Helium circulation control system and method

Abstract

The invention discloses a helium circulation system which comprises a helium compressor, a filter, a helium buffer tank and a recovery air bag. The load low-pressure gas return pipeline is connected with a gas inlet of the helium compressor, a gas outlet of the helium compressor is connected with the filter, and an outlet end of the filter is connected with the load high-pressure gas inlet pipeline; the load high-pressure air inlet pipeline and the load low-pressure air return pipeline are connected through a backflow pipeline, and a helium buffer tank and a recovery air bag are connected to the backflow pipeline side by side; the air outlet end of the buffer tank is connected with a loading valve, the air inlet end of the recovery air bag is connected with an unloading valve, and the backflow pipeline is connected with a bypass valve; the helium buffer tank only outputs circulating helium in a one-way mode, when the pressure of the high-pressure side is too high, the unloading valve controls exhausted gas to enter the recycling air bag, and the high pressure is kept in a stable state. The invention further discloses a helium circulation method. The device has the beneficial effects that the problem of impurity-containing pollution of gas of the helium pre-cooling system is solved, and gas pressure fluctuation is effectively inhibited.

Description

Technical Field

[0001] The present invention relates to the technical field of helium pre-cooling, and in particular to a helium circulation control system. Background Art

[0002] With the advancement of science and technology, helium pre-cooling systems have gained widespread application in scientific research and other fields. During large-scale superconducting magnet testing, helium pre-cooling systems maintain low temperatures of 300K to 80K. Helium compressors and gas control panels serve the helium pre-cooling system, providing a stable helium circulation loop. Frequent magnet replacement in superconducting magnet testing systems results in a high concentration of impurities in the circulation space. Complex testing conditions lead to large fluctuations in gas pressure, resulting in a pressure alarm and shutdown of the helium circulation compressor.

[0003] Current pressure relief methods, such as CN117847872B (A Control Method for Fully Automatic Operation of a Helium Compressor System), unload pressure to a buffer tank, potentially causing impurities to enter the high-purity storage tank. Commercially available compressor control systems circulate high-purity helium exceeding 99.999% purity, but are unable to prevent contaminated gas from circulating back into the helium storage tank and contaminating the high-purity helium. These systems also exhibit poor accuracy in responding to pressure fluctuations, and their anti-interference capabilities struggle to meet requirements.

[0004] The information disclosed in this background section is only intended to enhance understanding of the overall background of the invention and should not be considered as an admission or any form of suggestion that the information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0005] The technical problem to be solved by the present invention is how to solve the problem that during the circulation of helium circulating gas, helium containing impurities will be unloaded into a high-purity storage tank, causing the helium storage tank to contaminate a large amount of high-purity helium.

[0006] The present invention solves the above technical problems through the following technical means:

[0007] The helium circulation system includes a helium compressor, a filter, a helium buffer tank, and a recovery air bag; the load low-pressure return air pipeline is connected to the air inlet of the helium compressor, the air outlet of the helium compressor is connected to the filter, and the outlet end of the filter is connected to the load high-pressure air inlet pipeline; the load high-pressure air inlet pipeline and the load low-pressure return air pipeline are connected through a return pipeline, and the helium buffer tank and the recovery air bag are connected side by side on the return pipeline; a loading valve is connected to the air outlet end of the buffer tank, an unloading valve is connected to the air inlet end of the recovery air bag, and a bypass valve is connected to the return pipeline; the helium buffer tank only outputs helium in one direction to the circulating helium. When the pressure on the high-pressure side is too high, the unloading valve controls the exhaust to enter the recovery air bag to maintain the high pressure in a stable state.

[0008] In the present invention, the circulating gas and the helium buffer tank are only communicated in a one-way manner, that is, the helium only enters the circulation system from the helium buffer tank. When pressure fluctuations occur later, the helium will be unloaded and discharged into the recovery air bag, thereby solving the problem of gas contamination in the helium pre-cooling system, effectively suppressing gas pressure fluctuations, and effectively reducing the unloading of high-purity helium to the recovery air bag through a fast and stable system.

[0009] Preferably, a load is further included, the load is connected to the air inlet of the helium compressor through a load low-pressure return air pipeline, and the air outlet end of the filter is connected to the load through a load high-pressure inlet air pipeline.

[0010] Preferably, the filter includes a first-stage oil filter cartridge, a second-stage oil filter cartridge, and an activated carbon filter cartridge connected in sequence, the air inlet end of the first-stage oil filter cartridge is connected to the helium compressor, the bottom of the first-stage oil filter cartridge is connected to the oil return pipe, and the oil return pipe is connected to the oil return port of the helium compressor; the air outlet end of the activated carbon filter cartridge is connected to the load high-pressure air inlet pipe.

[0011] Preferably, a high-pressure side pressure sensor is further connected to the load high-pressure air intake pipe, and a low-pressure side pressure sensor is connected to the return pipe close to the load low-pressure air return pipe.

[0012] Preferably, the system further comprises a control unit, which is electrically connected to the helium compressor, the bypass valve, the unloading valve, and the loading valve.

[0013] The helium circulation method is applicable to the above-mentioned helium circulation system, and the method includes: when the helium compressor is started, the bypass valve and the loading valve jointly control the low-pressure intake pressure; after the low-pressure intake pressure stabilizes, the bypass valve alone controls the low-pressure side pressure; after the high-pressure side pressure reaches a preset pressure and enters a stable state, the loading valve and the unloading valve jointly control the high-pressure side pressure; when the high-pressure side pressure is too high, the unloading valve controls the exhaust to enter the recovery air bag to maintain the high pressure in a stable state.

[0014] Preferably, the helium circulation system includes four states: standby state X0, start-up state X1, running state X2, and shutdown state X3; the helium circulation system operates according to the above four states. When the helium circulation system is in the start-up state X1 or the running state X2, when the control system receives a helium circulation system shutdown command from the host computer, it will switch to the shutdown state X3.

[0015] Preferably, in the standby state X0, the helium compressor is in the closed state, the bypass valve, loading valve, and unloading valve are all in the closed state, the bypass valve is in automatic mode, and the loading valve and unloading valve are in manual mode; when the control unit receives the system startup instruction, the control unit checks the state of the helium compressor 1, whether the low pressure of the helium compressor meets the startup conditions, and whether the high pressure meets the requirements; if all are met, it will switch from the standby state X0 to the startup state X1, and execute the startup process X1 of the helium circulation control system; otherwise, reset the helium compressor system startup instruction and maintain the standby state X0.

[0016] Preferably, in the starting state X1, the helium compressor is started, and the bypass valve is set to the automatic mode, and the loading valve and the unloading valve are set to the automatic mode;

[0017] During the startup process, the helium in the helium buffer tank enters the helium compressor through the load low-pressure return pipe. The helium compressor compresses the helium and passes through the filter. A portion of the high-pressure gas returns to the load low-pressure return pipe through the return pipe to regulate the pressure on the low-pressure side.

[0018] The high-pressure side pressure of the helium circulation control system is increased in a linear or step-wise manner. When the high-pressure side pressure finally reaches the load demand pressure, the helium circulation system enters the operating state X2.

[0019] In operating state X2, by modifying the PID parameters, the loading valve and the unloading valve jointly regulate the high-pressure side pressure; when the high-pressure side pressure is higher than the pressure required by the load, the opening of the unloading valve is increased, and the unloading valve controls the exhaust to enter the recovery airbag.

[0020] Preferably, in shutdown state X3, the bypass valve, loading valve, and unloading valve are set to manual mode; the loading valve is closed, the helium buffer tank stops supplying gas, the unloading valve relieves pressure on the high-pressure side, the helium compressor is turned off, and the bypass valve is closed. If the pressure on the low-pressure side is higher than the set value, the load low-pressure return air pipe is connected to the recovery air bag to release the low-pressure side pressure.

[0021] The advantages of the present invention are:

[0022] In the present invention, the circulating gas and the helium buffer tank are only communicated in a one-way manner, that is, the helium only enters the circulation system from the helium buffer tank. When pressure fluctuations occur later, the helium will be unloaded and discharged into the recovery air bag, thereby solving the problem of gas contamination in the helium pre-cooling system, effectively suppressing gas pressure fluctuations, and effectively reducing the unloading of high-purity helium to the recovery air bag through a fast and stable system.

[0023] In the present invention, the high-pressure side unloading valve is connected to the recovery air bag. During pressure fluctuations, the high-pressure side unloading time and frequency can be controlled by modifying the PID parameters to reduce the waste caused by excessive system gas entering the recovery system due to pressure fluctuations.

[0024] The control system of the present invention has a high degree of modularization and can operate independently to provide high-pressure helium to the load end, or can be combined with the load end control system to be debugged and operated as an integral system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 1 is a schematic structural diagram of a helium circulation control system according to an embodiment of the present invention;

[0026] Figure 2 1 is a schematic structural diagram of a helium circulation control system according to an embodiment of the present invention;

[0027] Numbers in the figure:

[0028] 1. Helium compressor; 11. Load low-pressure return air pipe; 12. High-pressure outlet pipe; 13. Return pipe; 131. Low-pressure side safety valve; 132. Low-pressure side pressure sensor; 133. Low-pressure side pressure measuring manual valve; 134. Bypass valve;

[0029] 2. Filter; 21. First-stage oil filter cartridge; 211. First-stage manual oil drain valve; 212. Oil return valve; 22. Second-stage oil filter cartridge; 221. First liquid level sensor; 222. Second-stage manual oil drain valve; 223. High-pressure side safety valve; 23. Activated carbon filter cartridge;

[0030] 3. Helium buffer tank; 31. Buffer tank outlet pipe; 32. Loading valve; 33. Air supply manual valve; 34. Air supply side pressure sensor; 35. Air supply pressure measurement manual valve;

[0031] 4. Recover the airbag; 41. Unload the pipeline;

[0032] 5. Load; 51. Load high-pressure air intake pipe; 511. First high-pressure side manual valve; 512. High-pressure side pressure sensor; 513. High-pressure side unload manual valve; 514. Load high-pressure side manual valve; 515. Second high-pressure side manual valve. DETAILED DESCRIPTION

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] Example 1:

[0035] like Figure 1As shown, the helium circulation control system includes a helium compressor 1, a filter 2, a helium buffer tank 3, a recovery airbag 4, and a load 5. The load 5 is connected to the air inlet of the helium compressor 1 via a load low-pressure return air pipe 11. The high-pressure air outlet of the helium compressor 1 is connected to the filter 2 via a high-pressure outlet pipe 12. The air outlet end of the filter 2 is connected to the load 5 via a load high-pressure air inlet pipe 51. The load high-pressure air inlet pipe 51 is connected to the load low-pressure return air pipe 11 via a return pipe 13. The return pipe 13 is also connected to the recovery airbag 4, and the return pipe 13 is also connected to the helium buffer tank 3.

[0036] The outlet of the helium buffer tank 3 is connected to the helium compressor 1 along the buffer tank outlet pipe 31, a section of the return pipe 13 and the load low-pressure return pipe 11, so that the helium in the helium buffer tank 3 is fed into the helium compressor 1. After being compressed by the helium compressor 1, the gas is discharged from the high-pressure outlet pipe 12 into the filter 2. A part of the high-pressure helium after being filtered by the filter 2 passes through the front section of the load high-pressure inlet pipe 51 and the return pipe 13 and is re-mixed with the load low-pressure return pipe 11, and re-enters the air inlet of the helium compressor 1 to maintain the inlet pressure of the helium compressor 1 stable at 1.05 bar.

[0037] When load 5 requires helium flow, a portion of the high-pressure helium flows into load 5, then exits through the load's low-pressure return line 11 and re-enters the system. If the pressure on the high-pressure side (load high-pressure inlet line 51) fluctuates excessively during the cycle and requires unloading, the gas is discharged along the unloading line 41 into the recovery bag 4, maintaining a stable high-pressure side pressure.

[0038] In this embodiment, the load low-pressure return air pipe 11 is between AB in the figure, the high-pressure outlet pipe 12 is between CD in the figure, the load high-pressure intake air pipe 51 is between EF in the figure, the return pipe 13 is between GH in the figure, the unloading pipe 41 is between IJ, and the buffer tank outlet pipe 31 is between KL.

[0039] It should be noted that the high-pressure side refers to the elevated pressure of helium after being compressed by helium compressor 1 and filtered by filter 2. This pressure is measured by high-pressure-side pressure sensor 512. The low-pressure side refers to the pressure at which gas circulates into helium compressor 1. At this point, the helium pressure is lower, and this pressure is measured by low-pressure-side pressure sensor 132. Therefore, the terms high-pressure side and low-pressure side are relative.

[0040] like Figure 2As shown, the filter 2 includes a primary oil filter cartridge 21, a secondary oil filter cartridge 22, and an activated carbon filter cartridge 23, which are connected in sequence. The air inlet end of the primary oil filter cartridge 21 is connected to the high-pressure outlet pipe 12, to which the first outlet manual valve 121 is connected. The bottom of the primary oil filter cartridge 21 is connected to the oil return pipe, to which the primary manual oil drain valve 211 and the return oil valve 212 are connected in sequence. The return oil pipe is connected to the oil return port of the helium compressor 1, and the oil filtered by the primary oil filter cartridge 21 is returned to the helium compressor 1. The secondary oil filter cartridge 22 is equipped with a first liquid level sensor 221 and a secondary manual oil drain valve 222. The pipeline between the secondary oil filter cartridge 22 and the activated carbon filter cartridge 23 is also connected to a high-pressure side safety valve 223 to prevent overpressure.

[0041] The load high-pressure intake pipe 51 is also connected in sequence to a first high-pressure manual valve 511, a high-pressure pressure sensor 512, a high-pressure unload manual valve 513, and a load high-pressure manual valve 514. A second high-pressure manual valve 515 is also connected to the front end of the high-pressure pressure sensor 512.

[0042] The unloading pipe 41 is connected to the front end of the high-pressure side unloading manual valve 513 , and the unloading pipe 41 is also connected to an unloading valve 42 .

[0043] The buffer tank outlet pipe 31 is connected in sequence to a loading valve 32 , a manual air supply valve 33 , and an air supply side pressure sensor 34 . The front end of the air supply side pressure sensor 34 is also connected to an air supply pressure measuring manual valve 35 .

[0044] The return pipe 13 is connected to the low-pressure side of the pipeline. A low-pressure side safety valve 131 and a low-pressure side pressure sensor 132 are also connected to the front end of the low-pressure side pressure sensor 132. The low-pressure side pressure measuring manual valve 133 is also connected to the front end of the low-pressure side pressure sensor 132. The return pipe 13 is connected to the high-pressure side of the pipeline. A bypass valve 134 is connected.

[0045] In this embodiment, the circulating gas and the helium buffer tank 3 are only unidirectionally communicated, that is, after the helium enters the circulation system from the helium buffer tank 3, when pressure fluctuation occurs, the helium will be unloaded and discharged to the recovery air bag 4, thereby solving the problem of gas contamination in the helium pre-cooling system, effectively suppressing gas pressure fluctuations, and effectively reducing the unloading of high-purity helium to the recovery air bag 4 through a fast and stable system.

[0046] Example 2:

[0047] This embodiment provides helium circulation control, which is applied to a helium circulation control system containing impurities and uses existing control equipment.

[0048] In this embodiment, the helium circulation control system also includes a control unit electrically connected to the above-mentioned components and each valve. The control unit can obtain the parameters of the helium compressor 1 and the status of the helium compressor 1 through bus communication, and control the start and stop of the helium compressor 1, as well as the opening and stopping of each valve. At startup, the low-pressure intake pressure is jointly controlled by the opening of the bypass valve 134 and the loading valve 32. After the low-pressure intake pressure stabilizes, the bypass valve 134 controls the low-pressure side pressure alone. Because the loading valve 32 is open, the high-pressure side pressure of the system intake will continue to rise. After the high-pressure side pressure reaches the preset pressure and enters a stable state, the high-pressure side pressure is jointly controlled by the loading valve 32 and the unloading valve 42. The functions of the loading valve 32 and the unloading valve 42 are completely opposite. When the high-pressure side pressure is too high, the unloading valve 42 controls the exhaust gas to enter the recovery air bag 4 to maintain the high pressure in a stable state.

[0049] Loading valve 32 and unloading valve 42 utilize the same PID control logic, with 50% output as the threshold. Loading valve 32 opens when output exceeds 50%, while unloading valve 42 opens when output falls below 50%. PID parameters are dynamically adjusted during startup and after stabilization to address pressure fluctuations under varying operating conditions.

[0050] The control method includes four states, including: standby state X0, start state X1, running state X2, and stop state X3;

[0051] Standby state X0 is the system's initialization state. At this point, helium compressor 1 is in the off state, bypass valve 134 is in manual mode and closed, and loading valve 32 and unloading valve 42 are in manual mode and closed. Upon receiving a system startup command for helium compressor 1 from the host computer, the control unit checks the status of helium compressor 1, whether the low-pressure side pressure of helium compressor 1 meets the startup conditions, and whether the high-pressure side pressure meets the requirements. If these conditions are met, the control unit switches from standby state X0 to startup state X1 and executes the startup process X1 of the helium circulation control system. Otherwise, the system startup command for helium compressor 1 is reset, and the standby state X0 remains.

[0052] Specifically, in standby state X0,

[0053] X001: Get the real-time parameters of the low-pressure side pressure of the current gas and the current status of helium compressor 1.

[0054] Specifically, the low-pressure side pressure value is obtained by the low-pressure side pressure sensor 132, and it is determined whether the low-pressure side pressure is between 0.9 bar and 1.5 bar, and whether the helium compressor 1 is in a standby state without an alarm. If satisfied, proceed to the next step;

[0055] X002: Get the real-time parameters of the high-pressure side of the gas. If the pressure is higher than 11.8 bar, set the unloading valve 42 to automatic mode and change the set value to 11.8 bar to relieve the pressure. Wait until the pressure drops to 11.8 bar before proceeding to the next step.

[0056] Specifically, the low-pressure side pressure value is obtained by the low-pressure side pressure sensor 132, and the high-pressure side pressure value is obtained by the high-pressure side pressure sensor 512. If the low-pressure side pressure value and the high-pressure side pressure value do not meet the pressure range, it is not conducive to system startup.

[0057] X003: Set bypass valve 134 to automatic mode, modify the setpoint to 1.05, the proportional parameter P to 2.6, and the integral parameter I to 3.0. Set loading valve 32 and unloading valve 42 to manual mode and close them. After completing this operation, wait 20 seconds before proceeding to the next step.

[0058] Startup state X1, i.e.: start the helium compressor 1, and set the bypass valve 134 to automatic mode, and set the loading valve 32 and the unloading valve 42 to automatic mode. During the startup process, the helium in the helium buffer tank enters the helium compressor 1 through the load low-pressure return pipe. After the helium compressor 1 compresses the helium and passes through the filter 2, a part of the high-pressure gas returns to the load low-pressure return pipe 11 through the return pipe 13 to regulate the low-pressure side pressure; the high-pressure pressure of the helium circulation system undergoes a linear or / and step-by-step increase process. Finally, when the high-pressure pressure of the helium circulation system reaches the load demand pressure, the helium circulation control system enters the operating state X2.

[0059] Specifically, when starting state X1:

[0060] X101: Start helium compressor 1, open bypass valve 134 and loading valve 32, and start supplying gas from helium buffer tank 3. Obtain the high-pressure side pressure and the pressure of helium buffer tank 3, and calculate the high-pressure side pressure ratio K. After starting helium compressor 1, the high-pressure side pressure slowly rises. Based on the output value of bypass valve 134 PID calculation, the opening of bypass valve 134 and loading valve 32 are calculated according to the ratio K. Wait for the high-pressure pressure to rise to 11.5 bar (the required load pressure is generally 13 bar). Increase the ratio K by 0.05 per second until it reaches 1, and then proceed to the next step.

[0061] Wherein, K=high-pressure side pressure / (high-pressure side pressure+helium buffer tank pressure); the pressure of the helium buffer tank 3 is obtained by the gas supply side pressure sensor 34 .

[0062] It should be noted that the openings of the bypass valve 134 and the loading valve 32 are calculated according to the ratio K in order to coordinately control the two. The purpose of increasing the ratio K by 0.05 per second is to allow the loading valve 32 to gradually break away from the control of the bypass valve 134 and ultimately independently regulate the intake pressure.

[0063] X102: Reduce the proportional parameter P of the bypass valve 134 by 0.005 per second to 0.7 (0.7 is close to the P value in the stable state). The proportional parameter P parameter is used to reduce the adjustment range after a single calculation of the valve PID to avoid fluctuations in the valve opening;

[0064] Set the loading valve 32 and the unloading valve 42 to automatic mode. The loading valve 32 and the unloading valve 42 independently control the loading and unloading processes. The setting values ​​of the loading valve 32 and the unloading valve 42 are both modified to 12.5 bar, and the proportional parameter P is modified to 1.5 to obtain the difference between the current setting value and the high-pressure side pressure.

[0065] If the difference is less than 0, modify the integral parameter I of the loading valve 32 and the unloading valve 42 to 0.05. If the difference is greater than 1, modify the integral parameter I of the loading valve 32 and the unloading valve 42 to 3. If the difference is greater than 0 and less than 1, modify the integral parameter I of the loading valve 32 and the unloading valve 42 to 0.8. After waiting for 10 seconds, modify the set values ​​of the loading valve 32 and the unloading valve 42 according to the high-pressure side pressure. Calculate the difference T between the set value and the high-pressure side pressure. When the set value is lower than 13 bar and T is less than 0.1, increase the set value to 13 bar at a rate of 0.05 bar per second. Determine that the high-pressure side pressure is higher than the set value of the loading valve 32 and the unloading valve 42, and the set value is 13 bar, and the low-pressure side pressure is lower than 1.2 bar, and proceed to the next step;

[0066] It should be noted that in the process of controlling the high-pressure side pressure by the loading valve 32 and the unloading valve 42 , the PID parameters can be modified according to the pressure conditions to achieve a stable pressure state.

[0067] In this embodiment, the process of increasing the high-pressure side pressure may be linear or / and step-wise, and may increase rapidly in the initial stage and slowly in the later stage.

[0068] X103: Prompts that helium compressor 1 enters normal working mode.

[0069] Operating state X2 is the stable operating state of the helium compressor system. By modifying the PID parameters, the loading valve 32 and the unloading valve 42 jointly regulate the pressure; when the high-pressure side pressure is higher than the pressure required by the load, the opening of the unloading valve is increased, and the unloading valve controls the exhaust to enter the recovery airbag 4.

[0070] Specifically, when running in state X2:

[0071] X201: During operation, load-side fluctuations can cause changes in high-pressure-side pressure. If the high-pressure-side pressure is between 12.5 bar and 12.8 bar, and the openings of both loading valve 32 and unloading valve 42 are within 0.5%, the system is considered stable and the high-pressure-side pressure parameters are set to the set values ​​for loading valve 32 and unloading valve 42. If the high-pressure-side pressure is lower than 12.5 bar, the set values ​​for loading valve 32 and unloading valve 42 are modified to 12.5, and the integral parameter I is modified to 0.05. If the high-pressure-side pressure is higher than 13 bar, the integral parameter I is modified to 0.05. If the pressure is higher than the set value and automatically adjusted to lower it, and the openings of both loading valve 32 and unloading valve 42 are determined to be within 1%, the set value is modified to 12.8, and the integral parameter is modified to 0.8.

[0072] In this embodiment, when the high-pressure side pressure is too high, the unloading valve 42 will unload high-purity helium into the recovery bag 4. However, this process will result in waste of high-purity helium. Therefore, a fast response can reduce the unloading of helium into the recovery bag 4. Therefore, the PID parameters can be modified as needed to achieve the purpose of fast response and reduce waste.

[0073] During the stable operation of the system, if there is a stop signal, no matter what state it is in, as long as there is a stop signal, the next step of the shutdown state X3 will be carried out;

[0074] In shutdown state X3, the bypass valve 134, loading valve 32, and unloading valve 42 are set to manual mode, the loading valve is closed, the helium buffer tank 3 stops supplying gas, the unloading valve 42 relieves the pressure on the high-pressure side, the helium compressor 1 is shut down, and the bypass valve 134 is closed. If the pressure on the low-pressure side is higher than the set value, the load low-pressure return air pipeline is connected to the recovery air bag 4 to release the low-pressure side pressure.

[0075] Specifically, in shutdown state X3:

[0076] X301: Set the loading valve 32 and the unloading valve 42 to manual mode. The loading valve 32 is closed at a rate of 2% per second to gradually stop the gas supply. After the gas supply is stopped, the unloading valve 32 is opened at a rate of 0.1% per second to 20% to achieve pressure relief. If the high-pressure side pressure is too high, it will affect the next start-up of the helium compressor 1. Therefore, the high-pressure side pressure needs to be unloaded to the set state, such as when the high-pressure side pressure is slightly higher than the gas supply pressure, or when the high-pressure side pressure is lower than 6 bar, after pressure relief is completed, proceed to the next step;

[0077] X302: Shut down helium compressor 1. Since the inlet pressure will increase after stopping helium compressor 1, set the integral parameter of bypass valve 134 to 1.0 (the smaller the integral parameter value, the faster it closes). Close loading valve 32 and unloading valve 42. Wait until helium compressor 1 is shut down before proceeding to the next step.

[0078] X303: Set the bypass valve 134 to manual mode and close it. If the low-pressure side pressure is higher than 1.5 bar, open the valve connecting the low-pressure side to the recovery airbag 4 to release the low-pressure side pressure to no higher than 1.5 bar (slightly higher than atmospheric pressure). After completion, proceed to the next step.

[0079] X304: A pop-up window appears indicating that helium compressor 1 has been shut down.

[0080] In this embodiment, real-time pressure readings and helium compressor status are captured during operation. Once the load-side pressure meets startup conditions, the system starts and stops with a single button, automatically transitioning through steps. Pressure increases and decreases smoothly during operation, quickly handling fluctuations and effectively minimizing the impact of shocks on system stability. After startup, no personnel are required, and the system automatically shuts down in the event of an abnormality, maintaining stable control of both high and low pressures within normal ranges.

[0081] The high-pressure side unloading valve in this embodiment is connected to the recovery air bag. In actual application, the high-pressure side unloading time and frequency are controlled during pressure fluctuations to reduce the waste caused by excessive system gas entering the recovery system due to pressure fluctuations.

[0082] The control system of this embodiment has a high degree of modularity and can operate independently to provide high-pressure helium to the load end, or it can be combined with the load end control system to be debugged and operated as an integral system.

[0083] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. Helium circulation system, characterized in that: It includes a helium compressor, a filter, a helium buffer tank, and a recovery air bag; the load low-pressure return air pipe is connected to the air inlet of the helium compressor, the air outlet of the helium compressor is connected to the filter, and the outlet end of the filter is connected to the load high-pressure air inlet pipe; the load high-pressure air inlet pipe and the load low-pressure return air pipe are connected through a return pipe, and the helium buffer tank and the recovery air bag are connected side by side on the return pipe; Connect a loading valve to the outlet of the buffer tank, an unloading valve to the inlet of the recovery air bag, and a bypass valve to the return pipe; The helium buffer tank only outputs helium in one direction to the circulating helium. When the pressure on the high-pressure side is too high, the unloading valve controls the exhaust to enter the recovery air bag to maintain the high pressure in a stable state.

2. The helium circulation system according to claim 1, characterized in that: The system also includes a load, which is connected to the air inlet of the helium compressor through a load low-pressure return air pipeline, and the air outlet end of the filter is connected to the load through a load high-pressure inlet air pipeline.

3. The helium circulation system according to claim 1, characterized in that: The filter includes a first-stage oil filter cartridge, a second-stage oil filter cartridge, and an activated carbon filter cartridge connected in sequence. The air inlet end of the first-stage oil filter cartridge is connected to the helium compressor, the bottom of the first-stage oil filter cartridge is connected to the oil return pipe, and the oil return pipe is connected to the oil return port of the helium compressor; the air outlet end of the activated carbon filter cartridge is connected to the load high-pressure air inlet pipe.

4. The helium circulation system according to claim 1, characterized in that: A high-pressure side pressure sensor is also connected to the load high-pressure air intake pipe, and a low-pressure side pressure sensor is connected to the return pipe close to the load low-pressure air return pipe.

5. The helium circulation system according to claim 1, characterized in that: It also includes a control unit, which is electrically connected to the helium compressor, the bypass valve, the unloading valve, and the loading valve.

6. A helium circulation method, characterized in that: The helium circulation system is applicable to any one of claims 1 to 5 above, and the method includes: when the helium compressor is started, the bypass valve and the loading valve jointly control the low-pressure intake pressure; after the low-pressure intake pressure stabilizes, the bypass valve alone controls the low-pressure side pressure; after the high-pressure side pressure reaches a preset pressure and enters a stable state, the loading valve and the unloading valve jointly control the high-pressure side pressure; when the high-pressure side pressure is too high, the unloading valve controls the exhaust to enter the recovery air bag to maintain the high pressure in a stable state.

7. The helium circulation method according to claim 6, characterized in that: The helium circulation system includes four states: standby state X0, start state X1, running state X2, and stop state X3. The helium circulation system operates according to the above four states. When the helium circulation system is in the start state X1 or the running state X1, when the control system receives a helium circulation system stop command from the host computer, it will switch to the stop state X3.

8. The helium circulation method according to claim 7, characterized in that: In the standby state X0, the helium compressor is in the off state, the bypass valve, loading valve, and unloading valve are all in the closed state, the bypass valve is in automatic mode, and the loading valve and unloading valve are in manual mode. When the control unit receives the system start-up command, the control unit checks the state of the helium compressor 1, whether the low pressure of the helium compressor meets the start-up conditions, and whether the high pressure meets the requirements. If all are satisfied, it will switch from the standby state X0 to the start-up state X1 and execute the start-up process X1 of the helium circulation control system. Otherwise, the helium compressor system start-up command is reset and the standby state X0 is maintained.

9. The helium circulation method according to claim 7, characterized in that: Start state X1, start the helium compressor, and set the bypass valve to automatic mode, and set the loading valve and unloading valve to automatic mode; During the startup process, the helium in the helium buffer tank enters the helium compressor through the load low-pressure return pipe. The helium compressor compresses the helium and passes through the filter. A portion of the high-pressure gas returns to the load low-pressure return pipe through the return pipe to regulate the pressure on the low-pressure side. The high-pressure side pressure of the helium circulation control system is increased in a linear or step-wise manner. When the high-pressure side pressure reaches the load demand pressure, the helium circulation system enters the operating state X2. In operating state X2, by modifying the PID parameters, the loading valve and the unloading valve jointly regulate the high-pressure side pressure; when the high-pressure side pressure is higher than the pressure required by the load, the opening of the unloading valve is increased, and the unloading valve controls the exhaust to enter the recovery airbag.

10. The helium circulation method according to claim 7, characterized in that: In shutdown state X3, the bypass valve, loading valve, and unloading valve are set to manual mode; the loading valve is closed, the helium buffer tank stops supplying gas, the unloading valve relieves pressure on the high-pressure side, the helium compressor is shut down, and the bypass valve is closed. If the pressure on the low-pressure side is higher than the set value, the load low-pressure return air pipe is connected to the recovery air bag to release the low-pressure side pressure.

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