Weak magnetic stress damage and direction monitoring system for oil and gas pipeline
Through weak magnetic stress detection method and multi-directional excitation system, the difficulty of stress damage detection in oil and gas pipelines is solved, and the precise analysis of the degree of stress damage and the direction of the main stress is achieved, ensuring the safe operation of the pipeline.
Patent Information
- Application Number
- CN202411540661.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-31
- Publication Date
- 2025-01-07
AI Technical Summary
The difficulty in detecting damage caused by stress concentration during oil and gas pipelines, especially the judgment and analysis of the direction of main stress, affects the safe operation of the pipeline.
A weak magnetic stress damage and direction monitoring system for oil and gas pipelines based on weak magnetic stress detection method was designed. The multi-directional excitation system and weak magnetic detection probe are used to realize the main stress direction through the coupling characteristics between the excitation direction and the main stress signal direction. and analysis of stress damage degree.
Accurate detection and real-time early warning of the degree of stress damage and main stress direction of oil and gas pipelines is achieved, ensuring the safe operation of the pipeline, and improving the detection accuracy and anti-interference ability through hardware filtering and digital processing.
Smart Images
Figure CN119267811A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of nondestructive testing of oil and gas pipelines, and in particular relates to a weak magnetic stress damage and direction monitoring system for oil and gas pipelines. Background Art
[0002] As the main energy resources, oil and natural gas have an increasingly prominent strategic position. Pipeline transportation has become the main mode of international transportation of oil and natural gas due to its advantages such as large transportation volume, no restrictions on climate and other ground factors, and continuous operation. Therefore, the safe operation of oil and gas pipelines is crucial to ensuring energy transportation and safety. However, under the effects of welding, high temperature, high pressure and other environments during the production and application of pipelines, stress concentration will occur on the surface of the pipelines, resulting in local stress higher than its own strength limit, or even higher than the yield limit during the operation of the oil and gas pipelines, causing leakage, pipeline burst and other malignant accidents without significant plastic deformation. In addition, oil and gas pipelines will be affected by stress in all directions during operation, and different principal stress directions will cause different degrees of damage to the pipelines. Therefore, the comprehensive judgment and analysis of the degree of stress damage and the principal stress direction of the oil and gas pipelines is crucial for accurately assessing pipeline damage, providing accurate warning time, and thus ensuring the safety of oil and gas pipeline transportation. However, since stress damage can cause reversible or irreversible changes in the microstructures of pipeline materials such as magnetic domains and lattices, resulting in complex distribution of parameters such as stress and magnetic field, the detection of the degree of stress damage in oil and gas pipelines, especially the direction of the principal stress, has always been a difficult problem in the field of non-destructive testing of oil and gas pipelines. Summary of the invention
[0003] In view of the above problems, the present invention designs an oil and gas pipeline detection system based on a weak magnetic stress detection method. The weak magnetic detection method itself can realize non-destructive detection of stress damage and microscopic damage of ferromagnetic materials according to the natural magnetomechanical properties of ferromagnetic materials. Through our systematic experimental research, it is found that when the ferromagnetic material is excited, the value of the principal stress weak magnetic signal will change, but when the direction of the magnetic lines of force of the excitation system is perpendicular to the direction of the principal stress weak magnetic signal, the value of the principal stress weak magnetic signal remains unchanged. This characteristic can be used to determine the direction of the principal stress of the oil and gas pipeline. Based on the above weak magnetic stress detection characteristics, and combined with the intelligent control of system units such as multiple sets of weak magnetic detection probes, multi-directional excitation systems, and hardware filtering systems by a single-chip microcomputer, a weak magnetic stress damage and direction monitoring system for oil and gas pipelines is designed.
[0004] To achieve the above objectives, the present invention adopts the following technical solutions. The system structure of the present invention includes: an external frame, a carrying ring, an adjustment device, a connecting rod, a multi-directional excitation system, a weak magnetic detection probe, and a hardware main control system. The external frame is composed of multiple groups of components distributed in a circular array on the outside, which constitute the main frame of the detector and provide external protection for the pipeline; the bearing ring is arranged on the outer wall of the pipeline to be tested, and is used to carry multiple groups of multi-directional excitation systems; the adjustment device and the connecting rod are arranged on the bearing ring, which are used to connect the bearing ring with the pipeline body and the external frame, and the adjustment device can adjust the height and angle of the detector and fix the detector at a specified position; the multi-directional excitation system is evenly arranged on the bearing ring at the outer end of the pipeline body, and is used to provide external magnetic fields with different excitation directions for the acquisition monitoring point; the weak magnetic detection probe is used to obtain the weak magnetic signal of the acquisition monitoring point under different excitation directions; the hardware main control system is used to install control and processing chips such as single-chip microcomputers, hardware filters, and memories; the hardware main control system can use the standard value acquisition subroutine and the stepper motor data acquisition subroutine under the control of the system call and data processing main program to collect digital weak magnetic signals for each acquisition monitoring point without excitation (standard value) and under different excitation directions, and the acquired signals are analyzed by digital calculation of the data processing subroutine to determine the main stress direction and stress magnitude of the acquisition monitoring point.
[0005] The multi-directional excitation system includes multiple groups of stepper motors, multiple groups of excitation systems, and multiple groups of motor drive parts. The system is used to excite each acquisition monitoring point. It uses a stepper motor to drive the excitation system to rotate synchronously to change the excitation direction, and cooperates with the weak magnetic detection probe to collect weak magnetic signals under different excitation directions, and makes the collected weak magnetic signals correspond to the excitation direction. The magnetic force of the excitation system is parallel to the section of the curved surface of the pipeline surface, so that all the vertical components of the magnetic force lines passing through the section cancel each other, leaving only the horizontal component, and the direction is exactly the same, ensuring that the magnetic force lines of the external magnetic field are parallel to the section. The stepper motor and the motor drive part are used to drive the excitation system to rotate along the section parallel to the pipeline direction, thereby realizing the rotation of the magnetic force lines of the external magnetic field parallel to the section by 360 degrees, providing 360 degrees of different excitation directions for the detection signal collected by the system weak magnetic detection probe.
[0006] The hardware main control system comprises a plurality of groups of weak magnetic detection probes, a plurality of groups of stepper motors, a plurality of groups of excitation systems, a plurality of groups of motor drive systems, a conversion controller, a plurality of groups of hardware filter systems, an A / D converter, a single-chip microcomputer, an external memory, an infrared transmission system, and a PC; the connection structure of each device of the hardware main control system is as follows: the output ports of the plurality of groups of weak magnetic detection probe circuits are connected to the input ports of the plurality of groups of hardware filter systems correspondingly, and then connected to the input ports of the A / D converter correspondingly, the input ports of the A / D converter are connected to the output ports of the single-chip microcomputer, the plurality of groups of stepper motors are connected to the output ports of the plurality of motor drives, and then connected to the signal output ports of the single-chip microcomputer by the conversion controller, and the plurality of groups of excitation systems are connected to the output ports of the single-chip microcomputer; the storage signal output port of the single-chip microcomputer is connected to the storage signal input port of the external memory; the signal input and output ports of the single-chip microcomputer are connected to the input and output ports of the PC via the infrared transmission system.
[0007] The system call and data processing main program first defines the relevant parameters of the signal storage area, that is, defines the two-dimensional array ADTURN as the storage unit for different excitation direction detection data; the one-dimensional array INITIAL as the standard value storage unit; the one-dimensional array LINEADR as the direction detection data storage unit; TABLE as the stepper motor forward table storage unit. First, the multiple groups of weak magnetic detection probes and multiple groups of stepper motors 8 are initialized by numbering them respectively through the loop program. Then the standard value acquisition subroutine is called to obtain the weak magnetic signals of the stepper motors at different acquisition monitoring points when they are not rotating as standard values and put them into the standard value storage unit INITIAL, that is, as stress damage degree judgment data, and as the intermediate parameter for main stress direction judgment waiting for system call. The weak magnetic detection probe and stepper motor corresponding to different acquisition monitoring points are opened in a loop, and the data acquisition subroutine is called at the same time. The stepper motor is used to rotate 360 degrees and weak magnetic signals at different angles are collected. The system collects data once after each rotation of a certain angle, and puts the collected data into the different excitation direction detection data storage unit ADTURN; after completing data collection in all detection areas, the acquisition data processing subroutine is called to compare the values in the different excitation direction detection data storage unit ADTURN with the standard values in the standard value storage unit INITIAL, find the storage unit with the same standard value, and store the number of acquisition cycles as the main stress direction determination data in the direction detection data storage unit LINEADR. Finally, the stored data in the standard value storage unit INITIAL and the direction detection data storage unit LINEADR are displayed as stress value determination data and main stress direction determination data respectively.
[0008] The standard value acquisition subroutine first defines the variable R0 and uses it as a pointer to point to the standard value storage unit INITIAL corresponding to the current detection probe, and starts the IN0 channel to open the various signal acquisition and processing functions of the weak magnetic detection probe, hardware filtering system, and A / D converter, and assigns the converted value to the variable R1, and at the same time, by judging the value of the counting variable R2, the loop is collected several times, and the collected value is accumulated to R1. After the cycle is completed, the average number of the collection is stored in the standard value storage unit INITIAL[N] pointed to by R0. After completing the standard value collection of the corresponding area of a sensor, the value of N is increased to open the next sensor, and R0 is pointed to the standard value storage unit INITIAL[N] corresponding to the next sensor, and all the standard values are stored in the one-dimensional array INITIAL[N]. Thus, after multiple cycles of processing, the weak magnetic detection probe, hardware filtering system, and A / D converter are opened respectively, and the digital weak magnetic signal after hardware filtering and analog-to-digital conversion is stored in the standard value storage unit INITIAL after system analysis and processing, completing the standard value collection of each acquisition monitoring point.
[0009] The stepper motor data acquisition subroutine first points the data pointer DPTR to the stepper motor forward table TABLE, sets the value of the second bit J of the two-dimensional array, that is, R0 points to the first bit of the storage unit corresponding to the current detection area, defines the initial value of the loop count variable RI, R2, puts the content pointed to by the pointer DPTR into VALUE, and the motor driver outputs the value motorOutputvalue of VALUE, then the stepper motor rotates one step, that is, it rotates a certain angle, that is, by controlling the rotation of the stepper motor to drive the excitation field to change, providing 360° different excitation directions for collecting weak magnetic signals at the monitoring point. Then the pointer DPTR points to the next unit of the forward table. Start the IN0 channel, turn on the signal acquisition and processing functions of the multi-directional excitation system, weak magnetic detection probe, hardware filtering system, and A / D converter, wait for a period of time, and store the converted value in the R0 pointing area, that is, use the weak magnetic detection probe to collect the weak magnetic signal value of the pipeline surface under different excitation directions, and increase the value of J to make R0 point to the next storage unit, and increase R1 to calculate the number of cycles. After multiple cycles, the stepper motor rotates a certain angle, and the sensor also collects multiple data and puts them into the data acquisition storage area. When R1 is equal to 4, a small cycle is completed, and the value of the cycle count variable R2 is increased, and the value of R1 is reset. After multiple large cycles, the stepper motor rotates one circle. Then, use the multi-directional excitation system, weak magnetic detection probe, hardware filtering system, and A / D converter to store the weak magnetic signals of 360 degrees in different excitation directions in the different excitation direction detection data storage unit ADTURN, and complete the excitation and signal acquisition of different directions of the corresponding acquisition monitoring point.
[0010] The data processing subroutine first sets the value of the first bit N of the two-dimensional array of collected data storage, that is, starts processing from the data storage area corresponding to the first sensor, sets the value of the second bit J of the two-dimensional array of collected data storage to 1 through a for loop, and increments the value of J after completing one loop, and points the data pointer P2 to the current data storage area ADTURN[N][J] to be processed, and determines whether the value of the current P2 pointing area is the same as the value of the corresponding unit of the initial value storage area. If the value of the current P2 pointing area is different from the value of the corresponding unit of the initial value storage area, J is incremented to continue the comparison. If they are the same, the current value of J is stored as the data position record value in the data position storage unit LINEADR[N]. In the process, the value of N is incremented to compare the data in the storage area corresponding to the next detection probe, and the value of A is incremented to make P2 point to the next unit in the initial value storage area, and then the above cycle is continued. After multiple cycles, the stress value of the detection area of the monitoring point and the judgment data of the main stress direction are stored in the storage units of INITIAL and LINEADR waiting for the system call, and then the data of the different excitation direction detection data storage unit ADTURN is compared and analyzed with the data in the standard value storage unit INITIAL[N] to find the same data in the two groups of storage units and store them in the direction detection data storage unit LINEADR as the main stress direction judgment data.
[0011] As a preferred solution, the motor drive system of the present invention uses UIM242 to control the rotation of the stepper motor and drives the excitation system to rotate to change the direction of the external magnetic field. UIM242 controls the stepper motor through the CAN bus structure.
[0012] As another preferred solution, the conversion controller of the present invention uses UIM250121 to control several stepper motors through a CAN bus structure. UIM2501 can control several motor drive systems in the CAN bus structure to realize signal detection of multiple detection points at the same time.
[0013] As another preferred solution, the weak magnetic detection probe of the present invention is composed of a wire, an insulating substrate, InSb-In magnetoresistive elements MR1 and MR2, a permanent magnet, pins, etc., and a metal shell for shielding and protection. Weak magnetic signal detection is achieved based on the magnetoresistive effect.
[0014] As another preferred solution, the hardware filtering system of the present invention includes a multi-stage TL082 signal amplifier, an RC buffer circuit, and is integrated in an AD8039 to reduce the circuit scale. The signal is transmitted to the input port of the A / D converter after multi-stage filtering.
[0015] As another preferred solution, the A / D converter described in the present invention uses ADS1232 to be connected to several weak magnetic detection probes through an analog switch MAX4620. During detection, the weak magnetic detection probes at corresponding points are turned on by MAX4620 to realize signal detection of multiple points. The single-chip microcomputer forms a storage expansion part through a 628128 chip and a 74LS373 latch chip, and the single-chip microcomputer is connected to multiple excitation systems through SM245TS.
[0016] As another preferred solution, the infrared transmission system of the present invention comprises an infrared transmitting part and an infrared receiving part, which are respectively connected to a single-chip microcomputer and a PC to realize signal transmission. The transmitting part is composed of an IR333C transmitting tube driven by an amplifier circuit, and the receiving part is composed of a TSOP4838 receiving tube and an LM393DT comparator.
[0017] As another preferred solution, the data acquisition subroutine of the present invention controls a group of magnetoresistive sensors to collect 20 weak magnetic data that meet the threshold each time and sends them to the corresponding storage space.
[0018] As another preferred solution, the system call and data processing main program of the present invention respectively opens 7 weak magnetic detection probes and corresponding storage areas for data collection through loop statements, and ends the collection and enters the data processing subroutine when N is equal to 7.
[0019] As another preferred scheme, in the stepper motor data acquisition subroutine described in the present invention, the value of parameter j is set to 1, and the values of R1 and R2 are set to 0. The former means that the collected weak magnetic signals are stored in the storage area in sequence starting from the first unit, and the latter is used as a counting amount to cycle twenty times, that is, one collection monitoring point is collected twenty times.
[0020] The invention has beneficial effects.
[0021] 1. The present invention utilizes multiple sets of weak magnetic detection probes to perform weak magnetic signal detection on different acquisition and monitoring points of the pipeline, and utilizes the weak magnetic stress detection characteristics to compile a digital analysis program to realize the analysis and processing of the stress damage degree of the acquisition and monitoring points.
[0022] 2. The present invention provides excitation magnetic fields in different directions to each acquisition monitoring point through intelligent control of the multi-directional excitation system, and utilizes a digital analysis program under the coupling characteristics of the direction of the magnetic lines of force of the excitation system and the direction of the principal stress weak magnetic signal to realize the analysis and processing of the principal stress direction of the acquisition monitoring point.
[0023] 3. The present invention performs neutralization calculation and analysis on the stress damage degree data and the principal stress direction detection data in the system, and based on the dual judgment of the stress damage degree and direction, performs accurate real-time early warning of the oil and gas pipeline to ensure the safe operation of the pipeline.
[0024] 4. The present invention achieves a filtering effect on external interference through a hardware filtering system and digital processing of detection data, ensuring high accuracy and strong anti-interference ability of detection data; and uses a memory system and an infrared transmission system to increase the amount of stored data and detection speed and realize remote control. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. The protection scope of the present invention is not limited to the following description.
[0026] Figure 1 : System structure diagram.
[0027] Figure 2 : Structural diagram of multi-directional excitation system.
[0028] Figure 3 : Circuit structure diagram of hardware main control system.
[0029] Figure 4 : System call and data processing main program flow chart.
[0030] Figure 5 : Flowchart of standard value collection subroutine.
[0031] Figure 6 : Stepper motor data acquisition subroutine flow chart.
[0032] Figure 7 : Flowchart of the data acquisition and processing subroutine.
[0033] Figure 8 : Circuit diagram of stepper motor and motor drive system.
[0034] Fig. 9 : Conversion controller connection diagram.
[0035] Figure 10(a): Appearance of the weak magnetic detection probe.
[0036] Figure 10(b): Circuit diagram of weak magnetic field detection probe.
[0037] Fig.11 : Circuit diagram of hardware filtering system.
[0038] Fig.12 : Circuit diagram of data acquisition module.
[0039] Fig.13 : Circuit diagram of infrared transmission system. DETAILED DESCRIPTION
[0040] like Figure 1As shown, the system structure of the present invention includes: an external frame 1, a carrying ring 2, an adjusting device 3, a connecting rod 4, a multi-directional excitation system 5, a weak magnetic detection probe 6, and a hardware main control system 7. The external frame 1 is composed of multiple groups of components distributed in a circular array on the outside, which constitute the main frame of the detector and provide external protection for the pipeline; the carrying ring 2 is arranged on the outer wall of the pipeline to be tested, and is used to carry multiple groups of multi-directional excitation systems 5; the adjusting device 3 and the connecting rod 4 are arranged on the carrying ring 2, and are used to connect the carrying ring 2 with the pipeline body and the external frame 1. The adjusting device 3 can adjust the height and angle of the detector and fix the detector at a specified position; the multi-directional excitation system 5 is evenly distributed on the carrying ring 4 at the outer end of the pipeline body, and is used to provide external magnetic fields with different excitation directions for the acquisition monitoring points. field; the weak magnetic detection probe 6 is used to obtain the weak magnetic signal of the acquisition monitoring point under different excitation directions; the hardware main control system 7 is used to install control and processing chips such as single-chip microcomputers, hardware filters, and memories; the hardware main control system 7 can use the standard value acquisition subroutine and the stepper motor data acquisition subroutine under the control of the system call and data processing main program to collect digital weak magnetic signals without excitation (standard value) and under different excitation directions for each acquisition monitoring point, and determine the main stress direction and stress magnitude of the acquisition monitoring point through digital calculation and analysis of the acquired signals through the data processing subroutine.
[0041] like Figure 2 As shown, the multi-directional excitation system 5 includes multiple groups of stepper motors 8, multiple groups of excitation systems 9, and multiple groups of motor drive parts 10. This unit is used to excite each acquisition monitoring point. It uses the stepper motor 8 to drive the excitation system 9 to rotate synchronously to change the excitation direction, and cooperates with the weak magnetic detection probe 6 to collect weak magnetic signals under different excitation directions, and makes the collected weak magnetic signals correspond to the excitation direction. The magnetic force of the excitation system 9 is parallel to the section of the curved surface of the pipeline surface, so that all the vertical components of the magnetic force lines passing through the section cancel each other, leaving only the horizontal component, and the direction is exactly the same, ensuring that the magnetic force lines of the external magnetic field are parallel to the section. The stepper motor 8 and the motor drive part 10 are used to drive the excitation system 9 to rotate along the section parallel to the pipeline direction, thereby realizing the rotation of the magnetic force lines of the external magnetic field parallel to the section by 360 degrees, providing 360 degrees of different excitation directions for the detection signal collected by the weak magnetic detection probe 6 of the system.
[0042] like Figure 3As shown, the hardware main control system 7 includes multiple groups of weak magnetic detection probes 6, multiple groups of stepper motors 8, multiple groups of excitation systems 9, multiple groups of motor drive systems 10, conversion controllers 11, multiple groups of hardware filter systems 12, A / D converters 13, single-chip microcomputers 14, external storage devices 15, infrared transmission systems 16, and PCs 17; the connection structure of the components of the hardware main control system 7 is as follows: the output ports of the multiple groups of weak magnetic detection probes 6 circuits are connected to the input ports of the multiple groups of hardware filter systems 12, and then to the input ports of the A / D converters 13. The input port of the A / D converter 13 is connected to the output port of the single-chip computer 14, the multiple groups of stepper motors 8 are connected to the output ports of the multiple groups of motor drivers 10, and then the conversion controller 11 is connected to the signal output port of the single-chip computer 14, and the multiple groups of excitation systems 9 are connected to the output port of the single-chip computer 14; the storage signal output port of the single-chip computer 14 is connected to the storage signal input port of the external memory 15; the signal input and output ports of the single-chip computer 14 are connected to the input and output ports of the PC 17 via the infrared transmission system 16.
[0043] like Figure 4 As shown, the system call and data processing main program first define the relevant parameters of the signal storage area, that is, define the two-dimensional array ADTURN as the storage unit for different excitation direction detection data; the one-dimensional array INITIAL as the standard value storage unit; the one-dimensional array LINEADR as the direction detection data storage unit; TABLE as the stepper motor forward table storage unit. First, the multiple groups of weak magnetic detection probes 6 and multiple groups of stepper motors 8 are initialized by numbering the multiple detection probes and motors respectively through the loop program. Then call the standard value acquisition subroutine to obtain the weak magnetic signals of the stepper motor 8 at different acquisition monitoring points when it is not rotating as the standard value and put them into the standard value storage unit INITIAL, that is, as the stress damage degree judgment data, and as the main stress direction judgment intermediate parameter waiting for system call. The weak magnetic detection probe 6 and stepper motor 8 corresponding to different acquisition monitoring points are opened in a loop, and the data acquisition subroutine is called at the same time. The stepper motor 8 is rotated 360 degrees, and weak magnetic signals at different angles are collected. The system collects data once after each rotation of a certain angle, and the collected data is placed in the different excitation direction detection data storage unit ADTURN; after completing data collection in all detection areas, the acquisition data processing subroutine is called, and the values in the different excitation direction detection data storage unit ADTURN are compared with the standard values in the standard value storage unit INITIAL, and the storage unit with the same standard value is found, and the number of acquisition cycles is stored as the main stress direction determination data in the direction detection data storage unit LINEADR. Finally, the stored data in the standard value storage unit INITIAL and the direction detection data storage unit LINEADR are displayed as stress value determination data and main stress direction determination data, respectively.
[0044] like Figure 5 As shown, the standard value acquisition subroutine first defines the variable R0 and uses it as a pointer to point to the standard value storage unit INITIAL corresponding to the current detection probe, and starts the IN0 channel to start the various signal acquisition and processing functions of the weak magnetic detection probe 6, the hardware filtering system 12, and the A / D converter 13, and assigns the converted value to the variable R1, and at the same time, by judging the value of the counting variable R2, the loop is collected several times, and the collected value is accumulated to R1, and after the loop is completed, the average of the collection is stored in the standard value storage unit INITIAL[N] pointed to by R0, and after completing the standard value collection of a sensor corresponding area, the value of N is increased to open the next sensor, and R0 is pointed to the standard value storage unit INITIAL[N] corresponding to the next sensor, and all the standard values are stored in the one-dimensional array INITIAL[N]. Thus, after multiple cycles of processing, the weak magnetic detection probe 6, the hardware filtering system 12, and the A / D converter 13 are respectively turned on, and the digital weak magnetic signal after hardware filtering and analog-to-digital conversion is stored in the standard value storage unit INITIAL after system analysis and processing, completing the standard value collection of each acquisition monitoring point.
[0045] like Figure 6As shown, the stepper motor data acquisition subroutine first points the data pointer DPTR to the stepper motor forward table TABLE, sets the value of the second bit J of the two-dimensional array, that is, points R0 to the first bit of the storage unit corresponding to the current detection area, defines the initial values of the loop count variables R1 and R2, puts the content pointed to by the pointer DPTR into VALUE, and the motor driver outputs the value motorOutputvalue of VALUE, then the stepper motor rotates one step, that is, rotates a certain angle, that is, by controlling the rotation of the stepper motor 8 to drive the excitation field change, providing 360° different excitation directions for the weak magnetic signal of the monitoring point. Then the pointer DPTR points to the next unit of the forward table. Start the IN0 channel, start the various signal acquisition and processing functions of the multi-directional excitation system 5, the weak magnetic detection probe 6, the hardware filter system 12, and the A / D converter 13, wait for a period of time, and store the converted value in the R0 pointing area, that is, use the weak magnetic detection probe 6 to collect the weak magnetic signal value of the pipeline surface under different excitation directions, and increase the value of J to make R0 point to the next storage unit, and increase R1 to calculate the number of cycles. After multiple cycles, the stepper motor rotates a certain angle, and the sensor also collects multiple data and puts them into the data acquisition storage area. When R1 is equal to 4, a small cycle is completed, the value of the cycle count variable R2 is increased, and the value of R1 is reset. After multiple large cycles, the stepper motor 8 rotates one circle. Then, the multi-directional excitation system 5, the weak magnetic detection probe 6, the hardware filter system 12, and the A / D converter 13 are used to store the weak magnetic signals of 360 degrees in different excitation directions in the different excitation direction detection data storage unit ADTURN, and complete the different direction excitation and signal acquisition of the corresponding acquisition monitoring point.
[0046] like Figure 7As shown, the data processing subroutine first sets the value of the first bit N of the two-dimensional array of collected data storage, that is, starts processing from the data storage area corresponding to the first sensor, sets the value of the second bit J of the two-dimensional array of collected data storage to 1 through a for loop, and increments the value of J after completing one loop, and points the data pointer P2 to the current data storage area ADTURN[N][J] to be processed, and determines whether the value of the current P2 pointing area is the same as the value of the corresponding unit of the initial value storage area. If the value of the current P2 pointing area is different from the value of the corresponding unit of the initial value storage area, J is incremented to continue the comparison. If they are the same, the current value of J is stored as the data position record value in the data position storage unit LINEADR[ N], the value of N is incremented to compare the data in the storage area corresponding to the next detection probe, and the value of A is incremented to make P2 point to the next unit in the initial value storage area, and then the above cycle is continued. After multiple cycles, the stress value of the detection area of the monitoring point and the judgment data of the main stress direction are stored in the storage units of INITIAL and LINEADR waiting for the system call, and then the data of the different excitation direction detection data storage unit ADTURN is compared and analyzed with the data in the standard value storage unit INITIAL[N], and the same data in the two groups of storage units is found and stored in the direction detection data storage unit LINEADR as the main stress direction judgment data.
[0047] like Figure 8 As shown, the motor drive system 10 changes the external magnetic field by controlling the excitation system 9, that is, using UIM242 to control the rotation of the 42mm stepper motor 8, and at the same time drives the excitation system 9, that is, the excitation coil, to rotate to change the direction of the external magnetic field. The specific connection method is: the input port of the motor drive system 10 is connected to the signal output port of the single-chip microcomputer 14, and the output port of the motor drive system 10 is connected to the 42mm stepper motor 8. The A-, A+, B+, and B- interfaces of UIM-242 are respectively connected to the B-, B+, A-, and A+ interfaces of the 42mm stepper motor 8. Its wiring ports CANH and CANL are respectively connected to the high and low lines of the CAN bus of the UIM2501 conversion controller 11. The UIM2501 conversion controller 11 is connected to the single-chip microcomputer 14 through the RS232-TTL interface to realize the control of the stepper motor 8 by the single-chip microcomputer 14.
[0048] like Fig. 9As shown, the conversion controller 11 uses UIM2501 to control several 42mm stepper motors 8 through the CAN bus structure. UIM2501 can control several motor drive systems 10 in the CAN bus structure to detect signals at multiple detection points at the same time. The specific connection method is: the 3 and 4 interfaces of the UIM2501 conversion controller 11 are respectively connected to the high-order line CANH and the low-order line CANL, which uses a 120-ohm impedance twisted pair, connects the CANL interfaces of several UIM242 motor drivers 10 to the low-order line of the CAN bus, and connects the CANH interfaces to the high-order line of the CAN bus. The motor drivers are connected in parallel with each other, and the output port of the single-chip microcomputer 14 is connected to the UIM2501 conversion controller 11 using the RS-232 interface to realize the control of several stepper motors 8 by the single-chip microcomputer 14.
[0049] As shown in FIG10(a), the weak magnetic detection probe 6 is composed of a wire, an insulating substrate, InSb-In magnetoresistive elements MR1 and MR2, a permanent magnet, pins, etc., and a metal shell for shielding and protection is added. Weak magnetic signal detection is achieved based on the magnetoresistive effect. As shown in FIG10(b), the specific connection method of the weak magnetic detection probe 6 is as follows: MR1 and MR2 are a pair of magnetoresistive elements with approximately equal resistance values placed opposite to each other, connected to a resistor-capacitor coupled differential amplifier circuit, and amplified and filtered by two-stage amplifier circuits A1 and A2, and outputted to the hardware filter system 14 through a hysteresis comparator LM339 to avoid jump output, and the result is output to the hardware filter system 14 through Vout.
[0050] like Fig.11 As shown, the hardware filtering system 12 includes a multi-stage TL082 signal amplifier, an RC buffer circuit, and is integrated in an AD8039 to reduce the circuit scale. After multi-stage filtering, the signal is transmitted to the input short port of the A / D converter 13. The specific connection method is: the input port of the hardware filtering system 12 is connected to the output port of the weak magnetic detection probe 6, and the output port of the hardware filtering system 12 is connected to the input port of the A / D converter 13. The filter circuit filter structure is a seventh-order four-stage Butterworth Sallen-Key high-pass filter. The first stage of the filter circuit is an RC buffer, and the last three stages are all Sallen-Key structures. The -3dB cutoff frequency of the filter circuit is 20kHz, and the -40dB stop band is 10kHz. The weak magnetic signal is sent to the input port of the data acquisition module after the interference signal is removed by the filter circuit.
[0051] like Fig.12As shown, the A / D converter 13 uses ADS1232 to connect with several weak magnetic detection probes 6 through the analog switch MAX4620. During detection, the weak magnetic detection probes 6 at the corresponding points are turned on by MAX4620 to realize signal detection of multiple points. The single-chip microcomputer 14 forms a storage expansion part 15 through the 628128 chip and the 74LS373 latch chip, and the single-chip microcomputer 14 is connected with multiple excitation systems 9 through SM245TS. The specific connection method is as follows: the signal input interface of ADS1232 is connected to the output port of the hardware filter system 12, the P2.0, P2.1, and P2.2 interfaces of the AT89S52 microcontroller 14 are respectively connected to the LBEN, HBEN, and CE of the ADS1232, the signal output port of the MAX4620 is connected to the IN port of the AD1232, and the A0-A7 ports of the storage extension part 628128 are respectively connected to the P0.0-P0.7 of the microcontroller 14 via the latch 74LS373. The P1.4, P1.3, and P1.2 interfaces of the microcontroller 14 are respectively connected to the B0, B1, and B2 interfaces of the SM245TS, and the A0-A5 interfaces of the SM245TS are respectively connected to multiple excitation systems 9.
[0052] like Fig.13 As shown, the infrared transmission system 16 includes an infrared transmitting part and an infrared receiving part, which are respectively connected to the single-chip computer 14 and the PC 17 to realize signal transmission. The transmitting part is composed of an IR333C transmitting tube driven by an amplifier circuit, and the receiving part is composed of a TSOP4838 receiving tube and an LM393DT comparator. The specific connection method is: the infrared transmitting part is connected to the signal output port of the single-chip computer 14, the infrared receiving part is connected to the PC 17, the input port Vin of the infrared transmitting part is connected to the signal output port of the single-chip computer 14, after receiving the signal of the single-chip computer 1, it is amplified by the diode Q1 and then drives the IR333C to transmit the infrared signal, and the signal of the TSOP4838 of the infrared receiving part is amplified by the LM393DT and then input into the PC 17, so as to realize the display of the detection result on the PC 17.
[0053] The present invention sets 7 weak magnetic detection probes 6 on each carrying ring 2, and continuously loops sampling through the main program until the alarm system 7 is started, then the program stops and displays the detection address of the warning position and the specific value of the alarm data.
[0054] The data acquisition subroutine of the present invention controls a group of weak magnetic detection probes 6 each time to collect 20 weak magnetic data that meet the threshold value and send them to the corresponding storage space.
[0055] The system call and data processing main program of the present invention respectively opens 7 weak magnetic detection probes 6 and corresponding storage areas for data collection through loop statements, and ends the collection and enters the data processing subroutine when N is equal to 7.
[0056] In the stepper motor data acquisition subroutine of the present invention, the value of parameter j is set to 1, and the values of R1 and R2 are set to 0. The former means that the collected weak magnetic signals are stored in the storage area in sequence starting from the first unit, and the latter is used as a counting amount to cycle twenty times, that is, one collection monitoring point is collected twenty times.
[0057] The invention can be divided into a weak magnetic signal acquisition part and a signal processing and result display part.
[0058] The working process of weak magnetic signal acquisition part: the single chip microcomputer 14 drives the stepping motor 8 to rotate through the conversion controller 11 and several motor driving parts 10, and drives the excitation system 9 added to the stepping motor 8 to rotate synchronously, so as to provide 360 degrees of different excitation directions for the acquisition monitoring point. The weak magnetic detection probe 6 is used to collect the weak magnetic signal value of the pipeline without excitation and with excitation in different directions, and the detection data is transmitted to the single chip microcomputer 14 through the hardware filtering system 12 and the A / D converter 13, and then transmitted to the PC 17 through the infrared transmission system 16 for data processing and calculation.
[0059] The working process of the signal processing and result display part: under the control of the main data processing program of the system's single-chip microcomputer 14, PC 17 and other main control devices, the standard value acquisition subroutine is used to complete the acquisition of the standard value, that is, the weak magnetic signal of the acquisition monitoring point under non-excitation, and stored in the INITIAL storage unit, which is used as the stress value judgment data and the intermediate parameter for the main stress direction judgment. The stepper motor data acquisition subroutine is used to control the stepper motor 8, the excitation system 9 and the weak magnetic detection probe 6 to complete the weak magnetic signal acquisition under different excitation directions of 360 degrees, and through the data processing subroutine, the weak magnetic signal under different excitation directions and the INITIAL storage unit data are digitally calculated and analyzed, the main stress direction judgment data is extracted, and stored in the LINEADR unit waiting for display call. Based on the detection characteristics of the weak magnetic signal on the pipeline surface under different excitation directions, the stress value and the main stress direction judgment data in the INITIAL and LINEADR storage units are used as the judgment data, respectively, to realize the dual judgment of the pipeline and the stress value and the main stress direction.
[0060] It can be understood that the above specific description of the present invention is only used to illustrate the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that the present invention can still be modified or replaced by equivalents to achieve the same technical effects; as long as the use requirements are met, they are within the protection scope of the present invention.
Claims
1. A weak magnetic stress damage and direction monitoring system for oil and gas pipelines, the system structure of the present invention comprises: External frame, bearing ring, adjustment device, connecting rod, multi-directional excitation system, weak magnetic detection probe, hardware main control system; the external frame is composed of multiple groups of components distributed in a circular array on the outside, forming the main frame of the detector and providing external protection for the pipeline; the bearing ring is arranged on the outer wall of the pipeline to be tested, and is used to carry multiple groups of multi-directional excitation systems; the adjustment device and connecting rod are arranged on the bearing ring, and are used to connect the bearing ring with the pipeline body and the external frame; the adjustment device can adjust the height and angle of the detector, and fix the detector at a specified position; the multi-directional excitation system is evenly arranged on the bearing ring at the outer end of the pipeline body, and is used to The monitoring point is provided with external magnetic fields of different excitation directions; the weak magnetic detection probe is used to obtain weak magnetic signals of the monitoring point under different excitation directions; the hardware main control system is used to install control and processing chips such as single-chip microcomputer, hardware filtering, and memory; the hardware main control system can collect digital weak magnetic signals of each monitoring point without excitation (standard value) and under different excitation directions by using the standard value collection subroutine and the stepper motor data collection subroutine under the control of the system call and data processing main program, and the collected signals are analyzed by digital calculation of the data processing subroutine to determine the main stress direction and stress magnitude of the monitoring point; The multi-directional excitation system includes multiple groups of stepper motors, multiple groups of excitation systems, and multiple groups of motor drive parts; the system is used to excite each acquisition monitoring point, and uses a stepper motor to drive the excitation system to rotate synchronously to change the excitation direction, and cooperates with a weak magnetic detection probe to collect weak magnetic signals under different excitation directions, and makes the collected weak magnetic signals correspond to the excitation direction. The magnetic force of the excitation system is parallel to the section of the curved surface of the pipeline surface, so that all vertical components of the magnetic force lines passing through the section cancel each other out, leaving only horizontal components, and the directions are exactly the same, ensuring that the magnetic force lines of the external magnetic field are parallel to the section; the stepper motor and the motor drive part are used to drive the excitation system to rotate along the section parallel to the pipeline direction, thereby realizing the rotation of the magnetic force lines of the external magnetic field parallel to the section by 360 degrees, providing 360 degrees of different excitation directions for the detection signal collected by the system weak magnetic detection probe; The hardware main control system comprises multiple groups of weak magnetic detection probes, multiple groups of stepper motors, multiple groups of excitation systems, multiple groups of motor drive systems, conversion controllers, multiple groups of hardware filter systems, A / D converters, single-chip microcomputers, external memory, infrared transmission systems, and PCs; the connection structure of each device of the hardware main control system is as follows: the output ports of multiple groups of weak magnetic detection probe circuits are connected to the input ports of multiple groups of hardware filter systems correspondingly, and then connected to the input ports of the A / D converters correspondingly, the input ports of the A / D converters are connected to the output ports of the single-chip microcomputers, the multiple groups of stepper motors are connected to the output ports of the multiple motor drives, and then connected to the signal output ports of the single-chip microcomputers by the conversion controllers, and the multiple groups of excitation systems are connected to the output ports of the single-chip microcomputers; the storage signal output port of the single-chip microcomputer is connected to the storage signal input port of the external memory; the signal input and output ports of the single-chip microcomputer are connected to the input and output ports of the PC via the infrared transmission system; The system call and data processing main program first defines the relevant parameters of the signal storage area, that is, defines the two-dimensional array ADTURN as the storage unit for different excitation direction detection data; the one-dimensional array INITIAL as the standard value storage unit; the one-dimensional array LINEADR as the direction detection data storage unit; TABLE is the stepper motor forward table storage unit; first, through the loop program, the multiple detection probes and motors are numbered respectively to complete the initialization of multiple groups of weak magnetic detection probes and multiple groups of stepper motors 8; then the standard value acquisition subroutine is called to obtain the weak magnetic signals of the stepper motors at different acquisition monitoring points when they are not rotating and put them into the standard value storage unit INITIAL as standard values, that is, as stress damage degree judgment data, and as the intermediate parameter for main stress direction judgment. Wait for the system to call; open the weak magnetic detection probe and stepper motor corresponding to different acquisition monitoring points through a loop, call the data acquisition subroutine at the same time, use the stepper motor to rotate 360 degrees, and collect weak magnetic signals at different angles. The system collects data once after rotating a certain angle, and puts the collected data into the different excitation direction detection data storage unit ADTURN; after completing data collection in all detection areas, call the acquisition data processing subroutine, compare the values in the different excitation direction detection data storage units ADTURN with the standard values in the standard value storage unit INITIAL, find out the storage unit with the same standard value, and store the number of acquisition cycles as the principal stress direction determination data in the direction detection data storage unit LINEADR; Finally, the data stored in the standard value storage unit INITIAL and the direction detection data storage unit LINEADR are displayed as stress value determination data and principal stress direction determination data respectively; The standard value acquisition subroutine first defines a variable R0 and uses it as a pointer to point to the standard value storage unit INITIAL corresponding to the current detection probe, and starts the IN0 channel to start the various signal acquisition and processing functions of the weak magnetic detection probe, the hardware filtering system, and the A / D converter, and assigns the converted value to the variable R1, and at the same time, by judging the value of the counting variable R2, the loop is made to perform several acquisitions, and the acquired values are accumulated to R1. After the loop is completed, the average value of the acquisition is stored in the standard value storage unit INITIAL[N] pointed to by R0. After completing the standard value acquisition of a sensor corresponding to an area, the value of N is incremented to open the next sensor, and R0 is pointed to the standard value storage unit INITIAL[N] corresponding to the next sensor, and all standard values are stored in the one-dimensional array INITIAL[N]. Thus, after multiple cycles of processing, the weak magnetic detection probe, the hardware filtering system, and the A / D converter are respectively turned on, and the digital weak magnetic signal after hardware filtering and analog-to-digital conversion is stored in the standard value storage unit INITIAL after system analysis and processing, thereby completing the standard value acquisition of each acquisition monitoring point; The stepper motor data acquisition subroutine first points the data pointer DPTR to the stepper motor forward table TABLE, sets the value of the second bit J of the two-dimensional array, that is, points R0 to the first bit of the storage unit corresponding to the current detection area, defines the initial values of the loop count variables R1, R2, puts the content pointed to by the pointer DPTR into VALUE, and the motor driver outputs the value motorOutputvalue of VALUE, then the stepper motor rotates one step, that is, rotates a certain angle, that is, drives the excitation field to change by controlling the rotation of the stepper motor, and provides 360° different excitation directions for collecting the weak magnetic signal of the monitoring point; then points the pointer DPTR to the next unit of the forward table; starts the IN0 channel, turns on the various signal acquisition and processing functions of the multi-directional excitation system, weak magnetic detection probe, hardware filtering system, and A / D converter, and extends Wait for a while, store the converted value in the R0 pointing area, that is, use the weak magnetic detection probe to collect the weak magnetic signal value of the pipeline surface under different excitation directions, and increase the value of J to make R0 point to the next storage unit, and increase R1 to calculate the number of cycles. After multiple cycles, the stepper motor rotates a certain angle, and the sensor also collects multiple data and puts them into the data acquisition storage area. When R1 is equal to 4, a small cycle is completed, and the value of the cycle count variable R2 is increased, and the value of R1 is reset. After multiple large cycles, the stepper motor rotates one circle; then use the multi-directional excitation system, weak magnetic detection probe, hardware filtering system, and A / D converter to store the weak magnetic signals of 360 degrees in different excitation directions in the different excitation direction detection data storage unit ADTURN, and complete the excitation and signal acquisition of the corresponding acquisition monitoring points in different directions; The data processing subroutine first sets the value of the first bit N of the two-dimensional array of collected data storage, that is, starts processing from the data storage area corresponding to the first sensor, sets the value of the second bit J of the two-dimensional array of collected data storage to 1 through a for loop, and increments the value of J after completing one loop, and points the data pointer P2 to the current data storage area ADTURN[N][J] to be processed, and determines whether the value of the current P2 pointing area is the same as the value of the corresponding unit of the initial value storage area. If the value of the current P2 pointing area is different from the value of the corresponding unit of the initial value storage area, J is incremented to continue the comparison. If they are the same, the current value of J is stored as the data position record value in the data position storage unit LINEADR[N]. In the process, the value of N is incremented to compare the data in the storage area corresponding to the next detection probe, and the value of A is incremented to make P2 point to the next unit in the initial value storage area, and then the above cycle is continued. After multiple cycles, the stress value of the detection area of the monitoring point and the judgment data of the main stress direction are stored in the storage units of INITIAL and LINEADR waiting for the system call, and then the data of the different excitation direction detection data storage unit ADTURN is compared and analyzed with the data in the standard value storage unit INITIAL[N] to find the same data in the two groups of storage units and store them in the direction detection data storage unit LINEADR as the main stress direction judgment data.
2. According to claim 1, a weak magnetic stress damage and direction monitoring system for oil and gas pipelines is characterized in that As described above, the motor drive system of the present invention uses UIM242 to control the rotation of the stepper motor and drives the excitation system to rotate to change the direction of the external magnetic field. UIM242 controls the stepper motor through the CAN bus structure.
3. According to claim 1, a weak magnetic stress damage and direction monitoring system for oil and gas pipelines is characterized in that As described above, the conversion controller of the present invention uses UIM250121 to control several stepper motors through the CAN bus structure. UIM2501 can control several motor drive systems in the CAN bus structure to realize signal detection of multiple detection points at the same time.
4. According to claim 1, a weak magnetic stress damage and direction monitoring system for oil and gas pipelines is characterized in that The weak magnetic detection probe of the present invention is composed of a conductor, an insulating substrate, InSb-In magnetoresistive elements MR1 and MR2, a permanent magnet, pins, etc., and a metal shell for shielding and protection; weak magnetic signal detection is achieved based on the magnetoresistive effect.
5. According to claim 1, a weak magnetic stress damage and direction monitoring system for oil and gas pipelines is characterized in that The hardware filtering system of the present invention comprises a multi-stage TL082 signal amplifier and an RC buffer circuit, which are integrated in an AD8039 to reduce the circuit scale. The signal is transmitted to the input port of the A / D converter after multi-stage filtering.
6. According to claim 1, a weak magnetic stress damage and direction monitoring system for oil and gas pipelines is characterized in that The A / D converter of the present invention uses ADS1232 to be connected to several weak magnetic detection probes through the analog switch MAX4620. During detection, the weak magnetic detection probes at the corresponding points are turned on by MAX4620 to realize signal detection of multiple points. The single-chip microcomputer forms a storage expansion part through the 628128 chip and the 74LS373 latch chip, and the single-chip microcomputer is connected to multiple excitation systems through SM245TS.
7. According to claim 1, a weak magnetic stress damage and direction monitoring system for oil and gas pipelines is characterized in that The infrared transmission system of the present invention comprises an infrared transmitting part and an infrared receiving part, which are respectively connected to a single chip microcomputer and a PC to realize signal transmission. The transmitting part is composed of an IR333C transmitting tube driven by an amplifier circuit, and the receiving part is composed of a TSOP4838 receiving tube and an LM393DT comparator.