Helium leak detection system and leak rate calibration method thereof

Abstract

The application discloses a helium detection system and a leak rate calibration method thereof, and belongs to the technical field of equipment calibration. The method comprises the following steps: disconnecting the communication path between a standard leak rate source and a helium detector and the communication path between the standard leak rate source and a cavity, and simultaneously connecting the standard leak rate source with a vacuumizing device and connecting the cavity with the helium detector, so as to obtain a first leak rate value measured by the helium detector currently; the first leak rate value is used for representing a background leak rate value of the helium detection system; connecting the cavity with the standard leak rate source and the helium detector respectively, and simultaneously disconnecting the communication path between the standard leak rate source and the vacuumizing device, so as to obtain a second leak rate value measured by the helium detector currently; the second leak rate value is used for representing an actual leak rate value of the helium detection system; and based on the difference between the actual leak rate value and the background leak rate value, the leak rate value of the helium detection system after calibration is determined. The technical scheme provided by the application can significantly improve the accuracy and reliability of the leak rate calibration of the helium detection system.

Description

Technical Field

[0001] This application relates to the field of equipment calibration technology, specifically to a helium detection system and its leak rate calibration method. Background Technology

[0002] Helium detection technology is widely used for airtightness testing after laser welding of battery top covers. Standard leak rate sources (such as active leak holes) are core components for the calibration of helium detection systems, as they have known leak rates. Their role is to ensure the accuracy of the helium detector's test results.

[0003] In related technologies, the calibration of helium detection systems usually adopts the direct reading method, that is, directly connecting the gas path between the standard leak rate source and the helium detector, and the helium detector directly reads the leak rate value of the standard leak rate source as the calibration benchmark.

[0004] However, the above direct reading method has the following drawbacks: the pipeline where the standard leak rate source is located is prone to residual gas accumulation after long-term operation or shutdown, and the helium detection system itself has background leakage. Using the direct reading of the helium detector as the final calibration result will result in the calibrated leak rate value not being able to truly reflect the actual leak rate status of the standard leak rate source. Summary of the Invention

[0005] This application provides a helium detection system and a leak rate calibration method thereof, which aims to significantly improve the accuracy and reliability of leak rate calibration of the helium detection system.

[0006] In a first aspect, embodiments of this application provide a leak rate calibration method for a helium detection system. The helium detection system includes a standard leak rate source, a helium detector, a vacuum pumping device, and a cavity. The standard leak rate source is connected to the helium detector, the vacuum pumping device, and the cavity. The cavity is connected to both the helium detector and the vacuum pumping device. The method includes: controlling the connection path between the standard leak rate source and the helium detector, and the connection path between the standard leak rate source and the cavity, to disconnect; and simultaneously controlling the connection between the standard leak rate source and the vacuum pumping device, and the connection between the cavity and the helium detector. The system acquires a first leak rate value currently measured by the helium detector; wherein the vacuum pump is used to remove gas from the pipeline where the standard leak rate source is located; the first leak rate value is used to characterize the background leak rate value of the helium detection system; the system controls the cavity to be connected to both the standard leak rate source and the helium detector, and simultaneously controls the connection path between the standard leak rate source and the vacuum pump to be disconnected, thereby acquiring a second leak rate value currently measured by the helium detector; the second leak rate value is used to characterize the actual leak rate value of the helium detection system; based on the difference between the actual leak rate value and the background leak rate value, the calibrated leak rate value of the helium detection system is determined.

[0007] Optionally, the duration for which the standard leak rate source is connected to the vacuum pumping device and the duration for which the cavity is connected to the helium detector are both greater than a first preset duration.

[0008] Optionally, before obtaining the first leak rate value currently measured by the helium detector, the method further includes: controlling the standard leak rate source to connect with the helium detector, and simultaneously controlling the connection path between the standard leak rate source and the cavity and the connection path between the standard leak rate source and the vacuum pumping device to disconnect, thereby obtaining a third leak rate value currently measured by the helium detector; wherein, the third leak rate value is used to characterize the reference leak rate value of the helium detection system; determining the difference between the reference leak rate value and the nominal leak rate value of the standard leak rate source; and triggering an alarm signal and terminating the calibration process if the absolute value of the difference is greater than a deviation threshold.

[0009] Optionally, when the standard leak rate source is connected to the helium detector, the gas from the standard leak rate source flows through the pipeline where the standard leak rate source is located to remove residual gas from the pipeline.

[0010] Optionally, a calibration helium detection valve is provided between the standard leak rate source and the helium detector; the method further includes: controlling the closure or opening of the calibration helium detection valve to disconnect or connect the communication path between the standard leak rate source and the helium detector.

[0011] Optionally, a standard leak rate source and a vacuum pumping device are provided with a standard leak rate evacuation valve; the method further includes: controlling the closing or opening of the standard leak rate evacuation valve to disconnect or connect the communication path between the standard leak rate source and the vacuum pumping device.

[0012] Optionally, a cavity leak gauge valve is provided between the standard leak rate source and the cavity; the method further includes: controlling the closure or opening of the cavity leak gauge valve to disconnect or connect the communication path between the standard leak rate source and the cavity.

[0013] Optionally, a cavity helium detection valve is provided between the cavity and the helium detector; the method further includes: controlling the closure or opening of the cavity helium detection valve to disconnect or connect the communication path between the cavity and the helium detector.

[0014] Optionally, the duration of the connection between the standard leak rate source and the helium detector is controlled to be greater than a second preset duration.

[0015] On the other hand, this application also provides a helium detection system, including: a controller, a standard leak rate source, a helium detector, a vacuum pumping device, and a cavity; the standard leak rate source is connected to the helium detector, the vacuum pumping device, and the cavity respectively; the cavity is connected to the helium detector and the vacuum pumping device respectively; wherein, the controller is configured to: disconnect the communication path between the standard leak rate source and the helium detector and the communication path between the standard leak rate source and the cavity, and simultaneously connect the standard leak rate source to the vacuum pumping device and the cavity to the helium detector, and obtain a first leak rate value currently measured by the helium detector; wherein, the vacuum pumping device is used to remove gas from the pipeline where the standard leak rate source is located; the first leak rate value is used to characterize the background leak rate value of the helium detection system; The cavity is controlled to be connected to the standard leak rate source and the helium detector respectively, and the connection path between the standard leak rate source and the vacuum pumping device is simultaneously disconnected to obtain the second leak rate value currently measured by the helium detector; the second leak rate value is used to characterize the actual leak rate value of the helium detection system. The calibrated leak rate value of the helium detection system is determined based on the difference between the actual leak rate value and the background leak rate value.

[0016] In this application, when measuring the background leak rate of the helium detection system, the standard leak rate source is simultaneously disconnected from the helium detector and the cavity, and connected to the vacuum pumping device. This allows the standard leak rate source pipeline to be evacuated to remove residual gas, while the system's background leak rate is obtained through the connection between the cavity and the helium detector. Based on this, the cavity is then connected to both the standard leak rate source and the helium detector, and the vacuum pumping device is disconnected to obtain the actual leak rate value after eliminating residual interference. Finally, the difference between the two values ​​is used to determine the calibrated leak rate value. This calibration method not only effectively avoids contamination of the calibration measurement by residual gas in the standard leak rate source pipeline, but also accurately removes the system's background leakage from the actual measured value, ensuring that the calibrated leak rate value truly reflects the actual leak rate state of the standard leak rate source, significantly improving the accuracy and reliability of the helium detection system's leak rate calibration. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the calibration logic gas path of a helium detection system provided in this application embodiment; Figure 2A schematic flowchart illustrating a leak rate calibration method for a helium detection system provided in this application embodiment; Figure 3 A schematic diagram illustrating the process of measuring and determining a baseline leak rate value, provided for an embodiment of this application; Figure 4 A flowchart illustrating another leak rate calibration method for a helium detection system provided in this application embodiment; Figure 5 This is a flowchart illustrating another leak rate calibration method for a helium detection system provided in an embodiment of this application.

[0019] The attached figures are labeled as follows: 10. Standard leak rate source; 20. Helium detector; 30. Vacuum pumping device; 40. Chamber; 31. Product evacuation pump; 32. Chamber evacuation pump; 50. Valve device; 51. Calibration helium detection valve; 52. Helium detection main valve; 53. Leakage test and evacuation valve; 54. Cavity helium detection valve; 55. Cavity leakage test valve; 56. Product evacuation valve. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0022] The use of "applies to" or "configured to" in this application implies open and inclusive language, which does not exclude the applicability to or configuration to devices performing additional tasks or steps. Additionally, the use of "based on" implies openness and inclusivity, because processes, steps, calculations, or other actions "based on" one or more of the stated conditions or values ​​may in practice be based on additional conditions or values ​​beyond those stated.

[0023] In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0024] Please see Figure 1 , Figure 1 This is a schematic diagram of the calibration logic gas path of a helium detection system provided in an embodiment of this application. Figure 1 As shown, the helium detection system includes a standard leak rate source 10, a helium detector 20, a vacuum pumping device 30, and a cavity 40. The standard leak rate source 10 is connected to the helium detector 20, the vacuum pumping device 30, and the cavity 40, respectively; the cavity 40 is connected to the helium detector 20 and the vacuum pumping device 30, respectively.

[0025] Among them, the standard leakage rate source 10 is a component with a known nominal leakage rate value. It can be an active leak orifice, and its nominal leakage rate value at the time of manufacture is given by the product certificate and can be used as a reference value for the benchmark leakage rate value.

[0026] The helium detector 20 can employ a helium mass spectrometer to measure the concentration of helium in the pipeline in real time and convert the concentration into a corresponding leak rate value.

[0027] The vacuum pumping device 30 refers to a component capable of performing vacuum evacuation operations on a specific section of the helium detection system. It may include vacuum pump components such as the product evacuation pump 31 and the chamber evacuation pump 32. Its function is to discharge the gas (including residual helium) in the evacuated section to a sufficiently low pressure to eliminate interference from residual gas on leak rate measurement. In this embodiment, the vacuum pumping device 30 is mainly used to evacuate the pipeline where the standard leak rate source 10 is located (i.e., standard leak evacuation).

[0028] The cavity 40 refers to a sealed chamber used to contain the product under test. The cavity 40 is provided with an inlet for introducing helium gas and a detection port for drawing the gas inside the cavity to the helium detector 20. In this embodiment, the cavity 40 can be a detection cavity used for leak detection on the production line to contain the product under test, or it can be an independent cavity used only for the calibration process.

[0029] The system also includes a valve assembly 50 and a controller (not shown in the figure). The valve assembly 50 includes a calibration helium detection valve 51, a main helium detection valve 52, a leak-proof evacuation valve 53, a cavity helium detection valve 54, a cavity leak-proof valve 55, and a product evacuation valve 56. The gas flow path is controlled by closing or opening each valve. The leak-proof evacuation valve 53 is connected to the product evacuation pump 31. The controller can be a programmable logic controller (PLC) or a microcontroller for automatically executing valve sequences and processing data.

[0030] In addition, the system also includes vacuum tubing connecting the above components to form a calibration loop.

[0031] Please see Figure 2 , Figure 2 This is a flowchart illustrating a leak rate calibration method for a helium detection system provided in an embodiment of this application. This method is applied to the aforementioned helium detection system, such as... Figure 2 As shown, the leak rate calibration specifically includes the following steps S210 to S230.

[0032] Step S210: Disconnect the connection path between the standard leak rate source and the helium detector and the connection path between the standard leak rate source and the cavity, and simultaneously connect the standard leak rate source to the vacuum pumping device and the cavity to the helium detector to obtain the first leak rate value currently measured by the helium detector.

[0033] The vacuum pumping device is used to remove the gas from the pipeline where the standard leak rate source is located; the first leak rate value is used to characterize the background leak rate value of the helium detection system.

[0034] A connection path refers to a pipe segment between two components that allows gas to pass through, along with the combination of valves on that segment. When a corresponding valve is open, the connection path is connected; conversely, when a valve is closed, the connection path is disconnected. Multiple valves on the same connection path must be open simultaneously for the connection path to be truly connected.

[0035] The background leak rate refers to the measurable leak rate of the helium detection system itself when no standard leak rate source is connected (i.e., contributed only by the inherent leakage of the cavity, vacuum pipeline and each connecting flange); it is the background value that needs to be deducted in subsequent differential calibration.

[0036] In this embodiment, the controller first performs the following two actions simultaneously: disconnecting the connection path between the standard leak rate source and the helium detector; disconnecting the connection path between the standard leak rate source and the cavity; and simultaneously controlling: the standard leak rate source to connect with the vacuum pumping device; and the cavity to connect with the helium detector.

[0037] Under this valve combination, the vacuum pump continuously removes the helium gas accumulated in the pipeline where the standard leak rate source is located. To completely evacuate the pipeline, the control duration should be longer than a first preset duration, which can be between 5 and 15 seconds. The current leak rate value is read by the helium detector and recorded as the first leak rate value.

[0038] In step S220, the control chamber is connected to the standard leak rate source and the helium detector respectively, and the connection path between the standard leak rate source and the vacuum pumping device is disconnected at the same time to obtain the second leak rate value currently measured by the helium detector.

[0039] The second leak rate value is used to characterize the actual leak rate of the helium detection system.

[0040] The actual leak rate value refers to the leak rate value actually read by the helium detector after connecting to the standard leak rate source. This value includes both the leak rate contribution from the standard leak rate source and the contribution from the system's background leak rate, and is a measurement value used for differential calibration.

[0041] After completing step S210, the controller switches the valve state: the control chamber is connected to both the standard leak rate source and the helium detector; simultaneously, the connection path between the standard leak rate source and the vacuum pumping device is disconnected. Under this valve combination, the helium gas output from the standard leak rate source enters the chamber through the chamber's leak rate valve, and then enters the helium detector through the chamber's helium detection valve; after the helium detector reading stabilizes, the current leak rate value is recorded and designated as the second leak rate value.

[0042] Step S230: Determine the calibrated leak rate value of the helium detection system based on the difference between the actual leak rate value and the background leak rate value.

[0043] The calibrated leak rate value refers to the final result obtained by subtracting the actual leak rate value from the background leak rate value according to the method of this application, which is used to characterize the true leak rate level of the helium detection system during this calibration period.

[0044] The controller calculates the calibrated leak rate value L_corrected based on the obtained background leak rate value L_background and the actual leak rate value L_raw, using the following formula: L_corrected = L_raw L_background. The calculation results can be written to the calibration log file by the controller and displayed through the human-machine interface or the host system for use in subsequent product leak detection.

[0045] The technical solution of this application embodiment, when measuring the background leak rate value of the helium detection system, simultaneously disconnects the standard leak rate source from the helium detector and the cavity and connects it to the vacuum pumping device. This allows the standard leak rate source pipeline to be evacuated to remove residual gas, while the system's background leak rate value is obtained through the connection between the cavity and the helium detector. Based on this, the cavity is then connected to both the standard leak rate source and the helium detector, and the vacuum pumping device is disconnected to obtain the actual leak rate value after eliminating residual interference. Finally, the difference between the two values ​​is used to determine the calibrated leak rate value. This calibration method not only effectively avoids contamination of the calibration measurement by residual gas in the standard leak rate source pipeline but also accurately removes the system's background leakage from the actual measured value, ensuring that the calibrated leak rate value truly reflects the actual leak rate state of the standard leak rate source, significantly improving the accuracy and reliability of the helium detection system's leak rate calibration.

[0046] In some embodiments, the duration of connection between the control standard leak rate source and the vacuum pumping device, as well as the duration of connection between the cavity and the helium detector, are both greater than a first preset duration.

[0047] The first preset duration refers to the minimum duration during which the standard leak rate source and the vacuum pumping device, and the chamber and the helium detector, should remain connected during the baseline leak rate measurement process. Its value should ensure that the vacuum pumping device can fully remove residual gas from the pipeline containing the standard leak rate source to the set low pressure level, and that the helium detector reading tends to stabilize. For example, the first preset duration can be between 5 and 15 seconds. The first preset duration not only determines whether the pipeline has been completely evacuated, but also whether there is no external helium interference within the chamber. If the duration is too short, helium from the previous stage (baseline measurement) may still remain in the chamber, leading to a higher first leak rate value; if the duration is too long, it will reduce calibration efficiency.

[0048] By setting a minimum duration, the leak rate value can be avoided from being recorded before the helium detector reading has stabilized, ensuring that the first recorded leak rate value can reflect the steady-state measurement result.

[0049] Please see Figure 3 , Figure 3 This is a schematic diagram illustrating a process for measuring and determining a baseline leak rate value, as provided in an embodiment of this application. Figure 3 Before obtaining the first leak rate value currently measured by the helium detector, the method further includes steps S310 to S330.

[0050] Step S310: Control the connection between the standard leak rate source and the helium detector, and simultaneously control the connection path between the standard leak rate source and the cavity and the connection path between the standard leak rate source and the vacuum pumping device to disconnect, and obtain the third leak rate value currently measured by the helium detector; wherein, the third leak rate value is used to characterize the reference leak rate value of the helium detection system.

[0051] Step S320: Determine the difference between the baseline leak rate value and the nominal leak rate value of the standard leak rate source.

[0052] Step S330: If the absolute value of the difference is greater than the deviation threshold, trigger an alarm signal and terminate the calibration process.

[0053] The reference leak rate value refers to the leak rate value directly measured using the real-time leak rate value of the standard leak rate source and used as a reference. It can be used to correct deviations caused by changes in temperature and pressure difference, and can also remove the helium gas accumulated in the active calibration pipeline through gas flow in this pre-step process.

[0054] In this embodiment, the calibration helium detection valve and the main helium detection valve are opened, while other valves (such as the leak evacuation valve, the chamber helium detection valve, and the chamber leak calibrating valve) are closed, connecting the standard leak rate source to the helium detector. The connection path is: standard leak rate source, calibration helium detection valve, main helium detection valve, and helium detector, while the standard leak rate source is disconnected from the chamber and from the vacuum device. The helium detector reads the leak rate value of the active leak orifice and records it as the reference leak rate value of the helium detection system, denoted as L_base. This step, on the one hand, uses the real-time leak rate value of the active leak orifice as a reference to correct deviations caused by temperature and pressure differences; on the other hand, the gas flow removes the accumulated helium in the active calibration pipeline, reducing interference from residual gas. It is recommended that this step last for 10 to 30 seconds to ensure thorough flushing of the pipeline.

[0055] The controller compares the measured baseline leak rate value L_base with the nominal leak rate value of the standard leak rate source (the factory value given by the product certificate) and calculates the difference between the two. If the absolute value of the difference is greater than the deviation threshold, the controller triggers an alarm signal (e.g., an audible and visual alarm or sends an alarm message to the upper-level system) and terminates the current calibration process to avoid subsequent calibrations based on an inaccurate baseline. If the difference does not exceed the deviation threshold, subsequent calibration steps are performed.

[0056] This application embodiment introduces a reference value measurement and self-test step before the formal background measurement and calibration. On the one hand, it corrects the deviation caused by temperature and pressure difference drift of the active leak. On the other hand, it promptly alarms and terminates when the reference value deviates too much from the nominal value, preventing the output of incorrect calibration results under abnormal conditions of the standard leak rate source. This enhances the reliability and safety of the system and reduces false detections or missed detections caused by inaccurate calibration.

[0057] In some embodiments, when the standard leak rate source is connected to the helium detector, the gas from the standard leak rate source flows through the pipeline where the standard leak rate source is located to remove residual gas from the pipeline.

[0058] When the standard leak rate source is connected to the helium detector, the helium gas continuously output from the standard leak rate source flows along the pipeline where the source is located, carrying and displacing the residual helium gas accumulated in the pipeline, thereby cleaning the pipeline. This cleaning process is carried out simultaneously with the baseline measurement, ensuring both the accuracy of the baseline value and the cleanliness of the pipeline.

[0059] This application embodiment reduces reading errors caused by residual gas by simultaneously cleaning the pipeline where the standard leak rate source is located during the reference measurement stage using gas flow, thereby improving the repeatability and accuracy of calibration without requiring additional cleaning procedures or hardware.

[0060] In some embodiments, a calibration helium detection valve is provided between the standard leak rate source and the helium detector; the method further includes: controlling the closure or opening of the calibration helium detection valve to disconnect or connect the connection path between the standard leak rate source and the helium detector.

[0061] The calibration helium detection valve is a valve installed in the gas line between the standard leak rate source and the helium detector. It is an actuator that controls the opening and closing of the connection path between the standard leak rate source and the helium detector.

[0062] The controller controls the calibration helium detection valve via an output switch signal. When the calibration helium detection valve is opened in conjunction with the main helium detection valve, the connection path between the standard leak rate source and the helium detector is established; when the calibration helium detection valve is closed, this connection path is broken. The valve's on / off state is automatically executed by the controller (such as a PLC) according to a preset sequence.

[0063] By setting up dedicated valves for the standard leak rate source and helium detector pathways and having them precisely opened and closed by a controller, the baseline measurement (baseline leak rate value) and the background measurement (background leak rate value) can be switched sequentially on the same hardware, simplifying the gas path structure and improving the feasibility and automation of the control logic.

[0064] In some embodiments, a standard leak rate source and a vacuum pumping device are provided with a standard leak rate evacuation valve; the method further includes: controlling the closing or opening of the standard leak rate evacuation valve to disconnect or connect the connection path between the standard leak rate source and the vacuum pumping device.

[0065] The standard leak rate evacuation valve is a valve installed in the gas line between the standard leak rate source and the vacuuming device, used to control whether the pipeline where the standard leak rate source is located is evacuated.

[0066] In this embodiment, the controller controls the evacuation operation by switching the standard leak evacuation valve on and off. In step S210, the standard leak evacuation valve is opened, connecting the standard leak rate source to the vacuum pumping device, which then removes residual gas from the pipeline containing the standard leak rate source. In step S220, the standard leak evacuation valve is closed, disconnecting the connection. In this step, the standard leak evacuation valve is used to evacuate the active leak pipeline, preventing residual helium from affecting subsequent measurements.

[0067] By setting up a standard leak evacuation valve and controlling it with a controller, this embodiment of the application realizes on-demand evacuation of the pipeline where the standard leak rate source is located. This is a key execution method to eliminate residual gas interference and ensure accurate background measurement, without requiring any modification to other gas paths.

[0068] In some embodiments, a cavity leak gauge valve is provided between the standard leak rate source and the cavity; the method further includes: controlling the closure or opening of the cavity leak gauge valve to disconnect or connect the communication path between the standard leak rate source and the cavity.

[0069] The cavity leak gauge valve is a valve installed in the gas path between the standard leak rate source and the cavity, used to control whether the helium output from the standard leak rate source enters the cavity. In this embodiment, the controller controls the connection between the standard leak rate source and the cavity by opening and closing the cavity leak gauge valve. In step S210, the cavity leak gauge valve is closed to disconnect the standard leak rate source from the cavity (preventing the standard leak rate source from contributing to the measurement); in step S220, the cavity leak gauge valve is opened to connect the standard leak rate source to the cavity, and the helium gas flows through the cavity to the helium detector.

[0070] In some embodiments, a cavity helium detection valve is provided between the cavity and the helium detector; the method further includes: controlling the closure or opening of the cavity helium detection valve to disconnect or connect the communication path between the cavity and the helium detector.

[0071] The cavity helium detection valve is a valve located in the gas path between the cavity and the helium detector, used to control whether the gas in the cavity is sent to the helium detector for detection. The controller controls the connection between the cavity and the helium detector by opening and closing the cavity helium detection valve. In step S210, the cavity helium detection valve is opened to connect the cavity and the helium detector for background measurement; in step S220, the cavity helium detection valve remains open so that the actual leak rate value can be sent to the helium detector; when calibration is complete, the cavity helium detection valve is closed to safely shut off the calibration circuit.

[0072] In some embodiments, the duration of the connection between the control standard leak rate source and the helium detector is longer than a second preset duration.

[0073] The second preset duration refers to the minimum duration during which the connection state should be maintained during the baseline leak rate measurement phase, in order to ensure that the pipeline is fully flushed and the baseline reading is stable.

[0074] The second preset duration can be between 10 and 30 seconds. If the duration is too short, the helium gas accumulated in the active calibration pipeline will not be fully removed, which will result in a high reference leak rate value L_base and incomplete cleaning; if the duration is too long, it will reduce the calibration efficiency.

[0075] This application embodiment ensures that the pipeline where the standard leak rate source is located is fully cleaned and the benchmark reading is stable by setting a minimum duration (second preset duration) for the benchmark measurement stage, thereby improving the accuracy of the benchmark leak rate value and providing a reliable basis for subsequent alarm determination.

[0076] Please see Figure 4 , Figure 4 This is a flowchart illustrating another leak rate calibration method for a helium detection system provided in an embodiment of this application. Figure 4 As shown, the method specifically includes steps S410 to S440.

[0077] Step S410: Measurement of baseline leak rate and pipeline cleaning.

[0078] First, open the calibration helium detection valve and the main helium detection valve via the controller, and close other valves (such as the leak evacuation valve, the chamber helium detection valve, and the chamber leak calibrating valve). The helium detector reads the leak rate value of the active leak and records it as the reference leak rate value (L_base) of the helium detection system. L_base can be used to verify the stability of the active leak. If the deviation of L_base from the factory value exceeds a threshold, an alarm can be triggered and the calibration process terminated.

[0079] After the valve opens, helium gas flows into the pipeline through the active leak orifice, and a helium detector measures the stabilized leak rate. The controller records this value and uses it for subsequent calculations. It is recommended that this step last 10 to 30 seconds to ensure the pipeline is thoroughly flushed.

[0080] Step S420: Measure the background leakage rate of the cavity.

[0081] Close the calibration helium detection valve, open the leak test valve and the chamber helium detection valve, and close other valves (such as the chamber leak test valve). The helium detector reads the background leak rate value of the chamber (denoted as L_background).

[0082] In this step, the leak evacuation valve is used to evacuate the active leak pipeline to avoid the influence of residual helium. The helium detector reading should be recorded after it stabilizes, typically for 5 to 15 seconds.

[0083] Measuring the system's own background leakage (including background leakage in the cavity and vacuum lines) helps to isolate the contribution of active leaks and improve calibration accuracy.

[0084] Step S430: Measure the actual leakage rate.

[0085] Close the leak test valve and open the chamber leak test valve (keeping the chamber helium detector valve open). The helium detector reads the leak rate value (L_raw). Through the optimization of the previous steps, the reading in this step is more accurate, and the controller can calculate the corrected leak rate in real time.

[0086] After removing background and pipeline residues, this step allows for the measurement of the actual leakage rate of active leaks. This value incorporates both active leaks and potential background contributions, and the error has been minimized through previous steps.

[0087] The controller can calculate the calibrated leak rate value based on the measured value: L_corrected = L_raw L_background.

[0088] Step S440: Calibration complete.

[0089] After calibration, close the cavity helium detection valve to complete the leak calibration, and the system can enter normal testing mode.

[0090] At this point, all valves return to their initial positions, the controller stores the calibration data, and can output a calibration report. Safely closing the calibration loop prevents gas leaks from interfering with subsequent operations.

[0091] Please see Figure 5 , Figure 5 This is a flowchart illustrating another leak rate calibration method for a helium detection system provided in this application embodiment. This application embodiment is a specific example of the above-described implementation method; relevant users can program and control the valve sequence according to the above steps. For example, a PLC can be used to control the closing or opening of the solenoid valve. Figure 5 As shown, the method may include steps S510 to S540.

[0092] Step S510: Open the calibration helium detection valve and the main helium detection valve, wait for the helium detector reading to stabilize, and record the helium detector reading (L_base).

[0093] Step S520: Close the calibration helium detection valve, open the standard leak evacuation valve and the cavity helium detection valve, and record the helium detector reading (L_background).

[0094] Step S530: Close the evacuation valve for the helium leak tester, open the evacuation valve for the cavity, and record the reading of the helium detector (L_raw).

[0095] Step S540: Close the cavity helium detection valve to end the calibration.

[0096] The helium detection system provided in this application embodiment can be configured in automatic mode to reduce manual intervention.

[0097] In summary, the technical solutions of this application through the above embodiments have at least the following beneficial effects: 1. Improve calibration accuracy: By measuring the reference value in advance, the leakage rate deviation of the active leak is corrected, and the influence of temperature and pressure difference factors is reduced; by measuring the background leakage rate value, the interference of system background leakage is eliminated, making the final leakage rate value more realistic and reliable.

[0098] 2. Residual gas removal from pipelines: The gas flow during the reference value measurement phase effectively removes the helium gas accumulated in the active calibration pipeline, reducing reading errors caused by residual gas and improving calibration repeatability.

[0099] 3. Enhanced system reliability: The calibration logic adapts to environmental changes and alarms and terminates when the standard leak rate source is abnormal, reducing false or missed detections caused by inaccurate calibration and improving the overall performance and stability of the helium detection system.

[0100] 4. Improved efficiency: Through automated control, the overall calibration time is controllable, and repeated calibration is avoided, reducing operating costs.

[0101] 5. Simplified structure: This application does not require changes to the hardware structure, but only achieves the effect through logic optimization. It is easy to upgrade and implement on existing systems and has strong compatibility.

[0102] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0103] The above provides a detailed description of a helium detection system and its leak rate calibration method provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A leak rate calibration method for a helium detection system, characterized in that, The helium detection system includes a standard leak rate source, a helium detector, a vacuum pumping device, and a cavity; the standard leak rate source is connected to the helium detector, the vacuum pumping device, and the cavity; the cavity is connected to the helium detector and the vacuum pumping device; wherein, the method includes: The connection path between the standard leak rate source and the helium detector, as well as the connection path between the standard leak rate source and the cavity, are disconnected. Simultaneously, the connection between the standard leak rate source and the vacuum pumping device, and the connection between the cavity and the helium detector, are established to obtain the first leak rate value currently measured by the helium detector. The vacuum pumping device is used to remove gas from the pipeline where the standard leak rate source is located. The first leak rate value is used to characterize the background leak rate value of the helium detection system. The cavity is controlled to be connected to the standard leak rate source and the helium detector respectively, and the connection path between the standard leak rate source and the vacuum pumping device is simultaneously disconnected to obtain the second leak rate value currently measured by the helium detector; the second leak rate value is used to characterize the actual leak rate value of the helium detection system. The calibrated leak rate value of the helium detection system is determined based on the difference between the actual leak rate value and the background leak rate value.

2. The method according to claim 1, characterized in that, The duration for which the standard leak rate source is connected to the vacuum pumping device and the duration for which the cavity is connected to the helium detector are both greater than a first preset duration.

3. The method according to claim 1, characterized in that, Before obtaining the first leak rate value currently measured by the helium detector, the method further includes: The system controls the connection between the standard leak rate source and the helium detector, and simultaneously controls the connection path between the standard leak rate source and the cavity and the connection path between the standard leak rate source and the vacuum pumping device to disconnect, thereby obtaining the third leak rate value currently measured by the helium detector; wherein, the third leak rate value is used to characterize the reference leak rate value of the helium detection system; Determine the difference between the baseline leakage rate value and the nominal leakage rate value of the standard leakage source; If the absolute value of the difference is greater than the deviation threshold, an alarm signal is triggered and the calibration process is terminated.

4. The method according to claim 3, characterized in that, When the standard leak rate source is connected to the helium detector, the gas from the standard leak rate source flows through the pipeline where the standard leak rate source is located to remove residual gas from the pipeline.

5. The method according to claim 1, characterized in that, A calibration helium detection valve is provided between the standard leak rate source and the helium detector; the method further includes: Control the closure or opening of the calibration helium detection valve to disconnect or connect the connection path between the standard leak rate source and the helium detector.

6. The method according to claim 1, characterized in that, A standard leak rate source and a vacuum pumping device are provided with a leak rate valve; the method further includes: Control the closing or opening of the standard leak rate evacuation valve to disconnect or connect the connection path between the standard leak rate source and the vacuuming device.

7. The method according to claim 1, characterized in that, A cavity leakage valve is provided between the standard leakage rate source and the cavity. The method further includes: Control the opening or closing of the cavity leakage valve to disconnect or connect the communication path between the standard leakage rate source and the cavity.

8. The method according to claim 1, characterized in that, A cavity helium detection valve is provided between the cavity and the helium detector; the method further includes: Control the opening or closing of the cavity helium detection valve to disconnect or connect the communication path between the cavity and the helium detector.

9. The method according to claim 3, characterized in that, The duration of the connection between the standard leak rate source and the helium detector is controlled to be greater than a second preset duration.

10. A helium detection system, characterized in that, include: The system comprises a controller, a standard leak rate source, a helium detector, a vacuum pumping device, and a cavity; the standard leak rate source is connected to the helium detector, the vacuum pumping device, and the cavity; the cavity is connected to the helium detector and the vacuum pumping device; wherein, the controller is configured as follows: The connection path between the standard leak rate source and the helium detector, as well as the connection path between the standard leak rate source and the cavity, are disconnected. Simultaneously, the connection between the standard leak rate source and the vacuum pumping device, and the connection between the cavity and the helium detector, are established to obtain the first leak rate value currently measured by the helium detector. The vacuum pumping device is used to remove gas from the pipeline where the standard leak rate source is located. The first leak rate value is used to characterize the background leak rate value of the helium detection system. The cavity is controlled to be connected to the standard leak rate source and the helium detector respectively, and the connection path between the standard leak rate source and the vacuum pumping device is simultaneously disconnected to obtain the second leak rate value currently measured by the helium detector; the second leak rate value is used to characterize the actual leak rate value of the helium detection system. The calibrated leak rate value of the helium detection system is determined based on the difference between the actual leak rate value and the background leak rate value.

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