Leakage current spatial distribution detection device for underwater electric arc welding / cutting

Abstract

The invention discloses an underwater electric arc welding / cutting leakage current space distribution detection device, which comprises a leakage current matrix detection device which is tightly attached to the upper surface of a workpiece, the leakage current matrix detection device comprises a PCB, the PCB is provided with a central hole, and a plurality of detection electrode units which are independent from one another are uniformly arranged around the central hole; an underwater welding / cutting electric arc established between the welding wire / cutting wire and the workpiece always acts in the center hole; each detection electrode unit is connected with a pin of a first waterproof aviation plug on the PCB through an internal circuit of the PCB, and the first waterproof aviation plug is connected with a welding / cutting power supply through a second waterproof aviation plug and a multi-core cable; hall sensors are arranged on all wire cores of the multi-core cable and used for detecting leakage current signals. And according to the position of each detection electrode unit and the leakage current signal detected by the corresponding Hall sensor, determining the spatial distribution condition of the leakage current. According to the invention, the spatial distribution information of the leakage current can be accurately obtained in real time.

Description

Technical Field

[0001] The present invention relates to a leakage current detection system for underwater arc welding / cutting, and more particularly to a device for real-time monitoring of the spatial distribution of leakage current in underwater arc welding / cutting. Background Art

[0002] Underwater operations such as ocean engineering and ship maintenance involve welding / cutting operations. Since seawater contains a large amount of freely movable ions such as Na + , Cl - etc., it has stronger electrical conductivity compared to fresh water. Therefore, in a seawater environment, a small part of the current fails to be conducted to the workpiece to be operated through the welding / cutting arc, but is conducted to the surrounding of the workpiece through seawater. This part of the current that does not play a role during welding / cutting is the leakage current.

[0003] Since current is the main process parameter of underwater arc welding / cutting, the existence of leakage current reduces the actual effect of the welding / cutting current, resulting in insufficient energy during welding / cutting operations, and phenomena such as unreliable arc ignition, unstable arc, affecting weld formation, and the workpiece not being cut through, seriously affecting the quality of underwater arc welding / cutting operations.

[0004] The detection system and method for evaluating the leakage current of underwater welding / cutting arc disclosed in CN112620879B obtain leakage current information by setting a leakage current detection ring on the side of the welding tip. However, the placement of the leakage current detection ring increases the leakage current loop of the underwater arc, interfering with the original underwater arc leakage behavior; moreover, this leakage current detection ring can only detect the total value of the underwater arc leakage current at a specific radial position and cannot detect the distribution of the underwater arc leakage current. Summary of the Invention

[0005] Object of the Invention: The object of the present invention is to provide a device for detecting the spatial distribution of leakage current in underwater arc welding / cutting.

[0006] Technical solution: An underwater arc welding / cutting leakage current spatial distribution detection device of the present invention includes a leakage current matrix detection device disposed closely on the upper surface of the workpiece. The leakage current matrix detection device includes a PCB board. A central hole and a first waterproof aviation plug are spaced on the PCB board, and a number of mutually independent detection electrode units are evenly arranged around the central hole. The underwater welding / cutting arc established between the welding wire / cutting wire and the workpiece always acts within the central hole; each detection electrode unit is connected to the pins of the first waterproof aviation plug through the internal circuit of the PCB board, and the first waterproof aviation plug is connected to the welding / cutting power supply through a second waterproof aviation plug and a multi-core cable; Hall sensors are arranged on each core of the multi-core cable for detecting leakage current signals; according to the positions of each detection electrode unit and the leakage current signals detected by the corresponding Hall sensors, the spatial distribution of the leakage current is determined.

[0007] Further, the central hole is circular, suitable for the case where the underwater arc is stationary.

[0008] Further, the central hole is kidney-shaped, suitable for the case where the underwater arc is moving.

[0009] Further, the aperture of the central hole is determined according to the action range of the underwater arc welding / cutting arc.

[0010] Further, the number of detection electrode units is 6 to 30, determined according to the required fineness of the detected leakage current spatial distribution.

[0011] Further, the Hall sensor adopts a closed-loop Hall current sensor, with a detection range of 0 to 1A or 0 to 500mA, a detection accuracy of not less than 1%, and a response time of not less than 10μs.

[0012] Further, the leakage current matrix detection device is formed by potting waterproof treatment at the non-electrode detection unit position of the PCB board and stacking high-temperature resistant ceramic chips, and the thickness of the formed leakage current matrix detection device does not exceed 4mm.

[0013] Further, the underwater arc welding / cutting leakage current spatial distribution detection device further includes a data analysis device and a data acquisition card. The leakage current signals detected by each Hall sensor are connected to the data acquisition card and transmitted by the data acquisition card to the data analysis device, and the data analysis device is used for visual processing of the leakage current spatial distribution.

[0014] Further, the sampling rate of the data acquisition card is not less than 1KS / s.

[0015] Further, the data analysis device adopts an industrial control computer.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages:

[0017] (1) Each detection electrode unit is independent of each other, and the detection result can accurately reflect the magnitude of the leakage current at different positions, reflecting the spatial distribution of the leakage current. The real-time obtained spatial distribution information of the leakage current has a certain guiding role in improving the quality of underwater arc welding / cutting.

[0018] (2) During the detection of the leakage current in underwater arc welding / cutting, the central hole structure design is adopted, which can maintain an effective distance interval from the high-temperature arc zone and is not easily damaged during underwater arc welding / cutting, and can be reused.

[0019] (3) The leakage current matrix detection device is close to the surface of the base material, has little influence on the leakage current loop, and can more truly reflect the leakage current loop of the underwater welding / cutting current diffusing through the water environment and the workpiece.

[0020] (4) It has a simple structure, is safe and reliable, easy to operate, and the manufacturing cost of the key component, the leakage current matrix detection device, is low. Description of the Drawings

[0021] Figure 1 is a schematic structural diagram of a device for detecting the spatial distribution of leakage current in underwater arc welding / cutting provided by an embodiment of the present invention;

[0022] Figure 2 and Figure 3 is a schematic structural diagram of a PCB board with central holes of different shapes in an embodiment of the present invention. Detailed Embodiments

[0023] The present invention will be further described below with reference to the drawings.

[0024] Att Figures 1 to 3 The reference numerals in the drawings are as follows:

[0025] 1, data analysis device; 2, data acquisition card; 3, welding / cutting power supply; 4, Hall sensor; 5, first waterproof aviation plug; 6, leakage current matrix detection device; 7, workpiece; 8, second waterproof aviation plug; 9, water environment; 10, conductive rod; 11, wire feeder; 12, multi-core cable; 13, welding wire / cutting wire; 14, underwater arc welding / cutting arc; 15, conductive nozzle; 16, detection electrode unit; 17, central hole.

[0026] As Figures 1 to 3As shown in the figure, an embodiment of the present invention provides a leakage current spatial distribution detection device for underwater arc welding / cutting, which includes a data analysis device 1, a data acquisition card 2, and a leakage current matrix detection device 6 disposed closely on the upper surface of the workpiece 7. The workpiece 7 is placed in a water environment 9, which can be fresh water or seawater, and can be a laboratory environment or an actual water environment to meet the detection of underwater arc leakage current under different test environments. In this embodiment, the water environment 9 is constructed by placing tap water in a glass water tank of 1m * 1m * 1m, and the workpiece 7 is a Q235 steel of 150mm * 80mm * 10mm.

[0027] A wire feeder 11 is placed above the workpiece 7. A conductive rod 10 and a conductive nozzle 15 are successively installed below the wire feeder 11. The conductive rod 10 is connected to the negative electrode of the welding / cutting power supply 3 through a cable, and the workpiece 7 is connected to the positive electrode of the welding / cutting power supply 3 through a cable. The welding wire / cutting wire 13 is fed downward through the wire feeder 11, the conductive rod 10, and the conductive nozzle 15 to establish an underwater welding / cutting arc 14 with the workpiece 7.

[0028] The leakage current matrix detection device 6 includes a PCB board. A central hole 17 is provided at the left end of the PCB board, and 6 to 30 independent detection electrode units 16 are evenly arranged around the central hole 17. The detection electrode units 16 are insulated from each other. In this embodiment, the area of each detection electrode unit 16 is 4mm 2 . The underwater welding / cutting arc 14 always acts within the central hole 17. Therefore, the aperture of the central hole 17 is set to 10mm to 20mm. In this embodiment, the aperture is set to 10mm. The central hole 17 is circular or waist-shaped, which is suitable for the cases of stationary and moving underwater arcs respectively.

[0029] A first waterproof aviation plug 5 is provided at the right end of the PCB board. The number of cores of the first waterproof aviation plug 5 is not less than the number of detection electrode units 16. Each detection electrode unit 16 is connected to the pin of the first waterproof aviation plug 5 through the internal circuit of the PCB board. The first waterproof aviation plug 5 is connected to the positive electrode of the welding / cutting power supply 3 through a second waterproof aviation plug 8 (the second waterproof aviation plug 8 is matched with the first waterproof aviation plug 5, has the same number of cores, and complementary interface shapes) and a multi-core cable 12. The multi-core cable 12 is a shielded cable, the number of cores is not less than the number of cores of the first waterproof aviation plug 5, and it has waterproof property. Hall sensors 4 are provided on each wire core of the multi-core cable 12 for detecting leakage current signals. The leakage current signals detected by each Hall sensor 4 are connected to the data acquisition card 2 and transmitted to the data analysis device 1 by the data acquisition card 2. The data analysis device 1 is used to determine the spatial distribution of the leakage current according to the positions of the detection electrode units 16 and the leakage current signals detected by the corresponding Hall sensors 4, and perform visual display.

[0030] The leakage current matrix detection device 6 is formed by potting and waterproofing at the non-electrode detection unit position of the PCB board and stacking high-temperature resistant ceramic chips, and the thickness of the formed leakage current matrix detection device 6 does not exceed 4 mm.

[0031] The Hall sensor 4 uses a closed-loop Hall current sensor, with a detection accuracy of not less than 1% and a response time of not less than 10 μs. In this embodiment, the Hall current sensor uses a WCS2801 current sensor with a detection range of 0 - 1 A.

[0032] The sampling rate of the data acquisition card 2 is not less than 1 KS / s. The NIPCI-6251 data acquisition card used in this embodiment is a high-speed M series multi-functional data acquisition card with 16 analog inputs, which can collect the analog signals received by the data acquisition terminal board.

[0033] The data analysis device 1 uses an industrial control computer.

[0034] Next, taking Figure 2 the shown leakage current matrix detection device as an example, the usage method of the leakage current spatial distribution detection device described in the embodiment of the present invention will be introduced.

[0035] (1) Place the workpiece 7, the conductive rod 10, and the conductive nozzle 15 in the water environment 9. The workpiece 7 is connected to the positive electrode of the welding / cutting power supply 3, and the conductive rod 10 is connected to the negative electrode of the welding / cutting power supply 3.

[0036] (2) Fix the leakage current matrix detection device 6 closely against the upper surface of the workpiece 7.

[0037] (3) Connect the multi-core cable 12 to the first waterproof aviation plug 5 of the leakage current matrix detection device 6 through the second waterproof aviation plug 8, and the other end of the multi-core cable 12 converges into a node and is connected to the positive electrode of the welding / cutting power supply 3.

[0038] (4) Connect each Hall sensor 4 to the data acquisition card 2 in sequence, and connect the data acquisition card 2 to the data analysis device 1.

[0039] (5) Thread the welding wire / cutting wire 13 through the wire feeder 11, and under the conveying action of the wire feeder 11, pass through the conductive rod 10 and the conductive nozzle 15 in sequence. Adjust the position of the conductive rod 10 so that the projection of the welding wire / cutting wire 13 on the upper surface of the workpiece 7 is at the center or on the center line of the central hole 17 of the leakage current matrix detection device 6, and the vertical distance between the bottom of the conductive nozzle 15 and the upper surface of the workpiece 7 is between 10 - 30 mm.

[0040] (6) Turn on the welding / cutting power supply 3, and adjust the welding / cutting parameters as follows: the welding / cutting arc voltage is 30 - 45V, and the welding / cutting current is 350 - 500A. Turn on the wire feeder 11, ignite the arc to perform underwater arc welding / cutting. The leakage current signals of each detection electrode unit 16 collected by the Hall sensor 4 are transmitted to the data acquisition card 2, and finally the data acquisition card 2 uploads the collected leakage current signals to the data analysis device 1 for storage and visualization processing to obtain the leakage current spatial distribution result.

[0041] (7) For the case where the underwater welding / cutting arc 14 is stationary, extinguish the arc and turn off the wire feeder 11 after 3 - 5s (for the case where the underwater welding / cutting arc 14 is moving, extinguish the arc and turn off the wire feeder 11 when the underwater welding / cutting arc 14 reaches the end point).

[0042] (8) If further detection is required, replace the workpiece 7, and repeat steps (2) - (7) until all detections are completed.

[0043] (9) At the end of the test, turn off the wire feeder 11 and the welding / cutting power supply 3, sequentially disassemble the contact tip 15, the conducting rod 10, and the welding wire / cutting wire 13, pull out the second waterproof aviation plug 8, and take out the leakage current matrix detection device 6 and the workpiece 7.

[0044] The leakage current detection results of each detection electrode unit and the leakage current per unit area at the corresponding position obtained in this embodiment are shown in Table 1.

[0045] Table 1 Leakage current detection results

[0046] Detection electrode unit position R15(a) R15(b) R15(c) R15(d) R15(e) R15(f) Leakage current (A) 0.318 0.328 0.305 0.308 0.326 0.334 <![CDATA[Leakage current per unit area (A / m 2 )]]> 79375 81944 76332 77075 81534 83599 Detection electrode unit position R25(a) R25(b) R25(c) R25(d) R25(e) R25(f) Leakage current (A) 0.206 0.204 0.206 0.216 0.216 0.212 <![CDATA[Leakage current per unit area (A / m 2 )]]> 51613 50968 51390 54123 53967 52968

[0047] In Table 1, R15 indicates that the detection electrode unit is located on a circle with a radius of 15 mm centered on the central hole, and (a) - (f) represent six detection electrode units. The same applies to R25.

Claims

1. A leakage current spatial distribution detection device for underwater arc welding / cutting, characterized in that: The invention comprises a leakage current matrix detection device (6) arranged close to the upper surface of a workpiece (7), the leakage current matrix detection device (6) comprising a PCB board, a center hole (17) and a first waterproof aviation plug (5) are arranged at intervals on the PCB board, and a plurality of detection electrode units (16) independent of each other are evenly arranged around the center hole (17), and an underwater welding / cutting arc (14) established between a welding wire / cutting wire (13) and a workpiece (7) always acts in the center hole (17); each detection electrode unit (16) is respectively connected to a pin of the first waterproof aviation plug (5) through an internal circuit of the PCB board, and the first waterproof aviation plug (5) is connected to a welding / cutting power source (3) through a second waterproof aviation plug (8) and a multi-core cable (12); each wire core of the multi-core cable (12) is provided with a Hall sensor (4) for detecting a leakage current signal; according to the position of each detection electrode unit (16) and the leakage current signal detected by the corresponding Hall sensor (4), the spatial distribution of the leakage current is determined.

2. The leakage current spatial distribution detection device for underwater arc welding / cutting according to claim 1, characterized in that: The center hole (17) is circular, which is suitable for the situation where the electric arc is stationary underwater.

3. The leakage current spatial distribution detection device for underwater arc welding / cutting according to claim 1, characterized in that: The central hole (17) is waist-shaped and is suitable for underwater arc movement.

4. The leakage current spatial distribution detection device for underwater arc welding / cutting according to claim 2 or 3, characterized in that: The diameter of the center hole (17) is determined according to the action range of the underwater arc welding / cutting arc.

5. The device for detecting spatial distribution of leakage current in underwater arc welding / cutting according to claim 1, characterized in that: The number of detection electrode units (16) is 6 to 30, which is determined according to the fineness of the spatial distribution of the leakage current to be detected.

6. The device for detecting spatial distribution of leakage current in underwater arc welding / cutting according to claim 1, characterized in that: The Hall sensor (4) adopts a closed-loop Hall current sensor with a detection range of 0-1A or 0-500mA, a detection accuracy of not less than 1%, and a response time of not less than 10μs.

7. The leakage current spatial distribution detection device for underwater arc welding / cutting according to claim 1, characterized in that: The leakage current matrix detection device (6) is formed by performing a waterproofing process on the non-electrode detection unit position of the PCB board and stacking high-temperature resistant ceramic sheets. The thickness of the formed leakage current matrix detection device (6) does not exceed 4 mm.

8. The device for detecting spatial distribution of leakage current for underwater arc welding / cutting according to any one of claims 1 to 7, characterized in that: It also comprises a data analysis device (1) and a data acquisition card (2); the leakage current signal detected by each Hall sensor (4) is connected to the data acquisition card (2) and transmitted from the data acquisition card (2) to the data analysis device (1); the data analysis device (1) is used for visual processing of the spatial distribution of the leakage current.

9. The device for detecting spatial distribution of leakage current in underwater arc welding / cutting according to claim 8, characterized in that: The sampling rate of the data acquisition card (2) is not less than 1KS / s.

10. The device for detecting spatial distribution of leakage current in underwater arc welding / cutting according to claim 8, characterized in that: The data analysis device (1) adopts an industrial computer.

Images