Pipeline Positioning Detection Method for PSP Pipeline Welding Joints

Abstract

The present invention discloses a method for detecting the location of a welded pipe at a PSP pipe, specifically comprising the following steps: Step 1, obtaining a standard impedance of the PSP pipe; Step 2, obtaining the actual measured impedance of the PSP pipe; and Step 3, comparing the standard impedance obtained in Step 1 with the measured impedance obtained in Step 2, and adjusting the position of the PSP pipe based on the comparison result. The present invention can monitor the actual spigot depth of the pipe during welding in real time, determining whether the spigot depth relative to the spigot opening is the optimal standard for achieving pipe welding. This method solves the problems of poor weld precision and weak water pressure resistance caused by traditional manual pipe butt welding.

Description

Technical Field

[0001] The invention belongs to the technical field of PSP pipe processing equipment and relates to a pipeline positioning detection method for a welded joint of a PSP pipeline. Background Art

[0002] With the rapid development of urbanization, PSP steel-plastic composite pipes have become the preferred choice for water supply networks due to their significant advantages, including strong corrosion resistance, strong resistance to external pressure, and good impact resistance. Pipe electromagnetic hot-melt welding machines, as supporting equipment for PSP steel-plastic composite pipe connections, are also influencing the development and application of PSP pipes. Electromagnetic welding technology has become the technology with the greatest development potential due to its high efficiency and environmentally friendly energy-saving advantages. Traditional welding equipment currently on the market lacks welding detection capabilities, requires high operator training requirements, and large operating errors lead to weak pipe water pressure resistance, making it difficult to meet the current refined requirements of PSP pipe welding. Workers' familiarity with welding equipment seriously affects the welding accuracy of PSP pipes. Summary of the Invention

[0003] The purpose of the present invention is to provide a pipeline positioning detection method for the weld joint of PSP pipelines. The method can monitor the actual socket depth of the pipeline during welding in real time, and judge whether the socket depth relative to the socket is the optimal standard for achieving pipeline welding. This solves the problems of poor weld precision and weak water pressure resistance caused by traditional manual pipe docking.

[0004] The technical solution adopted by the present invention is a method for detecting the location of a welded joint of a PSP pipe, which specifically includes the following steps:

[0005] Step 1, obtaining the standard impedance of the PSP pipeline;

[0006] Step 2, obtaining the actual measured impedance of the PSP pipeline;

[0007] Step 3: Compare the standard impedance obtained in step 1 with the measured impedance obtained in step 2, and adjust the PSP pipeline position according to the comparison result.

[0008] The present invention is also characterized in that:

[0009] The specific process of step 1 is:

[0010] Assuming that the magnetic flux in the air gap is evenly distributed, the magnetic field strength in the air gap is the magnetic field strength at the outer diameter of the heated object. Consider the PSP pipe and the PSP pipe socket as a whole hollow cylindrical load, and assume that the inner diameter of the PSP pipe is r1, the outer diameter of the PSP pipe is r2, and the depth of the PSP pipe inserted into the PSP pipe socket is H. l The number of turns of the inductor coil is N, and the effective value of the current flowing through the coil is The frequency is ω, and the alternating current flowing through the induction coil generates an alternating magnetic flux around the coil. The magnetic flux passing through the pipe diameter causes eddy current heating in the pipe;

[0011] According to Poynting's theorem:

[0012]

[0013] Where S is the Poynting vector, which represents the flow of energy as the surface power density, E is the electric field intensity, H is the magnetic field intensity, k = 1 / δ, δ is the depth of penetration into the pipe diameter of the receiving port, ω is the frequency of the current flowing through the coil, σ is the conductivity, μ=μ0μ r , where μ0 is the vacuum permeability, μ0=4π×10 -7 H / m,μ r is the relative magnetic permeability of the pipe;

[0014] Combined formula:

[0015]

[0016] We can get:

[0017]

[0018] Where, I0: the first zero-order deformed Bessel function, K0: the second zero-order deformed Bessel function, I1: the first first-order deformed Bessel function, K1: the second first-order deformed Bessel function;

[0019] The heated equivalent load is the PSP pipe equivalent resistance R b and equivalent reactance X b They are

[0020]

[0021]

[0022] The specific process of step 2 is: connect the sensor to the power supply and detect the socket position of the PSP pipe. During the socket process, the sensor measures the voltage of the PSP pipe. Current The actual reactance x′ of the PSP pipeline is calculated using the following formula: b and the actual resistance R′ b :

[0023]

[0024] The specific process of step 3 is: compare the standard impedance and actual impedance of the PSP pipe. When the two are inconsistent, the connection depth of the PSP pipe needs to be adjusted.

[0025] When the actual impedance of the PSP pipe is greater than the standard impedance, it indicates that the connection depth of the PSP pipe is deeper, and the PSP pipe needs to be pulled outward; when the actual impedance of the PSP pipe is less than the standard impedance, it indicates that the connection depth of the PSP pipe is shallow, and the PSP pipe needs to be inserted deeper.

[0026] The beneficial effect of the present invention is that the present invention can monitor the position of the pipeline relative to the socket in real time and remind the docking difference by obtaining the impedance of the equivalent load, effectively improving the pipeline welding accuracy, improving the water pressure resistance of the weld, and greatly reducing the probability of poor welding process due to worker operation errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a block diagram of the principle of an electromagnetic heat fusion welding machine used in the pipeline positioning detection method for the weld joint of a PSP pipeline according to the present invention;

[0028] Figure 2 Schematic diagram of the sensor of the PSP pipe socket electromagnetic hot fusion welding machine used in the method for detecting the location of the pipe at the weld of the PSP pipe according to the present invention;

[0029] Figure 3 The present invention is a design flow chart of a pipeline positioning detection method for a welded joint of a PSP pipeline.

[0030] In the figure, 1. Mains power supply, 2. Rectifier circuit, 3. Filter circuit, 4. IGBT module, 5. Voltage transformer, 6. Current transformer, 7. Load, 8. Controller, 9. PSP pipe, 10. Sensor, 11. PSP pipe socket, 12. Power supply line, 13. Electromagnetic hot melt welding machine. DETAILED DESCRIPTION

[0031] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] The present invention is used for the pipeline positioning detection method of the PSP pipeline welding point, which adopts a digital electromagnetic heat fusion welding machine. Figure 1 As shown, it includes a mains power supply 1, a rectifier circuit 2, a filter circuit 3, an IGBT module 4, a voltage transformer 5, a current transformer 6, a load (pipeline equivalent impedance) 7, and a controller 8.

[0033] The mains power supply 1 is a 220V / 50Hz single-phase AC power supply, the rectifier circuit 2 is a rectifier bridge composed of rectifier diodes, the filter circuit 3 is a filter circuit composed of RC current, and the controller 8 adopts an STM32 digital signal processor, which is directly connected to the voltage transformer 5 and the current transformer to collect the bus voltage and current and the load voltage and current, complete the adjustment of the output voltage and current, and the judgment and matching of the pipeline equivalent impedance. Through the connection with the IGBT module, PWM technology is used to control the transmission of electric energy, thereby controlling the power adjustment of the electromagnetic hot melt welding machine to the load 7.

[0034] The present invention provides a method for detecting the location of a PSP pipe at a weld joint, using a PSP pipe socket electromagnetic hot-melt welding machine sensor, such as Figure 2 As shown, during welding, the PSP pipe 9 is inserted into the PSP pipe socket 11, ensuring two requirements: the PSP pipe 9 must be inserted into the optimal position of the PSP pipe socket 11; and the axes of the PSP pipe 9 and the PSP pipe socket 11 must coincide with each other. Therefore, the welding process has extremely high requirements for the socket depth of the pipe.

[0035] The PSP pipe socket 11 is installed at the center of the inductor 10 , and the inductor 10 is connected to the electromagnetic heat fusion welding machine 13 via a power supply line 12 .

[0036] The PSP pipe 9 and the PSP pipe socket 11 are regarded as a whole hollow cylindrical load. The socket depths of the pipe and the socket are different, and the load impedance will change accordingly. Based on this, a model simulation is carried out to obtain the load impedance of different types of pipes when they reach the socket depth. With the socket depth as the independent variable and the standard load impedance as the dependent variable, a process curve can be fitted. According to the standard curve, the optimal socket depth of different types of PSP pipes relative to the socket can be obtained, and the load impedance of the optimal socket depth is used as the standard for the welding of this type of pipe. During the welding process, the load impedance measured by the known sensor can be combined with the process curve to obtain the relative position of the pipe and the pipe socket at this time. By comparing the actual load impedance with the standard of this type of pipe, the next adjustment direction of the pipeline can be determined, and the precise docking of the pipeline can be achieved.

[0037] The present invention is used for the pipeline positioning detection method at the welding point of the PSP pipeline, and the process is as follows: Figure 3 As shown, please follow the steps below:

[0038] Step 1: Obtain the standard impedance of the PSP pipeline 9;

[0039] according to Figure 2 , assuming that the magnetic flux in the air gap is uniformly distributed, the magnetic field strength in the air gap is the magnetic field strength at the outer diameter of the heated object Consider the PSP pipe 9 and the PSP pipe socket 11 as a whole hollow cylindrical load, and assume that the inner diameter of the PSP pipe 9 is r1, the outer diameter of the PSP pipe 9 is r2, and the depth of the PSP pipe 9 inserted into the PSP pipe socket 11 is H. l The number of turns of the inductor coil is N, and the effective value of the current flowing through the coil is The frequency is ω, and the alternating current flowing through the induction coil generates an alternating magnetic flux around the coil. The flux linkage passing through the pipe diameter causes eddy current heating in the pipe:

[0040] According to Poynting's theorem:

[0041]

[0042] Where S is the Poynting vector, which represents the flow of energy as the surface power density, E is the electric field intensity, H is the magnetic field intensity, k = 1 / δ, δ is the depth of penetration into the pipe diameter of the receiving port, ω is the frequency of the current flowing through the coil, σ is the conductivity, μ=μ0μ r , where μ0 is the vacuum permeability, μ0=4π×10 -7 H / m,μ r is the relative magnetic permeability of the pipe.

[0043] Combined formula:

[0044]

[0045] We can get:

[0046]

[0047] Where, I0: the first zero-order deformed Bessel function, K0: the second zero-order deformed Bessel function, I1: the first first-order deformed Bessel function, K1: the second first-order deformed Bessel function.

[0048] Equivalent resistance of heated load R b and equivalent reactance X b They are

[0049]

[0050]

[0051] Substitute F and G obtained from formula (3) into the equivalent impedance (equivalent impedance includes equivalent resistance R b and equivalent reactance X b ) formula, the result includes inner diameter r1, outer diameter r2, height H lWhen the PSP pipe 9 does not reach the optimal socket depth of the PSP pipe socket 11 (when the measured impedance value of the PSP pipe 9 is consistent with the actual calculated impedance value of the PSP pipe 9, it is the optimal socket depth), the inner diameter, outer diameter and height of the load will change accordingly, resulting in a change in the overall load impedance. According to different socket depths and corresponding load impedances, a process curve can be fitted to obtain the heating load height H for different models at the connection. l impedance value.

[0052] Step 2: Connect the sensor 10 to the power supply and detect the socket position of the PSP pipe 9. During the socket process, the sensor 10 measures the voltage at the load end (PSP pipe 9). Current use

[0053] Calculate the current impedance and compare it with the standard load impedance corresponding to the pipeline. If the actual impedance is consistent with the standard impedance, it means that the installed pipeline has reached the optimal socket depth. If the actual impedance is inconsistent with the standard impedance, the actual impedance is used as the independent variable input value of the process curve to calculate the current relative socket depth of the pipeline and the pipeline socket, prompting the staff to adjust the pipeline position.

[0054] The depth of the pipe inserted into the sensor that needs to be adjusted is calculated based on the difference between the current impedance and the standard impedance according to formula (4) and formula (5).

[0055] Step 3: Feedback on pipe socket test results:

[0056] The depth of the PSP pipe 9 inserted into the sensor according to the adjustment needs reminds the operator to adjust the socket condition of the PSP pipe 9; when the depth to be adjusted is greater than the error standard of 0.5mm, the fault indicator light of the electromagnetic hot fusion welding machine 13 lights up and refuses to power on and weld until the operator adjusts the pipe position to be within the error standard range, the fault is eliminated, and the electromagnetic hot fusion welding machine starts to weld the pipe.

Claims

1. A method for detecting the location of a welded joint of a PSP pipe, characterized by: The specific steps include: Step 1, obtaining the standard impedance of the PSP pipeline; The specific process of step 1 is: Assuming that the magnetic flux in the air gap is evenly distributed, the magnetic field strength in the air gap is the magnetic field strength at the outer diameter of the heated object. , consider the PSP pipe (9) and the PSP pipe socket (11) as a whole hollow cylindrical load, and assume that the inner diameter of the PSP pipe (9) is 、The outer diameter of PSP pipe (9) is , the depth of the PSP pipe (9) inserted into the PSP pipe socket (11) is , the number of turns of the coil of the inductor (10) is N, and the effective value of the current flowing through the coil is , the frequency is , the alternating current flowing through the induction coil generates an alternating magnetic flux around the coil , the magnetic flux passing through the pipe diameter is eddy-current heated in the pipe: According to Poynting's theorem: （1） Where S is the Poynting vector, which represents the flow of energy as the surface power density, E is the electric field strength, and H is the magnetic field strength. , The depth of the pipe diameter penetrating into the socket. , is the frequency of the current flowing through the coil, is the conductivity, , in, is the vacuum permeability, , is the relative magnetic permeability of the pipe; Combined formula: （2） We can get: （3） Where, , , : The first zero-order deformed Bessel function, : The second zero-order deformed Bessel function, : The first first-order deformed Bessel function, : The second first-order deformed Bessel function; Equivalent resistance of the heated equivalent load, i.e., the PSP pipe (9) and equivalent reactance They are: Step 2, obtaining the actual measured impedance of the PSP pipeline; Step 3: Compare the standard impedance obtained in step 1 with the measured impedance obtained in step 2, and adjust the PSP pipeline position according to the comparison result.

2. The method for detecting the location of a welded joint of a PSP pipe according to claim 1, wherein: The specific process of step 2 is: connect the sensor (10) to the power supply and detect the socket position of the PSP pipe (9). During the socket process, the sensor (10) measures the voltage of the PSP pipe (9). , current , use formula (6) to calculate as follows: （6） in, is the actual reactance of the PSP pipe (9), is the actual resistance of the PSP pipe (9) .

3. The method for detecting the location of a welded joint of a PSP pipe according to claim 2, wherein: The specific process of step 3 is: comparing the standard impedance and the actual impedance of the PSP pipe (9); when the two are inconsistent, the connection depth of the PSP pipe (9) needs to be adjusted.

4. The method for detecting the location of a welded joint of a PSP pipe according to claim 3, wherein: When the actual impedance of the PSP pipe (9) is greater than the standard impedance, it indicates that the connection depth of the PSP pipe (9) is deep, and the PSP pipe (9) needs to be pulled outward; when the actual impedance of the PSP pipe (9) is less than the standard impedance, it indicates that the connection depth of the PSP pipe (9) is shallow, and the PSP pipe (9) needs to be plugged deeper.

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