Shielding gas mixing device and method for argon arc welding

Abstract

The invention relates to the technical field of argon arc welding, and discloses a shielding gas mixing method and device for argon arc welding. Two groups of independent gas paths are communicated to a mixing module through a pressure reducing valve, an electromagnetic proportional valve and a mass flow meter in sequence; a turbofan, a thin spiral pipe, a thick spiral pipe and a tapered flow channel are sequentially arranged in the mixing module in the gas flowing direction, and secondary mixing is carried out on the mixer through a secondary spiral pipe. And a PID control strategy is adopted, and the proportion and flow of the mixed gas are regulated and controlled according to real-time welding process parameters, so that the mixed protective gas protects a welding arc and a workpiece welding area at the optimal flow. Through turbulent mixing and real-time feedback adjustment, the problems that mixed gas used in traditional welding is high in cost, the static mixing efficiency is low, and the gas proportion fluctuates are solved.

Description

Technical Field

[0001] This invention relates to the field of argon arc welding technology, and in particular to a shielding gas mixing device and method for argon arc welding. Background Technology

[0002] Argon arc welding (argon arc welding) technology not only meets the high-quality welding needs of traditional manufacturing industries but also demonstrates enormous potential and value in fields such as new energy, aerospace, and automotive manufacturing. Argon arc welding is an arc welding method under inert gas protection. Currently, its shielding gas is mostly argon, but it can also be adapted to different welding materials, welding positions, and welding process requirements by mixing some hydrogen or helium into the argon. Based on the principles of ordinary electric arc welding, argon arc welding utilizes inert gases such as argon to protect the metal welding material. A high current melts the welding material into a liquid state on the substrate, forming a molten pool, achieving metallurgical bonding between the welded metal and the welding material. Because the shielding gas is continuously supplied during high-temperature molten welding, the welding material cannot come into contact with oxygen in the air, thus preventing oxidation. Therefore, it can weld stainless steel and ferrous metals. Argon arc welding can optimize the weld formation and appearance, better control the flow and solidification process of the molten pool, reduce the generation of defects such as porosity and slag inclusions, and improve the density and strength of the weld.

[0003] Existing argon arc welding equipment has certain limitations in terms of shielding gas. It can generally only use a single shielding gas, and the gas flow rate is difficult to adjust for different welding conditions. However, different materials and application scenarios have different requirements for shielding gas. Although a single shielding gas, such as pure argon, is suitable for most metals, it may not be as effective as a mixture of gases with a small amount of helium or nitrogen when welding active metals such as aluminum and magnesium. Alternatively, the mixed shielding gas may not be uniform enough to meet the requirements. If the ratio of the mixed gas is not properly controlled, it may cause fluctuations in the gas composition during the welding process, affecting the welding effect and failing to meet the increasingly complex welding needs.

[0004] In conclusion, it is crucial to design a method for obtaining high-quality mixed shielding gas for TIG welding, which would enable TIG welding to be applied to a wider range of working conditions and improve the flexibility and versatility of the process. Summary of the Invention

[0005] The purpose of this invention is to provide a shielding gas mixing device and method for argon arc welding. By using dual-path pressure stabilization gas supply, closed-loop flow control, and dynamic turbulent mixing, a uniformly mixed shielding gas with a suitable flow rate is output, which effectively improves the quality of the shielding gas for argon arc welding and achieves better welding results.

[0006] To achieve the above objectives, the present invention provides the following solution: A shielding gas mixing device for argon arc welding, characterized in that it comprises: a gas source input module, a mixing module, and an output and control module. The gas source input module consists of two sets of parallel independent gas paths, each set of gas paths being connected in sequence to a gas cylinder, a pressure reducing valve, an electromagnetic proportional valve, and a mass flow meter. The mixing module includes a composite mixing chamber, in which a turbine fan, a thin spiral tube, a coarse spiral tube, and a tapered flow channel are arranged sequentially along the gas flow direction. The turbine fan is used to force the gas to generate turbulence. Several thin spiral tubes are arranged in parallel along the gas flow direction, with one end opening towards the turbine fan and the other end opening towards the coarse spiral tube. Several coarse spiral tubes are arranged in parallel, with one end opening towards the thin spiral tube and the other end opening into the tapered flow channel. The tapered flow channel is connected to the protective gas outlet. The output and control module includes a current and voltage sensor, a PLC / controller, a preset process database, and a flow meter installed at the outlet of the mixed protective gas pipe. The PLC / controller is connected to the current and voltage sensor, the electromagnetic proportional valve, the mass flow meter, and the flow meter signal. The current and voltage sensor is used to collect the current and voltage signals during welding. The PLC / controller queries the preset process database based on the current and voltage signals at that moment to obtain the target gas ratio of the mixed gas and the target total flow rate of the protective gas, and issues control commands to the electromagnetic proportional valve to regulate the mixing ratio and flow rate of the two protective gases.

[0007] Furthermore, the PLC / controller incorporates a built-in PID control algorithm. In terms of flow control, it uses the target flow rate as the target signal and the measured value of the flow meter as the feedback signal to adjust the opening of the electromagnetic proportional valve. In terms of mixing ratio, it uses the test values ​​of the mass flow meters in the two gas paths to control the opening ratio of the electromagnetic proportional valves in the two gas paths, so as to achieve proportional control of the corresponding gas.

[0008] Furthermore, the mixing module also includes a venturi tube, which is disposed at the rear end of the tapered flow channel.

[0009] Furthermore, the number of turbine fans is two, and the two turbine fans are arranged side by side.

[0010] Furthermore, the inlet end of the fine spiral tube is coaxially and sealed with the outlet end of the turbine fan.

[0011] Furthermore, a buffer cavity is provided between the thin spiral tube and the thick spiral tube as a gas buffer area.

[0012] Furthermore, the tapered flow channel has a funnel-shaped structure with a larger diameter at the inlet end and a smaller diameter at the outlet end, and its inner wall is coated with a tungsten steel wear-resistant coating.

[0013] Furthermore, the two ends of several of the thin spiral tubes and the thick spiral tubes are respectively sealed and fixed on a sealing plate, and the tube openings are directed to the other side of the sealing plate.

[0014] Furthermore, the inner diameter of the fine spiral tube is 2-4 mm, and the inner diameter of the coarse spiral tube is 7-9 mm.

[0015] The mixing method of the shielding gas mixing device for argon arc welding is characterized by comprising the following steps: Dual-path pressure-stabilized gas supply: Two sets of independent gas cylinders output argon and auxiliary protective gas respectively. After the pressure is roughly adjusted by the pressure reducing valve, the gas flows into the mixing module through the electromagnetic proportional valve and mass flow meter. Dynamic turbulent mixing: The two gases are first forced to generate turbulence by a turbo fan, then flow through a thin spiral tube for initial mixing, and then enter a coarse spiral tube for secondary mixing. The two-stage spiral tube extends the mixing path, which prolongs the mixing time of the two gases and makes the gas mixing more uniform. The mixture is then delivered to the protective gas outlet through a tapered flow channel and / or a venturi tube. Flow closed-loop control: Current and voltage sensors collect welding current and voltage signals of the welding machine in real time. The PLC / controller queries the preset process database based on the current and voltage signals at that moment to obtain the target gas ratio of the mixed gas and the target total flow rate of the shielding gas. It then issues control commands to the electromagnetic proportional valve to regulate the mixing ratio and flow rate of the two shielding gases.

[0016] The beneficial effects of this invention are as follows: The shielding gas mixing device for argon arc welding provided by this invention includes a gas source input module, which consists of two independent gas paths. Each path is sequentially connected to a pressure reducing valve, an electromagnetic proportional valve, and a mass flow controller. The mixing module, the turbine fan, and the spiral tube all contribute to this process. The turbine fan forces turbulence, and the spiral tube extends the gas flow path, increasing the contact area between the two mixed gases and prolonging the mixing time, thus ensuring thorough mixing of the shielding gas. Finally, the gas is output through a tapered flow channel and a venturi tube. The venturi tube accelerates the flow of the gas and generates negative pressure to promote the flow of the mixed gas within the mixing module, preventing the gas from stagnating inside.

[0017] An electromagnetic proportional valve, a mass flow controller, and current / voltage sensors are connected to a PLC / controller to adjust the gas ratio and flow rate based on welding current and voltage signals. This invention effectively reduces the cost of mixed gases, improves static mixing efficiency, solves the problem of gas ratio fluctuations in actual welding, effectively improves the quality of shielding gas, enhances its welding performance, and allows for adjustment of the flow rate of uniformly mixed shielding gas to meet different welding requirements. This enables TIG welding to be applied to a wider range of working conditions, improving the flexibility and versatility of the process. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the shielding gas mixing device for argon arc welding according to the present invention.

[0019] Explanation of reference numerals in the attached figures: 1. Gas cylinder; 2. Pressure reducing valve; 3. Electromagnetic proportional valve; 4. Mass flow meter; 5. Turbine fan; 6. Fine spiral tube; 7. Coarse spiral tube; 8. Funnel structure; 9. Venturi tube; 10. Welding machine power supply; 11. Welding torch; 12. Electric arc; 13. Workpiece; 14. Current and voltage sensor; 15. PLC / controller. Detailed Implementation

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

[0021] In this patent description, terms such as "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" indicate the orientation or positional relationship based on the actual orientation or positional relationship shown. They are used only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe orientation or positional relationships in this invention are for illustrative purposes only and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood in conjunction with the embodiments and according to the specific circumstances.

[0022] Unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" in this invention 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 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 can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] The purpose of this invention is to provide a shielding gas mixing device and method for argon arc welding, which can fully mix the shielding gas for argon arc welding, dynamically output the shielding gas flow rate, effectively improve the quality of the shielding gas for argon arc welding, and improve its welding performance.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] like Figure 1 As shown, the shielding gas mixing device for argon arc welding provided by the present invention includes a gas source input module, a mixing module, an output module, and a control module.

[0026] The source input module consists of two sets of parallel, independent gas paths. Two gas cylinders 1 store argon and an auxiliary protective gas (such as carbon dioxide), respectively, and are delivered through independent gas paths. Each gas path is sequentially connected to gas cylinder 1, pressure reducing valve 2, electromagnetic proportional valve 3, and mass flow meter 4. The pressure reducing valve 2 first coarsely adjusts the high pressure of the gas cylinder to protect downstream equipment from damage due to excessive pressure, controls the input of protective gas, and also helps optimize system performance and efficiency, providing a stable pressure basis for subsequent precise control. The electromagnetic proportional valve 3, located after the pressure reducing valve 2, receives control signals from the control unit and dynamically adjusts the gas flow by changing the throttle opening through valve core displacement. The mass flow meter 4 monitors the instantaneous flow rate of a single gas path in real time.

[0027] Within the mixing module, a composite mixing chamber is formed, in which a turbine fan 5, a fine helical tube 6, a coarse helical tube 7, and a tapering flow channel 8 are sequentially arranged along the gas flow direction. Two turbine fans 5 are arranged side by side, with their orientation perpendicular to the airflow direction of the fine helical tube 6 and the coarse helical tube 7. The turbine fans 5 are used to force the gas to generate turbulence. The number of blades in the turbine fan 5 can be arbitrarily selected without affecting the gas mixing function, but the air outlet of the blades must point towards the air outlet to avoid unnecessary gas backflow. When the turbine fans are running, they swirl and mix the gas, which then flows towards the air inlet of the fine helical tube after initial mixing. Several fine helical tubes 6 are arranged in parallel along the gas flow direction, with one end opening towards the turbine fan 5 and the other end opening towards the coarse helical tube 7; several coarse helical tubes 7 are arranged in parallel, with one end opening towards the fine helical tube 6 and the other end opening into the tapering flow channel 8, which is connected to the protective gas outlet.

[0028] The thin spiral tube 6 and the thick spiral tube 7 are used to extend the gas flow path. The small space facilitates increased contact opportunities for gas molecules, thereby achieving more complete fusion. Both ends of several of the thin spiral tubes 6 and thick spiral tubes 7 are sealed and fixed to a sealing plate, with the tube openings leading to the other side of the sealing plate. The inlet and outlet ends of the arranged thin spiral tubes 6 and thick spiral tubes 7 are equipped with a mesh structure to ensure that the turbulence from the turbine fan 5 is evenly distributed to the spiral tubes, ensuring a uniform output of the mixed flow from the spiral tubes. The inner diameter of the thin spiral tube 6 is 2-4 mm, and the inner diameter of the thick spiral tube 7 is 7-9 mm.

[0029] A buffer cavity is provided between the thin spiral tube 6 and the thick spiral tube 7 as a gas buffer zone to further promote gas fusion.

[0030] The outlet end of the coarse spiral tube 7 is connected to a tapered flow channel 8, which restores the turbulence generated by the turbine fan to laminar flow. In laminar flow, the protective gas is accelerated and delivered through the venturi tube 9 and ejected from the protective gas nozzle, resulting in more uniform coverage of the welding area between the electric arc 12 and the workpiece 13. The tapered flow channel 8 has a funnel-shaped structure, and its inner wall is coated with a tungsten steel wear-resistant coating to extend its service life.

[0031] In the above embodiments, at least two of the following are protected by different types of protective gases: argon, carbon dioxide, helium, nitrogen, and hydrogen.

[0032] The present invention also provides a method for mixing shielding gas for argon arc welding, applied to the shielding gas mixing apparatus for argon arc welding described in any of the above claims, comprising the following steps: According to the required mixed gas, connect the two inlet pipes at the inlet end of the gas cylinder, such as argon and helium; in the gas circuit, the pressure reducing valve 2 first coarsely adjusts the high pressure of the gas cylinder, and then stabilizes the output gas pressure, which flows into the mixing module through the electromagnetic proportional valve 3 and the mass flow meter 4.

[0033] Inside the mixing module: the two gases are first forced to generate turbulence by the turbine fan 5, then flow through the thin spiral tube 6 for preliminary mixing, and then enter the coarse spiral tube 7 for secondary mixing. The two-stage spiral tubes extend the mixing path, which prolongs the mixing time of the two gases and makes the gas mixing more uniform. The gas is then transported to the protective gas outlet through the tapered flow channel 8 and / or the venturi tube 9.

[0034] Flow closed-loop control: The current and voltage sensor 14 collects the welding current and voltage signals of the welding machine 10 in real time. The PLC / controller queries the preset process database based on the current and voltage signals at that moment to obtain the target gas ratio of the mixed gas and the target total flow rate of the shielding gas. It then issues control commands to the electromagnetic proportional valve 3 to regulate the mixing ratio and flow rate of the two shielding gases.

[0035] Specifically, the PLC / controller has a built-in PID control algorithm. In terms of flow control, the target flow rate is used as the target signal and the measured value of the flow meter is used as the feedback signal to adjust the opening of the electromagnetic proportional valve 3. In terms of mixing ratio, the test values ​​of the mass flow meters 4 in the two gas paths are used to control the opening ratio of the electromagnetic proportional valve 3 in the two gas paths to achieve the proportional control of the corresponding gas.

[0036] The embodiments described above are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A shielding gas mixing device for argon arc welding, characterized in that, include: Gas input module, mixing module, and output and control module. The gas source input module consists of two sets of parallel independent gas paths, each set of gas paths being connected in sequence to a gas cylinder (1), a pressure reducing valve (2), an electromagnetic proportional valve (3), and a mass flow meter (4); The mixing module includes a composite mixing chamber, in which a turbine fan (5), a thin spiral tube (6), a coarse spiral tube (7), and a tapered flow channel (8) are arranged sequentially along the gas flow direction. The turbine fan (5) is used to force the gas to generate turbulence. Several thin spiral tubes (6) are arranged in parallel along the gas flow direction, with one end opening towards the turbine fan (5) and the other end opening towards the coarse spiral tube (7). Several coarse spiral tubes (7) are arranged in parallel, with one end opening towards the thin spiral tube (6) and the other end opening towards the tapered flow channel (8). The tapered flow channel (8) is connected to the protective gas outlet. The output and control module includes a current and voltage sensor (14), a PLC / controller, a preset process database, and a flow meter installed at the outlet of the mixing protective gas pipe. The PLC / controller is connected to the current and voltage sensor (14), the electromagnetic proportional valve (3), the mass flow meter (4), and the flow meter signal. The current and voltage sensor (14) is used to collect the current and voltage signals during welding by the welding machine (10). The PLC / controller queries the preset process database based on the current and voltage signals at that moment to obtain the target gas ratio of the mixed gas and the target total flow rate of the protective gas, and issues control commands to the electromagnetic proportional valve (3) to regulate the mixing ratio and flow rate of the two protective gases.

2. The shielding gas mixing device for argon arc welding as described in claim 1, characterized in that, The PLC / controller has a built-in PID control algorithm. In terms of flow control, the target flow rate is used as the target signal and the measured value of the flow meter is used as the feedback signal to adjust the opening of the electromagnetic proportional valve (3). In terms of mixing ratio, the test values ​​of the mass flow meters (4) on the two gas paths are used to control the opening ratio of the electromagnetic proportional valve (3) on the two gas paths to achieve the proportional control of the corresponding gas.

3. The shielding gas mixing device for argon arc welding as described in claim 1, characterized in that, The mixing module also includes a venturi tube (9) which is located at the rear end of the tapered flow channel (8).

4. The shielding gas mixing device for argon arc welding as described in claim 1, characterized in that, The number of turbine fans (5) is two, and the two turbine fans (5) are arranged side by side.

5. The shielding gas mixing device for argon arc welding as described in claim 1, characterized in that, The inlet end of the fine spiral tube (6) is coaxially and sealed with the outlet end of the turbine fan (5).

6. The shielding gas mixing device for argon arc welding as described in claim 1, characterized in that, A buffer cavity is provided between the thin spiral tube (6) and the thick spiral tube (7) as a gas buffer area.

7. The shielding gas mixing device for argon arc welding as described in claim 1, characterized in that, The tapered flow channel (8) has a funnel-shaped structure with a larger diameter at the inlet and a smaller diameter at the outlet, and its inner wall is coated with a tungsten steel wear-resistant coating.

8. The shielding gas mixing device for argon arc welding as described in claim 1, characterized in that, Both ends of several of the fine spiral tubes (6) and coarse spiral tubes (7) are respectively sealed and fixed on a sealing plate, and the tube openings are directed to the other side of the sealing plate.

9. The shielding gas mixing device for argon arc welding as described in claim 1, characterized in that, The inner diameter of the fine spiral tube (6) is 2-4 mm, and the inner diameter of the coarse spiral tube (7) is 7-9 mm.

10. A mixing method for a shielding gas mixing device for argon arc welding as described in any one of claims 1-7, characterized in that, Includes the following steps: Dual-path pressure-stabilized gas supply: The gas cylinders (1) of the two independent gas paths output argon and auxiliary protective gas respectively. After the pressure is roughly adjusted by the pressure reducing valve (2), the gas flows into the mixing module through the electromagnetic proportional valve (3) and the mass flow meter (4). Inside the mixing module: the two gases are first forced to generate turbulence by the turbine fan (5), then flow through the thin spiral tube (6) for preliminary mixing, and then enter the coarse spiral tube (7) for secondary mixing. The two-stage spiral tube extends the mixing path, which prolongs the mixing time of the two gases and makes the gas mixing more uniform. The gas is then transported to the protective gas outlet through the tapered flow channel (8) and / or Venturi tube (9). Flow closed-loop control: The current and voltage sensor (14) collects the welding current and voltage signals of the welding machine (10) in real time. The PLC / controller queries the preset process database based on the current and voltage signals at that moment to obtain the target gas ratio of the mixed gas and the target total flow of the shielding gas. It then issues control commands to the electromagnetic proportional valve (3) to regulate the mixing ratio and flow of the two shielding gases.

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