Argon and carbon dioxide mixing system and control method

Abstract

The application discloses an argon and carbon dioxide mixing system and a control method, and belongs to the technical field of gas mixing. The system comprises first and second parallel conveying pipes and a main conveying pipe, wherein a first-stage pressure stabilizing valve, a second-stage pressure stabilizing valve, an adjustable flow valve, a glass tube flowmeter and a straight-through check valve are sequentially arranged on each conveying pipe; an electromagnetic valve, a gas equalizer spiral mixing valve, a stainless steel ball valve and a buffer storage tank are sequentially arranged on the main conveying pipe. Argon enters through the first conveying pipe, and carbon dioxide enters through the second conveying pipe. Two-stage pressure stabilization is adopted to make the downstream pressure of the two branches consistent, the straight-through check valve realizes physical anti-backflow, the gas equalizer spiral mixing valve ensures uniform mixing at the molecular level, and the buffer storage tank suppresses the pressure pulse at the gas end. The control method comprises target flow calculation, pressure balance regulation, PID closed-loop flow proportioning, system pre-charging and online fault diagnosis, and realizes accurate proportioning, stable output, safe and reliable mixed gas supply.

Description

Technical Field

[0001] This invention relates to the field of gas mixing technology, and in particular to an argon and carbon dioxide mixing system and control method. Background Technology

[0002] In the field of metal welding, especially in gas metal arc welding (GMAW), using a mixture of argon and carbon dioxide as the shielding gas can effectively improve the droplet transfer pattern, reduce welding spatter, optimize weld formation, and achieve good mechanical properties. Different welding conditions place stringent requirements on the precision of the gas mixture ratio, the uniformity of mixing, and the stability of the output pressure. Therefore, a high-quality gas mixing and supply system is a key factor in ensuring welding quality.

[0003] Currently, common methods for supplying argon and carbon dioxide mixed gases are mainly divided into two categories: pre-mixing and online mixing. Pre-mixing involves filling a single storage tank with the two gases in a fixed ratio. Although convenient to use, the ratio is fixed and cannot be adjusted online, making it unsuitable for the frequent changes in process parameters required in flexible production. More importantly, due to the density difference between the two gases, the gases in the tank are prone to stratification after prolonged standing, leading to a drift in the actual output ratio and seriously affecting welding consistency.

[0004] The online mixing system draws gas from its own independent gas sources, combines them through pipelines, and then outputs the gas. However, existing online mixing systems generally suffer from the following technical defects: First, most systems use single-stage pressure reduction or simple throttling devices. When the pressure of the upstream gas source fluctuates with consumption, the output pressure and flow rate of the downstream stage change accordingly, leading to a decrease in mixing accuracy, especially under low flow conditions. Second, there is a lack of reliable physical backflow prevention measures between branches. When the pressure of one gas line drops instantaneously or the gas source is interrupted, the high-pressure gas from another line can easily flow back into the low-pressure pipeline, not only disrupting the mixing ratio but also potentially contaminating the gas source and causing safety hazards. Third, the merged gases often flow only through a simple T-joint, lacking forced mixing methods. Due to differences in density and flow rate, the two gases are prone to stratified flow. Even with long pipelines, it is difficult to achieve uniform mixing at the molecular level, resulting in the shielding gas composition actually delivered to the welding torch not matching the set value. Fourth, the system output is usually directly connected to the gas-consuming equipment. When there is a sudden large flow start-up or pulsating suction at the gas-consuming end, there is a lack of necessary buffering and pressure stabilization measures, causing drastic fluctuations in output pressure, which in turn disturbs the upstream flow regulation, creating a vicious cycle.

[0005] In summary, developing an argon-carbon dioxide mixing system and control method that can achieve highly stable output pressure, precise and constant ratio over a long period, absolute backflow prevention capability, efficient and uniform mixing, and effectively suppress pressure pulses at the gas end is an urgent problem to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide an argon and carbon dioxide mixing system and control method. This addresses problems in existing online mixing systems, such as unstable output pressure due to single-stage pressure reduction, low mixing accuracy, lack of reliable backflow prevention measures between branches leading to gas cross-contamination risks, lack of forced mixing after merging causing gas stratification and uneven composition, and pressure pulse disturbances at the gas consumption end affecting flow regulation. This invention establishes a pressure benchmark through two-stage pressure stabilization, physically isolates backflow with a straight-through one-way valve, forces uniform mixing with a gas equalizer and spiral mixing valve, and smooths pressure pulses with a buffer storage tank. This achieves a highly stable output pressure, precise and controllable mixing ratio, uniform mixing, and a safe and reliable supply of argon and carbon dioxide mixture, meeting the stringent requirements of high-quality welding processes for protective gases.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides an argon-carbon dioxide mixing system, comprising a first delivery pipe, a second delivery pipe, and a main delivery pipe. The first and second delivery pipes are arranged in parallel, and one end of each is connected to one end of the main delivery pipe. An argon gas source enters through the first delivery pipe, and a carbon dioxide gas source enters through the second delivery pipe.

[0008] On the first and second delivery pipes, a primary pressure regulating valve, a secondary pressure regulating valve, an adjustable flow valve, a glass tube flow meter, and a straight-through check valve are sequentially arranged along their respective airflow directions.

[0009] On the main delivery pipe, from its inlet end to its outlet end, there are sequentially arranged an electromagnetic valve, a gas equalizer spiral mixing valve, a stainless steel ball valve, and a buffer storage tank.

[0010] Furthermore, the primary and secondary pressure regulating valves progressively reduce the high-pressure gas from the gas source to a preset stable operating pressure. For argon gas sources, the primary pressure regulating valve initially reduces the pressure to 0.75-0.8 MPa, and the secondary pressure regulating valve further refines the pressure to a constant value within the range of 0.55-0.6 MPa. For carbon dioxide gas sources, the saturated vapor pressure inside the cylinder at room temperature is approximately 6 MPa. The primary pressure regulating valve can operate in either direct-flow mode or shallow pressure reduction mode, while the secondary pressure regulating valve similarly stabilizes the pressure of this branch at the same set value as the argon branch, for example, 0.60 MPa. This ensures that both gas streams enter the flow regulation stage at the same downstream pressure, eliminating the interference of pressure difference on the proportioning accuracy and ensuring the precision of subsequent flow control.

[0011] Furthermore, the straight-through check valve is a spring-reset structure, and its conduction direction is limited to from the delivery pipe to the main delivery pipe. When the system is operating normally, the airflow pushes open the valve core and enters the main pipe; when the pressure in any branch drops suddenly or the gas source is interrupted, the valve core immediately closes under the combined action of spring force and reverse pressure, physically isolating the reverse gas flow path, which can completely prevent any gas from flowing back into another gas source, ensuring the purity and safety of the gas source.

[0012] Furthermore, the gas equalizer spiral mixing valve is a tubular static mixer with built-in multi-layer spiral guide vanes, which causes the airflow that converges through the main delivery pipe to generate strong radial mixing, ensuring molecular-level uniform mixing within an extremely short pipe pass.

[0013] Furthermore, the buffer storage tank is used to smooth out pressure pulses caused by instantaneous flow fluctuations at the gas consumption point, providing a uniformly mixed gas with extremely stable pressure to the gas consumption point. The volume of the buffer storage tank can be designed according to the maximum instantaneous flow rate and allowable pressure fluctuation range at the gas consumption point, preferably ranging from 5 to 20 L.

[0014] Furthermore, in an optional embodiment, the adjustable flow valve is an electric needle valve and is electrically connected to a controller; the glass tube flow meter is equipped with a displacement-to-electrical signal conversion module, which can convert the float position into a standard electrical signal output to the controller, realizing remote transmission and closed-loop feedback of the flow signal. Further, it also includes a human-machine interface electrically connected to the controller, used to set the target mixing ratio of argon and carbon dioxide and the total output flow rate. The controller automatically calculates the target flow rate value required for each branch based on the set values, thereby realizing closed-loop automatic mixing control.

[0015] Secondly, the present invention also provides a method for controlling the mixing of argon and carbon dioxide based on the above system, comprising the following steps: S1. Set the required target mixing ratio of argon and carbon dioxide and the total output flow rate through the human-machine interface. The controller calculates the target flow rate values ​​of the first and second delivery pipes according to the set values. S2. Turn on the argon gas source and carbon dioxide gas source, and adjust the first-stage and second-stage pressure regulating valves on each branch respectively, so that the gas outlet pressure of both branches is stabilized at the same set value within the range of 0.55 to 0.6 MPa. S3. The controller collects the real-time flow signals from each glass tube flow meter in real time, compares them with the corresponding target flow values, and uses a PID algorithm to output control signals to the adjustable flow valve to adjust its opening until the real-time flow of both branches is stable at their respective target flow rates. S4. After the flow rates of the two branches stabilize, the controller opens the solenoid valve on the main delivery pipe. Argon and carbon dioxide flow into the main delivery pipe through the straight-through one-way valve and are forced to mix evenly in the spiral mixing valve of the gas equalizer. S5. The uniformly mixed gas flows through a stainless steel ball valve and enters a buffer storage tank for buffering and pressure stabilization, and finally outputs a stable mixture of argon and carbon dioxide to the gas user.

[0016] Furthermore, in step S4, before the controller opens the solenoid valve, the system pre-charge program is executed: the controller controls the solenoid valve to open for a preset short time to inject and fill the main delivery pipe and buffer storage tank with the mixed gas, so as to completely replace the residual atmosphere in the pipeline. After the flow of the two branches stabilizes again, the controller controls the solenoid valve to continue to open to enter the formal gas supply state.

[0017] Furthermore, during the mixed gas output process, the controller continuously monitors the real-time flow of each branch. When it is determined that the deviation between the actual flow and the target flow of any branch exceeds the preset deviation threshold, and this state continues for more than the preset time threshold, the controller determines that it is in a fault state, automatically closes the solenoid valve and issues an alarm signal.

[0018] Furthermore, when it is necessary to stop the gas supply, the following shutdown procedure shall be performed: the controller shall first close the solenoid valve, then the operator shall sequentially close the carbon dioxide gas source and the argon gas source, and finally close the stainless steel ball valve and depressurize the pipeline.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. Dual pressure stabilization: Each branch adopts a two-stage series pressure stabilization to completely filter out gas source pressure fluctuations and match the different gas source pressure characteristics of argon and carbon dioxide, ultimately ensuring that the two branches obtain the same and constant downstream pressure, providing a solid pressure benchmark for accurate proportioning.

[0020] 2. Precise and adjustable proportions: The adjustable flow valve, in conjunction with the glass tube flow meter, enables fine adjustment and local visualization of the flow rate, making operation intuitive and simple; in automatic mode, the proportioning accuracy is significantly improved through PID closed-loop control.

[0021] 3. Absolutely prevents backflow: The spring-reset structure of the straight-through check valve physically isolates any potential backflow path, ensuring that the two gases do not contaminate each other, and the system is extremely safe.

[0022] 4. Highly uniform mixing: The gas equalizer's spiral mixing valve has built-in multi-layer spiral guide vanes, which force the airflow to be repeatedly divided, rotated, and merged, achieving molecular-level uniform mixing of argon and carbon dioxide within an extremely short path and eliminating stratification.

[0023] 5. Stable and continuous output: The buffer storage tank acts as a terminal pressure stabilizing container, absorbing the pressure difference between peak and trough gas supply, so that the output mixed gas pressure is stable and unaffected by instantaneous disturbances at the gas consumption end.

[0024] 6. High automation scalability: Key components can be smoothly upgraded to electric control elements. With the help of human-machine interface and controller, it is easy to integrate into automated welding system to realize remote ratio adjustment, fault diagnosis and centralized monitoring. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the argon and carbon dioxide mixing system in an embodiment of the present invention; Figure 2 This is a schematic flowchart of the argon and carbon dioxide mixing control method in an embodiment of the present invention; Figure 3 This is a data analysis chart comparing the stability of the mixing ratio of the embodiments of the present invention with that of the traditional system.

[0026] Component names and reference numerals: 10-First delivery pipe; 11-First-stage pressure regulating valve; 12-Second-stage pressure regulating valve; 13-Adjustable flow valve; 14-Glass tube flow meter; 15-Straight-through check valve; 20-Second delivery pipe; 30-Main delivery pipe; 31-Solenoid valve; 32-Gas equalizer spiral mixing valve; 33-Stainless steel ball valve; 34-Buffer storage tank; 100-Argon gas source; 200-Carbon dioxide gas source; 300-Gas-using equipment. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to experimental examples and specific embodiments. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0028] Example 1 like Figure 1 As shown, this embodiment provides an argon and carbon dioxide mixing system, including a first delivery pipe 10, a second delivery pipe 20, and a main delivery pipe 30. The first delivery pipe 10 and the second delivery pipe 20 are arranged in parallel, and their outlets merge and connect to the inlet of the main delivery pipe 30. An argon source 100 is connected to the first delivery pipe 10, and a carbon dioxide source 200 is connected to the second delivery pipe 20.

[0029] On the first delivery pipe 10, a filter, a union, a primary pressure regulating valve 11, a secondary pressure regulating valve 12, an adjustable flow valve 13, a glass tube flow meter 14, and a straight-through check valve 15 are installed sequentially from upstream to downstream along the argon gas flow direction. The corresponding components are arranged in the exact same order on the second delivery pipe 20.

[0030] For argon gas source 100, the full-fill pressure of its cylinder is approximately 1.0 MPa. The primary pressure regulator 11 initially reduces the pressure to approximately 0.8 MPa, and the secondary pressure regulator 12 further refines the pressure to a constant operating pressure of approximately 0.6 MPa. For carbon dioxide gas source 200, the saturated vapor pressure inside its cylinder at room temperature is approximately 6 MPa. Therefore, its primary pressure regulator 11 operates in direct-flow mode, and the secondary pressure regulator 12 similarly stabilizes the pressure of this branch at approximately 0.6 MPa. In this way, both gases enter their respective flow regulation stages with identical downstream pressures, fundamentally eliminating potential mixing interference caused by pressure differences.

[0031] The straight-through check valve 15 adopts a spring-reset structure, and its conduction direction is strictly limited to the direction from each delivery pipe to the main delivery pipe 30. When the system is working normally, the two gas streams open the valve core under the action of pressure difference and flow into the main pipe; when the pressure of any branch drops suddenly or is interrupted, the valve core closes instantly under the action of spring force and reverse pressure, completely eliminating the possibility of backflow of gas from the main pipe or the other branch.

[0032] In a preferred automated embodiment, the adjustable flow valve 13 is a high-precision electric needle valve, whose drive motor is electrically connected to a PLC controller. The float linkage of the glass tube flowmeter 14 is equipped with a displacement-to-electrical signal conversion module, which converts the float position into a 4-20mA current signal, feeding it back to the controller in real time, thereby achieving remote transmission and closed-loop control of the flow signal. The human-machine interface uses a touchscreen, connected to the controller via an industrial bus. Operators set the desired target mixing ratio of argon and carbon dioxide and the total output flow rate via the touchscreen. The controller's internal program automatically calculates the target flow rates for the first delivery pipe 10 and the second delivery pipe 20.

[0033] The main delivery pipe 30 is equipped with a solenoid valve 31, a gas equalizer spiral mixing valve 32, a stainless steel ball valve 33, and a buffer storage tank 34 sequentially from its inlet to its outlet. The gas equalizer spiral mixing valve 32 is a tubular static mixer with built-in three-layer staggered spiral guide vanes. When two streams of air with different densities enter, they are repeatedly cut, twisted, and re-merged by the vanes, forming a strong radial mixture within a very short axial distance, ensuring that molecular-level uniform mixing is achieved when leaving the equalizer. The buffer storage tank 34 is a stainless steel pressure vessel, the volume of which can be selected in the range of 5 to 20L according to the actual working conditions. In this embodiment, 10L is selected. Its outlet is connected to the gas-using equipment 300. This volume can effectively absorb the instantaneous pressure pulsation caused by the jogging operation of the welding torch, providing a smooth and stable pressure output to the gas-using end.

[0034] Example 2 Based on the above system, the present invention provides a method for controlling the mixing of argon and carbon dioxide, the control process of which is as follows: Figure 2 As shown, the specific steps include:

[0035] S1. The operator inputs process parameters through the human-machine interface, such as a target mixing ratio of argon to carbon dioxide of 80:20 and a total output flow rate of 25 L / min. Based on the received set values, the controller automatically calculates the target flow rate of the first delivery pipe 10 as 20.0 L / min and the target flow rate of the second delivery pipe 20 as 5.0 L / min.

[0036] S2. Manually open the storage tank valves of argon gas source 100 and carbon dioxide gas source 200, and observe the high-pressure gauges on each branch to confirm sufficient gas supply. Then, adjust the primary pressure regulating valve 11 and the secondary pressure regulating valve 12 on the first delivery pipe 10 and the second delivery pipe 20 respectively, until the pressure gauge after the secondary pressure regulating valve consistently displays approximately 0.6 MPa. At this point, both branches have the same downstream pressure, eliminating mixing interference caused by pressure differences.

[0037] S3. The controller initiates the automatic proportioning program. The controller rapidly acquires real-time flow signals from the two branch glass tube flow meters 14, compares them with the target flow value calculated in step S1, and uses an incremental PID algorithm, taking the flow deviation as input, to output a control signal to the positioner of the electric needle valve, smoothly adjusting the valve core opening. For example, when the actual flow rate of the argon branch is detected to be 19.2 L / min, lower than the target of 20.0 L / min, the controller increases the valve opening of that branch, while simultaneously monitoring the carbon dioxide branch to maintain 5.0 L / min. Through continuous closed-loop regulation, the flow rates of the two branches are accurately stabilized at the set values.

[0038] S4. Once the controller determines that the flow rates of both branches have reached a steady state (e.g., flow fluctuations are less than a preset value and maintained for a preset confirmation time), the system prepares to supply gas to the main pipe. Before this, a system pre-charging procedure is executed to replace any residual gas that may have accumulated in the main pipe: the controller first controls the solenoid valve 31 to open for a preset short time (e.g., 2-3 seconds) and then closes it, injecting fresh mixed gas into the main delivery pipe 30 and the buffer storage tank 34 to replace the atmosphere in the pipeline. After the pre-charging is completed, it is confirmed again that the flow rates of both branches remain stable, and the controller then controls the solenoid valve 31 to remain open. Argon and carbon dioxide converge in the main pipe through their respective straight-through one-way valves 15 and enter the gas equalizer spiral mixing valve 32, where they are forcibly and uniformly mixed under the action of the spiral blades.

[0039] S5. The uniformly mixed gas flows through the manually opened stainless steel ball valve 33 and enters the buffer storage tank 34. Inside the tank, the mixed gas is finally buffered and stabilized, and pressure fluctuations are effectively smoothed. It is then delivered to gas-using equipment such as welding torches 300 at a stable flow rate and pressure, achieving a high-quality welding shielding gas supply.

[0040] During continuous gas supply, the controller performs online fault diagnosis. The controller sets a flow deviation threshold (e.g., ±0.3 L / min) and a duration threshold (e.g., 3 seconds). If the controller detects that the actual flow rate of any branch deviates from the target flow rate by more than the deviation threshold, and this abnormal state persists beyond the time threshold, it is determined to be a system fault (e.g., gas supply depletion, pipeline leakage, or valve jamming). At this time, the controller immediately executes protective actions: automatically closing solenoid valve 31, simultaneously displaying an alarm window on the touchscreen, and triggering an audible and visual alarm to prompt the operator to check and handle the situation.

[0041] When welding operations are completed and shutdown is required, the following standard shutdown procedure should be followed: The operator issues a stop gas supply command via the touchscreen. The controller first automatically closes solenoid valve 31, cutting off the main gas flow. Then, the operator manually closes the storage tank valves of carbon dioxide source 200 and argon source 100 in sequence, finally closing the stainless steel ball valve 33 and opening the pre-set pressure relief valve on the pipeline to safely vent any residual gas in the system pipeline. This standard operation avoids the risk of backflow that may be caused by incorrect shutdown sequence and ensures the equipment is in a safe condition.

[0042] Example 3 To verify the beneficial effects of the present invention, the system described in the above embodiments was constructed and compared with a conventional mixing system with a single-stage pressure reduction, no homogenizer, and a buffer tank. The change in carbon dioxide volume fraction was continuously monitored at the outlet using a gas analyzer, and the results are shown in the figure below. Figure 3 The data analysis chart shown.

[0043] Test conditions: The mixing ratio was set to 80%Ar + 20%CO2, the total flow rate was 25L / min, and the simulated gas consumption end was opened and closed instantaneously at a frequency of 10 times / minute for 30 minutes.

[0044] Figure 3 In the diagram, curve A represents the measured CO2 ratio of the traditional system, showing a large fluctuation range between approximately 17.5% and 22.3%, with a maximum deviation exceeding 2 percentage points, especially exhibiting a significant spike at the start and stop of the gas consumption. Curve B represents the measured CO2 ratio of the system of this invention, which remained stable within a narrow range of 19.8% to 20.2% throughout the entire test, with a maximum deviation of only about 0.2 percentage points, and no momentary loss of control.

[0045] This data fully demonstrates that, through the robust pressure benchmark provided by two-stage pressure regulation, PID closed-loop flow regulation, efficient homogenization by the static mixer, and end-of-pipe pressure regulation by the buffer storage tank, the system of this invention achieves proportioning accuracy and output stability that are unmatched by traditional solutions, providing a reliable guarantee for high-quality welding.

[0046] 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, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An argon-carbon dioxide mixing system, comprising a first delivery pipe (10), a second delivery pipe (20), and a main delivery pipe (30), characterized in that: The first delivery pipe (10) and the second delivery pipe (20) are connected in parallel, and one end of each is connected to one end of the main delivery pipe (30); the argon source (100) is connected to the first delivery pipe (10), and the carbon dioxide source (200) is connected to the second delivery pipe (20); On the first delivery pipe (10) and the second delivery pipe (20), a first-stage pressure regulating valve (11), a second-stage pressure regulating valve (12), an adjustable flow valve (13), a glass tube flow meter (14) and a straight-through check valve (15) are sequentially arranged along the airflow direction. On the main delivery pipe (30), an electromagnetic valve (31), a gas equalizer spiral mixing valve (32), a stainless steel ball valve (33) and a buffer storage tank (34) are arranged sequentially from the connection end to the outlet end along the airflow direction.

2. The argon and carbon dioxide mixing system according to claim 1, characterized in that: The first-stage pressure regulator (11) reduces the pressure of the argon gas source to 0.75-0.8MPa, and the second-stage pressure regulator (12) further reduces the pressure to a constant working pressure of 0.55-0.6MPa. For the carbon dioxide gas source, its first-stage pressure regulator (11) operates in a direct or shallow pressure reduction mode, and its second-stage pressure regulator (12) also stabilizes the pressure of the branch at 0.6MPa, so that the downstream working pressure of the two branches remains consistent.

3. The argon and carbon dioxide mixing system according to claim 1, characterized in that: The straight-through check valve (15) is a high-precision spring-reset check valve, and its conduction direction is limited to the direction from the first delivery pipe (10) or the second delivery pipe (20) to the main delivery pipe (30).

4. The argon and carbon dioxide mixing system according to claim 1, characterized in that: The gas equalizer spiral mixing valve (32) is a tubular static mixer with built-in multi-layer spiral guide vanes, used to make argon and carbon dioxide generate strong radial mixing after they are combined.

5. The argon and carbon dioxide mixing system according to claim 1, characterized in that: The adjustable flow valve (13) is an electric needle valve and is electrically connected to a controller; the glass tube flow meter (14) is equipped with a displacement-to-electrical signal conversion module to feed back real-time flow signals to the controller.

6. The argon and carbon dioxide mixing system according to claim 5, characterized in that: It also includes a human-machine interface electrically connected to the controller, used to set the target mixing ratio of argon and carbon dioxide and the total output flow rate; the controller automatically calculates the target flow rate required for each branch according to the set values.

7. A method for controlling the mixing of argon and carbon dioxide, applied to the mixing system according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Set the required target mixing ratio of argon and carbon dioxide and the total output flow rate through the human-machine interface. The controller calculates the target flow rate values ​​of the first delivery pipe (10) and the second delivery pipe (20) according to the set values. S2. Turn on the argon gas source (100) and the carbon dioxide gas source (200), and adjust the first-stage pressure regulating valve (11) and the second-stage pressure regulating valve (12) on each branch respectively, so that the gas outlet pressure of the two branches is stabilized at the same set value in the range of 0.55 to 0.6 MPa. S3. The controller collects the real-time flow signals fed back by each glass tube flow meter (14) in real time, compares them with the corresponding target flow values, and uses the PID algorithm to output control signals to the adjustable flow valve (13) to adjust its opening until the real-time flow of both branches is stable at their respective target flow rates. S4. After the flow rates of the two branches stabilize, the controller opens the solenoid valve (31) on the main delivery pipe (30). Argon and carbon dioxide flow into the main delivery pipe (30) through the straight-through one-way valve (15) and are forced to mix evenly in the spiral mixing valve (32) of the gas equalizer. S5. The uniformly mixed gas flows through the stainless steel ball valve (33) and enters the buffer storage tank (34) for buffering and pressure stabilization, and finally outputs a stable mixture of argon and carbon dioxide to the gas-using end.

8. The method for controlling the mixing of argon and carbon dioxide according to claim 7, characterized in that: In step S4, before the controller opens the solenoid valve (31), it first executes the system pre-charge program: controls the solenoid valve (31) to open for a preset short time and then close it, injecting the mixed gas into the main delivery pipe (30) and the buffer storage tank (34) to replace the residual atmosphere in the pipeline. After the flow rates of the two branches stabilize again, the solenoid valve (31) is controlled to continue to open to enter the formal gas supply state.

9. The method for controlling the mixing of argon and carbon dioxide according to claim 7, characterized in that: During the mixed gas output process, the controller continuously monitors the real-time flow of each branch. When it is determined that the deviation between the actual flow of any branch and the target flow exceeds the preset deviation threshold, and this state continues to exceed the preset time threshold, the controller determines that it is in a fault state, automatically closes the solenoid valve (31) and issues an alarm signal.

10. The method for controlling the mixing of argon and carbon dioxide according to claim 7, characterized in that: When it is necessary to stop the gas supply, the following shutdown procedure shall be performed: the controller first controls the solenoid valve (31) to close, then the operator shuts off the carbon dioxide gas source (200) and the argon gas source (100) in sequence, and finally closes the stainless steel ball valve (33) and depressurizes the pipeline.

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