Multi-component gas quantitative mixing device and method of use thereof

Abstract

The application provides a multi-component gas quantitative mixing device and a use method thereof, and belongs to the technical field of gas mixing. The device comprises a gas path system and a PLC control unit. The gas path system comprises at least two gas input branches. An electromagnetic valve, a pressure sensor and a gas flow controller are sequentially arranged on each branch. The outlets of the branches are connected to a gas storage tank through a first connecting pipe. A pressure sensor is arranged on the first connecting pipe to monitor the pressure of the gas storage tank. The outlet of the gas storage tank is connected to a vacuum pump. A combustible gas detection alarm is arranged on the gas storage tank. The PLC control unit automatically controls the gas mixing process according to the set total flow, concentration and target pressure range. The method is performed by using the device. The application sets multiple point pressure sensors at key nodes, constructs a full-process pressure monitoring network, cooperates with a high-pressure-difference flow controller and a vacuum pump for vacuum pretreatment, and realizes high-precision, full-automatic, safe and reliable quantitative mixing of multi-component gas under high-pressure conditions.

Description

Technical Field

[0001] This invention relates to the field of gas mixing technology, and in particular to a multi-element gas quantitative mixing device and its usage method. Background Technology

[0002] In industrial production and scientific research experiments, it is often necessary to mix multiple gases in specific proportions to prepare standard gases or simulate specific atmospheres. Existing gas mixing devices typically use mass flow controllers (MFCs) to control the flow rate of each gas before mixing and sending the mixture into a storage tank. However, existing technologies have the following problems: 1. Difficulty in high-pressure gas distribution: When the pressure difference between the gas source pressure and the gas storage tank pressure changes significantly, the flow control accuracy of ordinary MFC will decrease significantly, making it difficult to achieve stable gas distribution under high-pressure conditions.

[0003] 2. Limited pressure monitoring points: Traditional devices only install pressure sensors on the gas storage tank, which cannot monitor the pressure status of each branch and key node of the pipeline in real time. When an abnormal pressure occurs in a certain link, it is difficult to locate it in time.

[0004] 3. Low gas mixing efficiency: The residual gas in the gas storage tank affects the concentration accuracy of the next gas mixing, often requiring manual purging, which is cumbersome and difficult to guarantee consistency.

[0005] 4. Insufficient safety: When gas mixing involves combustible gases, there is a lack of effective leak monitoring and interlock protection mechanisms, which poses a safety hazard.

[0006] 5. Low level of automation: Most existing devices are manually operated or semi-automatically controlled, making it difficult to achieve a fully automatic process of "automatic start-up and shutdown on demand and precise quantitative gas distribution". Summary of the Invention

[0007] In view of this, the present invention aims to provide a multi-gas quantitative mixing device and its usage method to solve the problems of poor high-pressure gas mixing stability, incomplete pressure monitoring, low gas mixing efficiency, insufficient safety and low degree of automation in the prior art.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows: The present invention provides a multi-element gas quantitative mixing device, comprising: The gas path system includes at least two gas input branches. Each gas input branch is equipped with a solenoid valve, a pressure sensor, and a gas flow controller in sequence. The outlets of each gas input branch merge and are connected to the inlet of the gas storage tank through a first connecting pipe, and a pressure sensor is installed on the first connecting pipe. A gas storage tank with a vacuum pump connected to its outlet; a vacuum solenoid valve and a pressure sensor are installed between the gas storage tank and the vacuum pump; and a combustible gas detector and alarm are installed on the gas storage tank. The PLC control unit is electrically connected to the gas flow controller, solenoid valve and pressure sensor installed on each gas input branch, and is also electrically connected to the combustible gas detector alarm.

[0009] Furthermore, the gas flow controller is a high pressure differential gas flow controller with a working pressure differential range of 1MPa to 6MPa, and has a quantitative control function for cumulative flow.

[0010] Furthermore, the ultimate vacuum of the vacuum pump is ≤10Pa and the pumping speed is ≥1L / min; the gas storage tank is a pressure vessel with a pressure resistance of 10MPa or higher, and the gas storage tank is externally wrapped with a heating jacket.

[0011] Furthermore, the pressure sensor installed on the first connecting pipe is electrically connected to the PLC control unit to monitor the real-time pressure inside the gas storage tank; The gas storage tank is also connected to a second connecting pipe, which is equipped with a suction solenoid valve and a pressure sensor.

[0012] Furthermore, the combustible gas detector is configured to send an alarm signal to the PLC control unit when the detected combustible gas concentration reaches a preset concentration threshold.

[0013] Furthermore, the PLC control unit is used to receive the set gas distribution parameters, which include the total flow rate, the concentration of each component gas, and the target pressure range; when the pressure sensor on the first connecting pipe detects that the pressure in the gas storage tank is lower than the lower limit of the target pressure range, the gas distribution process is started; when the pressure in the gas storage tank is greater than or equal to the upper limit of the target pressure range, the gas distribution process is stopped. The PLC control unit is also used to set the target cumulative flow of each gas flow controller, and automatically close the solenoid valve on the corresponding gas input branch when the target cumulative flow is reached; The PLC control unit is also used to receive alarm signals sent by the combustible gas detector. When the PLC control unit receives the alarm signal, it controls all solenoid valves to close; at the same time, the combustible gas detector issues an audible and visual alarm.

[0014] Furthermore, the PLC control unit is also configured to monitor the instantaneous flow rate of each gas flow controller in real time. When the deviation of the instantaneous flow rate from the set value exceeds a preset threshold, an abnormality is indicated by flashing red on the control interface of the PLC control unit.

[0015] The present invention also provides a method for using a multi-gas quantitative mixing device, comprising the following steps: Step S1: Set the gas distribution parameters through the PLC control unit. The gas distribution parameters include the total flow rate, the concentration of each component gas, and the target pressure range. Step S2: Start the vacuuming process. Connect the gas tank outlet to the vacuum pump, open the gas tank outlet pipeline solenoid valve, start the vacuum pump to evacuate the gas tank until the pressure inside the gas tank is lower than the preset vacuum threshold, then close the gas tank solenoid valve and the vacuum pump. Step S3: Start the gas distribution process. The gas system includes at least two gas input branches. Each gas input branch is equipped with a solenoid valve, a pressure sensor, and a gas flow controller in sequence. Open the solenoid valves on each gas input branch in sequence and control each gas flow controller to output gas at the set flow rate. After the components of gas are combined, they enter the gas storage tank through the first connecting pipe. A pressure sensor is installed on the first connecting pipe. Step S4: During the gas distribution process, the pressure inside the gas storage tank is monitored in real time by the pressure sensor on the first connecting pipe. When the pressure inside the gas storage tank reaches the upper limit of the target pressure range, the solenoid valves on all gas input branches are closed to stop the gas distribution. Step S5: During the gas mixing process, the concentration of combustible gas is monitored in real time. When the concentration of combustible gas reaches the preset alarm threshold, all solenoid valves are immediately closed and an alarm is issued.

[0016] Furthermore, the gas flow controller operates within a differential pressure range of 1 MPa to 6 MPa and has a quantitative control function for cumulative flow; the vacuum pump has an ultimate vacuum of ≤10 Pa and a pumping speed of ≥1 L / min. Step S3 also includes: setting a target cumulative flow for each gas flow controller, and automatically closing the solenoid valve on the gas input branch corresponding to the gas flow controller when the cumulative flow of any gas flow controller reaches the target value; Step S4 also includes: when the gas in the gas tank is used up, and the pressure sensor installed on the first connecting pipe detects that the pressure in the gas tank has dropped to the lower limit of the target pressure range, the PLC control unit automatically repeats steps S2 to S4, re-vacuums and distributes gas to achieve automatic replenishment of the gas tank pressure.

[0017] Furthermore, step S6 is included: during the gas distribution process, the instantaneous flow rate of each gas flow controller is monitored in real time, and when the deviation between the instantaneous flow rate and the set value exceeds the preset threshold, an abnormal prompt is issued on the control interface of the PLC control unit.

[0018] Compared with the prior art, the multi-element gas quantitative mixing device and its usage method described in this invention have the following advantages: (1) Multi-point pressure monitoring with strong diagnostic capabilities: Pressure sensors are installed in each gas input branch, the first connecting pipe, the gas storage tank and the vacuum pump, forming a full-process pressure monitoring network. This allows for real-time location of pressure anomalies, facilitating troubleshooting and maintenance. (2) Stable high-pressure gas distribution: The high-pressure differential gas flow controller is adopted to maintain high-precision flow control of ±0.5%FS within the pressure difference range of 1MPa~6MPa, which solves the technical problem of flow fluctuation under high pressure conditions; (3) High gas purity: The gas storage tank is evacuated by a vacuum pump before each gas mixing to eliminate the influence of residual gas on the gas mixing concentration and ensure the accuracy and consistency of gas mixing. (4) Safety interlock protection: The integrated combustible gas detector alarm will automatically shut off all valves and sound an alarm once a leak is detected, which significantly improves the safety of gas distribution involving combustible gases. (5) Fully automatic operation: The PLC control unit realizes the full-process automatic control of parameter setting, automatic vacuuming, automatic gas distribution, pressure trigger start and stop, and automatic cut-off of accumulated amount, which reduces the intensity of manual operation and improves the gas distribution efficiency. (6) Real-time monitoring of abnormalities: Real-time monitoring of the instantaneous flow of each gas flow controller, and active alarm when the deviation exceeds the limit to prevent the gas concentration from being inaccurate due to equipment failure. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the gas path and control principle of the multi-gas quantitative mixing device of the present invention.

[0020] Explanation of reference numerals in the attached figures: 1. First gas input branch; 2. Second gas input branch; 3. Third gas input branch; 101. First solenoid valve; 102. First pressure sensor; 103. First gas flow controller; 201. Second solenoid valve; 202. Second pressure sensor; 203. Second gas flow controller; 301. Third solenoid valve; 302. Third pressure sensor; 303. Third gas flow controller; 4. First connecting pipe; 5. Fourth pressure sensor; 6. Gas storage tank; 7. Combustible gas detector alarm; 8. Second connecting pipe; 9. Suction solenoid valve; 10. Fifth pressure sensor; 11. Vacuum pump. Detailed Implementation

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0022] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] This invention provides a multi-element gas quantitative mixing device, comprising: The gas path system includes at least two gas input branches. Each gas input branch is equipped with a solenoid valve, a pressure sensor and a gas flow controller in sequence. The outlets of each gas input branch merge and are connected to the inlet of the gas storage tank 6 through a first connecting pipe 4. A pressure sensor is installed on the first connecting pipe 4. A gas storage tank 6 has a vacuum pump 11 connected to its outlet. A vacuum solenoid valve 9 and a pressure sensor are installed between the gas storage tank 6 and the vacuum pump 11. A combustible gas detector alarm 7 is installed on the gas storage tank 6. The PLC control unit is electrically connected to the gas flow controller, solenoid valve, and pressure sensor installed on each gas input branch, and is also electrically connected to the combustible gas detector alarm 7. The PLC control unit receives set gas distribution parameters, including total flow rate, concentration of each component gas, and target pressure range. When the pressure sensor on the first connecting pipe 4 detects that the pressure inside the gas storage tank 6 is lower than the lower limit of the target pressure range, the gas distribution process is initiated; when the pressure inside the gas storage tank 6 is greater than or equal to the upper limit of the target pressure range, the gas distribution process is stopped.

[0024] By installing pressure sensors in each gas input branch, the first connecting pipe 4, and between the gas storage tank 6 and the vacuum pump 11, a full-process pressure monitoring network from the gas source inlet to the gas storage tank 6 is formed, which can monitor the pressure status of each node in real time and provide data support for flow control and fault diagnosis.

[0025] The gas flow controller is a high-pressure differential gas flow controller with an operating pressure differential range of 1MPa to 6MPa, and it features quantitative control of cumulative flow. The PLC control unit is configured to set the target cumulative flow for each gas flow controller and automatically close the solenoid valve on the corresponding gas input branch when the target cumulative flow is reached. This design ensures accurate flow control under high-pressure differential conditions and achieves quantitative gas distribution through cumulative flow cutoff.

[0026] The vacuum pump 11 has an ultimate vacuum of ≤10Pa and a pumping rate of ≥1L / min; the gas storage tank 6 is a pressure vessel with a pressure resistance of ≥10MPa, and a heating jacket is installed on the outside of the gas storage tank 6. The high vacuum of the vacuum pump 11 ensures that residual gas in the gas storage tank 6 is fully removed, while the heating jacket is used to maintain a constant temperature inside the tank and prevent gas concentration stratification.

[0027] A pressure sensor installed on the first connecting pipe 4 is electrically connected to the PLC control unit and is used to monitor the real-time pressure inside the gas storage tank 6. This pressure sensor serves as a redundant monitoring point, mutually verifying the pressure sensor on the first connecting pipe 4, thus improving the reliability of the pressure data. A second connecting pipe 8 is also connected to the gas storage tank 6. The second connecting pipe 8 is equipped with a suction solenoid valve and a pressure sensor. Through the second connecting pipe 8, the prepared gas from the gas storage tank 6 can be supplied to the experimental equipment, which is existing technology.

[0028] The combustible gas detector 7 is configured to send an alarm signal to the PLC control unit when the detected combustible gas concentration reaches a preset concentration threshold. Upon receiving the alarm signal, the PLC control unit is configured to close all solenoid valves; simultaneously, the combustible gas detector 7 will issue an audible and visual alarm. This safety interlock mechanism can quickly cut off the gas supply in the event of a gas leak, ensuring the safety of equipment and personnel.

[0029] The PLC control unit is also configured to monitor the instantaneous flow rate of each gas flow controller in real time. When the instantaneous flow rate deviates from the set value by more than a preset threshold, an abnormality is indicated by flashing red on the control interface of the PLC control unit. This function can promptly detect malfunctions of the gas flow controllers and prevent inaccurate gas concentration mixing.

[0030] The present invention also provides a method for using a multi-gas quantitative mixing device, comprising the following steps: Step S1: Set the gas distribution parameters through the PLC control unit. The gas distribution parameters include the total flow rate, the concentration of each component gas, and the target pressure range. Step S2: Start the vacuuming process. Connect the outlet of the gas storage tank 6 to the vacuum pump 11. Open the vacuum solenoid valve 9 on the outlet pipeline of the gas storage tank 6 and start the vacuum pump 11 to evacuate the gas storage tank 6 until the pressure inside the gas storage tank 6 is lower than the preset vacuum threshold. Then close the vacuum solenoid valve 9 and the vacuum pump 11. The ultimate vacuum of the vacuum pump 11 is ≤10Pa and the pumping rate is ≥1L / min. Step S3: Start the gas distribution process. The gas system includes at least two gas input branches. Each gas input branch is equipped with a solenoid valve, a pressure sensor, and a gas flow controller in sequence. The solenoid valves on each gas input branch are opened in sequence, and each gas flow controller is controlled to output gas at a set flow rate. After the components of the gas are combined, they enter the gas storage tank 6 through the first connecting pipe 4. A pressure sensor is installed on the first connecting pipe 4. The working differential pressure range of the gas flow controller is 1MPa~6MPa, and it has a quantitative control function for cumulative flow. Step S3 also includes: setting a target cumulative flow for each gas flow controller, and automatically closing the solenoid valve on the gas input branch corresponding to the gas flow controller when the cumulative flow of any gas flow controller reaches the target value; Step S4: During the gas distribution process, the pressure inside the gas storage tank 6 is monitored in real time by the pressure sensor on the first connecting pipe 4. When the pressure inside the gas storage tank 6 reaches the upper limit of the target pressure range, the solenoid valves on all gas input branches are closed to stop the gas distribution. Step S4 also includes: when the gas in the gas tank 6 is used up, and the pressure sensor installed on the first connecting pipe 4 detects that the pressure in the gas tank 6 has dropped to the lower limit of the target pressure range, the PLC control unit automatically repeats steps S2 to S4, re-vacuums and distributes gas to achieve automatic replenishment of the pressure in the gas tank 6.

[0031] Step S5: During the gas mixing process, the concentration of combustible gas is monitored in real time. When the concentration of combustible gas reaches the preset alarm threshold, all solenoid valves are immediately closed and an alarm is issued.

[0032] Step S6: Monitor the instantaneous flow rate of each gas flow controller in real time during the gas mixing process. When the deviation between the instantaneous flow rate and the set value exceeds the preset threshold, issue an abnormal prompt on the control interface of the PLC control unit.

[0033] Example 1

[0034] like Figure 1 As shown, this embodiment provides a multi-element gas quantitative mixing device for preparing a methane-nitrogen mixed standard gas.

[0035] The device includes three gas input branches: a first gas input branch 1 for inputting methane (CH4), a second gas input branch 2 for inputting nitrogen (N2), and a third gas input branch 3 for inputting argon (Ar, as a balancing gas). Each branch is sequentially equipped with a solenoid valve, a pressure sensor, and a gas flow controller. Specifically, the first gas input branch 1 is equipped with a first solenoid valve 101, a first pressure sensor 102, and a first gas flow controller 103; the second gas input branch 2 is equipped with a second solenoid valve 201, a second pressure sensor 202, and a second gas flow controller 203; and the third gas input branch 3 is equipped with a third solenoid valve 301, a third pressure sensor 302, and a third gas flow controller 303. The outlets of the three branches converge and are connected to the inlet of a gas storage tank 6 via a first connecting pipe 4, on which a fourth pressure sensor 5 is installed. In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features that are specified as "first," "second," etc., can explicitly or implicitly include one or more of the same feature.

[0036] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] The outlet pipe of the gas storage tank 6 is connected to the vacuum pump 11, and a suction solenoid valve 9 and a fifth pressure sensor 10 are installed on the outlet pipe. A combustible gas detector alarm 7 is also installed on the gas storage tank 6.

[0038] Each gas flow controller adopts a high pressure differential mass flow controller with a working pressure differential range of 1MPa~6MPa, an accuracy of ±0.5%FS, a 485 communication interface and a quantitative accumulation function, and a power supply voltage of 24VDC.

[0039] The gas storage tank 6 is a pressure vessel with a volume of 5L and a pressure resistance of 15MPa, and is externally covered with an electric heating jacket (not shown in the figure) to maintain a stable internal temperature. The vacuum pump 11 is a small rotary vane vacuum pump with an ultimate vacuum of 5Pa and a pumping speed of 1.5L / min.

[0040] The PLC control unit uses a Siemens S7-1200 series PLC, equipped with a touch screen human-machine interface, and connects to each gas flow controller via 485 communication. It controls each solenoid valve through switch signals and acquires signals from each pressure sensor and combustible gas detector 7 through analog signals.

[0041] The gas mixing method in this embodiment is as follows: Step S1: The operator inputs the gas mixing parameters through the touch screen of the PLC control unit: total flow rate 5L / min, methane concentration 10%, nitrogen concentration 20%, argon concentration 70%, target pressure range 0.8MPa~1.0MPa, and vacuum threshold 100Pa.

[0042] Step S2: The PLC control unit controls the vacuum solenoid valve 9 to open and starts the vacuum pump 11 to evacuate the gas storage tank 6. The fifth pressure sensor 10 provides real-time feedback on the internal pressure of the gas storage tank 6. When the pressure drops below 100Pa, the PLC control unit closes the vacuum solenoid valve 9 and the vacuum pump 11.

[0043] Step S3: The PLC control unit calculates the set flow rate of each gas flow controller based on the total flow rate and the concentration of each component: the first gas flow controller 103 is set to 0.5L / min, the second gas flow controller 203 is set to 1.0L / min, and the third gas flow controller 303 is set to 3.5L / min. The PLC control unit also sets the target cumulative flow rate of each gas flow controller to 5L, 10L, and 35L respectively (corresponding to the volume required to fill the gas storage tank 6 from vacuum to 1.0MPa).

[0044] The PLC control unit sequentially opens the first solenoid valve 101, the second solenoid valve 201, and the third solenoid valve 301, and activates each gas flow controller. The gases are mixed according to a set ratio and then enter the gas storage tank 6 through the first connecting pipe 4. During this process, the first pressure sensor 102, the second pressure sensor 202, and the third pressure sensor 302 monitor the pressure of their respective gas input branches in real time, while the fourth pressure sensor 5 monitors the pressure of the mixed gas, ensuring that the pressure at each node is within the normal range.

[0045] Step S4: During the gas distribution process, the PLC control unit reads the pressure value of the fourth pressure sensor 5 in real time (this pressure value is equal to the pressure inside the gas storage tank 6). When the pressure reaches 1.0 MPa, the PLC control unit immediately closes the solenoid valves on all branches, stopping the gas distribution.

[0046] Step S5: During the gas mixing process, if the combustible gas detector 7 detects that the methane concentration reaches 10% LEL (preset alarm threshold), the PLC control unit will immediately close all solenoid valves, pop up an alarm window, and sound a buzzer to ensure safety.

[0047] Step S6: During the gas distribution process, the PLC control unit compares the instantaneous flow rate of each gas flow controller with the set value in real time. If the deviation exceeds 5%, the corresponding flow display area will flash red to remind the operator to check the gas source pressure or the status of the gas flow controller.

[0048] Through the above process, a mixed standard gas with a pressure of 1.0 MPa, a methane concentration of 10%, a nitrogen concentration of 20%, and an argon concentration of 70% is finally obtained in the gas storage tank 6, and the gas mixing accuracy meets the usage requirements.

[0049] Example 2

[0050] The difference between this embodiment and embodiment 1 is that when the gas in the gas storage tank 6 is used up and the fourth pressure sensor 5 detects that the pressure drops to the lower limit of the target pressure range (e.g., 0.8MPa), the PLC control unit automatically repeats steps S2 to S4 to re-evacuate and distribute gas, thereby automatically replenishing the pressure of the gas storage tank without manual intervention.

[0051] Example 3

[0052] The difference between this embodiment and embodiment 1 is that the heating jacket of the gas storage tank 6 is connected to the PLC control unit. The PLC control unit can automatically control the heating jacket to start and stop according to the preset temperature (such as 35°C) to ensure that the mixed gas is stored under constant temperature conditions and prevent the gas from causing concentration stratification or pressure fluctuations due to temperature changes.

[0053] Example 4

[0054] The difference between this embodiment and Embodiment 1 is that when a pressure sensor (such as the first pressure sensor 102) on a certain input branch detects an abnormal pressure (such as being below the normal supply pressure range of the gas source or above the upper limit of the equipment's pressure resistance), the PLC control unit immediately closes the solenoid valve of that branch and displays "Branch 1 pressure abnormal" on the touch screen, thus preventing damage to the gas flow controller or mismatch in gas distribution due to abnormal pressure. This function benefits from the layout design of the multi-point pressure monitoring network of this invention.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-element gas quantitative mixing device, characterized in that, include: The gas path system includes at least two gas input branches. Each gas input branch is equipped with a solenoid valve, a pressure sensor, and a gas flow controller in sequence. The outlets of each gas input branch merge and are connected to the inlet of the gas storage tank through a first connecting pipe, and a pressure sensor is installed on the first connecting pipe. A gas storage tank with a vacuum pump connected to its outlet; a vacuum solenoid valve and a pressure sensor are installed between the gas storage tank and the vacuum pump; and a combustible gas detector and alarm are installed on the gas storage tank. The PLC control unit is electrically connected to the gas flow controller, solenoid valve and pressure sensor installed on each gas input branch, and is also electrically connected to the combustible gas detector alarm.

2. The multi-element gas quantitative mixing device according to claim 1, characterized in that: The gas flow controller is a high pressure differential gas flow controller with a working pressure differential range of 1MPa to 6MPa, and has a quantitative control function for cumulative flow.

3. The multi-element gas quantitative mixing device according to claim 1, characterized in that: The vacuum pump has an ultimate vacuum of ≤10Pa and a pumping speed of ≥1L / min; the gas storage tank is a pressure vessel with a pressure resistance of ≥10MPa, and the gas storage tank is externally wrapped with a heating jacket.

4. The multi-element gas quantitative mixing device according to claim 1, characterized in that: The pressure sensor installed on the first connecting pipe is electrically connected to the PLC control unit and is used to monitor the real-time pressure in the gas storage tank. The gas storage tank is also connected to a second connecting pipe, which is equipped with a suction solenoid valve and a pressure sensor.

5. The multi-element gas quantitative mixing device according to claim 1, characterized in that: The combustible gas detector is configured to send an alarm signal to the PLC control unit when the detected combustible gas concentration reaches a preset concentration threshold.

6. The multi-element gas quantitative mixing device according to claim 1, characterized in that: The PLC control unit is used to receive the set gas distribution parameters, which include the total flow rate, the concentration of each component gas, and the target pressure range. When the pressure sensor on the first connecting pipe detects that the pressure in the gas storage tank is lower than the lower limit of the target pressure range, the gas distribution process is started. When the pressure in the gas storage tank is greater than or equal to the upper limit of the target pressure range, the gas distribution process is stopped. The PLC control unit is also used to set the target cumulative flow of each gas flow controller, and automatically close the solenoid valve on the corresponding gas input branch when the target cumulative flow is reached; The PLC control unit is also used to receive alarm signals sent by the combustible gas detector. When the PLC control unit receives the alarm signal, it controls all solenoid valves to close; at the same time, the combustible gas detector issues an audible and visual alarm.

7. The multi-element gas quantitative mixing device according to claim 1, characterized in that: The PLC control unit is also configured to monitor the instantaneous flow rate of each gas flow controller in real time. When the instantaneous flow rate deviates from the set value by more than a preset threshold, an abnormality is indicated by flashing red on the control interface of the PLC control unit.

8. A method of using a multi-gas quantitative mixing device, comprising the multi-gas quantitative mixing device according to any one of claims 1 to 6, characterized in that, Includes the following steps: Step S1: Set the gas distribution parameters through the PLC control unit. The gas distribution parameters include the total flow rate, the concentration of each component gas, and the target pressure range. Step S2: Start the vacuuming process. Connect the gas tank outlet to the vacuum pump, open the gas tank outlet pipeline solenoid valve, start the vacuum pump to evacuate the gas tank until the pressure inside the gas tank is lower than the preset vacuum threshold, then close the gas tank solenoid valve and the vacuum pump. Step S3: Start the gas distribution process. The gas system includes at least two gas input branches. Each gas input branch is equipped with a solenoid valve, a pressure sensor, and a gas flow controller in sequence. Open the solenoid valves on each gas input branch in sequence and control each gas flow controller to output gas at the set flow rate. After the components of gas are combined, they enter the gas storage tank through the first connecting pipe. A pressure sensor is installed on the first connecting pipe. Step S4: During the gas distribution process, the pressure inside the gas storage tank is monitored in real time by the pressure sensor on the first connecting pipe. When the pressure inside the gas storage tank reaches the upper limit of the target pressure range, the solenoid valves on all gas input branches are closed to stop the gas distribution. Step S5: During the gas mixing process, the concentration of combustible gas is monitored in real time. When the concentration of combustible gas reaches the preset alarm threshold, all solenoid valves are immediately closed and an alarm is issued.

9. The method of using the multi-element gas quantitative mixing device according to claim 8, characterized in that: The gas flow controller operates within a differential pressure range of 1 MPa to 6 MPa and has a quantitative control function for cumulative flow; the vacuum pump has an ultimate vacuum of ≤10 Pa and a pumping speed of ≥1 L / min. Step S3 also includes: setting a target cumulative flow for each gas flow controller, and automatically closing the solenoid valve on the gas input branch corresponding to the gas flow controller when the cumulative flow of any gas flow controller reaches the target value; Step S4 also includes: when the gas in the gas tank is used up, and the pressure sensor installed on the first connecting pipe detects that the pressure in the gas tank has dropped to the lower limit of the target pressure range, the PLC control unit automatically repeats steps S2 to S4, re-vacuums and distributes gas to achieve automatic replenishment of the gas tank pressure.

10. The method of using the multi-element gas quantitative mixing device according to claim 8, characterized in that, It also includes step S6: real-time monitoring of the instantaneous flow rate of each gas flow controller during the gas mixing process, and issuing an abnormal prompt on the control interface of the PLC control unit when the deviation between the instantaneous flow rate and the set value exceeds the preset threshold.

Images