阅读说明：本技术 一种超导磁体低温系统 (Superconducting magnet cryogenic system ) 是由 袁金辉 莫耀敏 乐志良 于 2021-09-15 设计创作，主要内容包括：本发明公开了一种超导磁体低温系统,包括冷头组件、排气管以及连接于所述冷头组件和所述排气管之间的旁通管,还包括设于所述冷头组件上、用以检测所述冷头组件的温度的温度检测器；设于所述排气管上、用以检测所述排气管内气体的压力的压力检测器；设于所述旁通管上、用以控制所述旁通管打开和关闭的控制阀；与所述温度检测器、所述压力检测器和所述控制阀相连并根据所述温度检测器和所述压力检测器二者的检测结果控制所述控制阀开闭的监控单元。上述超导磁体低温系统通过在旁通管上设置电磁阀,并根据温度检测器和压力检测器二者的检测结果,以智能关闭和打开电磁阀,从而可以减少冷头故障时的液氦挥发率,进而可以降低超导磁体的使用成本。(The invention discloses a superconducting magnet low-temperature system which comprises a cold head assembly, an exhaust pipe, a bypass pipe and a temperature detector, wherein the bypass pipe is connected between the cold head assembly and the exhaust pipe; the pressure detector is arranged on the exhaust pipe and used for detecting the pressure of the gas in the exhaust pipe; the control valve is arranged on the bypass pipe and used for controlling the bypass pipe to be opened and closed; and the monitoring unit is connected with the temperature detector, the pressure detector and the control valve and controls the control valve to be opened and closed according to the detection results of the temperature detector and the pressure detector. According to the superconducting magnet low-temperature system, the electromagnetic valve is arranged on the bypass pipe, and the electromagnetic valve is intelligently closed and opened according to the detection results of the temperature detector and the pressure detector, so that the liquid helium volatilization rate during cold head failure can be reduced, and the use cost of the superconducting magnet can be reduced.)

1. A superconducting magnet cryogenic system comprising a coldhead assembly, an exhaust pipe (6), and a bypass pipe (8) connected between the coldhead assembly and the exhaust pipe (6), characterized by further comprising:

the temperature detector (101) is arranged on the cold head assembly and used for detecting the temperature of the cold head assembly;

a pressure detector (106) provided in the exhaust pipe (6) and configured to detect a pressure of the gas in the exhaust pipe (6);

a control valve (108) arranged on the bypass pipe (8) and used for controlling the opening and the closing of the bypass pipe (8);

and the monitoring unit (105) is connected with the temperature detector (101), the pressure detector (106) and the control valve (108) and controls the control valve (108) to open and close according to the detection results of the temperature detector (101) and the pressure detector (106).

2. A superconducting magnet cryogenic system according to claim 1, further comprising a signal wire connection (103), the temperature detector (101) being electrically connected to the signal wire connection (103) by a temperature signal wire (102), the signal wire connection (103) being electrically connected to the monitoring unit (105) by a signal wire harness (104).

3. A superconducting magnet cryogenic system according to claim 2, wherein the signal wire joint (103) is fixedly connected to an outer side wall of the exhaust pipe (6).

4. A superconducting magnet cryogenic system according to claim 2, further comprising a 4K vessel (2) and a heater (110) provided on an inner side wall of the 4K vessel (2), the heater (110) being electrically connected to the signal line connector (103) via a heating signal line (111).

5. A superconducting magnet cryogenic system according to claim 1, wherein the control valve (108) is a solenoid valve, the solenoid valve being electrically connected to the monitoring unit (105) by a control harness (109).

6. Superconducting magnet cryogenic system according to claim 1, wherein the pressure detector (106) is electrically connected with the monitoring unit (105) by a pressure signal line (107).

7. A superconducting magnet cryogenic system according to any of claims 1 to 6, wherein the coldhead assembly comprises a coldhead vessel (11), a coldhead primary (12), a coldhead secondary (13) and a condenser (14) mounted on the coldhead secondary (13), the temperature detector (101) being provided on the coldhead vessel (11), the coldhead primary (12), the coldhead secondary (13) or the condenser (14).

8. A superconducting magnet cryogenic system according to claim 7, wherein the temperature detector (101) is a temperature probe that is detachably connected to an outer sidewall of the coldhead stage (13).

9. Superconducting magnet cryogenic system according to claim 7, wherein the monitoring unit (105) is provided with a rechargeable battery.

10. Superconducting magnet cryogenic system according to claim 7, characterized in that the bypass conduit (8) is a stainless steel bellows to which the control valve (108) is detachably connected.

Technical Field

The invention relates to the technical field of superconducting magnets, in particular to a superconducting magnet cryogenic system.

Background

As shown in fig. 1, in a conventional MRI superconducting magnet system, one end of the bypass pipe 8 communicates with the coldhead tank 11 through a mounting flange 10 of the coldhead 9, and the other end communicates with the exhaust pipe 6. When the cold head 9 works normally, the first-stage cold head 12 cools the cold screen 3, the temperature of the cold screen 3 is maintained in a 50K temperature area, the second-stage cold head 13 is provided with a condenser 14, and after the liquid helium 1 in the 4K container 2 is heated and evaporated to form helium gas 4, the helium gas is condensed into the liquid helium 1 again on the condenser 14 of the second-stage cold head 13, so that the zero volatilization of the liquid helium 1 of the magnet is realized.

However, when the cold head 9 is stopped, the cold head first stage 12 and the cold head second stage 13 are both changed from the cold source to the heat source, the temperature of the cold screen 3 begins to rise, the cold head second stage 13 and the condenser 14 become the heat source, the temperature is quickly higher than 4.2K, at this time, after the liquid helium 1 in the 4K container 2 is evaporated, the liquid helium cannot be condensed again to be liquid, the 4K container 2 is continuously pressurized until the safety valve 7 is opened, and the helium 4 is discharged through the exhaust pipe 6; meanwhile, after the first cold head 12 and the second cold head 13 become heat sources, heated hot helium gas around the first cold head rises under the action of buoyancy lift, flows to the neck pipe 5 through the bypass pipe 8, and then flows into the 4K container 2 through the neck pipe 5, so that the hot helium gas flows into the 4K container 2, the hot helium gas and the cold helium gas in the 4K container 2, the liquid helium 1 and the inner surface of the 4K container 2 can carry out convective heat exchange, the volatilization of the liquid helium 1 can be accelerated in the process, and especially the liquid helium 1 is obviously accelerated to volatilize before the pressure in the magnet is increased until the safety valve 7 is opened. Thus, when the coldhead 9 is stopped, the liquid helium 1 is consumed more, which increases the use cost of the superconducting magnet.

Therefore, how to avoid the problem that the superconducting magnet consumes large liquid helium when the cold head is stopped is a technical problem that needs to be solved by those skilled in the art at present.

Disclosure of Invention

The invention aims to provide a superconducting magnet low-temperature system which can effectively reduce the loss of liquid helium when a cold head stops, thereby reducing the use cost of the superconducting magnet.

In order to achieve the above object, the present invention provides a superconducting magnet cryogenic system, including a cold head assembly, an exhaust pipe, and a bypass pipe connected between the cold head assembly and the exhaust pipe, further including:

the temperature detector is arranged on the cold head assembly and used for detecting the temperature of the cold head assembly;

the pressure detector is arranged on the exhaust pipe and used for detecting the pressure of the gas in the exhaust pipe;

the control valve is arranged on the bypass pipe and used for controlling the bypass pipe to be opened and closed;

and the monitoring unit is connected with the temperature detector, the pressure detector and the control valve and controls the control valve to be opened and closed according to the detection results of the temperature detector and the pressure detector.

Optionally, the temperature monitoring device further comprises a signal wire connector, the temperature detector is electrically connected with the signal wire connector through a temperature signal wire, and the signal wire connector is electrically connected with the monitoring unit through a signal wire harness.

Optionally, the signal line connector is fixedly connected to an outer side wall of the exhaust pipe.

Optionally, the heating device further comprises a 4K container and a heater arranged on the inner side wall of the 4K container, wherein the heater is electrically connected with the signal wire joint through a heating signal wire.

Optionally, the control valve is an electromagnetic valve, and the electromagnetic valve is electrically connected with the monitoring unit through a control wire harness.

Optionally, the pressure detector is electrically connected to the monitoring unit through a pressure signal line.

Optionally, the cold head assembly comprises a cold head container, a cold head first stage, a cold head second stage and a condenser mounted on the cold head second stage, and the temperature detector is arranged on the cold head container, the cold head first stage, the cold head second stage or the condenser.

Optionally, the temperature detector is a temperature probe detachably connected to the outer side wall of the secondary stage of the cold head.

Optionally, the monitoring unit is provided with a rechargeable battery.

Optionally, the bypass pipe is a stainless steel bellows, and the control valve is detachably connected to the stainless steel bellows.

Compared with the background art, the superconducting magnet cryogenic system provided by the embodiment of the invention comprises a cold head assembly, an exhaust pipe and a bypass pipe, wherein the bypass pipe is connected between the cold head assembly and the exhaust pipe, and gas in the cold head assembly can enter the exhaust pipe through the bypass pipe; furthermore, the system also comprises a temperature detector, a pressure detector, a control valve and a monitoring unit, wherein the temperature detector is arranged on the cold head assembly and is used for detecting the temperature of the cold head assembly; the pressure detector is arranged on the exhaust pipe and is used for detecting the pressure of the gas in the exhaust pipe; the control valve is arranged on the bypass pipe, and the control unit is used for controlling the opening and closing of the bypass pipe; the monitoring unit is connected with the temperature detector, the pressure detector and the control valve, and the monitoring unit can control the control valve to open and close according to the detection results of the temperature detector and the pressure detector.

Specifically, the monitoring unit judges according to the detection results of the temperature detector and the pressure detector that when the cold head of the cold head assembly is shut down (the data detected by the temperature detector is higher than a preset temperature value) and the safety valve is not opened (the data detected by the pressure detector continuously rises), the monitoring unit sends an instruction to the control valve to close the control valve so as to prevent hot helium gas in a cold head container of the cold head assembly from flowing into a neck pipe and a 4K container communicated with the exhaust pipe through a bypass pipe, so that the volatilization of liquid helium when the cold head is shut down for a short time can be reduced; the monitoring unit judges according to the detection results of the temperature detector and the pressure detector that the safety valve is opened (the data detected by the pressure detector is not increased and is reduced slightly) and the cold head is still in a shutdown state (the data detected by the temperature detector is higher than a preset temperature value), the monitoring unit sends an instruction to the control valve to enable the control valve to be opened again, so that a small part of helium in the 4K container passes through the cold head container and the bypass pipe of the cold head assembly and is exhausted into the air through the exhaust pipe and the safety valve, and the circulation path can cool the first stage and the second stage of the cold head assembly, so that the volatilization of liquid helium when the cold head is shut down for a long time can be reduced; when the monitoring unit judges through the temperature value of the cold head subassembly that gathers and learns, the cold head has started work, and the monitoring unit sends the instruction and gives the control valve, makes the control valve be in the open mode.

Therefore, compared with the traditional method that liquid helium is volatilized in an accelerated mode when the cold head is stopped, the superconducting magnet low-temperature system provided by the embodiment of the invention has the advantages that the control valve is arranged on the bypass pipe, and the control valve is intelligently closed and opened according to the detection results of the temperature detector and the pressure detector, so that the volatilization rate of the liquid helium when the cold head is in failure can be reduced, and the use cost of the superconducting magnet can be further reduced.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a schematic diagram of a superconducting magnet in the prior art;

fig. 2 is a schematic connection diagram of a superconducting magnet cryogenic system solenoid valve provided by the embodiment of the invention when the solenoid valve is closed;

fig. 3 is a schematic connection diagram of a superconducting magnet cryogenic system solenoid valve provided by the embodiment of the invention when the solenoid valve is opened.

Wherein:

1-liquid helium, 2-4K container, 3-cold screen, 4-helium, 5-neck tube, 6-exhaust tube, 7-safety valve, 8-by-pass tube, 9-cold head, 10-mounting flange, 11-cold head container, 12-cold head first stage, 13-cold head second stage and 14-condenser;

101-temperature detector, 102-temperature signal line, 103-signal line joint, 104-signal line bundle, 105-monitoring unit, 106-pressure detector, 107-pressure signal line, 108-control valve, 109-control line bundle, 110-heater, 111-heating signal line.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The core of the invention is to provide a superconducting magnet low-temperature system which can effectively reduce the loss of liquid helium when a cold head is shut down, thereby reducing the use cost of the superconducting magnet.

In order that those skilled in the art will better understand the disclosure, the invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

It should be noted that the following directional terms such as "upper end, lower end, left side, right side" and the like are defined based on the drawings of the specification.

Referring to fig. 2 and 3, fig. 2 is a schematic connection diagram illustrating a superconducting magnet cryogenic system solenoid valve according to an embodiment of the present invention when closed; fig. 3 is a schematic connection diagram of a superconducting magnet cryogenic system solenoid valve provided by the embodiment of the invention when the solenoid valve is opened.

The superconducting magnet low-temperature system provided by the embodiment of the invention comprises a cold head assembly, an exhaust pipe 6 and a bypass pipe 8, wherein the cold head assembly comprises a cold head 9, a mounting flange 10, a cold head container 11, a cold head primary stage 12 and a cold head secondary stage 13; the bypass pipe 8 is connected between the cold head container 11 and the exhaust pipe 6, one end of the bypass pipe 8 penetrates through the mounting flange 10 to be communicated with the cold head container 11, and the other end of the bypass pipe 8 is communicated with the exhaust pipe 6; the gas in the coldhead tank 11 can enter the gas outlet pipe 6 through the bypass pipe 8.

Further, the system further comprises a temperature detector 101, a pressure detector 106, a control valve 108 and a monitoring unit 105, wherein the temperature detector 101 is arranged on the cold head assembly, and the temperature detector 101 is used for detecting the temperature of the cold head assembly; the pressure detector 106 is provided on the exhaust pipe 6, and the pressure detector 106 is used for detecting the pressure of the gas in the exhaust pipe 6; a control valve 108 is provided on the bypass pipe 8, the control unit being adapted to control the opening and closing of the bypass pipe 8; the monitoring unit 105 is connected to the temperature detector 101, the pressure detector 106, and the control valve 108, and the monitoring unit 105 can control the control valve 108 to open and close according to the detection results of both the temperature detector 101 and the pressure detector 106.

The bypass pipe 8 is a stainless steel bellows, and the control valve 108 is detachably connected to the stainless steel bellows.

Specifically, when the monitoring unit 105 judges that the cold head 9 of the cold head assembly is stopped (the data detected by the temperature detector 101 is higher than the preset temperature value) and the safety valve 7 is not opened (the data detected by the pressure detector 106 continuously rises) according to the detection results of the temperature detector 101 and the pressure detector 106, the monitoring unit 105 sends an instruction to the control valve 108 to close the control valve 108 so as to prevent the hot helium gas 4 in the cold head container 11 of the cold head assembly from flowing into the neck pipe 5 and the 4K container 2 communicated with the exhaust pipe 6 through the bypass pipe 8, so that the volatilization of the liquid helium 1 when the cold head 9 is stopped for a short time can be reduced; the monitoring unit 105 judges according to the detection results of the temperature detector 101 and the pressure detector 106 that the safety valve 7 is opened (the data detected by the pressure detector 106 is not increased any more and is reduced a little) and the cold head 9 is still in the shutdown state (the data detected by the temperature detector 101 is higher than the preset temperature value), the monitoring unit 105 sends an instruction to the control valve 108 to reopen the control valve 108, so that a small part of helium gas 4 in the 4K container 2 passes through the cold head container 11 and the bypass pipe 8 of the cold head assembly and is discharged into the air through the exhaust pipe 6 and the safety valve 7, and the circulation path can cool the first stage 12 and the second stage 13 of the cold head assembly, thereby reducing the volatilization of liquid helium 1 when the cold head 9 is shut down for a long time; when the monitoring unit 105 judges that the cold head 9 is started up to work through the collected temperature value of the cold head assembly, the monitoring unit 105 sends an instruction to the control valve 108 to enable the control valve 108 to be in an open state.

Due to the conventional zero-volatilization magnet soaked by the liquid helium 1, when the cold head 9 is stopped, the consumption of the liquid helium 1 is large, so that the use cost of the superconducting magnet is increased. Particularly, the fault of short-time power failure (within 30 minutes) of a hospital often occurs, and the traditional cryogenic system cannot effectively reduce the loss of the liquid helium 1 of the fault.

Compared with the traditional method that the liquid helium 1 is volatilized in an accelerated manner when the cold head 9 is stopped, the superconducting magnet low-temperature system provided by the embodiment of the invention has the advantages that the control valve 108 is arranged on the bypass pipe 8, and the control valve 108 is intelligently closed and opened according to the detection results of the temperature detector 101 and the pressure detector 106, so that the volatilization rate of the liquid helium 1 when the cold head 9 is in failure can be reduced, and the use cost of the superconducting magnet can be further reduced.

In order to facilitate the electrical connection between the temperature detector 101 and the monitoring unit 105, the temperature detector 101 and the signal line connector 103 are electrically connected through a temperature signal line 102, and the signal line connector 103 and the monitoring unit 105 are electrically connected through a signal wire harness 104.

Of course, the signal line connector 103 is fixed to the outer wall of the exhaust pipe 6 as needed.

In addition, the system also comprises a 4K container 2 and a heater 110 arranged on the inner side wall of the 4K container 2, wherein the liquid helium 1 in the 4K container 2 is heated by the heater 110 and then is evaporated to form helium gas 4, and then is condensed to the liquid helium 1 again on the condenser 14 of the secondary cold head 13.

To facilitate monitoring of the heating temperature in the 4K container 2, the heater 110 is electrically connected to the signal line connector 103 through a heating signal line 111. In this way, the monitoring unit 105 can monitor the heating temperature of the heater 110 in the 4K container 2 based on the monitoring of the temperature detector 101, which is beneficial to improving the accuracy of the system control.

Preferably, the control valve 108 may be an electromagnetic valve, and the electromagnetic valve is electrically connected to the monitoring unit 105 through a control harness 109.

The pressure detector 106 and the monitoring unit 105 are electrically connected by a pressure signal line 107.

On the basis of the above, since the coldhead assembly includes the coldhead container 11, the coldhead first stage 12, the coldhead second stage 13, and the condenser 14 mounted on the coldhead second stage 13, the temperature detector 101 may be provided on the coldhead container 11, the coldhead first stage 12, the coldhead second stage 13, or the condenser 14.

Herein, for the convenience of disassembly and assembly, the temperature detector 101 is embodied as a temperature probe, and the temperature probe is detachably connected to the outer side wall of the cold head secondary stage 13. Thus, the temperature detected by the temperature probe is the temperature of the cold head second stage 13 in the cold head assembly.

In addition, the monitoring unit 105 is also equipped with a rechargeable battery, and when the external power supply of the monitoring unit 105 is interrupted, the rechargeable battery can supply power to the monitoring unit 105 to ensure the normal operation of the monitoring unit 105, such as collecting temperature and pressure signals and controlling the opening of the solenoid valve.

The control principle of the superconducting magnet cryogenic system is described in detail below.

As shown in fig. 2, when the coldhead 9 is stopped and the pressure in the 4K container 2 does not reach the opening pressure of the safety valve 7, a control valve 108 is attached to the bypass pipe 8 and a temperature detector 101 is attached to the coldhead stage 13 in order to reduce the volatilization of the liquid helium 1. Because the cold head 9 is shut down, the temperature of the second cold head stage 13 is higher than 4.2K, when the temperature detector 101 monitors that the temperature of the second cold head stage 13 is higher than 4.2K, the temperature detector 101 transmits a temperature signal to the monitoring unit 105 through the temperature signal line 102, the signal line connector 103 and the signal wiring harness 104, the monitoring unit 105 can judge that the cold head 9 is in a shut-down state, at the moment, the monitoring unit 105 gives an instruction to the electromagnetic valve through controlling the wiring harness 109, and closes the electromagnetic valve to block the hot helium gas 4 in the cold head container 11 from flowing into the 4K container 2 through the bypass pipe 8, so that the convection between the hot helium gas 4 and the 4K container 2 can be inhibited, and further the volatilization of the liquid helium 1 can be reduced.

When the pressure in the 4K vessel 2, as detected by the pressure detector 106, does not rise any more and drops a little, it indicates that the safety valve 7 is opened and the helium gas 4 in the magnet flows through the neck 5, the exhaust pipe 6, the safety valve 7 and is discharged to the atmosphere. The monitoring unit 105 receives the magnet pressure signal collected by the pressure detector 106 through the pressure signal line 107, and can determine that the safety valve 7 has opened by recognizing that the pressure is no longer rising and has slightly dropped. At this point, the monitoring unit 105 will give a command to the solenoid valve and cause the solenoid valve to open, as shown in FIG. 3, so that a small portion of the helium gas 4 in the 4K vessel 2 will pass through the coldhead vessel 11, the bypass line 8, and be vented to atmosphere through the vent line 6 and the relief valve 7. The circulation path cools and cools the first cold head stage 12 and the second cold head stage 13 in the cold head container 11, so that the sensible heat of the cold helium gas 4 is fully utilized, and the volatilization of the liquid helium 1 when the cold head 9 is stopped for a long time can be reduced.

That is, the circulation state of the helium gas 4 in the bypass pipe 8 is controlled by the solenoid valve. When the monitoring unit 105 collects the temperature of the cold head secondary 13 in the magnet and the pressure in the 4K vessel 2, it is determined whether the solenoid valve needs to be closed or opened by a set value. When the monitoring unit 105 judges that the cold head 9 is stopped and the safety valve 7 is not opened, an instruction is immediately sent to the electromagnetic valve to close the electromagnetic valve, so that the hot helium gas 4 in the cold head container 11 is prevented from flowing into the neck pipe 5 and the 4K container 2 through the bypass pipe 8, and the volatilization of the liquid helium 1 when the cold head 9 is stopped for a short time is reduced; when the monitoring unit 105 judges that the safety valve 7 is opened and the cold head 9 is in a stop state through a signal transmitted by the pressure detector 106, the monitoring unit 105 sends an instruction to the electromagnetic valve to reopen the electromagnetic valve, so that the volatilization of the liquid helium 1 when the cold head 9 is stopped for a long time is reduced; when the monitoring unit 105 judges through the collected secondary cold head 13 temperature value that the cold head 9 is started to work, the monitoring unit 105 sends an instruction to the electromagnetic valve to make the electromagnetic valve in an open state.

It is noted that, in this specification, relational terms such as first and second, and the like are used solely to distinguish one entity from another entity without necessarily requiring or implying any actual such relationship or order between such entities.

The superconducting magnet cryogenic system provided by the invention is described in detail above. The principles and embodiments of the present invention are explained herein using specific examples, which are provided only to help understand the concepts of the present invention and the core concepts thereof. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.