Gas distribution quality control system, method and device

Abstract

The invention provides a gas distribution quality control system and method and a gas distribution device. The gas distribution quality control system comprises a calibration module for carrying out flow calibration on a mass flow controller; the gas distribution module calculates the ratio of the first gas to the second gas according to the concentration value of the to-be-prepared gas, obtains the first gas with the first flow and the second gas with the second flow according to the ratio, and enables the first gas with the first flow and the second gas with the second flow to be mixed to obtain the to-be-prepared gas; the verification module performs flow verification on each mass flow controller according to the verification instruction or when a verification period condition is satisfied; and the control module generates a calibration instruction, sends the calibration instruction to the calibration module, sends a gas distribution instruction to the gas distribution module after calibration is completed, and re-calibrates the mass flow controllers which do not pass the flow precision verification when the mass flow controllers do not pass the flow precision verification. According to the embodiment of the invention, automatic calibration and verification functions can be realized, so that the gas distribution precision is ensured.

Description

Technical Field

[0001] This application relates to the field of gas detection technology, and in particular to a gas mixing and control system, method and apparatus. Background Technology

[0002] In laboratory, factory production, and industrial settings, particularly during chemical production and testing, it is often necessary to prepare various mixed gases. Some of these mixtures are for dilution purposes, such as adding N2 to SF6 gas to create a SF6-containing mixture, or mixing SF6 gas with N2, CO, SO2, H2S, etc., to obtain a multi-component mixture for chemical testing or for producing standard gases for the verification, testing, calibration, and performance evaluation of gas analyzers, purity meters, combustible gas detectors, gas leak detectors, and various gas sensors. However, in these settings, the standard and dilution gases used in preparing mixed gases are very specific and do not require frequent replacement. Therefore, there is no need to calibrate the range of the mass flow controller when using the gas mixing device.

[0003] With increasing emphasis on environmental protection, various gas mixtures are needed for calibration testing of different gases in the environment. This means that the types of gases requiring preparation are increasing in fields such as atmospheric environmental monitoring and occupational safety, necessitating the use of multiple standard gases. A mass flow controller is a device used to accurately measure and control the mass flow rate of gases or liquids. It is an indispensable key component in many high-tech industrial fields such as semiconductors, photovoltaics, scientific research, and biopharmaceuticals. However, the control accuracy of a mass flow controller is affected by the detection accuracy and range of its own mass flow sensor, resulting in low precision in the final prepared gas mixture. Furthermore, besides the inherent accuracy issues of the equipment itself, other factors may also affect the precision of the prepared gas mixture during the preparation process. Therefore, there is an urgent need to provide a gas flow control system, method, and apparatus for preparing gas mixtures to solve the above problems. Summary of the Invention

[0004] This application is made in view of at least one of the aforementioned technical problems existing in the prior art. According to one aspect of this application, a gas distribution and control system is provided, the gas distribution and control system being applied to a gas distribution device, the gas distribution device including at least two mass flow controllers; the gas distribution and control system includes a calibration module, a gas distribution module, a verification module, and a control module; wherein... The calibration module is used to perform flow calibration on the mass flow controller indicated by the calibration command based on the gas type connected to the gas distribution device before gas distribution, according to the calibration command of the control module. The gas mixing module is used to acquire parameter information of the gas to be mixed, calculate the required ratio of the first gas and the second gas based on the parameter information of the gas to be mixed, acquire the first gas at a first flow rate and the second gas at a second flow rate based on the ratio, and allow the first gas at the first flow rate and the second gas at the second flow rate to enter the mixing gas passage so that the first gas at the first flow rate and the second gas at the second flow rate are mixed to obtain the gas to be mixed; wherein, the first gas at the first flow rate and the second gas at the second flow rate are obtained by the at least two mass flow controllers detecting the mass flow rate of the gas in real time and automatically adjusting the valve opening according to the ratio; The verification module is used to verify multiple preset flow points of each mass flow controller according to the verification instruction or when the verification period condition is met, using a linear fitting algorithm, and return the verification result to the control module. The control module is used to generate a calibration command and send it to the calibration module when the gas type and mass flow controller do not match, and to send a gas distribution command to the gas distribution module after calibration is completed, and to send a command to the calibration module to calibrate the mass flow controller that failed the flow accuracy calibration when there is a mass flow controller that failed the calibration.

[0005] In some embodiments, the calibration module is specifically used for: Connect any type of gas to the gas distribution device; Detect whether the gas mixing device stores any of the types of the gas; If the gas distribution device does not store the type of any of the gases, the switch on any one of the gas passages is turned on, allowing any one of the gases to flow through the mass flow controller on any one of the gas passages and finally into the calibration passage; wherein, the calibration passage is equipped with a volumetric flow meter, which displays the actual flow value of any one of the gases; Read the detected flow values ​​of the mass flow controller at each predicted flow point; Divide the actual flow rate value by the detected flow rate value to obtain the gas coefficient of any given gas.

[0006] In some embodiments, the verification module is specifically used for: Collect measured data at multiple preset flow points across the entire range of any mass flow controller; And curve fitting is performed based on the measured data; If any one of the multiple preset flow points has a deviation, and the deviation exceeds a preset threshold, then any one of the mass flow controllers is calibrated.

[0007] In some embodiments, the verification module is specifically used for: The plurality of preset flow points include any three points from 10%, 15%, 20%, 40%, 60%, 80%, and 100% of the mass flow controller's range.

[0008] In some embodiments, the system further includes a pressure sensing module; The pressure sensing module is used to monitor the pressure of the first gas passage and the second gas passage in real time, and send the pressure values ​​of the first gas passage and the second gas passage to the control module so that the control module can issue an alarm when the pressure fluctuation value exceeds a preset fluctuation threshold.

[0009] In some embodiments, the gas distribution module is specifically used for: Turn on the first and second switches on the first and second gas passages respectively, and connect the first and second gases; According to the required ratio of the first gas and the second gas, adjust the mass flow controllers on the first gas passage and the second gas passage to obtain the first gas at the first flow rate and the second gas at the second flow rate; The third and fourth switches on the first and second gas passages are turned on respectively, so that the first gas at the first flow rate and the second gas at the second flow rate enter the mixed gas passage, and the first gas at the first flow rate and the second gas at the second flow rate are mixed to obtain the gas to be prepared.

[0010] In some embodiments, both the first gas passage and the second gas passage include two mass flow controllers connected in parallel with different ranges.

[0011] In some embodiments, the gas distribution module is further specifically used for: Based on the required ratio of the first and second gases, one of the two mass flow controllers is activated to perform gas mixing.

[0012] In some embodiments, the first gas is a standard gas and the second gas is a dilution gas.

[0013] According to another aspect of this application, a gas flow control method is also provided, applied to a gas distribution device, the gas distribution device including at least two mass flow controllers; the method includes: Check whether each mass flow controller matches the corresponding access gas type; In the event of a mismatch between the mass flow controller and the type of gas being supplied, before gas distribution, the mass flow controller that is mismatched with the type of gas supplied to the gas distribution device shall be calibrated for flow rate. Obtain the parameter information of the gas to be prepared, and calculate the required ratio of the first gas and the second gas based on the parameter information of the gas to be prepared; According to the ratio, a first gas at a first flow rate and a second gas at a second flow rate are obtained, and the first gas at a first flow rate and the second gas at a second flow rate are introduced into a mixed gas passage to mix the first gas at a first flow rate and the second gas at a second flow rate to obtain the gas to be prepared; wherein, the first gas at a first flow rate and the second gas at a second flow rate are obtained by the at least two mass flow controllers detecting the mass flow rate of the gas in real time and automatically adjusting the valve opening according to the ratio; The method further includes: according to the verification instruction or when the verification period condition is met, using a linear fitting algorithm to verify multiple preset flow points of each mass flow controller, and calibrating the mass flow controllers that fail the verification.

[0014] In some embodiments, prior to gas distribution, flow calibration is performed on a mass flow controller that does not match the type of gas connected to the gas distribution device, including: Turn on the switch on the gas access path to allow the gas to flow through the corresponding mass flow controller and finally into the calibration path; wherein, the calibration path is equipped with a volumetric flow meter; wherein, the volumetric flow meter displays the actual flow value of any gas; Read the detected flow values ​​of the mass flow controller at each predicted flow point; Divide the actual flow rate value by the detected flow rate value to obtain the gas coefficient of any given gas.

[0015] In some embodiments, according to a verification instruction or when the verification period condition is met, a linear fitting algorithm is used to verify multiple preset flow points of each mass flow controller, including: Collect measured data at multiple preset flow points across the full range of any mass flow controller; And curve fitting is performed based on the measured data; If any one of the multiple preset flow points has a deviation, and the deviation exceeds a preset threshold, then any one of the mass flow controllers is calibrated.

[0016] In some embodiments, the plurality of preset flow points include any three points selected from 10%, 15%, 20%, 40%, 60%, 80%, and 100% of the mass flow controller's range.

[0017] In some embodiments, the method further includes: The pressure of the first gas passage and the second gas passage is monitored in real time, and an alarm is issued when the pressure fluctuation value exceeds the preset fluctuation threshold.

[0018] In some embodiments, a first gas at a first flow rate and a second gas at a second flow rate are obtained according to the ratio, and the first gas at the first flow rate and the second gas at the second flow rate are introduced into a mixing gas passage to mix the first gas at the first flow rate and the second gas at the second flow rate to obtain the gas to be prepared, including: Turn on the first and second switches on the first and second gas passages respectively, and connect the first and second gases; According to the required ratio of the first gas and the second gas, adjust the mass flow controllers on the first gas passage and the second gas passage to obtain the first gas at the first flow rate and the second gas at the second flow rate; The third and fourth switches on the first and second gas passages are turned on respectively, so that the first gas at the first flow rate and the second gas at the second flow rate enter the mixed gas passage, and the first gas at the first flow rate and the second gas at the second flow rate are mixed to obtain the gas to be prepared.

[0019] In some embodiments, the first gas passage and the second gas passage each include two mass flow controllers connected in parallel with different ranges; the method further includes obtaining a first gas at a first flow rate and a second gas at a second flow rate according to the mixing ratio, and allowing the first gas at the first flow rate and the second gas at the second flow rate to enter a mixing gas passage to mix the first gas at the first flow rate and the second gas at the second flow rate to obtain the gas to be prepared. Based on the required ratio of the first and second gases, one of the two mass flow controllers is activated to perform gas mixing.

[0020] According to another aspect of this application, a gas mixing device is also provided, the device comprising a first gas passage, a second gas passage, a mixed gas passage, and a controller; wherein, The first gas passage and the second gas passage are connected in parallel, and both the first gas passage and the second gas passage are connected in series with the mixed gas passage; the first gas passage is provided with a first switch, a first mass flow controller and a third switch connected in series; the second gas passage is provided with a second switch, a third mass flow controller and a fourth switch connected in series. The controller is used for: In the event of a mismatch between the mass flow controller and the type of gas being supplied, the mass flow controller that is incompatible with the type of gas supplied shall be calibrated according to the type of gas supplied to the gas supply device before gas supply is supplied. Obtain the parameter information of the gas to be prepared, and calculate the required ratio of the first gas and the second gas based on the parameter information of the gas to be prepared; According to the ratio, instructions are sent to the first mass flow controller and the third mass flow controller to obtain the first gas at a first flow rate and the second gas at a second flow rate corresponding to the ratio, so as to obtain the first gas at the first flow rate and the second gas at the second flow rate; The first gas at the first flow rate and the second gas at the second flow rate are introduced into the mixing gas passage to mix the first gas at the first flow rate and the second gas at the second flow rate to obtain the gas to be prepared; The controller is also used to verify multiple preset flow points of each mass flow controller using a linear fitting algorithm according to a verification instruction or when the verification period condition is met, and to calibrate the mass flow controllers that fail the verification.

[0021] In some embodiments, the first gas passage includes a first mass flow controller and a second mass flow controller connected in parallel; the second gas passage includes a third mass flow controller and a fourth mass flow controller connected in parallel; wherein the first mass flow controller and the second mass flow controller have different ranges, and the third mass flow controller and the fourth mass flow controller have different ranges. The controller is also configured to select the first mass flow controller or the second mass flow controller based on the gas distribution parameters, and to select the third mass flow controller or the fourth mass flow controller.

[0022] In some embodiments, the device further includes a first pressure transmitter and a second pressure transmitter; The first pressure transmitter and the second pressure transmitter are respectively installed at any position in the first gas passage and at any position in the first gas passage to monitor the pressure fluctuations of the gas flowing through the first gas passage and in the first gas passage.

[0023] In some embodiments, both the first gas passage and the second gas passage are connected in series with a calibration passage.

[0024] Compared with traditional technologies, the embodiments of this application have the following beneficial effects: 1. The calibration module in this application embodiment performs multi-point flow calibration on the mass flow controller according to the type of gas connected before gas mixing. It performs targeted calibration for different gas types to avoid calibration errors caused by differences in gas characteristics, thus laying the foundation for subsequent high-precision gas mixing. 2. The gas mixing module in this embodiment calculates the gas ratio based on the concentration value of the gas to be mixed, and automatically adjusts the valve opening by detecting the gas mass flow rate in real time through a mass flow controller to ensure accurate control of the gas flow rate, thereby ensuring the accuracy of the gas mixing concentration; at the same time, both the first gas passage and the second gas passage are equipped with mass flow controllers of different ranges connected in parallel, and the appropriate range controller can be selected according to the flow rate requirements, taking into account the high-precision control requirements of both small and large flow rates. 3. The verification module in this application embodiment can perform accuracy verification of the mass flow controller using a linear fitting algorithm according to instructions or periodic conditions, and perform secondary calibration when the accuracy fails to pass, so as to avoid the decrease in accuracy caused by long-term use and ensure the long-term reliability of the mass flow controller system. 4. The pressure sensing module in this application embodiment can monitor the pressure of the gas passage in real time and issue an alarm when the pressure fluctuation exceeds the preset wave threshold, so as to avoid the impact of pressure fluctuation on flow stability and gas distribution accuracy in a timely manner and further improve gas distribution stability. 5. The overall system has a simple structure and is easy to operate. Through the synergistic effect of calibration, gas mixing, verification, and pressure monitoring, it achieves high-precision, stable and reliable gas mixing throughout the entire process, and is suitable for gas mixing needs in various scenarios such as laboratories and industrial production. Attached Figure Description

[0025] Figure 1 A schematic flowchart of a gas distribution control system according to an embodiment of this application is shown; Figure 2 A schematic flowchart illustrating a multi-point flow calibration process 200 according to an embodiment of this application is shown. Figure 3 A schematic flowchart illustrating a gas mixing method according to an embodiment of this application is shown; Figure 4 A schematic flowchart of the verification process S203 according to an embodiment of this application is shown; Figure 5 A schematic flowchart illustrating step S203 according to another embodiment of this application is shown; Figure 6A schematic flowchart illustrating a process 600 for monitoring the pressure of a gas passage according to an embodiment of this application is shown. Figure 7 A schematic flowchart illustrating step S601 according to an embodiment of this application is shown; Figure 8 A schematic flowchart of 800 according to an embodiment of this application is shown; Figure 9 A schematic block diagram of a gas distribution device 900 according to an embodiment of this application is shown. Detailed Implementation

[0026] To enable those skilled in the art to better understand the technical solutions of the embodiments of this application, the application will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] In gas analysis, industrial production, and laboratory testing, it is often necessary to prepare mixed gases of specific concentrations according to actual needs. The accuracy of gas mixing directly affects the accuracy and reliability of subsequent experiments or production. Existing gas mixing devices are often used to quantitatively dilute standard gases of known concentrations from existing gas cylinders. However, users who are unfamiliar with gas components and the principles of MFC gas flow control are prone to operational errors, leading to inaccurate gas mixing without their knowledge. Furthermore, gas mixing devices typically use single-range mass flow controllers to control gas flow, making it difficult to simultaneously meet the high-precision control requirements of both small and large flow rates. The calibration process before gas mixing is also cumbersome, lacking specific calibration for different gas types, which can easily lead to significant mixing errors. In addition, the lack of real-time monitoring of gas path pressure during the mixing process means that pressure fluctuations can affect flow stability, thus impacting mixing accuracy. Moreover, existing gas mixing and control systems lack periodic verification and secondary calibration mechanisms. Over long-term use, the accuracy of the mass flow controller will decrease, compromising long-term gas mixing reliability and failing to meet the requirements for high-precision, long-term stable gas mixing.

[0028] To address at least one of the aforementioned technical problems, this application provides a gas flow control system for gas mixing. The gas flow control system is applied to a gas mixing device, which includes at least two mass flow controllers. The gas flow control system includes a calibration module, a gas mixing module, a verification module, and a control module. The calibration module is used to perform flow calibration on the mass flow controllers indicated by the calibration command, based on the calibration command from the control module, according to the type of gas connected to the gas mixing device before gas mixing. The gas mixing module is used to acquire parameter information of the gas to be mixed, calculate the required ratio of a first gas and a second gas based on the parameter information, acquire a first gas flow rate at a first flow rate and a second gas flow rate at a second flow rate based on the ratio, and allow the first gas flow rate at a first flow rate and the second gas flow rate at a second flow rate to enter a mixed gas passage, so that the first gas flow rate at a first flow rate and the second gas flow rate at a second flow rate... The second gas is mixed to obtain the gas to be prepared; wherein, the first gas at the first flow rate and the second gas at the second flow rate are obtained by real-time detection of the gas mass flow rate by at least two mass flow controllers and automatic adjustment of the valve opening according to the mixing ratio; the verification module is used to verify multiple preset flow points of each mass flow controller using a linear fitting algorithm according to a verification instruction or when the verification period conditions are met, and return the verification results to the control module; the control module is used to generate a calibration instruction and send it to the calibration module when the gas type and mass flow controller do not match, and to send a gas mixing instruction to the gas mixing module after calibration, and to send an instruction to the calibration module to calibrate the mass flow controller that failed the flow accuracy verification when a mass flow controller fails the verification. This embodiment of the application can realize automatic calibration and verification functions to ensure gas mixing accuracy.

[0029] Figure 1 A schematic block diagram of a gas distribution and control system according to an embodiment of this application is shown. The gas distribution and control system is applied to a gas distribution device, which includes at least two mass flow controllers.

[0030] like Figure 1 As shown, the gas mixing and control system 100 according to an embodiment of this application may include a calibration module 101, a gas mixing module 102, a verification module 103, and a control module 104.

[0031] The calibration module 101 is used to perform flow calibration on the mass flow controller indicated by the calibration command based on the gas type connected to the gas distribution device before gas distribution, according to the calibration command of the control module.

[0032] The flow rate of the mass flow controller in this embodiment refers to the gas mass flow rate, which characterizes the gas mass passing through the mass flow controller per unit time.

[0033] Specifically, the calibration module is used for: Connect any type of gas to the gas distribution device; Detect whether the gas mixing device stores any of the types of the gas; If the gas distribution device does not store the type of any of the gases, the switch on any one of the gas passages is turned on, allowing any one of the gases to flow through the mass flow controller on any one of the gas passages and finally into the calibration passage; wherein, the calibration passage is equipped with a volumetric flow meter, which displays the actual flow value of any one of the gases; Read the detected flow values ​​of the mass flow controller at each predicted flow point; Divide the actual flow rate value by the detected flow rate value to obtain the gas coefficient of any given gas.

[0034] Since the flow detection principle of mass flow controllers is based on the physical parameters of fluids such as thermal conductivity, density, viscosity, and heat capacity, and these physical properties vary significantly among different types of gases, the detection signal output by the mass flow controller will differ even at the same actual flow rate. Therefore, the flow response curves of the same mass flow controller for different gases will not be the same. If uniform calibration parameters are used, significant flow errors will occur due to differences in gas characteristics.

[0035] When using a gas distribution device, if a standard gas has been previously connected to the device, the corresponding mass flow controller's flow calibration data is already stored in the storage unit. In this case, the user can select the corresponding gas type via a touchscreen or other input device, without needing to perform flow calibration on the mass flow controller again. If the gas to be connected is not stored in the gas distribution device, targeted flow calibration is required for that gas.

[0036] During calibration, the switch on the current gas path is turned on, allowing the gas to flow through the mass flow controller and ultimately into the preset calibration path. A volumetric flow meter is installed in the calibration path, and the actual flow rate measured by the volumetric flow meter is used as the flow reference to calibrate the mass flow controller. Specifically, the control unit of the gas distribution device controls the mass flow controller to sequentially operate to each preset flow point. After the flow rate at each flow point stabilizes (flow fluctuation less than a preset small threshold, such as ±0.1%), the actual flow rate value of the gas displayed on the volumetric flow meter is read, and the detection value of the mass flow controller at that flow point is recorded. The current gas type, each calibration flow point, and the corresponding mass flow controller detection value and volumetric flow meter actual flow value are all input into the storage unit of the gas distribution device for storage, completing the multi-point flow calibration of the mass flow controller corresponding to that gas type. The preset flow points can include 10%, 15%, 20%, 40%, 60%, 80%, and 100%.

[0037] For example, in the field of gas monitoring, different types of gases are involved, such as SO2 and NO at concentrations of one part per million (ppm). x Gases such as CO and CH4 can be used, as well as gases like O2 and CO2 at concentrations in the one percent range. MFCs are typically factory-calibrated using N2 or air as a reference. For example, a 5L / min N2 MFC is a flow controller that controls flow rates from 0 to 5L / min based on N2, with a default MFC coefficient of 1, which also serves as the reference coefficient. If used to control other gases at concentrations in the one percent range, data changes will occur. Without secondary calibration, the accuracy of the flow rate will be severely affected, thus impacting the precision of gas mixing. Therefore, for gas mixing devices that can handle various types of incoming gases, calibration is essential.

[0038] Generally, gas mixing devices pre-store various gas types (containing multiple components) and their corresponding gas coefficients. For example, when N2 is connected, the gas coefficient corresponding to N2 is selected. When O2 or CO2 with a concentration at the 1% level is connected, the corresponding gas coefficient is selected. If the connected gas is a standard gas at the 1 / 1 million (ppm) level and the remaining background gas is nitrogen with a volume greater than 99%, this gas can be considered as N2, and the gas coefficient corresponding to N2 is also used. For example, during calibration, after connecting a background gas with a volume greater than 99% nitrogen, the display interface prompts: "Does the N2 concentration of the connected gas exceed 99%?" If "Yes" is selected, the current MFC gas coefficient is the gas coefficient corresponding to N2, which is 1. If "No" is selected, the system prompts to enter the automatic calibration process. Alternatively, if the user chooses not to enter the automatic calibration process and instead inputs the gas component name, such as 50% O2-N2, 25% CO2-21% O2-N2, etc., then the automatic calibration process will begin. The gas mixing device uses a quadratic curve fitting algorithm to set the flow rate according to the MFC's preset flow points. The flow points are selected according to the principle of denser flow rates in the lower range and sparser flow rates in the higher range, ranging from 10%, 15%, 20%, 30%, 40%, 60%, 80%, to 100%. That is, the interval between the first, second, and third flow points is 5%, the interval between the third, fourth, and fifth flow points is 10%, and the interval between the fifth, sixth, seventh, and eighth flow points is 20%. Once the set values ​​for each MFC flow point are established, and the VFM calibration value fluctuation is less than the fluctuation threshold (e.g., 0.5%), the current gas distribution device is considered to be in a stable state. An array of values ​​is obtained; after obtaining eight sets of values, automatic fitting calculation is performed. The quadratic fitting function expression is as follows: Where x represents the set value; y represents the return value; A0 represents the coefficient of the quadratic term; A1 represents the coefficient of the linear term; and A2 represents a constant.

[0039] Each input coefficient A0, A1, and A2 can be obtained from at least three sets of set values ​​and return value arrays.

[0040] Then, based on the quadratic fitting expression: Where y represents the return value; Indicates the calibration value; A 00 A represents the coefficient of the quadratic term; 11 A represents the coefficient of the linear term; 22 Represents a constant.

[0041] Each output coefficient A can be obtained by using at least three sets of return values ​​and calibration values. 00 A 11 A 22The two sets of functions corresponding to the input and output coefficients are used to fit the setpoint and calibration value, resulting in a normalized setpoint, return value, and calibration value: Setpoint = Return Value = Calibration Value = True Value. The calibrated input and output coefficients are automatically saved to the corresponding gas coefficient name, allowing for direct selection the next time the standard gas is used.

[0042] This application uses a standard flow meter as the flow reference to calibrate and correct the measurement value of the mass flow controller (MFC), normalizing the non-standard concentration / flow value output by the MFC to the standard true value that conforms to the reference, eliminating errors caused by gas characteristics, environmental conditions and device drift, and ensuring accurate and reliable gas mixing concentration.

[0043] It is worth noting that when setting preset flow points, the lower flow points can be set more densely. As can be seen from the preset flow points mentioned above, there are four lower flow points such as 10%, 15%, 20%, and 40%, while there are three higher flow points such as 60%, 80%, and 100%. This results in a higher accuracy of the calibrated flow values.

[0044] The gas mixing device in this embodiment can connect to multiple gas groups, each corresponding to a gas passage. These multiple gas groups may include standard gases and dilution gases, or they may all be standard gases. The multiple gas passages are hardware-independent; the user can configure which passage interface connects to the standard gas and which to the dilution gas. A sealing structure should be provided at the interface between the gas passages and the gas mixing device to prevent gas leakage from affecting calibration accuracy.

[0045] In this embodiment, before gas distribution, multi-point flow calibration is performed on each mass flow controller in the gas distribution device according to the type of gas connected to the gas distribution device. Targeted calibration is performed for different gas types to avoid calibration errors caused by differences in gas characteristics and to ensure the detection and control accuracy of the mass flow controller under different gas types.

[0046] Continue to combine Figure 1 The gas mixing module 102 is used to acquire parameter information of the gas to be mixed, calculate the required ratio of the first gas and the second gas based on the parameter information of the gas to be mixed, acquire the first gas at a first flow rate and the second gas at a second flow rate based on the ratio, and allow the first gas at a first flow rate and the second gas at a second flow rate to enter the mixing gas passage so that the first gas at a first flow rate and the second gas at a second flow rate are mixed to obtain the gas to be mixed; wherein, the first gas at a first flow rate and the second gas at a second flow rate are obtained by the at least two mass flow controllers detecting the mass flow rate of the gas in real time and automatically adjusting the valve opening according to the ratio.

[0047] To clearly illustrate this application, the embodiments are described using the first gas as a standard gas and the second gas as a dilution gas, but this is not intended to limit the scope of protection of this application. In specific implementations, the first gas and the second gas can also be different types of standard gases. Of course, the embodiments of this application are not limited to two types of inlet gases; multiple inlet gases can be used to prepare gas mixtures with more components. For example, a third gas, a fourth gas, etc., can also be inlet.

[0048] In one embodiment of this application, the gas distribution module 102 is specifically used for: The gas distribution module is specifically used for: Turn on the first and second switches on the first and second gas passages respectively, and connect the first and second gases; According to the required ratio of the first gas and the second gas, adjust the mass flow controllers on the first gas passage and the second gas passage to obtain the first gas at the first flow rate and the second gas at the second flow rate; The third and fourth switches on the first and second gas passages are turned on respectively, so that the first gas at the first flow rate and the second gas at the second flow rate enter the mixed gas passage, and the first gas at the first flow rate and the second gas at the second flow rate are mixed to obtain the gas to be prepared.

[0049] In another embodiment of this application, both the first gas passage and the second gas passage include two mass flow controllers connected in parallel with different ranges. Accordingly, the gas distribution module 102 is further specifically used to: activate one of the two mass flow controllers to perform gas distribution according to the required ratio of the first gas and the second gas.

[0050] This application employs a dynamic proportional dilution method for gas mixing. The gas mixing process typically involves setting two mass flow controllers in the standard gas path and the dilution gas path, respectively. By setting different flow rates for the two mass flow controllers, different dilution ratios are achieved, thereby quantitatively diluting the standard gas with the dilution gas to prepare a proportioned gas (the gas to be mixed). For details, refer to the conventional dynamic proportional dilution method; further elaboration is omitted here.

[0051] Both the first gas passage and the second gas passage include two mass flow controllers connected in parallel with different ranges to meet the requirements of different flow ranges.

[0052] When high-precision, low-flow-rate control is required, a mass flow controller with a smaller range can be selected. For high-flow-rate scenarios, a mass flow controller with a larger range should be used. This not only enhances the flexibility of the mass flow control system but also ensures accurate control across various flow ranges. Furthermore, the system automatically determines and selects the appropriate mass flow controller based on the user-defined mixing ratio, eliminating the need for manual intervention and further simplifying the operation process.

[0053] Since the flow rate and accuracy of the mass flow controller determine the accuracy of the gas to be prepared, it is necessary to select a mass flow controller with an appropriate range based on the dilution factor and range. For example, in the field of continuous emission monitoring of flue gas, the common dilution factor is within 10 times, and the flow rate of the gas to be prepared is usually no more than 5 L / min. In this case, the range of both mass flow controllers can be 5 L / min. However, in the field of atmospheric environmental monitoring, the dilution factor is usually thousands of times. In this case, the range of the MFC in the dilution gas path is 10 L / min, and the range of the MFC in the standard gas path is 100 mL / min.

[0054] For example, the first gas passage, i.e. the standard gas passage, is equipped with a first MFC and a second MFC connected in parallel, and the second gas passage, i.e. the dilution gas passage, is equipped with a third MFC and a fourth MFC connected in parallel. The flow path is controlled by the MCU control unit to combine them. The combination may include the first MFC and the third MFC, the first MFC and the fourth MFC, the second MFC and the third MFC, or the second MFC and the fourth MFC. If the flow rate of the first MFC is 500 mL / min (i.e., output range 50~500 mL / min), the flow rate of the second MFC is 5 L / min (output range 500~5000 mL / min), the flow rate of the third MFC is 500 mL / min (output range 50~500 mL / min), and the flow rate of the fourth MFC is 5 L / min (output range 500~5000 mL / min), then the flow rate of the first and third MFCs is 500 mL / min with a dilution factor of 1~10, the flow rate of the second and third MFCs is 5000 mL / min with a dilution factor of 10~100, and the flow rate of MFC2 and MFC4 is 5000 mL / min with a dilution factor of 1~10. Based on actual mixing requirements, any combination of the first and third MFCs, the first and fourth MFCs, the second and third MFCs, or the second and fourth MFCs can be selected.

[0055] The verification module 103 is used to verify multiple preset flow points of each mass flow controller according to the verification instruction or when the verification period condition is met, using a linear fitting algorithm, and return the verification result to the control module.

[0056] In one embodiment of this application, the verification module 103 is specifically used to: collect measured data at the plurality of preset flow points across the full range of any mass flow controller; perform curve fitting based on the measured data; and calibrate any mass flow controller when any of the plurality of preset flow points has a deviation and the deviation exceeds a preset threshold.

[0057] Gas distribution devices may develop inaccurate metering issues after a certain period of use due to factors such as aging. Therefore, periodic calibration is necessary. Specifically, two methods can be used: manual trigger calibration and automatic trigger calibration. Manual trigger calibration involves manually operating the calibration program on the touchscreen. Automatic trigger calibration allows setting a fixed calibration cycle in the system software. For example, if the calibration cycle is 168 hours and the calibration baseline time is 12:00 noon on January 25, 2026, then the automatic calibration function will be triggered at 12:00 noon on the following week.

[0058] Specifically, three flow points can be selected and fitted into a continuous calibration curve, allowing any setpoint of the mass flow controller (MFC) to be calculated accurately from the actual flow rate. Preferably, for flow calibration of the mass flow controller in the standard gas path, three flow points (10%, 50%, and 80%) are selected. The deviation values ​​of these three flow points are calculated. If any deviation value at any of these three flow points exceeds a preset deviation threshold, the standard gas is recalibrated. For example, if the preset deviation threshold is 1%, the flow rate of the mass flow controller in the standard gas path needs to be recalibrated if any of the three flow points deviates from the calibration curve by 1%. Since these three flow points are evenly distributed across the calibration curve, they can serve as typical flow points for gas verification without significantly increasing the computational load.

[0059] The embodiments of this application can automatically calibrate each mass flow controller at a preset time period to ensure the gas accuracy of the standard gas and the gas to be prepared during actual use.

[0060] Continue to combine Figure 1 The control module 104 is used to generate a calibration command and send it to the calibration module when the gas type and mass flow controller do not match, and to send a gas distribution command to the gas distribution module after calibration is completed, and to send a command to the calibration module to calibrate the mass flow controller that failed the flow accuracy calibration when there is a mass flow controller that failed the calibration.

[0061] Continue to combine Figure 1The gas control system further includes a pressure sensing module 105. The pressure sensing module 105 is used to monitor the pressure of the first gas passage and the second gas passage in real time, and send the pressure values ​​of the first gas passage and the second gas passage to the control module, so that the control module issues an alarm when the pressure fluctuation value exceeds a preset fluctuation threshold.

[0062] During the gas mixing process, if pressure fluctuations occur in the first gas passage and the second gas passage, it will affect the stability of the flow control of the mass flow controller (MFC). Therefore, in this embodiment, pressure transmitters are installed at the inlet of both the standard gas passage and the dilution gas passage to monitor the pressure fluctuations in the standard gas passage and the dilution gas passage, so as to ensure that the gas pressure entering the MFC is stable and reliable, to ensure the stability of the MFC flow control, and thus to ensure the stability of the gas mixing concentration.

[0063] Compared with traditional technologies, the embodiments of this application have the following beneficial effects: 1. The calibration module in this application embodiment performs multi-point flow calibration on the mass flow controller according to the type of gas connected before gas mixing. It performs targeted calibration for different gas types to avoid calibration errors caused by differences in gas characteristics, thus laying the foundation for subsequent high-precision gas mixing. 2. The gas mixing module in this embodiment calculates the gas ratio based on the concentration value of the gas to be mixed, and automatically adjusts the valve opening by detecting the gas mass flow rate in real time through a mass flow controller to ensure accurate control of the gas flow rate, thereby ensuring the accuracy of the gas mixing concentration; at the same time, both the first gas passage and the second gas passage are equipped with mass flow controllers of different ranges connected in parallel, and the appropriate range controller can be selected according to the flow rate requirements, taking into account the high-precision control requirements of both small and large flow rates. 3. The verification module in this application embodiment can perform accuracy verification of the mass flow controller using a linear fitting algorithm according to instructions or periodic conditions, and perform secondary calibration when the accuracy fails to pass, so as to avoid the decrease in accuracy caused by long-term use and ensure the long-term reliability of the mass flow controller system. 4. The pressure sensing module in this application embodiment can monitor the pressure of the gas passage in real time and issue an alarm when the pressure fluctuation exceeds the preset wave threshold, so as to avoid the impact of pressure fluctuation on flow stability and gas distribution accuracy in a timely manner and further improve gas distribution stability. 5. The overall system has a simple structure and is easy to operate. Through the synergistic effect of calibration, gas mixing, verification, and pressure monitoring, it achieves high-precision, stable and reliable gas mixing throughout the entire process, and is suitable for gas mixing needs in various scenarios such as laboratories and industrial production.

[0064] Figure 2 A schematic flowchart of a gas mixing method according to an embodiment of this application is shown; as follows: Figure 2 As shown, the gas mixing method 200 according to an embodiment of this application may include the following steps S201, S202, S203 and S204: In step S201, it is detected whether each mass flow controller matches the corresponding access gas type; if so, step S203 is executed; if not, step S202 is executed. In step S202, before gas distribution, the mass flow controller that does not match the gas type connected to the gas distribution device is calibrated according to the gas type connected to the gas distribution device. In step S203, the parameter information of the gas to be prepared is obtained, and the required ratio of the first gas and the second gas is calculated based on the parameter information of the gas to be prepared. In step S204, a first gas at a first flow rate and a second gas at a second flow rate are obtained according to the ratio. The first gas at the first flow rate and the second gas at the second flow rate are then introduced into the mixed gas passage to mix the first gas at the first flow rate and the second gas at the second flow rate, thereby obtaining the gas to be prepared.

[0065] In one embodiment of this application, such as Figure 3 As shown, step S202, which calibrates the mass flow controller that does not match the gas type connected to the gas distribution device, includes steps S301, S302, and S303: In step S301, the switch on the access gas passage is turned on, so that the access gas flows through the corresponding mass flow controller and finally flows into the calibration passage. In step S302, the detected flow rate values ​​of the mass flow controller at each predicted flow rate point are read; In step S303, the actual flow rate value is divided by the detected flow rate value to obtain the gas coefficient of any gas.

[0066] Specifically, any gas can be connected to any gas passage of the gas distribution device. The device is then checked to see if it stores the type and corresponding flow rate of the gas. If the device does not store the type and corresponding flow rate of the gas, the switch on any gas passage is turned on, allowing the gas to flow into the calibration passage (which is equipped with a mass flow controller and a volumetric flow meter). The flow rate values ​​detected by the mass flow controller at each flow rate point are read, and the actual flow rate value of the gas is displayed by the volumetric flow meter. The actual flow rate value is divided by the detected flow rate value to obtain the gas coefficient of the gas, and this gas coefficient is stored.

[0067] The first gas at the first flow rate and the second gas at the second flow rate are obtained by real-time detection of the gas mass flow rate by the at least two mass flow controllers and automatic adjustment of the valve opening according to the ratio.

[0068] In one embodiment of this application, such as Figure 4 As shown, step S203 involves obtaining a first gas at a first flow rate and a second gas at a second flow rate according to the specified ratio, and then introducing the first gas at the first flow rate and the second gas at the second flow rate into a mixing gas passage to mix them and obtain the gas to be prepared. This includes steps S401, S402, and S403. In step S401, the first switch and the second switch on the first gas passage and the second gas passage are turned on respectively, and the first gas and the second gas are connected. In step S402, according to the required ratio of the first gas and the second gas, the mass flow controllers on the first gas passage and the second gas passage are adjusted to obtain the first gas at the first flow rate and the second gas at the second flow rate. In step S403, the third and fourth switches on the first gas passage and the second gas passage are turned on respectively, so that the first gas at the first flow rate and the second gas at the second flow rate enter the mixed gas passage, so that the first gas at the first flow rate and the second gas at the second flow rate are mixed to obtain the gas to be prepared.

[0069] This application embodiment uses a mass flow controller to detect the gas mass flow rate in real time and automatically adjust the valve opening to ensure accurate control of the gas flow rate, thereby ensuring the accuracy of the gas concentration.

[0070] Both the first gas passage and the second gas passage include two mass flow controllers connected in parallel with different ranges.

[0071] Accordingly, such as Figure 5 As shown, step S203, which involves obtaining a first gas at a first flow rate and a second gas at a second flow rate according to the specified ratio, and then introducing the first gas at the first flow rate and the second gas at the second flow rate into the mixing gas passage to mix them and obtain the gas to be prepared, further includes step S501: In step S501, one of the two mass flow controllers is activated to perform gas mixing according to the required ratio of the first gas and the second gas.

[0072] The embodiments of this application can enable the selection of a controller with an appropriate range based on flow rate requirements, thus balancing the high-precision control needs for both small and large flow rates.

[0073] like Figure 6 As shown, this application can also perform flow accuracy verification on each mass flow controller according to the verification instruction or when the verification period conditions are met. The verification process 600 includes step S601: In step S601, according to the verification instruction or when the verification period condition is met, a linear fitting algorithm is used to verify multiple preset flow points of each mass flow controller, and to calibrate the mass flow controllers that fail the verification.

[0074] In one embodiment of this application, such as Figure 7 As shown, step S601, based on the verification instruction or when the verification period condition is met, uses a linear fitting algorithm to verify multiple preset flow points of each mass flow controller, including steps S701, S702, and S703: In step S701, the measured data at multiple preset flow points across the full range of any mass flow controller are collected. In step S702, curve fitting is performed based on the measured data; In step S703, if any one of the plurality of preset flow points has a deviation and the deviation exceeds a preset threshold, the mass flow controller is calibrated.

[0075] In one embodiment of this application, the pressure of the gas passage can also be monitored to avoid excessive pressure fluctuations that could affect the accuracy of gas distribution. Figure 8 As shown, the process 800 for monitoring the pressure of the gas passage includes step S801: In step S801, the pressure of the first gas passage and the second gas passage is monitored in real time, and an alarm is issued when the pressure fluctuation value exceeds the preset fluctuation threshold.

[0076] This application embodiment monitors pressure at the inlet of both the standard gas path and the dilution gas path, and identifies and monitors pressure fluctuations to ensure stable and reliable gas pressure entering the MFC, thereby ensuring stable MFC flow control and ultimately stable gas concentration. Each flow path connects two or more MFCs with different ranges in parallel via switches, which can meet the requirements of wide mixing ratios and wide dilution ratios. Furthermore, In this embodiment, the user only needs to make a simple judgment and selection to match the gas coefficient. When the gas connected is a special gas, the MFC can be calibrated using a calibration process to ensure the accuracy of gas mixing. Moreover, the system can automatically calculate the ratio of standard gas and dilution gas according to the gas to be mixed, and then automatically match the MFC according to the ratio, making gas mixing simple and efficient. This embodiment can also realize the function of periodic automatic verification or manual verification to ensure the accuracy of gas mixing.

[0077] The following is combined Figure 9 The gas distribution device of this application is described, wherein, Figure 9 A schematic block diagram of a gas distribution device 900 according to an embodiment of this application is shown.

[0078] like Figure 9 As shown, the gas distribution device 900 includes a first gas passage, a second gas passage, a mixed gas passage, and a controller 909. The first gas passage and the second gas passage are connected in parallel, and both the first gas passage and the second gas passage are connected in series with the mixed gas passage. A first switch 901, a first mass flow controller 905, and a third switch 903 are connected in series on the first gas passage; a second switch 902, a third mass flow controller 907, and a fourth switch 904 are connected in series on the dilution gas passage.

[0079] The controller 909 is used for: In the event of a mismatch between the mass flow controller and the type of gas being supplied, the mass flow controller that is incompatible with the type of gas supplied shall be calibrated according to the type of gas supplied to the gas supply device before gas supply is supplied. Obtain the parameter information of the gas to be prepared, and calculate the required ratio of the first gas and the second gas based on the parameter information of the gas to be prepared; According to the ratio, instructions are sent to the first mass flow controller and the third mass flow controller to obtain the first gas at a first flow rate and the second gas at a second flow rate corresponding to the ratio, so as to obtain the first gas at the first flow rate and the second gas at the second flow rate; The first gas at the first flow rate and the second gas at the second flow rate are introduced into the mixing gas passage to mix the first gas at the first flow rate and the second gas at the second flow rate to obtain the gas to be prepared; The controller 909 is also used to verify multiple preset flow points of each mass flow controller according to a verification instruction or when the verification period conditions are met, using a linear fitting algorithm, and to calibrate the mass flow controllers that fail the verification.

[0080] The first gas includes a standard gas, and the second gas includes a dilution gas.

[0081] In one embodiment of this application, the following is continued: Figure 9 The standard gas pathway may include two or more mass flow controllers with different flow rates to meet different gas mixing requirements. In one example, the standard gas pathway may include a first mass flow controller 905 and a second mass flow controller 906 connected in parallel; the dilution gas pathway includes a third mass flow controller 907 and a fourth mass flow controller 908 connected in parallel. The first mass flow controller 905 and the second mass flow controller 906 have different flow rates, and the third mass flow controller 907 and the fourth mass flow controller 908 have different flow rates. For example, the first MFC has a flow rate of 500 mL / min (output range 50~500 mL / min), the second MFC has a flow rate of 5 L / min (output range 500~5000 mL / min), the third MFC has a flow rate of 500 mL / min (output range 50~500 mL / min), and the fourth MFC has a flow rate of 5 L / min (output range 500~5000 mL / min). The controller can be selected as the first or second mass flow controller, or the third or fourth mass flow controller, according to the gas distribution requirements, thus broadening its applicability.

[0082] Continue to combine Figure 9 The controller 909 in this application embodiment may include a microcontroller unit (MCU).

[0083] In one embodiment of this application, both the first gas passage and the second gas passage are connected in series with a calibration passage. A volumetric flow meter (VFM) 910 is provided on the calibration passage. The volumetric flow meter (VFM) 910 is used to measure the actual flow rate of the standard gas connected to the gas distribution device.

[0084] The embodiments of this application can calibrate the standard gas before each gas mixing to ensure the accuracy of the gas mixing. The calibration process can be referred to the description above.

[0085] In this embodiment, the user can set the gas mixing parameters of the gas to be mixed through the input device of the gas mixing device (e.g., keyboard, touch screen, etc.), and then calculate the mixing ratio of the first gas and the second gas according to the preset program, and automatically perform gas mixing. The gas mixing parameters may include the name of the standard gas, the concentration of the standard gas, the concentration of the gas to be mixed, and the total flow rate of the gas to be mixed, etc. The controller 909 automatically calculates the standard gas flow rate, dilution gas flow rate, dilution factor, and dilution ratio according to the set parameters.

[0086] For example, the controller 909 calculates the required ratio of standard gas and dilution gas based on the input standard gas name, standard gas concentration, concentration value of the gas to be prepared, and total flow rate of the gas to be prepared.

[0087] During the gas mixing process, the controller 909 controls the opening of the first switch 901 and the second switch 902 on the first gas passage and the second gas passage, respectively. According to the required ratio of the first gas and the second gas, the controller adjusts the preset range mass flow controllers on the first gas passage and the second gas passage to obtain the first gas at a first flow rate and the second gas at a second flow rate. Then, the controller opens the third switch and the fourth switch on the first gas passage and the second gas passage, respectively, so that the first gas at the first flow rate and the second gas at the second flow rate enter the mixing gas passage according to the ratio, and mixes the first gas and the second gas at the preset concentration to obtain the gas to be prepared.

[0088] For example, the first switch may include a pressure reducing valve and a check valve. The pressure reducing valve precisely reduces and stabilizes the high-pressure standard gas input into the pipeline to the low pressure value required by the downstream system, while the check valve prevents gas backflow to avoid affecting the accuracy of gas distribution. Similarly, the second switch may also include a pressure reducing valve and a check valve with the same function. The third and fourth switches may include three-way solenoid valves. Three-way solenoid valves can directly interface with control systems such as controllers, microcontrollers, sensors, and host computers, enabling remote operation or automatic closed-loop control via electrical signals without manual on-site intervention.

[0089] In one embodiment of this application, the device further includes a first pressure transmitter 911 and a second pressure transmitter 912; wherein the pressure transmitters are located at the positions of the first switch 901 and the second switch 902 to monitor the gas pressure flowing through the positions of the first switch 901 and the second switch 902. The pressure transmitters can send the detected gas pressure to a display interface for display. The controller 909 calculates the pressure, and if the pressure fluctuation exceeds a preset threshold range within a certain time range, it sends an alarm prompt to prompt the user to shut down the gas distribution device. For example, when distributing gas, the pressure needs to be controlled between 0.15 and 0.2 MPa. If the pressure fluctuation within 10 seconds is less than 0.005 MPa, it is considered normal fluctuation, indicating that the gas pressure is relatively stable; if the pressure fluctuation within 10 seconds is greater than 0.005 MPa, it indicates that the gas pressure is unstable. At this time, the alarm command sent by the MCU 909 can be delivered through voice, sound, or text prompts to alert the user to the gas distribution device.

[0090] In one example, continue combining Figure 9The gas mixing device may include two gas inlets, corresponding to a first gas (e.g., a standard gas) and a second gas (e.g., a dilution gas), respectively. The first gas passage includes: a first switch 901 connected in parallel to a first MFC 905 and a second MFC 906, and then connected to a third switch 903. The second gas passage includes: a second switch 902 connected in parallel to a third MFC 907 and a fourth MFC 908, and then connected to a fourth switch 904. Both the first and second gas passages are connected to a mixing passage; one passage mixes the gas to be prepared, and the other passage is connected to a VFM 910 for venting.

[0091] Continue to combine Figure 9 The first gas passage also includes a first pressure transmitter P1 911, and the second gas passage includes a second pressure transmitter P2 912. The first pressure transmitter P1 911 and the second pressure transmitter P2 912 are respectively connected to a first switch 901 and a second switch 902 for monitoring the pressure in the first and second gas passages. All electrical components are connected to the controller, and the monitored data is displayed on the interface for manual control and adjustment by the user.

[0092] Both the standard gas passage and the dilution gas passage include mass flow controllers with at least two ranges.

[0093] It is worth noting that the standard gas in this embodiment is not limited to one channel, but can be expanded to multiple channels as needed, such as two, three, four, or five channels. The MFC set in each standard gas channel is not limited to two MFCs, but can be expanded to more, such as two, three, or four MFCs, with corresponding flow rates of 0~50 ml / min, 0~500 ml / min, or 0~5000 ml / min, thus making it more widely applicable.

[0094] To help understand the embodiments of this application, the application will be described in more detail below by way of examples.

[0095] like Figure 9As shown, the standard gas pathway includes a first MFC 905 and a second MFC 906, and the dilution gas pathway includes a third MFC 907 and a fourth MFC 908. The MCU 909 controls the combinations of these MFCs, with possible combinations including the first MFC 905 and the third MFC 907, the first MFC 905 and the fourth MFC 908, the second MFC 906 and the third MFC 907, and the second MFC 906 and the fourth MFC 908. The first MFC 905 has a flow rate of 500 mL / min and an output range of 50-500 mL / min; the second MFC 906 has a flow rate of 5 L / min and an output range of 500-5000 mL / min; the third MFC 907 has a flow rate of 500 mL / min and an output range of 50-500 mL / min; and the fourth MFC 908 has a flow rate of 5 L / min and an output range of 500-5000 mL / min. The mixing flow rate of the first MFC 905 and the third MFC 907 is 500 mL / min, with a dilution factor of 1-10; the mixing flow rate of the second MFC 906 and the third MFC 907 is 5000 mL / min, with a dilution factor of 10-100; the mixing flow rate of the second MFC 906 and the fourth MFC 908 is 5000 mL / min, with a dilution factor of 1-10. The standard gas passage and the dilution gas passage are respectively separated into two outputs through the third switch (three-way solenoid valve) 903 and the fourth switch (three-way solenoid valve) 904. One output is for the gas to be prepared, and the other is output through VFM910.

[0096] The embodiments of this application can automatically match the selection of each MFC according to the user-defined outlet flow rate and gas concentration requirements, thereby ensuring the accuracy of the gas to be prepared.

[0097] This application embodiment can also perform manual or automatic calibration on each MFC. The calibration process can be referred to the above-described calibration procedure. Figure 2 The details of its introduction will not be repeated here.

[0098] In addition, embodiments of this application also support periodic automatic or manual verification of each MFC flow. In one embodiment of this application, the controller 909 can also use a linear fitting algorithm to verify multiple preset flow points of each mass flow controller according to a verification instruction or when the verification period conditions are met, and calibrate the mass flow controllers that fail the verification to ensure that the flow accuracy does not exceed the tolerance and to ensure the matching accuracy.

[0099] After the gas mixing device has been used for a period of time, the MFC flow calibration function can be triggered manually or automatically. The calibration process is as follows: Connect the standard gas and dilution gas, select the corresponding gas coefficient, and operate through the menu on the display interface of the gas mixing device to enter the flow calibration interface. Then, it automatically performs linear calibration at three flow points: 10%, 50%, and 80%. Calculate the deviation value of the calibration curve composed of the three flow points. If the deviation value at any point exceeds 1% of the reading, an alarm is triggered. To ensure the accuracy of the calibration, the gas coefficient can be calibrated a second time. Then, manually adjust the MFC settings to ensure the accuracy of the gas to be prepared.

[0100] Although exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above exemplary embodiments are merely illustrative and are not intended to limit the scope of this application. Various changes and modifications can be made therein by those skilled in the art without departing from the scope and spirit of this application. All such changes and modifications are intended to be included within the scope of this application as claimed in the appended claims.

[0101] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed.

[0102] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0103] Similarly, it should be understood that, in order to streamline this application and aid in understanding one or more of the various inventive aspects, features of this application may sometimes be grouped together in a single embodiment, figure, or description thereof in the description of exemplary embodiments of this application. However, this approach should not be construed as reflecting an intention that the claimed application requires more features than are expressly recited in each claim. Rather, as reflected in the corresponding claims, its inventive point lies in solving the corresponding technical problem with features fewer than all features of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of this application.

[0104] Those skilled in the art will understand that, apart from the mutual exclusion of features, all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or elements of any method or apparatus so disclosed may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0105] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features but not others included in other embodiments, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the claims, any one of the claimed embodiments can be used in any combination.

[0106] The various component embodiments of this application can be implemented in hardware, or as software modules running on one or more processors, or a combination thereof. Those skilled in the art will understand that microprocessors or digital signal processors (DSPs) can be used in practice to implement some or all of the functions of some modules according to the embodiments of this application. This application can also be implemented as an apparatus program (e.g., a computer program and computer program product) for performing part or all of the methods described herein. Such an implementation of this application can be stored on a computer-readable medium, or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, provided on a carrier signal, or provided in any other form.

[0107] The above description is merely a specific embodiment or illustration of the embodiments of this application. The scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. The scope of protection of this application shall be determined by the scope of the claims.

Claims

1. A gas control system for gas distribution, characterized in that, The gas distribution and control system is applied to a gas distribution device, which includes at least two mass flow controllers. The system includes a calibration module, a gas distribution module, a verification module, and a control module. The calibration module is used to perform flow calibration on the mass flow controller indicated by the calibration command based on the gas type connected to the gas distribution device before gas distribution, according to the calibration command of the control module. The gas mixing module is used to acquire parameter information of the gas to be mixed, calculate the required ratio of the first gas and the second gas based on the parameter information of the gas to be mixed, acquire the first gas at a first flow rate and the second gas at a second flow rate based on the ratio, and allow the first gas at the first flow rate and the second gas at the second flow rate to enter the mixing gas passage so that the first gas at the first flow rate and the second gas at the second flow rate are mixed to obtain the gas to be mixed; wherein, the first gas at the first flow rate and the second gas at the second flow rate are obtained by the at least two mass flow controllers detecting the mass flow rate of the gas in real time and automatically adjusting the valve opening according to the ratio; The verification module is used to verify multiple preset flow points of each mass flow controller according to the verification instruction or when the verification period condition is met, using a linear fitting algorithm, and return the verification result to the control module. The control module is used to generate a calibration command and send it to the calibration module when the gas type and mass flow controller do not match, and to send a gas distribution command to the gas distribution module after calibration is completed, and to send a command to the calibration module to calibrate the mass flow controller that failed the flow accuracy calibration when there is a mass flow controller that failed the calibration.

2. The system according to claim 1, characterized in that, in, The calibration module is specifically used for: Connect any type of gas to the gas distribution device; Detect whether the gas mixing device stores any of the types of the gas; If the gas distribution device does not store the type of any of the gases, the switch on any one of the gas passages is turned on, allowing any one of the gases to flow through the mass flow controller on any one of the gas passages and finally into the calibration passage; wherein, the calibration passage is equipped with a volumetric flow meter, which displays the actual flow value of any one of the gases; Read the detected flow values ​​of the mass flow controller at each predicted flow point; Divide the actual flow rate value by the detected flow rate value to obtain the gas coefficient of any given gas.

3. The system according to claim 1, characterized in that, The verification module is specifically used for: Collect measured data at multiple preset flow points across the entire range of any mass flow controller; And curve fitting is performed based on the measured data; If any one of the multiple preset flow points has a deviation, and the deviation exceeds a preset threshold, then any one of the mass flow controllers is calibrated.

4. The system according to claim 3, characterized in that, The verification module is specifically used for: The plurality of preset flow points include any three points from 10%, 15%, 20%, 40%, 60%, 80%, and 100% of the mass flow controller's range.

5. The system according to claim 1, characterized in that, The system also includes a pressure sensing module; The pressure sensing module is used to monitor the pressure of the first gas passage and the second gas passage in real time, and send the pressure values ​​of the first gas passage and the second gas passage to the control module so that the control module can issue an alarm when the pressure fluctuation value exceeds a preset fluctuation threshold.

6. The system according to claim 1, characterized in that, The gas distribution module is specifically used for: Turn on the first and second switches on the first and second gas passages respectively, and connect the first and second gases; According to the required ratio of the first gas and the second gas, adjust the mass flow controllers on the first gas passage and the second gas passage to obtain the first gas at the first flow rate and the second gas at the second flow rate; The third and fourth switches on the first and second gas passages are turned on respectively, so that the first gas at the first flow rate and the second gas at the second flow rate enter the mixed gas passage, and the first gas at the first flow rate and the second gas at the second flow rate are mixed to obtain the gas to be prepared.

7. The system according to claim 6, characterized in that, in, Both the first gas passage and the second gas passage include two mass flow controllers connected in parallel with different ranges.

8. The system according to claim 7, characterized in that, The gas distribution module is also specifically used for: Based on the required ratio of the first and second gases, one of the two mass flow controllers is activated to perform gas mixing.

9. A method for gas chromatography-mass control, characterized in that, The method is applied to a gas distribution device, the gas distribution device including at least two mass flow controllers; the method includes: Check whether each mass flow controller matches the corresponding access gas type; In the event of a mismatch between the mass flow controller and the type of gas being supplied, before gas distribution, the mass flow controller that is mismatched with the type of gas supplied to the gas distribution device shall be calibrated for flow rate. Obtain the parameter information of the gas to be prepared, and calculate the required ratio of the first gas and the second gas based on the parameter information of the gas to be prepared; According to the ratio, a first gas at a first flow rate and a second gas at a second flow rate are obtained, and the first gas at a first flow rate and the second gas at a second flow rate are introduced into a mixed gas passage to mix the first gas at a first flow rate and the second gas at a second flow rate to obtain the gas to be prepared; wherein, the first gas at a first flow rate and the second gas at a second flow rate are obtained by the at least two mass flow controllers detecting the mass flow rate of the gas in real time and automatically adjusting the valve opening according to the ratio; The method further includes: according to the verification instruction or when the verification period condition is met, using a linear fitting algorithm to verify multiple preset flow points of each mass flow controller, and calibrating the mass flow controllers that fail the verification.

10. A gas distribution device, characterized in that, The device includes a first gas passage, a second gas passage, a mixed gas passage, and a controller; wherein... The first gas passage and the second gas passage are connected in parallel, and both the first gas passage and the second gas passage are connected in series with the mixed gas passage; the first gas passage is provided with a first switch, a first mass flow controller and a third switch connected in series; the second gas passage is provided with a second switch, a third mass flow controller and a fourth switch connected in series. The controller is used for: In the event of a mismatch between the mass flow controller and the type of gas being supplied, the mass flow controller that is incompatible with the type of gas supplied shall be calibrated according to the type of gas supplied to the gas supply device before gas supply is supplied. Obtain the parameter information of the gas to be prepared, and calculate the required ratio of the first gas and the second gas based on the parameter information of the gas to be prepared; According to the ratio, instructions are sent to the first mass flow controller and the third mass flow controller to obtain the first gas at a first flow rate and the second gas at a second flow rate corresponding to the ratio, so as to obtain the first gas at the first flow rate and the second gas at the second flow rate; The first gas at the first flow rate and the second gas at the second flow rate are introduced into the mixing gas passage to mix the first gas at the first flow rate and the second gas at the second flow rate to obtain the gas to be prepared; The controller is also used to verify multiple preset flow points of each mass flow controller using a linear fitting algorithm according to a verification instruction or when the verification period condition is met, and to calibrate the mass flow controllers that fail the verification.

Images