A high efficiency cooling TIG welding system for DC positive polarity welding of aluminum alloys

Abstract

The application discloses a high-efficiency cooling TIG welding system for direct current positive polarity welding of aluminum alloy, and belongs to the technical field of TIG welding, which comprises a welding torch, wherein the welding torch comprises a welding torch body, a gas pipe, a tungsten electrode, a protective cover and a cooling box body; the gas inlet of the gas pipe installed on the welding torch body is connected with a gas source; the gas outlet of the gas pipe is located in the protective cover; the main body of the tungsten electrode is arranged in the protective cover, and the welding end of the tungsten electrode extends out of the protective cover; the tungsten electrode is connected with the positive electrode of a direct current power supply through the gas pipe; the cooling box body is provided with a cooling medium; the cooling box body is arranged in the protective cover and leaves a gap between the cooling box body and the gas outlet of the protective cover; and the main body of the tungsten electrode is arranged in the cooling box body or is in close contact with the cooling box body. The cooling box body is arranged in the protective cover, and the tungsten electrode is arranged in the cooling box body, so that the tungsten electrode can be rapidly cooled during the direct current positive polarity welding of the aluminum alloy, the purpose of avoiding the burning of the tungsten electrode is achieved, and the quality and efficiency of the TIG welding of the aluminum alloy are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of TIG welding technology, specifically relating to a TIG welding system, and more particularly to a high-efficiency cooling TIG welding system for DC positive polarity welding of aluminum alloys. Background Technology

[0002] TIG, or Tungsten Inert Gas Welding, is a high-quality welding process widely used in industrial production. It can be used to weld various metals. A traditional TIG welding system includes a power source, a gas source, a wire feeder, and a welding torch, also called a welding gun. The torch consists of a torch body, a gas hose, a tungsten electrode, and a protective shield. The gas hose, mounted on the torch body and electrically conductive, has its inlet connected to the gas source. The gas outlet of the gas hose is located inside the insulated protective shield, which is fixed to the gas hose. The tungsten electrode is placed inside the protective shield, with its welding end extending out through the gas outlet. The tungsten electrode is connected to one pole of the power source (any pole for AC power, negative or positive for DC power) via the gas hose. The tungsten electrode is a rod made of tungsten, typically cylindrical in shape, with a tapered welding end. During operation, the workpiece is connected to the other pole of the power supply, and the welding end of the tungsten electrode is brought close to the workpiece. The welding wire is fed to the welding position of the workpiece by the wire feeder. The welding wire is connected to both the workpiece and the welding end of the tungsten electrode. Under the high temperature generated by the high current, the workpiece and the welding wire melt locally, thus achieving the welding function. The tungsten electrode will not melt and can be used for a long time. During the welding process, the gas source sends the protective gas (helium or argon) into the protective cover. The protective gas is sent out to the welding area through the gas outlet of the protective cover, which serves to protect the electrode and the molten pool.

[0003] When welding TIG, the tungsten electrode of the welding torch is connected to the positive terminal of the DC power supply and the workpiece is connected to the negative terminal of the DC power supply. This is called DC positive polarity welding or DC reverse polarity welding (DCEP). When the tungsten electrode is connected to the negative terminal of the DC power supply and the workpiece is connected to the positive terminal of the DC power supply, this is called DC negative polarity welding or DC positive polarity welding (DCEN).

[0004] Currently, TIG welding of aluminum alloys generally uses AC power. This is because aluminum alloys have an oxide film on their surface, which needs to be removed using "cathode atomization" during DC positive welding. However, DC positive welding generates a large amount of heat in the tungsten electrode, leading to severe tungsten electrode burn-out. When using AC TIG welding of aluminum alloys, the "cathode atomization" effect on the workpiece occurs during DC positive welding, while the workpiece is melted during DC negative welding. This reduces heat generation in the tungsten electrode and prevents burn-out. This is why AC power is generally used for TIG welding of aluminum alloys.

[0005] However, conventional AC TIG welding is prone to arc instability due to the rapid changes in current polarity, leading to excessive porosity in the weld and insufficient weld strength for certain applications. Furthermore, the tungsten electrode material limits the current output of traditional AC TIG welding, restricting the amount of wire melted per unit time and hindering efficient welding. In contrast, assuming no high-temperature damage to the tungsten electrode, DC positive polarity TIG welding of aluminum alloys offers the following advantages: 1. The arc provides "cathode atomization" to the base material throughout the welding process, maximizing the removal of oxide films from the base material surface and those generated during welding; 2. The absence of polarity changes during welding results in excellent arc stability, significantly reduced weld porosity, and weld strength far exceeding that of traditional AC TIG welding; 3. Higher thermal efficiency compared to traditional AC TIG welding, resulting in a substantial improvement in welding efficiency.

[0006] In summary, if a technical solution can be found that can rapidly cool the tungsten electrode to prevent it from burning out while welding aluminum alloys with DC positive polarity, the above problems can be solved, and the quality and efficiency of TIG welding of aluminum alloys can be significantly improved. Summary of the Invention

[0007] The purpose of this invention is to provide a high-efficiency cooling TIG welding system for DC positive polarity welding of aluminum alloys in order to solve the above-mentioned problems.

[0008] The present invention achieves the above objectives through the following technical solutions: A high-efficiency cooled TIG welding system for DC positive polarity welding of aluminum alloys includes a welding torch. The welding torch includes a torch body, a gas pipe, a tungsten electrode, and a protective cover. The gas pipe, which is mounted on the welding torch body and is conductive, has its inlet connected to a gas source. The gas outlet of the gas pipe is located inside the insulated protective cover. The protective cover is connected to the gas pipe to fix the protective cover. The main body of the tungsten electrode is placed inside the protective cover, and the welding end of the tungsten electrode extends outside the protective cover through the gas outlet. The tungsten electrode is connected to the positive terminal of a DC power supply through the gas pipe. The high-efficiency cooled TIG welding system for DC positive polarity welding of aluminum alloys also includes a cooling box containing a cooling medium. The cooling box is placed inside the protective cover with a gap between it and the gas outlet of the protective cover. The main body of the tungsten electrode is placed inside the cooling box or in close contact with the cooling box, and the welding end of the tungsten electrode is outside the cooling box. The cooling medium inside the aforementioned cooling chamber can be a liquid, gaseous, or solid medium, as long as it can lower the temperature inside the cooling chamber to the required low temperature. Depending on the actual application, the cooling chamber can exist independently without being connected to other equipment, such as using ice or dry ice as the cooling medium, and then placing it inside without connecting it to other equipment; the cooling chamber can also be connected to a refrigeration system via a gas pipe, such as using cold air as the cooling medium and continuously supplying cold air to the cooling chamber via an external air conditioner; the cooling chamber can also be connected to a liquid refrigeration system via a liquid pipe, such as using cold water as the cooling medium and continuously supplying cold water to the cooling chamber via an external cold water preparation device.

[0009] Preferably, to meet the continuous low temperature requirement of approximately 2-15°C within the cooling chamber and for ease of implementation, the cooling medium within the cooling chamber is cold water. The tungsten electrode is in close contact with the cooling chamber. The high-efficiency cooling TIG welding system for DC positive polarity welding of aluminum alloys further includes a cooling chamber inlet pipe, a cooling chamber outlet pipe, a cold water preparation device, a cold water pipe, and a hot water pipe. The outlet of the cooling chamber inlet pipe is connected to the cold water inlet of the cooling chamber, and the inlet of the cooling chamber outlet pipe is connected to the hot water outlet of the cooling chamber. The cold water inlet and hot water outlet of the cooling chamber are located on opposite outer walls of the cooling chamber and are axially offset from the tungsten electrode. The cooling chamber inlet pipe and the cooling chamber outlet pipe pass through corresponding through holes on the protective cover. The inlet of the cooling chamber inlet pipe is connected to the cold water outlet of the cold water preparation device via the cold water pipe, and the outlet of the cooling chamber outlet pipe is connected to the hot water inlet of the cold water preparation device via the hot water pipe.

[0010] Preferably, to ensure reliable conductive and mechanical connection between the tungsten electrode and the cooling box, the cylindrical cooling box is open at one end and closed at the other. The open end of the cooling box is connected to the box cover plate via threads. Both the cooling box and the box cover plate are conductive, while the cooling box inlet pipe and the cooling box outlet pipe are non-conductive. A central tube protruding towards the open end is located in the middle of the closed end of the cooling box. One end of the central tube is open, corresponding to the closed end of the cooling box, and close to the air outlet of the protective cover. A cylindrical inner cavity is formed inside the cooling box at the outer periphery of the central tube. The cold water inlet and hot water outlet of the cooling box are respectively connected to… The annular cylindrical inner cavity is interconnected. The inner circumference of the central tube of the housing is provided with internal threads, and the outer circumference of the tungsten electrode is provided with external threads. The tungsten electrode is placed inside the central tube of the housing and is threadedly connected. The other end of the protective cover opposite to its air outlet is open and connected to the protective cover cover plate by screws. The cooling tank inlet pipe and the cooling tank outlet pipe pass through the corresponding through holes on the protective cover cover plate. The air pipe passes through the screw hole in the middle of the protective cover cover plate and the two are threadedly connected. The end of the air pipe located inside the protective cover is threadedly connected to the housing cover plate. The gas outlet of the air pipe is located on the pipe wall between the protective cover cover plate and the housing cover plate.

[0011] Preferably, for ease of processing and assembly, the cold water inlet of the cooling box and the outlet of the cooling box water inlet pipe, and the hot water outlet of the cooling box and the inlet of the cooling box water outlet pipe are respectively connected by threads.

[0012] Preferably, in order to improve the sealing performance between the cooling box and other components and to facilitate processing and assembly, the inner side of the cold water inlet and the inner side of the hot water outlet of the cooling box are respectively provided with sealed inner cavities. The end of the central tube of the box near the box cover is open. Sealing gaskets are respectively provided between the outlet of the cooling box inlet pipe and the corresponding sealed inner cavity, between the inlet of the cooling box outlet pipe and the corresponding sealed inner cavity, between the open end of the cooling box and the box cover, and between the open end of the central tube of the box near the box cover and the box cover. The sealing gaskets are provided with a central through hole, and the size of the multiple sealing gaskets matches the size of the corresponding connection parts.

[0013] Preferably, to achieve a continuous supply of low-temperature chilled water and automated temperature regulation, and for ease of implementation, the inlet of the chilled water pipe and the outlet of the hot water pipe are connected by a connecting pipe. The high-efficiency cooling TIG welding system for DC positive polarity welding of aluminum alloys further includes a water tank, a water pump, a first temperature sensor, a second temperature sensor, and a controller. The water tank and the water pump are connected in series on the hot water pipe. The first temperature sensor is installed on the cooling tank inlet pipe near its inlet and is used to detect the water temperature inside the cooling tank inlet pipe. The second temperature sensor is installed on the cooling tank outlet pipe near its outlet and is used to detect the water temperature inside the cooling tank outlet pipe. The chilled water preparation device includes a liquid... The system comprises a nitrogen tank, a cryogenic nitrogen chamber, a first cryogenic solenoid valve, and a second cryogenic solenoid valve. The outlet of the liquid nitrogen tank is connected to the cryogenic nitrogen chamber, which has a thermal insulation function, via a liquid nitrogen pipe. The first cryogenic solenoid valve is installed on the liquid nitrogen pipe. The connecting pipe passes through the cryogenic nitrogen chamber. A nitrogen venting pipe is connected to the side wall of the cryogenic nitrogen chamber opposite to the connection point with the liquid nitrogen pipe. The second cryogenic solenoid valve is installed on the nitrogen venting pipe. The signal output terminals of the first and second temperature sensors are respectively connected to the signal input terminals of the controller. The control input terminals of the water pump, the first cryogenic solenoid valve, and the second cryogenic solenoid valve are respectively connected to the control output terminals of the controller. The controller described above is a conventional component of existing technology and can take the form of a microcontroller, control board, control cabinet, electrical control box, etc. The first and second cryogenic solenoid valves are solenoid valves capable of operating at temperatures below -100 degrees Celsius, such as liquid nitrogen cryogenic solenoid valves.

[0014] Depending on the actual needs, the connecting pipe can be a single piece integrally formed with the cold water pipe and the hot water pipe. This structure adjusts the water temperature in the cold water pipe by changing the amount of nitrogen in the low-temperature nitrogen tank, but its adjustment accuracy is not very high. Alternatively, the connecting pipe can include a first connecting pipe and a second connecting pipe. One end of the first connecting pipe and one end of the second connecting pipe are respectively connected to the inlet of the cold water pipe, and the other ends of the first connecting pipe and the second connecting pipe are respectively connected to the outlet of the hot water pipe. The first connecting pipe passes through the low-temperature nitrogen tank, and a first proportional regulating valve is installed on the first connecting pipe outside the low-temperature nitrogen tank. A second proportional regulating valve is installed on the second connecting pipe. The control input terminals of the first and second proportional regulating valves are respectively connected to the control output terminals of the controller. This structure mainly adjusts the water temperature in the cold water pipe by changing the mixing ratio of low-temperature water and high-temperature water, and its adjustment accuracy is higher.

[0015] The beneficial effects of this invention are as follows: This invention, by placing a cooling chamber within a protective cover and then placing the tungsten electrode inside, enables rapid cooling of the tungsten electrode during DC positive polarity TIG welding of aluminum alloys to prevent it from burning out, significantly improving the quality and efficiency of TIG welding. Using cold water as the cooling medium within the cooling chamber, and fully encasing the tungsten electrode with a threaded connection, ensures excellent heat transfer and a stable, reliable connection. Real-time water temperature monitoring via a temperature sensor enables closed-loop control, achieving prolonged and efficient cooling of the tungsten electrode. This keeps the electrode in a constant low-temperature environment, providing intense cooling and preventing or significantly reducing electrode burn-off during full DC positive polarity TIG welding, increasing welding efficiency and resulting in welds with superior performance. Using liquid nitrogen as a cold source for rapid cooling of hot water in the pipes offers advantages such as good cooling effect, high cooling efficiency, and adjustable cooling temperature, facilitating automated control. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the high-efficiency cooling TIG welding system for DC positive polarity welding of aluminum alloys described in this invention; Figure 2 This is a cross-sectional view of the protective cover, cooling box and related components of the high-efficiency cooling TIG welding system for DC positive polarity welding of aluminum alloys described in this invention. Figure 3 This is one of the structural schematic diagrams of the cold water preparation device for the high-efficiency cooling TIG welding system for DC positive polarity welding of aluminum alloys described in this invention; Figure 4 This is the second schematic diagram of the cold water preparation device for the high-efficiency cooling TIG welding system for DC positive polarity welding of aluminum alloys described in this invention.

[0017] In the diagram, 1-cold water pipe, 2-workpiece, 3-cold water preparation device, 30-low temperature nitrogen tank, 31-liquid nitrogen tank, 32-liquid nitrogen pipe, 33-first low temperature solenoid valve, 34-second low temperature solenoid valve, 35-nitrogen discharge pipe, 36-second connecting pipe, 37-first connecting pipe, 38-second proportional regulating valve, 39-first proportional regulating valve, 4-first temperature sensor, 5-cooling tank inlet pipe, 6-welding torch, 7-gas pipe, 8-protective cover, 9- 10-Second temperature sensor, 11-Tungsten electrode, 12-Hot water pipe, 13-Water pump, 14-Controller, 15-Water tank, 16-Protective cover support step, 17-Protective cover plate, 18-Sealing gasket, 19-Cooling box support step, 20-Cooling box body, 21-Gas outlet, 22-Box cover plate, 23-Cold water inlet, 24-Hot water outlet, 25-Box body center pipe, 26-Circular cylindrical inner cavity, 27-Gas outlet. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings: like Figures 1-4 As shown, the high-efficiency cooling TIG welding system for DC positive polarity welding of aluminum alloys according to the present invention includes a welding torch 6. The welding torch 6 includes a welding torch body (not separately marked in the figure), a gas pipe 7, a tungsten electrode 11, a protective cover 8, and a cooling box 20. The gas pipe 7, which is installed on the welding torch body and is conductive, has its inlet connected to a gas source (not shown in the figure, which is also one of the devices in the TIG welding system). The gas outlet of the gas pipe 7 is located inside the insulated protective cover 8. The protective cover 8 is connected to the gas pipe 7 to fix the protective cover 8. The main body of the tungsten electrode 11 is placed inside the protective cover 8, and the welding end of the tungsten electrode 11 (i.e., the welding end of the tungsten electrode 11) is located inside the protective cover 8. Figure 1 The part indicated by the number 11 in the middle extends out of the protective cover 8 through the air outlet 27. The tungsten electrode 11 is connected to the positive terminal of the DC power supply (not shown in the figure, which is also one of the devices of the TIG welding system) through the gas pipe 7. The cooling box 20 is equipped with a cooling medium. The cooling box 20 is placed inside the protective cover 8 and a gap is left between it and the air outlet 27 of the protective cover 8. The main body of the tungsten electrode 11 is placed inside the cooling box 20 or in close contact with the cooling box 20, and the welding end of the tungsten electrode 11 is placed outside the cooling box 20.

[0019] like Figures 1-4 As shown, the present invention also discloses the following more optimized specific structures: To meet the continuous low-temperature requirement of approximately 2-15°C within the cooling chamber 20 and for ease of implementation, the cooling medium within the cooling chamber 20 is cold water. The tungsten electrode 11 is in close contact with the cooling chamber 20. The high-efficiency cooling TIG welding system for DC positive polarity welding of aluminum alloys also includes a cooling chamber inlet pipe 5, a cooling chamber outlet pipe 9, a cold water preparation device 3, a cold water pipe 1, and a hot water pipe 12. The outlet of the cooling chamber inlet pipe 5 is connected to the cold water inlet 23 of the cooling chamber 20, and the inlet of the cooling chamber outlet pipe 9 is connected to the hot water outlet 24 of the cooling chamber 20. The cold water inlet 23 and hot water outlet 24 are located on opposite outer walls of the cooling box 20 and are staggered axially with respect to the tungsten electrode 11. More preferably, the cold water inlet 23 is closer to the air outlet 27 of the protective cover 8, and the hot water outlet 24 is closer to the air pipe 7, which provides better cooling effect. The cooling box inlet pipe 5 and cooling box outlet pipe 9 pass through corresponding through holes on the protective cover 8. The inlet of the cooling box inlet pipe 5 is connected to the cold water outlet of the cold water preparation device 3 via the cold water pipe 1, and the outlet of the cooling box outlet pipe 9 is connected to the hot water inlet of the cold water preparation device 3 via the hot water pipe 12. For ease of operation, the entire section of the cold water pipe 1 and the section connected to the cooling box 20 can be made of flexible hose.

[0020] To ensure a reliable conductive and mechanical connection between the tungsten electrode 11 and the cooling box 20, the cylindrical cooling box 20 is open at one end and closed at the other. The open end of the cooling box 20 is connected to the box cover plate 22 via threads. Both the cooling box 20 and the box cover plate 22 are conductive, while the cooling box inlet pipe 5 and the cooling box outlet pipe 9 are non-conductive. A central tube 25 protruding towards the open end is located in the middle of the closed end of the cooling box 20. One end of the central tube 25 is open and close to the air outlet 27 of the protective cover 8. A circular cylindrical inner cavity 26 is formed inside the cooling box 20 at the outer periphery of the central tube 25. The cold water inlet 23 and the hot water outlet 24 of the cooling box 20 communicate with the circular cylindrical inner cavity 26. The inner wall of the circumference is provided with internal threads, and the outer wall of the circumference of the tungsten electrode 11 is provided with external threads. The tungsten electrode 11 is placed inside the central tube 25 of the box and is threadedly connected. The other end of the protective cover 8 opposite to its air outlet 27 is open and connected to the insulated protective cover plate 17 by screws. The cooling box inlet pipe 5 and the cooling box outlet pipe 9 pass through the corresponding through holes on the protective cover plate 17 respectively. The air pipe 7 passes through the screw hole in the middle of the protective cover plate 17 and the two are connected by threads. The end of the air pipe 7 located inside the protective cover 8 is connected to the box cover plate 22 by threads. Specifically, the box cover plate 22 is provided with a countersunk hole and the hole wall of the countersunk hole is provided with threads and is connected to the threads on the outer wall of one end of the air pipe 7. The gas outlet 21 of the air pipe 7 is located on the pipe wall between the protective cover plate 17 and the box cover plate 22.

[0021] For ease of processing and assembly, the cold water inlet 23 of the cooling box 20 is connected to the outlet of the cooling box inlet pipe 5, and the hot water outlet 24 of the cooling box 20 is connected to the inlet of the cooling box outlet pipe 9 by threads.

[0022] To improve the sealing performance between the cooling box 20 and other components and to facilitate processing and assembly, the inner side of the cold water inlet 23 and the inner side of the hot water outlet 24 of the cooling box 20 are respectively provided with sealed inner cavities (not marked in the figure). The end of the central tube 25 of the box is open near the box cover plate 22. Sealing gaskets 18 are respectively provided between the outlet of the cooling box inlet pipe 5 and the corresponding sealed inner cavity, between the inlet of the cooling box outlet pipe 9 and the corresponding sealed inner cavity, between the open end of the cooling box 20 and the box cover plate 22, and between the open end of the central tube 25 near the box cover plate 22 and the box cover plate 22. The sealing gaskets 18 are provided with a central through hole and the size of the multiple sealing gaskets 18 matches the size of the corresponding connection parts.

[0023] To achieve a continuous supply of low-temperature chilled water and to automate the temperature regulation of the chilled water, and to facilitate implementation, the inlet of the chilled water pipe 1 and the outlet of the hot water pipe 12 are connected by a connecting pipe. The high-efficiency cooling TIG welding system for DC positive polarity welding of aluminum alloys also includes a water tank 15, a water pump 13, a first temperature sensor 4, a second temperature sensor 10, and a controller 14. The water tank 15 and the water pump 13 are connected in series on the hot water pipe 12. The first temperature sensor 4 is installed on the cooling tank inlet pipe 5 near its inlet and is used to detect the water temperature in the cooling tank inlet pipe 5. The second temperature sensor 10 is installed on the cooling tank outlet pipe 9 near its outlet and is used to detect the water temperature in the cooling tank outlet pipe 9. The chilled water preparation device 3 includes a liquid nitrogen tank 31 and a low-temperature nitrogen... The gas tank 30, the first cryogenic solenoid valve 33 and the second cryogenic solenoid valve 34 are connected. The outlet of the liquid nitrogen tank 31 is connected to the cryogenic nitrogen gas tank 30 with heat preservation function through the liquid nitrogen pipe 32. The first cryogenic solenoid valve 33 is installed on the liquid nitrogen pipe 32. The connecting pipe passes through the cryogenic nitrogen gas tank 30. A nitrogen discharge pipe 35 is connected to the side wall of the cryogenic nitrogen gas tank 30 opposite to the connection point of the liquid nitrogen pipe 32. The second cryogenic solenoid valve 34 is installed on the nitrogen discharge pipe 35. The signal output terminals of the first temperature sensor 4 and the second temperature sensor 5 are respectively connected to the signal input terminals of the controller 14. The control input terminals of the water pump 13, the first cryogenic solenoid valve 33 and the second cryogenic solenoid valve 34 are respectively connected to the control output terminals of the controller 14.

[0024] According to actual needs, such as Figure 3 As shown, the connecting pipe is a single piece integrally formed with the cold water pipe 1 and the hot water pipe 12. This structure achieves the purpose of regulating the water temperature in the cold water pipe 1 by changing the amount of nitrogen in the low-temperature nitrogen tank, but its regulation precision is not very high; or, as... Figure 4 As shown, the connecting pipes include a first connecting pipe 37 and a second connecting pipe 36. One end of the first connecting pipe 37 and one end of the second connecting pipe 36 are respectively connected to the inlet of the cold water pipe 1. The other end of the first connecting pipe 37 and the other end of the second connecting pipe 36 are respectively connected to the outlet of the hot water pipe 12. The first connecting pipe 37 passes through the low-temperature nitrogen box 30. A first proportional regulating valve 39 is installed on the first connecting pipe 37 and placed outside the low-temperature nitrogen box 30. A second proportional regulating valve 38 is installed on the second connecting pipe 36. The control input end of the first proportional regulating valve 39 and the control input end of the second proportional regulating valve 38 are respectively connected to the control output end of the controller 14. This structure mainly achieves the purpose of regulating the water temperature in the cold water pipe 1 by changing the mixing ratio of low-temperature water and high-temperature water, and its regulation accuracy is high.

[0025] Figure 1The image also shows a protective cover support step 16 provided on the protective cover 8, which facilitates the quick positioning of the protective cover cover 17 to enable the rapid installation of the protective cover cover 17. Figure 1 The diagram also shows a cooling box support step 19 provided on the cooling box 20, which facilitates the support of the associated sealing gasket 18 and the box cover 22 to achieve the sealed installation of the box cover 22; these structures are conventional adaptive structures.

[0026] like Figures 1-4 As shown, during use, first connect the air inlet of the gas pipe 7 of the welding torch 6 to the gas source, and connect the gas pipe 7 of the welding torch 6 to the positive terminal of the DC power supply. Since the gas pipe 7 is threadedly connected to the box cover plate 22, the box cover plate 22 is threadedly connected to the cooling box 20, and the central tube 25 of the cooling box 20 is threadedly connected to the tungsten electrode 11, the tungsten electrode 11 is connected to the positive terminal of the DC power supply. Connect the workpiece 2 (aluminum alloy) to the negative terminal of the DC power supply. Then, control the first cryogenic solenoid valve 33 to open through the controller 14, injecting cryogenic nitrogen into the cryogenic nitrogen tank 30. Since the liquid nitrogen in the liquid nitrogen tank 31 is high-pressure liquid nitrogen, which is higher than the pressure in the cryogenic nitrogen tank 30, the liquid nitrogen will naturally flow out after the first cryogenic solenoid valve 33 is opened. The gas flows into the low-temperature nitrogen tank 30 and vaporizes into low-temperature nitrogen gas due to the decrease in pressure and increase in temperature. During the injection of low-temperature nitrogen gas into the low-temperature nitrogen tank 30, the second low-temperature solenoid valve 34 is opened as needed to discharge the air and high-temperature nitrogen gas in the low-temperature nitrogen tank 30. Then, the water pump 13 is started to circulate the room temperature water in the water tank 15. After passing through the low-temperature nitrogen tank 30, the water becomes cold water and enters the annular cylindrical inner cavity 26 of the cooling tank body 20 after passing through the cold water pipe 1 and the cooling tank inlet pipe 5. The tungsten electrode 11 is strongly cooled by the pipe wall of the central pipe 25 of the tank body. Then, the water flows back to the water tank 15 through the cooling tank outlet pipe 9 and the hot water pipe 12, forming a circulation. Then the welding operation can begin. The welding wire is fed to the welding position on the workpiece 2 and between the welding end of the tungsten electrode 11 and the welding end of the tungsten electrode 11. The welding wire is connected to both the workpiece 2 and the welding end of the tungsten electrode 11. Under the high temperature generated by the high current, the workpiece 2 and the welding wire melt locally, thereby achieving the welding function. At the same time, the gas source sends the protective gas (helium or argon) into the protective cover 8. The protective gas is sent out to the welding position through the gas outlet 27 of the protective cover 8, which serves to protect the electrode and the molten pool.

[0027] During the welding process, the first temperature sensor 4 and the second temperature sensor 10 detect the temperature of the cold water in the cooling tank inlet pipe 5 and the temperature of the hot water in the cooling tank outlet pipe 9, respectively, and transmit their temperature information to the controller 14. The controller 14 controls the opening and closing or opening degree of the first low-temperature solenoid valve 33, the second low-temperature solenoid valve 34, the first proportional regulating valve 39, and the second proportional regulating valve 38 according to the actual detected temperature and the required cold water temperature in the cooling tank 20, thereby realizing the regulation and control of the cold water temperature in the cold water pipe 1, ensuring that the cold water temperature in the cooling tank 20 is maintained within a certain constant range, and realizing the long-term and efficient cooling function of the tungsten electrode 11.

[0028] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the technical solutions of the present invention. Any technical solution that can be implemented based on the above embodiments without creative effort should be considered to fall within the scope of protection of the patent of the present invention.

Claims

1. A high-efficiency cooled TIG welding system for DC positive polarity welding of aluminum alloys, comprising a welding torch, the welding torch including a torch body, a gas pipe, a tungsten electrode, and a protective cover, wherein the gas pipe, which is mounted on the welding torch body and is conductive, has its inlet connected to a gas source, and its gas outlet is located inside the insulated protective cover, the protective cover being connected to the gas pipe for fixing the protective cover, the main body of the tungsten electrode being placed inside the protective cover and the welding end of the tungsten electrode extending outside the protective cover through the gas outlet of the protective cover, and the tungsten electrode being connected to the positive terminal of a DC power supply through the gas pipe, characterized in that: The high-efficiency cooling TIG welding system for DC positive polarity welding of aluminum alloys further includes a cooling box containing a cooling medium. The cooling box is placed inside the protective cover with a gap between it and the air outlet of the protective cover. The main body of the tungsten electrode is placed inside the cooling box or in close contact with it, while the welding end of the tungsten electrode is outside the cooling box. The cooling medium inside the cooling box is cold water. The tungsten electrode is in close contact with the cooling box. The high-efficiency cooling TIG welding system for DC positive polarity welding of aluminum alloys also includes a cooling box inlet pipe, a cooling box outlet pipe, a cold water preparation device, a cold water pipe, and a hot water pipe. The outlet of the cooling box inlet pipe... The cooling tank is connected to the cold water inlet of the cooling box, and the inlet of the cooling box outlet pipe is connected to the hot water outlet of the cooling box. The cold water inlet and hot water outlet of the cooling box are located on opposite outer walls of the cooling box and are offset axially from the tungsten electrode. The cooling box inlet pipe and cooling box outlet pipe pass through corresponding through holes on the protective cover. The inlet of the cooling box inlet pipe is connected to the cold water outlet of the cold water preparation device through the cold water pipe, and the outlet of the cooling box outlet pipe is connected to the hot water inlet of the cold water preparation device through the hot water pipe. One end of the cylindrical cooling box is open. The other end is closed. The open end of the cooling box is connected to the box cover plate by threads. Both the cooling box and the box cover plate are conductive. The cooling box inlet pipe and the cooling box outlet pipe are non-conductive. A central tube protruding towards the open end is provided in the middle of the closed end of the cooling box. One end of the central tube is open and close to the air outlet of the protective cover. A cylindrical inner cavity is formed in the cooling box at the outer periphery of the central tube. The cold water inlet and hot water outlet of the cooling box are respectively connected to the cylindrical inner cavity. The inner circumference of the central tube is provided with... The tungsten electrode has an internal thread, and its outer circumference is provided with an external thread. The tungsten electrode is placed inside the central tube of the housing and is threadedly connected. The protective cover has an opening at the other end opposite to its air outlet and is connected to the protective cover cover plate by screws. The cooling tank inlet pipe and the cooling tank outlet pipe pass through corresponding through holes on the protective cover cover plate. The air pipe passes through the screw hole in the middle of the protective cover cover plate and the two are threadedly connected. The end of the air pipe located inside the protective cover is threadedly connected to the housing cover plate. The gas outlet of the air pipe is located on the pipe wall between the protective cover cover plate and the housing cover plate.The inlet of the cold water pipe and the outlet of the hot water pipe are connected by a connecting pipe. The high-efficiency cooling TIG welding system for DC positive polarity welding of aluminum alloys also includes a water tank, a water pump, a first temperature sensor, a second temperature sensor, and a controller. The water tank and the water pump are connected in series on the hot water pipe. The first temperature sensor is installed on the cooling tank inlet pipe near its inlet and is used to detect the water temperature in the cooling tank inlet pipe. The second temperature sensor is installed on the cooling tank outlet pipe near its outlet and is used to detect the water temperature in the cooling tank outlet pipe. The cold water preparation device includes a liquid nitrogen tank, a low-temperature nitrogen tank, a first low-temperature solenoid valve, and a second low-temperature... The liquid nitrogen tank outlet is connected to the cryogenic nitrogen tank with insulation function via a liquid nitrogen pipe. A first cryogenic solenoid valve is installed on the liquid nitrogen pipe. The connecting pipe passes through the cryogenic nitrogen tank. A nitrogen venting pipe is connected to the side wall of the cryogenic nitrogen tank opposite to the connection point with the liquid nitrogen pipe. A second cryogenic solenoid valve is installed on the nitrogen venting pipe. The signal output terminals of the first and second temperature sensors are respectively connected to the signal input terminals of the controller. The control input terminals of the water pump, the first cryogenic solenoid valve, and the second cryogenic solenoid valve are respectively connected to the control output terminals of the controller.

2. The high-efficiency cooling TIG welding system for DC positive polarity welding of aluminum alloys according to claim 1, characterized in that: The cold water inlet of the cooling box and the outlet of the cooling box water inlet pipe are respectively connected by threads, and the hot water outlet of the cooling box and the inlet of the cooling box water outlet pipe are respectively connected by threads.

3. The high-efficiency cooling TIG welding system for DC positive polarity welding of aluminum alloys according to claim 2, characterized in that: The cooling box has sealed cavities on the inner side of the cold water inlet and the inner side of the hot water outlet. A sealing gasket is provided on the opening end of the central tube of the box near the box cover plate, between the outlet of the cooling box water inlet pipe and the corresponding sealed cavity, between the inlet of the cooling box water outlet pipe and the corresponding sealed cavity, between the opening end of the cooling box and the box cover plate, and between the opening end of the central tube of the box near the box cover plate and the box cover plate. The sealing gasket has a central through hole, and the size of the multiple sealing gaskets matches the size of the corresponding connection parts.

4. The high-efficiency cooling TIG welding system for DC positive polarity welding of aluminum alloys according to any one of claims 1-3, characterized in that: The connecting pipe is a single pipe integrally formed with the cold water pipe and the hot water pipe; or, the connecting pipe includes a first connecting pipe and a second connecting pipe, one end of the first connecting pipe and one end of the second connecting pipe are respectively connected to the inlet of the cold water pipe, and the other ends of the first connecting pipe and the second connecting pipe are respectively connected to the outlet of the hot water pipe. The first connecting pipe passes through the low-temperature nitrogen box, and a first proportional regulating valve is installed on the first connecting pipe and placed outside the low-temperature nitrogen box. A second proportional regulating valve is installed on the second connecting pipe, and the control input terminals of the first proportional regulating valve and the second proportional regulating valve are respectively connected to the control output terminal of the controller.

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