A method for calibrating the volume of a gas measurement system

Abstract

This application relates to the field of gas measurement, and discloses a method for calibrating the volume of a gas measurement system, including the following steps: evacuating the system to remove residual gas and setting the initial valve state; injecting high-purity He gas into the target area and allowing the gas to fill the target pipe section through diffusion; measuring the He gas signal intensity of the pipe section closest to the mass spectrometer using a mass spectrometer, and calculating the volume of this pipe section in combination with the known volume of the mass spectrometer; opening the valves section by section in the order from the closest to the farthest from the mass spectrometer, and recursively calculating the volume of each section through the difference in signal intensity; finally, recording and outputting the volume data of each pipe section and the total volume of the system. This method uses recursive calculation, significantly improving the calibration accuracy, being applicable to the volume calibration requirements of various complex pipe systems, and providing reliable volume distribution data support for subsequent gas measurement and analysis.

Description

Technical Field

[0001] The present invention relates to the technical field of gas measurement, and specifically to a method for calibrating the volume of a gas measurement system. Background Art

[0002] Gas measurement systems are widely used in scientific research and industrial applications. The accurate calibration of their volume distribution is the key to ensuring the accuracy of the system's measurement results. However, existing volume calibration methods usually have difficulty adapting to gas measurement systems with complex pipeline structures, such as multi-section pipelines, irregular fillers, and cold trap structures. In such systems, the direct measurement of the volume of each pipe section is often restricted by the pipeline shape, position, and internal complex environment, making it difficult to accurately obtain the actual volume of each pipe section.

[0003] In traditional methods, the volume of the system is usually calibrated as a whole at one time, or the volume is estimated based on the system's geometric structure. However, these methods have significant limitations. The overall calibration cannot distinguish the specific distribution of each section's volume and can only obtain the total volume of the system, while the geometric structure estimation is prone to large deviations due to ignoring the internal complexity of the pipeline or actual installation errors. In addition, due to the measurement process being easily affected by gas mixing, signal interference, and equipment errors, existing methods also have obvious deficiencies in terms of accuracy and applicability.

[0004] Especially in scenarios with high requirements for volume parameters such as rare gas measurement and high-precision gas flow control, existing technologies often cannot meet the actual needs. Therefore, a technical method that can adapt to complex pipeline systems, calibrate the volume section by section, and ensure the accuracy, reliability, and traceability of the calibration results is needed to overcome the defects of existing technologies and provide support for the further optimization of gas measurement systems. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the present invention provides a method for calibrating the volume of a gas measurement system, which solves the problems of insufficient accuracy, poor adaptability, and inability to obtain complete volume distribution data in the existing gas measurement system volume calibration methods in complex pipeline structures.

[0006] To achieve the above objectives, the present invention is realized through the following technical solutions: A method for calibrating the volume of a gas measurement system, including the following steps:

[0007] S1. Preparation: Evacuate the gas measurement system to remove the residual gas in the system and set each valve of the system to the initial state;

[0008] S2. Calibrate the volume of the pipe section (V1) closest to the mass spectrometer:

[0009] S2.1, High-purity gas injection: Inject high-purity He gas into the mass spectrometer by diffusion; measure the signal intensity of He gas through the mass spectrometer; during the measurement process, evacuate the remaining pipelines except the mass spectrometer to remove residual gas;

[0010] S2.2, Reverse-diffuse the gas in the mass spectrometer to the target section, measure the signal intensity of He gas through the mass spectrometer again, and calculate the volume of this pipe section in combination with the internal cavity volume of the mass spectrometer;

[0011] S2.3, Repeat the above processes of S2.1 and S2.2 multiple times, and the average value can obtain the volume of the pipe section closest to the mass spectrometer;

[0012] S3, Calibrate the volumes of other pipe sections:

[0013] S3.1, High-purity gas injection: Inject high-purity He gas into the entire pipeline;

[0014] S3.2, Open the corresponding valves section by section in the order from the closest to the farthest from the mass spectrometer, measure the signal intensity difference through the mass spectrometer, and recursively calculate the volume of each section;

[0015] S3.3, Record and output: Record the volume of each pipe section to obtain the complete volume distribution data of the system;

[0016] S3.4, Repeat S3.1 - 3.3 multiple times and take the average value.

[0017] Preferably, when calibrating the volume of the pipe section closest to the mass spectrometer in the above steps, it specifically includes:

[0018] When calibrating the volume of the pipe section closest to the mass spectrometer in the above steps, it specifically includes:

[0019] Make high-purity He gas diffuse into the mass spectrometer by opening and closing the corresponding valves;

[0020] Measure the signal intensity of He gas through the mass spectrometer and record the initial signal value;

[0021] Close all other valves connected to this pipe section;

[0022] Reverse-diffuse the gas in the mass spectrometer to this pipe section and measure the reverse-diffusion signal value;

[0023] Use the following formula to calculate the volume of the pipe section:

[0024]

[0025] Where, is the volume of the pipe section closest to the mass spectrometer to be calibrated, is the signal intensity of He gas measured by the mass spectrometer, is the He gas signal intensity after He gas back-diffusion into the pipe section (V1) closest to the mass spectrometer within the mass spectrometer, is the internal cavity volume of the mass spectrometer.

[0026] 4. Preferably, when calibrating the volumes of other pipe sections, it is carried out section by section in the order from near to far from the mass spectrometer; when calibrating a certain pipe section, first diffuse the gas in this pipe section into the pipe section (V1) closest to the mass spectrometer, and measure the gas entering the mass spectrometer from the pipe section (V1) closest to the mass spectrometer; calculate according to the following recurrence formula:

[0027]

[0028] wherein, is the volume of the th pipe section to be calibrated, is the He gas signal intensity related to the th pipe section measured by the mass spectrometer, is the signal intensity of He gas in the initial calibration pipe section measured by the mass spectrometer, is the sum of the volumes of the previous pipe sections.

[0029] Preferably, during the calibration process, the injection amount of high-purity He gas is controlled within 1×10 -3 ccSTP to 5×10 - 3 ccSTP.

[0030] Preferably, the number of repeated measurements for calibrating the volume of each pipe section is at least 3 times, and the average value is taken as the final volume value of this section.

[0031] Preferably, the gas measurement system includes a plurality of valves, pipes and a mass spectrometer, wherein:

[0032] Valve GVTP and GVIP1 are connected to the vacuum pump; valves GV2-GV8 are successively connected to each pipe section of the gas measurement system to realize the isolation or connection of each pipe section; valve GVMS is connected to the mass spectrometer inlet, and the initial state of the system is: GVTP, GVIP1, GV2, GV3, GV4, GV5, GV6, GV7 are in the open state, and the remaining valves are in the closed state.

[0033] The present invention provides a method for calibrating the volume of a gas measurement system. It has the following beneficial effects:

[0034] 1. By means of the step-by-step recursive calibration method, combining the signal intensity measurement of the mass spectrometer and the known reference volume parameters, the present invention avoids the result deviation problem caused by system complexity or measurement error accumulation in the traditional overall calibration method, thereby greatly improving the accuracy of volume calibration.

[0035] 2. Through the technical solution of segment-by-segment isolation calibration, the present invention can flexibly handle gas measurement systems with complex pipeline structures, including special structures such as multi-segment pipelines, irregular fillers, cold traps, etc., ensuring the adaptability and accuracy of the calibration process and having a wide range of applications.

[0036] 3. By recording, sorting, and outputting the volume of each pipeline segment and the total volume of the system, the present invention realizes the traceability of volume distribution data, providing reliable basic data support for subsequent experimental design, equipment calibration, and improvement of measurement accuracy.

[0037] 4. By precisely controlling the gas diffusion path and valve state, the present invention ensures the independent connection of the target pipeline segment to the mass spectrometer, reducing the possibility of gas mixing or interference in the uncalibrated area, thus ensuring the reliability of signal measurement and the accuracy of volume calculation.

[0038] 5. By generating complete system volume distribution data, the present invention provides a scientific basis for the calibration and optimization of gas measurement systems, especially applicable to application scenarios such as gas flow measurement and rare gas analysis that require high-precision volume parameter support, further enhancing the practicality and functionality of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a schematic diagram of the method flow of the present invention;

[0040] Figure 2 is a schematic diagram of the gas measurement system of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0042] Please refer to the attached Figure 1 - attached Figure 2 , the present invention provides a method for calibrating the volume of a gas measurement system. By means of segment-by-segment calibration, the internal volume of each segment of the gas measurement system is accurately measured, and it is applicable to complex gas measurement systems with multiple pipeline segments, valves, mass spectrometers, and other related components. This method can effectively solve the problem of large errors in traditional volume calibration methods caused by complex and irregular internal volumes of the system.

[0043] As Figure 1 shown, the method for calibrating the volume of a gas measurement system may include the following steps:

[0044] S1. Preparation: Evacuate the gas measurement system to remove residual gas inside the system and set each valve of the system to its initial state;

[0045] S2. Calibrate the volume of the pipe segment closest to the mass spectrometer:

[0046] S2.1. Injection of high-purity gas: Inject high-purity He gas into the mass spectrometer by diffusion; Measure the signal intensity of the He gas through the mass spectrometer; During the measurement process, evacuate the remaining pipelines except the mass spectrometer to remove residual gas;

[0047] S2.2. Reverse diffusion of the gas in the mass spectrometer to the target segment, measure the signal intensity of the He gas through the mass spectrometer again, and calculate the volume of this pipe segment in combination with the internal cavity volume of the mass spectrometer;

[0048] S2.3. Repeat the above processes of S2.1 and S2.2 multiple times, and the average value can be obtained as the volume of the pipe segment closest to the mass spectrometer.

[0049] S3. Calibrate the volumes of other pipe segments:

[0050] S3.1. Injection of high-purity gas: Inject high-purity He gas into the entire pipeline;

[0051] S3.2. Open the corresponding valves one by one in the order from the closest to the farthest from the mass spectrometer, measure the signal intensity difference through the mass spectrometer, and recursively calculate the volume of each segment;

[0052] S3.3. Record and output: Record the volume of each pipeline segment to obtain the complete volume distribution data of the system.

[0053] S3.4. Repeat S3.1 - 3.3 multiple times and calculate the average value.

[0054] The following will explain each step of the method of the present invention in detail.

[0055] For step S1, in this embodiment, step S1 is mainly the preparation work of the gas measurement system to ensure the accuracy and stability of the subsequent calibration process.

[0056] Specifically, in this embodiment, first, it is necessary to perform an evacuation operation on the gas measurement system to remove possible residual gas and impurities inside the system and ensure the cleanliness of the measurement environment. The evacuation operation can be achieved by connecting a vacuum pump, and the vacuum pump should have sufficient pumping speed and ultimate vacuum degree to meet the experimental requirements.

[0057] As an option, in specific implementation, a combined system of a mechanical pump and a molecular pump can be used to evacuate the pipeline. The mechanical pump is used to initially remove the gas under atmospheric pressure, and the molecular pump is used to further reduce the air pressure in the system to achieve a high-vacuum state. It should be noted that the evacuation operation should continue until the system reaches the preset vacuum conditions. For example, the system vacuum degree can reach < 10 -3 Pa to ensure that the influence of residual gas on the subsequent high-purity He gas calibration process is minimized.

[0058] In one possible implementation, the connection between the vacuum pump and the system is controlled by a main valve (such as GVTP). After opening the main valve, the vacuum pump starts to evacuate the system. After the vacuum degree reaches the requirement, the main valve is closed to isolate the vacuum pump from the system. This operation mode can reduce the interference of external gas leakage on the system vacuum degree.

[0059] It should be noted that during the evacuation process, to avoid gas residues caused by irregular fillers in the system (such as adsorbents in the cold trap) or complex pipeline structures, the evacuation can be assisted by a heating operation. For example, by applying appropriate heating on the pipeline surface to raise the system temperature to 100°C - 200°C, the presence of residual gas or adsorbed gas can be further reduced.

[0060] In this embodiment, each valve in the system needs to be set to a specific initial state according to the requirements of the experimental design. The setting of the states of these valves is crucial for the diffusion path of He gas and the signal acquisition of the mass spectrometer. Specifically, in the initial state, all valves directly related to the target pipe segments (such as GVTP, GVIP1) should be in the open state, while the valves related to non-target areas or non-working modules (such as GVMS or valves connected to other pipe segments) should be in the closed state. It should be understood that this setting of valve states ensures that the gas flow path is controllable in subsequent operations and avoids interference in non-calibration areas.

[0061] In an exemplary operation, the system can be divided into several independent sub-regions, and each sub-region is isolated or connected by valves to ensure that the evacuation only acts on the target area. Other areas can be independently evacuated by opening the valves when needed. This method of segmented evacuation is particularly suitable for systems with complex pipeline structures.

[0062] It can be understood that the above setting of the initial states of the valves is adjustable. According to the actual structure of different systems and experimental requirements, the opening or closing states of specific valves can be appropriately adjusted, but it should be ensured that the target area is in the working state and the non-target area is in the isolated state.

[0063] As an optimization measure, after setting the valve state, the vacuum degree of the system can be monitored in real time through a pressure sensor. Exemplarily, the pressure sensor can be arranged at the connection between the target area and the vacuum pump, or set at the entrance of the mass spectrometer, to ensure that the vacuum conditions in each target area meet the experimental requirements. If the pressure sensor detects that the pressure value does not meet the preset requirements, it can be corrected by extending the vacuum pumping time or checking for possible leakage points.

[0064] It should be noted that the above preparatory work plays a fundamental role in the technical solution of the present invention. Its core purpose is to ensure that the internal environment of the system is in a pure state, providing a reliable guarantee for the subsequent He gas injection and calibration processes.

[0065] For step S2, in this embodiment, step S2 mainly involves the injection operation of high-purity He gas to ensure that the target pipe section of the gas measurement system is filled with high-purity calibration gas, laying a foundation for subsequent volume calibration.

[0066] Specifically, in this embodiment, the injection of high-purity He gas is completed through a preset gas injection path. The gas source can be a high-purity He gas cylinder or a gas generation device. As an option, the high-purity He gas used should meet the purity requirements, usually reaching ≥99.999% to avoid interference from other impurity gases on the mass spectrometry measurement results.

[0067] In a possible implementation manner, high-purity He gas is introduced into the system through a connected injection pipeline (such as the area between SV1 and SV2). It should be noted that the injection path of He gas should be as short as possible to reduce gas diffusion delay and gas loss due to too long a path. In specific operations, open the SV1 valve to inject high-purity He gas into a predetermined injection volume at a stable flow rate. After maintaining for a certain time (such as 2 minutes), close SV1. It can be understood that this gas injection method ensures that the He gas in the injection volume can be fully filled through the control of time and flow rate.

[0068] It should be noted that after the He gas is injected, it gradually fills the target pipe section through diffusion. In this embodiment, the diffusion operation is achieved by opening the valves related to the target pipe section. For example, by opening the SV2 valve and other control valves (such as GV2) connected to the target pipe section, the injected He gas diffuses from the area between SV1 and SV2 to the target pipe section. The diffusion operation time is generally controlled within 1 - 2 minutes to ensure that the He gas can fully enter the target area. As an option, the air pressure change in the target pipe section can be monitored through a pressure sensor. When the air pressure reaches equilibrium, it indicates that the diffusion process has been completed.

[0069] In a possible implementation, to further improve the diffusion efficiency, a heating operation can be performed on the target pipe section. For example, by setting a heating tape or a heating jacket outside the pipe section, the temperature of the pipe section is raised to 30°C - 50°C to increase the diffusion speed and uniformity of He gas. It should be noted that this heating operation is particularly applicable to pipe sections containing complex fillers, such as irregular structures like cold traps.

[0070] The control of the diffusion path is a key technical point in this embodiment. Specifically, to ensure the accuracy of the He gas diffusion range, other valves irrelevant to the target pipe section (such as GV3 and subsequent valves) should be in the closed state during the diffusion process. This operation mode can effectively isolate non-target pipe sections, ensuring that the diffusion occurs only within the target pipe section, thereby avoiding the interference of gas in other areas.

[0071] It can be understood that during the diffusion process, if the diffusion range of He gas cannot be fully controlled, it may lead to gas leakage to non-target areas or uncalibrated areas, thus affecting the subsequent measurement accuracy. Therefore, to further reduce the complexity of the diffusion path, in some embodiments, the system can be divided into multiple independent modules to gradually guide the gas diffusion to the target pipe section. Exemplarily, the pressure in the target pipe section can be used to determine whether the diffusion is complete through the pressure difference with its adjacent pipe section. For example, if the pressure in the target pipe section reaches a stable value close to the pressure in the injection area, it can be considered that the diffusion process is complete.

[0072] It should be noted that the completion of the diffusion process is marked by the He gas in the target pipe section reaching a stable state, and the gas state at this time is crucial for subsequent mass spectrometry measurements. In this case, to avoid the influence of fluctuations in the He gas concentration on the measurement, a period of time (such as 1 - 2 minutes) can be waited after the diffusion is completed to ensure that the gas distribution in the target pipe section is completely uniform.

[0073] As a possible improvement, after the diffusion is completed, the He gas concentration in the target pipe section can be preliminarily measured by a mass spectrometer to ensure that the gas purity and concentration meet the expected requirements. If the measurement result deviates from the set value, high-purity He gas can be re-injected and the above diffusion steps can be repeated until the gas in the target pipe section reaches a stable state.

[0074] Step S2 in this embodiment can ensure the purity and uniformity of the gas in the target pipe section through precise control of He gas injection and diffusion, providing reliable experimental conditions for subsequent volume calibration.

[0075] For step S2, in this embodiment, step S2 involves the calibration operation of the volume of the pipe section closest to the mass spectrometer. By measuring the He gas signal intensity and combining the known volume parameters of the mass spectrometer, the actual volume of the target pipe section is calculated, providing a basis for calibrating other pipe sections subsequently.

[0076] Specifically, when calibrating the volume of the target pipe section closest to the mass spectrometer, it is first necessary to adjust the gas path of the system to ensure that only this target pipe section is connected to the mass spectrometer, and the valves of the other pipe sections are in the closed state. It should be noted that at this time, the target pipe section is already filled with highly pure He gas with uniform diffusion, and the other parts of the system have been pumped to a vacuum state to avoid interference from gases in other areas on the measurement signal.

[0077] In a possible implementation, by opening the control valve (such as GVMS) between the target pipe section (such as V1) and the mass spectrometer, and closing the valves of other pipe sections (such as GV2, GVIP2, etc.), He gas enters the mass spectrometer from the target pipe section. In an exemplary operation, the mass spectrometer detects the intensity of the He gas signal through its internal sensor and records this signal value, denoted as the first measurement signal value. 。

[0078] As an option, the running time of the mass spectrometer can be set according to the specific situation of the system structure, generally controlled to measure 10 cycles to ensure the stability of signal detection. After the first signal measurement is completed, the He gas in the mass spectrometer is back-diffused into the target pipe section. The implementation method of the back-diffusion operation is to close the valve corresponding to the target pipe section (such as GV2), and open the connection valve between the mass spectrometer and the target pipe section (such as GVMS), so that the He gas in the mass spectrometer flows back into the target pipe section again. It can be understood that the back-diffusion operation can effectively eliminate the influence of gas residue in the mass spectrometer on subsequent measurements.

[0079] In a possible implementation, after the above back-diffusion operation, the signal measurement of the mass spectrometer is carried out again, and the signal value after back-diffusion is recorded, denoted as the second measurement signal value. 。It should be noted that the stability of the second signal measurement is crucial for the accuracy of volume calculation. Therefore, usually 30 seconds to 1 minute need to be waited after the back-diffusion is completed to ensure uniform gas distribution.

[0080] In this embodiment, the volume of the target pipe section is calculated by the following formula:

[0081]

[0082] Where:

[0083] is the volume of the pipe section closest to the mass spectrometer;

[0084] is the intensity of the He gas signal measured for the first time;

[0085] is the intensity of the He gas signal measured for the second time after back-diffusion;

[0086] is the internal cavity volume of the mass spectrometer, a known parameter provided by the mass spectrometer manufacturer.

[0087] As an optimization method, when calculating the volume, multiple repeated measurements (e.g., 3 times or more) can be made on the values of the first and second signal measurements, and then the average value is taken to reduce the influence of experimental errors on the calculation results. It can be understood that repeated measurements help to eliminate the deviations caused by fluctuations of the equipment itself or changes in gas flow, thereby improving the accuracy of volume calibration.

[0088] In an exemplary operation, the internal cavity volume of the mass spectrometer is usually a fixed value, such as 1000 cc, but the actual volume may vary depending on different models. It should be noted that the internal cavity volume of the mass spectrometer, as a known reference value, its accuracy is crucial for the calculation of the volume of the target pipe section. Therefore, the mass spectrometer should be calibrated before use to ensure that the reference value it provides is accurate.

[0089] As a possible extension method, in order to verify the reliability of the volume calculation results, the calculated volume of the target pipe section can be compared with the theoretical estimated value. The theoretical estimated value can be calculated from the geometric dimensions (such as length and inner diameter) of the target pipe section. If the difference between the two is large, the mass spectrometry signal measurement process should be rechecked for abnormalities, such as gas leakage or signal detection errors.

[0090] It should be noted that the volume calibration of the target pipe section closest to the mass spectrometer is the basis for the volume calibration of other subsequent pipe sections, and its result directly affects the accuracy of subsequent recursive calculations. Therefore, the rigor of the calibration process and the reliability of the data should be ensured during operation. This step realizes the accurate calibration of the volume of the target pipe section through the measurement of the signal intensity of high-purity He gas and in combination with the known reference volume, providing a reliable basis for the volume calibration of the entire gas measurement system.

[0091] For step S3, in this embodiment, step S3 mainly involves the operation of calibrating the volumes of other pipe sections farther away from the mass spectrometer, and calculates the volume of each pipe section in turn by means of successive recursion. This step takes the volume of the pipe section closest to the mass spectrometer as the known basis and, in combination with the change relationship of the mass spectrometry measurement signal intensity, completes the calibration of the volumes of the remaining pipe sections.

[0092] Specifically, in this embodiment, when calibrating the volumes of pipe sections farther away from the mass spectrometer (such as V2, V3, etc.), the target pipe sections need to be measured one by one in the order from the closest to the farthest from the mass spectrometer. It can be understood that this successive recursive operation method can avoid the interference of system complexity on the calibration process and gradually improve the calibration accuracy.

[0093] In a possible implementation, first, it is necessary to adjust the valve state of the system to ensure that the current target pipe section is connected to the mass spectrometer and the calibrated pipe sections, while the other uncalibrated pipe sections remain isolated. For example, when calibrating the second pipe section V2, the valve connected to V2 (such as GV2) needs to be opened, and at the same time, the valves related to other pipe sections (such as V3 and further pipe sections) (such as GV3, GV4, etc.) need to be closed. Through this valve operation, it is ensured that the He gas only diffuses from the current target pipe section to the calibrated part and finally enters the mass spectrometer.

[0094] Exemplarily, when calibrating the target pipe section (such as V3), it is necessary to open the valve GV3 to enable the gas in the target pipe section to diffuse to the calibrated area (V1, V2). Subsequently, close the valve GV2 so that only the gas in the pipe section closest to the mass spectrometer enters the mass spectrometer for measurement. Record the obtained signal value, which is denoted as the signal value of the current section. As an option, the deviation caused by environmental fluctuations or equipment errors can be reduced by repeating the measurement of the signal value (for example, repeating the measurement 3 times) and taking the average value. When calibrating the volume of each target pipe section, it is necessary to diffuse the gas inside it to the pipe section closest to the mass spectrometer and only measure the gas in the pipe section closest to the mass spectrometer, which can reduce the error transfer during data calculation and improve the accuracy of volume calibration.

[0095] It should be noted that during the calibration process of each pipe section, the calibrated part in the diffusion path should always be in a vacuum state. This can be achieved by opening the vacuum pump control valve (such as GVTP) to evacuate the calibrated part. For example, when calibrating V2, the calibrated pipe section part of V1 needs to be evacuated to ensure that there is no residual gas in it, thereby avoiding the interference of gas mixing on the measurement of the current section.

[0096] In this embodiment, the volume of the target pipe section is calculated by the following formula:

[0097]

[0098] Where:

[0099] is the volume of the th pipe section to be calibrated;

[0100] is the signal intensity of the He gas measured by the mass spectrometer in the th pipe section;

[0101] is the signal intensity of the He gas measured by the mass spectrometer in the initial calibrated pipe section (such as V1);

[0102] is the sum of the volumes of the preceding pipe sections.

[0103] Specifically, when calibrating V2, the above formula is used:

[0104]

[0105] wherein, is the volume of the first calibrated pipe segment, is the signal intensity of the current segment.

[0106] In a possible optimized implementation, the calibration accuracy can be improved by adjusting the diffusion time. For example, during the diffusion process, by opening GV2 and keeping it for 2 minutes, the He gas is fully diffused into the connected area between V2 and V1. After the diffusion is completed, GV2 is closed, and the gas in V1 enters the mass spectrometer for measurement to ensure that the diffusion range coincides with the measurement path.

[0107] It should be noted that when calibrating the third segment (such as V3) and more distant pipe segments, the recursive calculation should be performed based on the volumes of the calibrated parts (such as V1 and V2).

[0108] It can be understood that this recursive calculation method can ensure that the calibration result of each segment volume is based on the measurement data of the previous segment, avoiding the cumulative error that may occur in independent calibration.

[0109] As an improvement measure, the accuracy of the calculation result can be further improved by performing multiple measurements on the target pipe segment and performing fitting analysis on the measurement results. For example, by performing linear fitting on the measurement results of different diffusion times, the error caused by signal fluctuations or experimental condition changes can be reduced.

[0110] In an exemplary operation, for a pipe segment containing multiple complex structures (such as cold traps or fillers), the diffusion efficiency can also be improved by heating operations to ensure the stability of the signal intensity. The heating temperature can be controlled at 30°C - 50°C, and the specific temperature can be adjusted according to the system material and structural characteristics.

[0111] It should be noted that the process of calibrating the volumes of other pipe segments should be carried out segment by segment, and the calibration of each segment is based on the calibrated volume, and is strictly completed in the order from near to far. This sequential calibration method can not only improve the overall measurement accuracy, but also verify the calibration result of the current segment through the gradually accumulated volume values.

[0112] This embodiment realizes the accurate calibration of the volumes of other pipe segments farther away from the mass spectrometer through the recursive calculation of the mass spectrometry measurement signal intensity, providing reliable data support for the complete volume distribution of the entire gas measurement system.

[0113] For step S3.3, in this embodiment, step S3.3 mainly involves the recording and output of the calibration results of the volume of the gas measurement system. By sorting out and summarizing the calibration data of the volumes of each section of the pipeline, a complete system volume distribution is obtained, thereby providing an accurate reference basis for subsequent gas measurement, analysis, and equipment calibration.

[0114] Specifically, in this embodiment, after the calibration of the volumes of all pipe sections is completed, the volume value of each pipe section is recorded according to its connection order relative to the mass spectrometer, and the total volume of the system is obtained through cumulative calculation . The calculation formula is as follows:

[0115]

[0116] Where:

[0117] is the volume of the th pipe section;

[0118] is the total number of pipe sections in the system.

[0119] As an option, when recording volume data, a tabular form can be used to record the number, connection position, volume value of each pipe section, and relevant conditions during measurement (such as ambient temperature, gas type, diffusion time, etc.). This information can provide a traceability basis for subsequent analysis.

[0120] It should be noted that the recording of the system volume distribution can select different output forms according to specific requirements. For example, in a laboratory environment, volume data is usually saved in the form of a spreadsheet or database for subsequent reference and use; in an industrial environment, it can also be directly output to a display screen or printing device through the control system integrated in the equipment.

[0121] In a possible implementation, the recorded data can be automatically sorted out and processed through a software program. Exemplarily, the measurement data can be transmitted to the data processing software through the communication interface between the sensor and the computer (such as RS232, USB, etc.), and the volume calculation, data storage, and output operations are completed in the software. For example, the software can automatically calculate the volume of each section according to the input signal strength value and the calibration formula, and generate a system volume distribution map. This automated processing method can improve the efficiency of data recording and output and avoid errors that may be caused by manual recording.

[0122] It is understandable that during data output, uncertainty factors in the calibration process should be clearly marked. For example, calibration accuracy information can be appended to the output results, such as the measurement error range of signal intensity or the uncertainty in the calculation of the volume of different segments. Specifically, the error range can be calculated based on the measured signal intensity value in the calibration formula and the sensitivity of the measuring device. For example, for the measured value the error range , and the calculation error range of the volume can be estimated through the error propagation formula.

[0123] It should be noted that for a complex pipeline system, distribution information of spatial positions can also be appended to the calibration results. For example, through a 3D modeling tool, the volume values of each pipeline segment can be combined with their spatial positions to generate a visual volume distribution model. Such a visual result can help technicians more intuitively understand the volume distribution characteristics of the system and provide a basis for the design of subsequent gas measurement experiments.

[0124] In some embodiments, the output of the calibration results can also be combined with the control system of the mass spectrometer itself to achieve linkage with the subsequent measurement process. For example, the calibration results can be directly stored in the built-in memory of the mass spectrometer to make it the reference data for subsequent gas measurements. When the mass spectrometer is running, it can automatically calibrate the signals according to the stored volume distribution data, thereby improving the accuracy of the measurement results.

[0125] In this embodiment, by taking the recording, sorting, and output of the volume values of each pipeline segment as the final step of the calibration method, not only the acquisition of the complete volume distribution data of the system is realized, but also reliable basic support is provided for subsequent applications.

[0126] Generally speaking, the present invention evacuates the gas measurement system, injects high-purity gas, and uses a mass spectrometer to measure the gas signal intensity of each segment one by one. By combining the structure of the system and the calculation formula, the volume of each pipe segment is calibrated in sequence, and finally the complete volume distribution data of the system is obtained. This method adopts a recursive calculation method, calibrating step by step from the pipe segment closest to the mass spectrometer to the far end, avoiding the problem of error accumulation in the direct measurement of the volume of a complex system, and has the characteristics of high precision and high reliability. It provides technical support for the calibration and optimization of gas measurement systems and is applicable to the calibration requirements of complex pipeline volumes in laboratory and industrial fields.

[0127] To better understand the present invention, the above method will be described in detail below with specific embodiments.

[0128] Embodiment:

[0129] This embodiment takes the system in Figure 2 as an example to illustrate the calibration method of the present invention in detail:

[0130] Before starting the calibration, the states of the system valves are as follows: GVTP, GVIP1, GV2, GV3, GV4, GV5, GV6, and GV7 are in the open state, and the rest of the valves are in the closed state.

[0131] 1. Calibrate the volume of system V1 between GV2 and GVMS by means of reverse diffusion .

[0132] a) Take high-purity He gas into the volume between SV1 and SV2. The specific operation is as follows: Open SV1 and close SV1 after 2 minutes.

[0133] b) The He standard gas diffuses into the entire system. The specific operation is as follows: Close GVTP and GVIP1, open GV8 and SV2, and close SV2 after 2 minutes. At this time, the gas has diffused from between SV1 and SV2 to the entire pipeline.

[0134] c) Mass spectrometry measurement. Close GVIP2, open GVMS, and close GVMS after 1 minute for mass spectrometry measurement 4 He, and the test result is recorded as S1. At the same time, open GVTP to evacuate the residual gas in the system pipeline to keep it in a vacuum state.

[0135] d) After the mass spectrometry measurement, reverse-diffuse the gas in the mass spectrometer into the pipe section closest to the mass spectrometer (V1), that is, the part from GV2 to GVMS. The specific operation is as follows: Close GV2 and open GVMS. After 1 minute, conduct mass spectrometry measurement 4 He, and the test result is recorded as S2. After the measurement, close GVMS, open GV2 and GVIP2. The volume of the inner cavity of the mass spectrometer is provided by the mass spectrometer manufacturer, then .

[0136] e) Repeat the above steps three times or more, and take the average of multiple as the volume of V1 between GV2 - GVMS fixed value.

[0137] 2. Calibrate the volumes of each part from V2 - V8 .

[0138] a) Take high-purity He gas into the volume between SV1 and SV2: Open SV1 and close SV1 after 2 minutes.

[0139] b) The He standard gas diffuses throughout the system. The specific operation is as follows: Close GVTP and GVIP1, open GV8 and SV2, and after 2 minutes, close SV2. At this time, the gas has diffused from between SV1 and SV2 throughout the pipeline. Subsequently, close all valves (GV1, GV2, GV3, GV4, GV5, GV6, GV7). In this way, the gas is isolated and stored separately in V1 - V8.

[0140] c) Close GVIP2, open GVMS. The gas in part V1, that is, the gas between GV2 and GVMS, enters the mass spectrometer. After 1 minute, close GVMS for mass spectrometry measurement 4 He, and the test result is recorded as Sig1. After the measurement is completed, open GVIP2 and GVMS to evacuate the residual gas, and close GVMS after 5 minutes.

[0141] d) Calibrate the volume . The specific operation is as follows: Open GV2, and after 2 minutes, close GV2. Close GVIP2, open GVMS, and after 1 minute, close GVMS for mass spectrometry measurement 4 He, and the test result is recorded as Sig2. After the measurement is completed, open GVIP2, GVMS, and GV2, and close GVMS after 5 minutes. The formula is .

[0142] e) Calibrate the volume . The specific operation is as follows: Open GV3, and after 2 minutes, close GV2. Close GVIP2, open GVMS, and after 1 minute, close GVMS for mass spectrometry measurement 4 He, and the test result is recorded as Sig3. After the measurement is completed, open GVIP2, GVMS, and GV2, and close GVMS after 5 minutes. The formula is .

[0143] f) Calibrate the volume . The specific operation is as follows: Open GV4, after 2 minutes, close GV2, and open GVIP1. Close GVIP2, open GVMS, after 1 minute, close GVMS, open GV2, and perform mass spectrometry measurement 4 He, and the test result is recorded as Sig4. After the measurement is completed, open GVIP2. The formula is .

[0144] g) Calibrate the volume . The specific operation is as follows: Close GVIP1, open GV5, after 2 minutes, close GV2, and open GVIP1. Close GVIP2, open GVMS, after 1 minute, close GVMS, open GV2, and perform mass spectrometry measurement 4 He, and the test result is recorded as Sig5. After the measurement is completed, open GVIP2. The formula is .

[0145] h) Calibration volume The specific operation is as follows: Close GVIP1, open GV6, after 2 minutes, close GV2, and open GVIP1. Close GVIP2, open GVMS, after 1 minute, close GVMS, open GV2, and perform mass spectrometry measurement 4 He, and the test result is recorded as Sig6. After the measurement is completed, open GVIP2. The formula is .

[0146] i) Calibration volume The specific operation is as follows: Close GVIP1, open GV7, after 2 minutes, close GV2, and open GVIP1. Close GVIP2, open GVMS, after 1 minute, close GVMS, open GV2, and perform mass spectrometry measurement 4 He, and the test result is recorded as Sig7. After the measurement is completed, open GVIP2. The formula is .

[0147] j) Calibration volume The specific operation is as follows: Close GVIP1, open GV8, after 2 minutes, close GV2, and open GVIP1. Close GVIP2, open GVMS, after 1 minute, close GVMS, open GV2, and perform mass spectrometry measurement 4 He, and the measured signal quantity is recorded as Sig8. After the measurement is completed, open GVIP2. Close GV8 and open GVIP1 The formula is .

[0148] k) Repeat the above steps more than three times, and take the average value as the fixed value of each part of the volume

[0149] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents

Claims

1. A method for calibrating the volume of a gas measurement system, characterized in that: The following steps are involved: S1. Evacuate the gas measurement system to remove residual gas and reset the valve to its initial state; S2. Calibrate the volume of the tube section closest to the mass spectrometer: S2.

1. Diffuse and inject high-purity He gas into the mass spectrometer; measure the He gas signal intensity through the mass spectrometer; during the measurement, except for the mass spectrometer, the remaining pipelines are evacuated to remove residual gas; S2.2, diffuse the gas in the mass spectrometer back to the target section, measure the He gas signal intensity for a second time, and calculate the volume of the tube section in combination with the volume of the mass spectrometer cavity; S2.

3. Repeat S2.1 and S2.2 several times and calculate the average value to obtain the volume of the tube section closest to the mass spectrometer; S3. Calibrate the volume of other pipe sections: S3.

1. Inject high purity He gas into the entire pipeline; S3.

2. Open the corresponding valves one by one in the order from the closest to the mass spectrometer to the farthest, measure the signal intensity difference through the mass spectrometer, and recursively calculate the volume of each section; S3.

3. Record the volume of each section of the pipeline to obtain the complete volume distribution data of the system; S3.

4. Repeat S3.1 to S3.3 several times and calculate the average value; The volume of the tube section closest to the mass spectrometer should be calibrated as follows: Open and close the corresponding valve to allow high-purity He gas to diffuse into the mass spectrometer; Measure the He signal intensity and record the initial signal value; Close all other valves connected to this pipe section; Back-diffuse the gas in the mass spectrometer to the tube section and measure the signal value; Calculate the volume of a pipe segment: in, is the volume of the tube section closest to the mass spectrometer to be calibrated, To measure the He signal intensity for the mass spectrometer, is the He signal intensity after the He gas in the mass spectrometer diffuses back to the tube section closest to the mass spectrometer, is the volume of the mass spectrometer cavity; When calibrating the volume of other pipe sections, proceed section by section in the order from near to far from the mass spectrometer; when calibrating a certain pipe section, first diffuse the gas in the pipe section to the pipe section closest to the mass spectrometer, and take the gas in the pipe section closest to the mass spectrometer into the mass spectrometer for measurement; calculate according to the recursive formula: in, To be calibrated Pipeline volume, For mass spectrometer measurement The gas signal strength of the pipeline segment, The signal intensity of He gas in the initial calibration tube section is measured for the mass spectrometer. For the front The sum of the volumes of the pipeline segments; During the calibration process of each pipe section, the calibrated pipe section in the diffusion path is kept in a vacuum state.

2. A method for calibrating the volume of a gas measurement system according to claim 1, characterized in that: During the calibration process, the injection amount of high-purity He gas was controlled at 1×10 -3 ccSTP~5×10 -3 ccSTP.

3. A method for calibrating the volume of a gas measurement system according to claim 1, characterized in that: The volume calibration of each pipe section was repeated at least 3 times, and the average value was taken as the final volume value of the section.

4. A method for calibrating the volume of a gas measurement system according to claim 1, characterized in that: The gas measurement system comprises a plurality of valves, pipes and a mass spectrometer, wherein: Valves GVTP and GVIP1 are connected to the vacuum pump; valves GV2-GV8 are connected to the various sections of the pipeline of the gas measurement system in sequence to achieve isolation or connection of the various pipe sections; valve GVMS is connected to the inlet of the mass spectrometer. The initial state of the system is: GVTP, GVIP1, GV2, GV3, GV4, GV5, GV6, and GV7 are in the open state, and the remaining valves are in the closed state.

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