid helium through the liquid injection port 005 until the liquid helium level reaches the level required for the magnet test.

In this embodiment, after the liquid injection is stopped, the safety relief valve 009 is closed to adjust to the automatic interlock state, the pressure of the liquid helium in the vertical test Dewar is controlled by the pressure control valve 008, and the current lead flow controller 013 is adjusted at the same time so that the current lead When the temperature reaches the working temperature range, the superconducting magnet to be tested has the test conditions.

In this embodiment, a quench will be caused during the magnet power-on test process, the heat generated will consume liquid helium and bring about an increase in pressure. The pressure control valve 008 automatically adjusts the pressure. Relief valve 009 quickly relieves pressure. If too much liquid helium is consumed, and the liquid helium level does not meet the level required for the magnet test, the refill valve can be opened to replenish liquid helium.

In this embodiment, after the test, the remaining liquid helium needs to be evaporated into helium into the helium recovery airbag 010, the liquid nitrogen injection into the liquid nitrogen cold shield is stopped, the liquid helium heater 015 in the Dewar is turned on, and the liquid helium is evaporated through the heater . When the temperature at the bottom of the dewar is higher than the temperature of liquid helium, the connection valve with the helium recovery airbag can be closed, the emptying port 011 can be opened, and the rewarming of the vertical test dewar can be accelerated by blowing in nitrogen at room temperature.

The above is only used to illustrate the technical solution of the present invention, not to limit the present invention. Although the above embodiments have been described in detail, those skilled in the art can do so without departing from the scope of the technical solution. Within the scope of the present invention, substitutions, modifications and simple changes may be made, but these substitutions, modifications and simple changes do not make the essence of the corresponding technical solutions depart from the scope of the present invention.

Claims (6)

1. a high-field superconducting magnet low temperature vertical test system, is characterized in that, comprises: The vertical test Dewar (001) is used to store the liquid helium for the vertical test of the high-field superconducting magnet, and a radiation protection screen (002) is arranged above the liquid helium surface, and the radiation protection screen (002) is used to reduce the liquid helium heat transfer with the top flange of the vertical test dewar (001); The vertical test Dewar (001) is provided with a pressure sensor (003) for monitoring the internal pressure of the vertical test Dewar (001), a liquid level for monitoring the internal liquid level of the vertical test Dewar (001) meter(014); The vertical test Dewar (001) is provided with a safety valve (004) for taking off when the pressure in the vertical test Dewar (001) reaches a take-off pressure threshold; The vertical test Dewar (001) is provided with a bursting disc (006), which is used for the vertical test Dewar (001) when the pressure in the vertical test Dewar (001) reaches a set burst pressure threshold. ) blasting at the top; The vertical test Dewar (001) is provided with a gas return vaporizer (007), one end of which is connected to the vertical test Dewar (001) through a cryogenic pipeline, and the other end is connected to the helium recovery airbag (010) through the first normal temperature pipeline. ) connection, for recovering and heating the low-temperature helium in the vertical test Dewar (001) to the helium recovery airbag (010) after being heated to room temperature; the first normal temperature pipeline includes two parallel branches , the first branch is provided with a safety relief valve (009) for rapid pressure relief; the second branch is provided with a pressure control valve (008) for controlling the liquid helium pressure in the vertical test Dewar (001) ; The second normal temperature pipeline is a current lead return pipeline, one end of which is connected to the gas outlet of the current lead end of the high-field superconducting magnet, and the other end is connected to the gas outlet of the gas return vaporizer (007), and the second normal temperature pipeline is provided with a current lead The flow controller (013), the current lead flow controller (013) is used to control the cold helium flow of the cooling current lead, so that the current lead temperature reaches the working temperature zone, and the helium of the second normal temperature pipeline and the first normal temperature pipeline are The helium gas is combined at the outlet of the return gas vaporizer (007) and returned to the helium recovery air bag (010); The vertical test Dewar (001) is provided with a liquid injection port (005) for injecting liquid nitrogen or liquid helium into the vertical test Dewar (001); The vertical test Dewar (001) is provided with an evacuation port (011) and a heater (015) for discharging nitrogen gas or connecting the normal temperature nitrogen gas through the evacuation port (011), and transferring the liquid nitrogen from the liquid injection port (005) ) reverse discharge. 2. high-field superconducting magnet low-temperature vertical test system according to claim 1, is characterized in that, the top flange of described vertical test Dewar (001) is used for suspending high-field superconducting magnet to be measured, and makes it soak in liquid helium. 3. The low-temperature vertical test system for high-field superconducting magnets according to claim 1, characterized in that, the threshold value of the take-off pressure is 1.5bara; the threshold value of the burst pressure is 2bara; when the pressure reaches 1.3bar, the safety leakage The discharge valve (009) is fully open. 4. The high-field superconducting magnet low-temperature vertical testing system according to claim 3, wherein the pressure control range of the pressure control valve (008) is 1 bar-1.3 bara. 5. The low-temperature vertical testing system for high-field superconducting magnets according to claim 1, wherein the radiation protection screen (002) comprises a vertically distributed 7-layer copper screen. 6. The high-field superconducting magnet low-temperature vertical testing system according to claim 1, wherein when the safety relief valve (009) is opened, the liquid injection port (005) is directed to the vertical testing Dewar Liquid helium is injected into (001), and the safety relief valve (009) is closed after the liquid injection is stopped.

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