Oil and gas pipeline stress damage monitoring system based on weak magnetic method

Abstract

The invention belongs to the technical field of nondestructive testing of oil and gas pipelines, and particularly relates to an oil and gas pipeline stress damage monitoring system based on a weak magnetic method. In order to carry out accurate nondestructive fixed-point monitoring on the stress damage of the oil and gas pipeline under various complex working conditions, the stress damage of the oil and gas pipeline is monitored in real time at a fixed point by intelligently controlling a plurality of groups of weak magnetic sensors densely distributed on a monitoring pipe section by utilizing main control equipment such as a PC (Personal Computer), a single chip microcomputer and the like based on a metal weak magnetic detection principle; a digital calculation mode is used for replacing a traditional analog signal mode to carry out detection data analysis and processing, and the oil and gas pipeline stress damage monitoring system based on the weak magnetic method is designed.

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 stress damage monitoring system for oil and gas pipelines based on a weak magnetic method. Background Art

[0002] In energy transmission, the safe operation of pipelines is crucial. As time goes by, external environmental corrosion will cause the continuous accumulation of pipeline stress damage, increasing the risk of bursting, leakage and other operations of oil and gas pipelines. Therefore, real-time non-destructive stress detection of oil and gas pipelines, especially important and vulnerable pipeline parts, is crucial to ensure the safe operation of oil and gas pipelines. Weak magnetic detection technology can perform stress detection based on the spontaneous leakage magnetic signal of stress damage without applying any external excitation. It has the characteristics of fast signal acquisition speed, dynamic detection support, low environmental interference and no need for coupling agent. It can effectively detect the early microscopic stress damage of oil and gas pipelines, so it has been widely used in the field of oil and gas pipeline detection. However, at present, weak magnetic detection technology is mainly used for detection in oil and gas pipelines, that is, using transmission media such as oil and gas to push the detector to move in the pipeline and periodically detect pipeline damage. This is difficult to meet the requirements of detection time and detection cycle for some key and vulnerable pipe sections that require long-term real-time fixed-point monitoring. In addition, traditional weak magnetic detection usually uses analog signals to analyze and process detection data, which makes it difficult for the detection system to have high early warning accuracy, and the hardware structure is complex, expensive, and there are many interference factors. Summary of the invention

[0003] In response to the above problems, the present invention is based on the principle of metal weak magnetic detection, utilizes PC, single chip microcomputer and other main control equipment to intelligently control multiple groups of weak magnetic sensors densely distributed on the monitoring pipe section, performs fixed-point real-time monitoring of oil and gas pipeline stress damage, and replaces the traditional analog signal method with digital calculation method to analyze and process the detection data, and designs an oil and gas pipeline stress damage monitoring system based on weak magnetic method.

[0004] To achieve the above purpose, the present invention adopts the following technical scheme. The system of the present invention includes two parts: an external structure and an internal circuit structure. The external structure includes a fixed pipe clamp, a bracket assembly, a protective shell, a detector substrate, and multiple groups of weak magnetic sensors, wherein the fixed pipe clamp is used for the installation and disassembly of the detection system; the bracket assembly is used for the installation and fixation of the protective shell; the protective shell is used to protect the internal circuit structure and maintain the stability of the detector; the detector substrate is composed of packaging materials and a heat sink, and is used to fix multiple groups of weak magnetic sensor detection probes; multiple groups of weak magnetic sensors are used for weak magnetic signal collection at different test points on the surface of oil and gas pipelines. The internal circuit structure includes multiple groups of weak magnetic sensors, multiple groups of hardware filtering systems, multiple groups of infrared transmission systems, analog / digital converters, clock modules, PCs, external storage devices, alarm systems, power-off protection devices, and single-chip microcomputers. The main points of its structure are as follows: the output ports of multiple groups of weak magnetic sensor circuits are connected to the input ports of multiple groups of hardware filtering systems respectively, and then connected to the input ports of multiple groups of infrared transmission systems respectively; the output ports of multiple groups of infrared transmission systems are connected to the detection signal input ports of analog / digital converters; the detection signal output ports of analog / digital converters are connected to the detection signal input ports of single-chip microcomputers; the signal output port of the clock module is connected to the signal input port of the single-chip microcomputer; the signal input and output ports of the PC are connected to the signal output and input ports of the single-chip microcomputer respectively; the storage signal input port of the external memory is connected to the storage signal output port of the single-chip microcomputer; the signal input port of the alarm system is connected to the alarm signal output port of the single-chip microcomputer; the signal input port of the power-off protection device is connected to the power-off protection signal output port of the single-chip microcomputer. The system of the present invention contains a system call and a data processing main program, which is responsible for the calculation analysis and subroutine call of the whole system; contains a data acquisition subroutine, which controls multiple groups of weak magnetic sensors, multiple groups of hardware filtering systems, multiple groups of infrared transmission systems, and analog / digital converters to collect, hardware filter, infrared transmit and digitally convert weak magnetic detection signals on the surface of oil and gas pipelines; contains a digital filtering subroutine, which can further digitally filter the collected digital weak magnetic signals to eliminate interference factors; contains a data judgment subroutine, which can complete the stress damage degree detection and damage positioning functions based on the weak magnetic stress detection characteristics, and use the display function and alarm system of the PC to display, locate and warn the stress damage of the oil and gas pipeline in real time. The system software sets ADTURN1 as a weak magnetic detection data storage area; ADTURN2 as a filter processing data storage area; ADTURN3 as an abnormal data address storage area; ADTURN4 as an abnormal data value storage area.

[0005] The system calls and data processing main program, which first sets system parameters such as acquisition time setting, filter parameter setting and critical value setting, defines ADTURN1 as weak magnetic detection data storage area, and defines ADTURN2 as filter processing data storage area. The sensor is defined by for loop int i=0; i<1; i++ and N value int N=i. The sensor probe is started with int N=1, and R1 is used as a data pointer to point to the filter processing data storage area ADTURN2. The system can turn on the Nth probe with printf("%d probe has been turned on\n",N), and the N value changes from 1 to 36 cycles with the program, so as to complete the switching calculation of different probes in the main program. Call the data acquisition subroutine to control multiple groups of weak magnetic sensors, multiple groups of hardware filtering systems, multiple groups of infrared transmission systems, and analog / digital converters to complete the system functions of weak magnetic data acquisition, hardware filtering, infrared transmission, and analog / digital conversion, and store the collected and processed digital weak magnetic signals in the weak magnetic detection data storage area ADTURN1 to complete the preliminary acquisition of weak magnetic data. Then the digital filtering subroutine is called to perform digital calculation and benchmark numerical processing on the digital weak magnetic signal in the weak magnetic detection data storage area ADTURN1, so as to realize further digital filtering of the digital weak magnetic signal, and store the filtered detection data in the filter processing data storage area ADTURN2 to wait for system call. The R1 pointer points to the next storage space of the filter processing data storage area ADTURN2, and the N value count is increased by one, that is, the next detection probe is turned on, and the detection probe switching is further completed. Finally, the data judgment subroutine is called to realize the location of oil and gas pipeline defect damage by using the matrix distribution equation, and the data in the filter processing data storage area ADTURN2 is compared with the critical value set in the parameter setting to find the weak magnetic detection probe that exceeds the critical value, and the detection probe data and probe position are displayed in real time through the PC through the data group of the abnormal data address storage area ADTURN3 pointed by the R3 pointer and the abnormal data value storage area ADTURN4 pointed by the R4 pointer, so as to realize the stress damage degree detection and accurate damage positioning, and realize the synchronous warning of abnormal signals through the alarm system.

[0006] The data acquisition subroutine first defines the high-intensity interference threshold High Value, the purpose is to directly eliminate the external large-value interference, so that the collected data is more reliable, assign 20 to R5, and use R0 as a data pointer to point to the first address ADTURN1 of the weak magnetic detection data storage area, and complete the definition of the interference threshold and the data storage area. Start the IN0 channel, and collect, filter, transmit and digitally convert the weak magnetic detection signal through multiple groups of weak magnetic sensors, multiple groups of hardware filtering systems, multiple groups of infrared transmission systems, and analog / digital converters. Then compare and analyze the R0 pointing value with the high-intensity interference threshold to determine whether the collected value is greater than the interference threshold. If the collected value is greater than the interference threshold, the data collected this time is abandoned, data collection is performed again, and the IN0 channel is restarted for analog / digital conversion. If the collected data is less than the interference threshold, the R5 count is reduced by one, and the R0 pointer points to the next storage unit, and the collected digital weak magnetic signal is judged for the interference threshold, and the collected data that meets the threshold is sent to the weak magnetic detection data storage area ADTURN1, so as to achieve the purpose of accurate collection and storage of the detection data. Finally, determine whether R5 is 0. If R5 is not 0, re-collect data and restart the IN0 channel for analog / digital conversion. If R5 is 0, it means that the collection of digital weak magnetic signals has been completed, the data collection subroutine ends, and returns to the main program. Then, the collected data is subjected to hardware filtering, infrared transmission, and analog / digital conversion to form a digital weak magnetic signal. After the interference threshold is judged, it is sent to the weak magnetic detection data storage area ADTURN1 to wait for the system main program to call.

[0007] The digital filtering subroutine first defines two maximum loop times and max loop2=60, clear registers R6 and R5, point R0 pointer to the first address ADTURN1 of the weak magnetic detection data storage area, and complete the definition of the maximum number of system cycles, registers and data storage areas. Assign the value pointed by R0 to R5 and point R0 to the next storage unit, judge the value pointed by R0 and the size of R5. If the value pointed by R0 is not greater than R5, the R5 value and the value pointed by R0 are swapped, and the counts of R5 and R6 are increased by one. If the value pointed by R0 is greater than R5, the counts of R5 and R6 are increased by one; judge whether R5 is equal to max loop2, if not, point R0 to the next storage unit, if equal, judge whether R6 is equal to max loop1; if not, clear R5, if equal, point R0 to the tenth value of the storage area, through the two cycles of max loop1 and max loop2, the digital weak magnetic signals collected by the weak magnetic detection data storage area ADTURN1 are arranged in order according to their numerical values. Define the reference number B to be equal to the value pointed to by R0, clear R2 and R5, point R0 to the first address ADTURN1 of the weak magnetic detection data storage area, subtract the reference number B from the value pointed to by R0 and add the value of R2, and assign it to R2. Use the weighted filtering and majority filtering mixed operation of a large amount of detection data to perform reference numerical processing on the sorted digital weak magnetic signal detection data through digital calculation, and realize further digital filtering of the digital weak magnetic signal. Finally, point the R0 pointer to the next storage unit, add one to the R5 count, and determine whether R5 is equal to max loop2; if not, reassign R2, if equal, add the reference number to the R2 value and assign it to R2, the digital filtering subroutine ends, and returns to the main program, and then further digitally filters the digital weak magnetic signal in the weak magnetic detection data storage area ADTURN1, and sends it to the R2 register after the reference numerical processing to wait for the system call.

[0008] The data judgment subroutine first defines the abnormal data address storage area ADTURN3 and the abnormal data value storage area ADTURN4, and points the R1, R3, and R4 pointers to the filter processing data storage area first address ADTURN2, the abnormal data address storage area ADTURN3, and the abnormal data value storage area ADTURN4, respectively, and the R5 register is cleared to complete the definition of the storage area and the register. R5 counts plus one to determine whether the value pointed to by R1 is greater than the critical value; if greater, R1 is assigned to the position pointed to by R4 and the R5 value is assigned to the position pointed to by R3, and R3 and R4 are respectively pointed to the next storage unit to determine whether R5 is equal to 36. If not greater, directly determine whether R5 is equal to 36. Then compare and analyze the detection data after filtering in the filter processing data storage area ADTURN2 with the preset critical value. If not equal, R1 is pointed to the next storage unit and R5 is counted again and added by one to perform critical value judgment. If equal, R3 and R4 are respectively pointed to the first address ADTURN3 of the abnormal data address storage area and the first address ADTURN4 of the abnormal data value storage area, thereby completing the storage of data in the abnormal data value storage area ADTURN4 and the abnormal data address storage area ADTURN3. Determine whether the value pointed to by R4 is 0, and perform abnormal detection data analysis and corresponding sensor storage unit analysis in the two storage areas. Finally, if the values ​​pointed to by the R3 and R4 pointers are both equal to 0, it means there is no abnormal data, and the PC displays "None" and returns to the main program for a new round of data collection. If not 0, the PC displays the address *R3 and the value *R4, and points R3 and R4 to the next storage unit respectively. It is judged again whether the value pointed to by the R4 pointer is 0. If not equal to 0, the new address *R3 and data *R4 are displayed again. If equal to 0, the alarm system is activated and returns to the main program for a new round of data collection. In this way, the detection data exceeding the critical value in the filtering processing data storage area ADTURN2 is found, and the detection data value and detection probe position in the abnormal data value storage area ADTURN4 pointed to by R4 and the abnormal data address storage area ADTURN3 pointed to by R3 are used as stress damage degree and damage location information, which are displayed in real time through a PC, and when there is a probe exceeding the critical value, the alarm system is turned on to form a real-time early warning function of the system.

[0009] As a preferred solution, the multiple groups of weak magnetic sensors described in the present invention adopt the HMC1021 model, and the circuit includes two comparators and multiple resistors and capacitors. The comparator is used to compare two input signals and judge the magnitude relationship of the input voltage, current or digital signal. In analog circuits, it is used for signal detection and shaping; in digital circuits, it can realize logical judgment. Resistors are used for voltage division and current limiting, and capacitors are used for charge storage, filtering, and coupling AC signals.

[0010] As a preferred solution, the multi-group hardware filtering system of the present invention comprises two parts: LM324 chip high-pass filtering and LM324 chip low-pass filtering. The LM324 operational amplifier is mainly used for signal amplification. The high-pass filtering attenuates signals below the cut-off frequency and allows signals above the cut-off frequency to pass through, which is used to remove low-frequency noise and extract rapidly changing signal components. The low-pass filtering attenuates signals above the cut-off frequency and allows signals below the cut-off frequency to pass through, which is used to remove high-frequency noise and smooth signals.

[0011] As a preferred solution, the multi-group infrared transmission system of the present invention comprises two parts: an 8050 chip infrared transmitting circuit and an LM386 chip infrared receiving circuit. The infrared transmitting circuit is used to convert the electrical signal into an infrared light signal and transmit it out, the 8050 transistor is used for signal amplification, and is also used for electronic switches to control the on and off of the circuit; the infrared receiving circuit is used to receive the infrared light signal emitted by the transmitting circuit, convert it into an electrical signal, and then amplify and filter it, and the LM386 power amplifier is used to amplify the input low-power signal to enhance the driving capability.

[0012] As a preferred solution, the analog / digital converter of the present invention comprises an ADS1232 analog / digital conversion chip and a MAX4636 analog multiplexer, wherein the ADS1232 analog / digital conversion chip is used to convert analog signals into digital signals, and quantize and encode the input analog quantities with high precision and high resolution, wherein a clock module is used to provide a synchronization signal for the system, and finally a PC displays abnormal values ​​and probe positions, and a power-off protection device is always in a protection state; the MAX4636 analog multiplexer is used to realize switching and routing of different analog signal sources; the clock module is used to provide a synchronization signal for the digital system, and is also used for timing and controlling data transmission; the PC is used to display the values ​​of the final abnormal data and the probe positions; the power-off protection device is used to save data to prevent system program interruption and data loss due to power failure.

[0013] As a preferred solution, the external memory of the present invention comprises a 74LS373 latch chip and a 628128 external memory chip. The 74LS373 chip is used to store and maintain input data under the control of an enable signal. The 628128 chip is used to meet the needs of storing and processing a large amount of data.

[0014] As a preferred solution, the alarm system of the present invention includes a 3DG6 NPN transistor, a 3AX81 PNP transistor and a buzzer. The transistor is used to amplify the alarm signal, control the on and off of the alarm device, and realize circuit logic control; the buzzer emits a sound alarm. When the system detects an abnormal or dangerous situation, the buzzer is driven to sound, which serves as a warning.

[0015] Beneficial effects of the present invention:

[0016] 1. The present invention is based on the principle of pipeline weak magnetic detection and utilizes multiple groups of weak magnetic sensors permanently installed at monitoring points to monitor stress damage in oil and gas pipelines, thereby realizing long-term, efficient, real-time early warning monitoring and damage location of stress damage in key and vulnerable sections of pipelines.

[0017] 2. In view of the remote geographical location, harsh and complex monitoring environment, and other problems of oil and gas pipelines, the present invention sets up an infrared transmission system to enable operators to operate the monitoring system remotely, realize long-distance real-time monitoring and processing of the pipeline, and meet the system's field working environment requirements.

[0018] 3. The present invention writes a data analysis program based on the principle of weak magnetic detection to perform stress damage assessment, and locates damage based on the matrix distribution equations of sensors at different monitoring points in the program, thereby realizing the establishment of a fully digital weak magnetic stress damage monitoring system, thereby reducing costs while improving early warning accuracy.

[0019] 4. The present invention utilizes weighted filtering and majority filtering hybrid operations of a large amount of detection data to write a digital filtering program to shield system noise and improve the system's anti-interference ability, and cooperates with the hardware filtering system to further improve the system's anti-interference ability and detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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.

[0021] Figure 1 System overall structure diagram;

[0022] Figure 2 System call and data processing main program flow chart;

[0023] Figure 3 Data collection subroutine flow chart;

[0024] Figure 4 Digital filtering subroutine flow chart;

[0025] Figure 5 Data judgment subroutine flow chart;

[0026] Figure 6 Weak magnetic sensor circuit diagram;

[0027] Figure 7 Circuit diagram of hardware filtering system;

[0028] Figure 8 Infrared transmission system circuit diagram;

[0029] Fig. 9 Analog / digital converter circuit diagram;

[0030] Fig.10 External memory circuit diagram;

[0031] Fig.11 Alarm system circuit diagram. DETAILED DESCRIPTION

[0032] like Figure 1As shown, the system of the present invention includes two parts: an external structure and an internal circuit structure. The external structure includes a fixed pipe clamp 1, a bracket assembly 2, a protective shell 3, a detector substrate 4, and multiple groups of weak magnetic sensors 5, wherein the fixed pipe clamp 1 is used for the installation and removal of the detection system; the bracket assembly 2 is used for the installation and fixation of the protective shell 3; the protective shell 3 is used to protect the internal circuit structure and maintain the stability of the detector; the detector substrate 4 is composed of packaging materials and a heat sink, and is used for fixing multiple groups of weak magnetic sensors 5 detection probes; multiple groups of weak magnetic sensors 5 are used for weak magnetic signal collection at different test points on the surface of the oil and gas pipeline. The internal circuit structure includes multiple groups of weak magnetic sensors 5, multiple groups of hardware filtering systems 6, multiple groups of infrared transmission systems 7, analog / digital converters 8, clock modules 9, PCs 10, external memory 11, alarm systems 12, power-off protection devices 13, and single-chip microcomputers 14. The main points of its structure are as follows: the output ports of multiple groups of weak magnetic sensor 5 circuits are connected to the input ports of multiple groups of hardware filtering systems 6, and then connected to the input ports of multiple groups of infrared transmission systems 7; the output ports of multiple groups of infrared transmission systems 7 are connected to the detection signal input ports of analog / digital converters 8; the detection signal output ports of analog / digital converters 8 are connected to the detection signal input ports of single-chip microcomputers 14; the signal output port of clock module 9 is connected to the signal input port of single-chip microcomputers 14; the signal input and output ports of PC 10 are connected to the signal output and input ports of single-chip microcomputers 14; the storage signal input port of external memory 11 is connected to the storage signal output port of single-chip microcomputers 14; the signal input port of alarm system 12 is connected to the alarm signal output port of single-chip microcomputers 14; the signal input port of power-off protection device 13 is connected to the power-off protection signal output port of single-chip microcomputers 14. This system contains a system call and data processing main program, which is responsible for the overall calculation analysis and subroutine call of the system; contains a data acquisition subroutine, which controls multiple groups of weak magnetic sensors 5, multiple groups of hardware filtering systems 6, multiple groups of infrared transmission systems 7, and analog / digital converters 8 to collect, hardware filter, infrared transmit and digitally convert weak magnetic detection signals on the surface of oil and gas pipelines; contains a digital filtering subroutine, which can further digitally filter the collected digital weak magnetic signals to eliminate interference factors; contains a data judgment subroutine, which can complete the stress damage degree detection and damage location functions based on the weak magnetic stress detection characteristics, and use the display function of the PC 10 and the alarm system 12 to display, locate and warn the stress damage of the oil and gas pipeline in real time. The system software sets ADTURN1 as the weak magnetic detection data storage area; ADTURN2 as the filter processing data storage area; ADTURN3 as the abnormal data address storage area; ADTURN4 as the abnormal data value storage area.

[0033] like Figure 2As shown, the system calls and processes the main program of data. It first sets the system parameters such as the acquisition time, filter parameters and critical value, defines ADTURN1 as the weak magnetic detection data storage area, and defines ADTURN2 as the filter processing data storage area. The sensor is defined by the for loop int i=0; i<1; i++ and the N value int N=i. The sensor probe is started with intN=1, and R1 is used as the data pointer to point to the filter processing data storage area ADTURN2. The system can open the Nth probe with printf("The %dth probe has been turned on\n",N), and the N value changes from 1 to 36 cycles with the program, so as to complete the switching calculation of different probes in the main program. The data acquisition subroutine is called to control multiple groups of weak magnetic sensors 5, multiple groups of hardware filtering systems 6, multiple groups of infrared transmission systems 7, and analog / digital converters 8 to complete the system functions of weak magnetic data acquisition, hardware filtering, infrared transmission, and analog / digital conversion, and the collected and processed digital weak magnetic signals are stored in the weak magnetic detection data storage area ADTURN1 to complete the preliminary acquisition of weak magnetic data. Then, the digital filtering subroutine is called to perform digital calculation and benchmark numerical processing on the digital weak magnetic signal in the weak magnetic detection data storage area ADTURN1, so as to realize further digital filtering of the digital weak magnetic signal, and store the filtered detection data in the filter processing data storage area ADTURN2 to wait for system call. The R1 pointer points to the next storage space of the filter processing data storage area ADTURN2, and the N value count is increased by one, that is, the next detection probe is turned on, and the detection probe switching is further completed. Finally, the data judgment subroutine is called to realize the location of oil and gas pipeline defect damage by using the matrix distribution equation, and the data in the filter processing data storage area ADTURN2 is compared with the critical value set in the parameter setting to find the weak magnetic detection probe that exceeds the critical value, and the detection probe data and probe position are displayed in real time through the PC 10 through the data group of the abnormal data address storage area ADTURN3 pointed by the R3 pointer and the abnormal data value storage area ADTURN4 pointed by the R4 pointer, so as to realize the stress damage degree detection and accurate damage positioning, and realize the abnormal signal synchronous warning through the alarm system 12.

[0034] like Figure 3As shown, the data acquisition subroutine first defines the high-intensity interference threshold High Value, the purpose is to directly eliminate the external large-value interference, so that the collected data is more reliable, assign 20 to R5, and use R0 as a data pointer to point to the first address ADTURN1 of the weak magnetic detection data storage area, and complete the definition of the interference threshold and data storage area. Start the IN0 channel, and collect, filter, transmit and digitally convert the weak magnetic detection signal through multiple groups of weak magnetic sensors 5, multiple groups of hardware filtering systems 6, multiple groups of infrared transmission systems 7, and analog / digital converters 8. Then compare and analyze the R0 pointing value with the high-intensity interference threshold to determine whether the collected value is greater than the interference threshold. If the collected value is greater than the interference threshold, the data collected this time is abandoned, data collection is performed again, and the IN0 channel is restarted for analog / digital conversion. If the collected data is less than the interference threshold, the R5 count is reduced by one, and the R0 pointer points to the next storage unit. The collected digital weak magnetic signal is judged for the interference threshold, and the collected data that meets the threshold is sent to the weak magnetic detection data storage area ADTURN1, so as to achieve the purpose of accurate collection and storage of the detection data. Finally, determine whether R5 is 0. If R5 is not 0, re-collect data and restart the IN0 channel for analog / digital conversion. If R5 is 0, it means that the collection of digital weak magnetic signals has been completed, the data collection subroutine ends, and returns to the main program. Then, the collected data is subjected to hardware filtering, infrared transmission, and analog / digital conversion to form a digital weak magnetic signal. After the interference threshold is judged, it is sent to the weak magnetic detection data storage area ADTURN1 to wait for the system main program to call.

[0035] like Figure 4 As shown, the digital filter subroutine first defines two maximum loop times and maxloop2=60, clear registers R6 and R5, point R0 pointer to the first address ADTURN1 of the weak magnetic detection data storage area, and complete the definition of the maximum number of system cycles, registers and data storage areas. Assign the value pointed by R0 to R5 and point R0 to the next storage unit, judge the value pointed by R0 and the size of R5. If the value pointed by R0 is not greater than R5, the R5 value and the value pointed by R0 are swapped, and the counts of R5 and R6 are increased by one. If the value pointed by R0 is greater than R5, the counts of R5 and R6 are increased by one; judge whether R5 is equal to max loop2, if not, point R0 to the next storage unit, if equal, judge whether R6 is equal to max loop1; if not, clear R5, if equal, point R0 to the tenth value of the storage area, through the two cycles of max loop1 and max loop2, the digital weak magnetic signals collected by the weak magnetic detection data storage area ADTURN1 are arranged in order according to their numerical values. Define the reference number B to be equal to the value pointed to by R0, clear R2 and R5, point R0 to the first address ADTURN1 of the weak magnetic detection data storage area, subtract the reference number B from the value pointed to by R0 and add the value of R2, and assign it to R2. Use the weighted filtering and majority filtering mixed operation of a large amount of detection data to perform reference numerical processing on the sorted digital weak magnetic signal detection data through digital calculation, and realize further digital filtering of the digital weak magnetic signal. Finally, point the R0 pointer to the next storage unit, add one to the R5 count, and determine whether R5 is equal to max loop2; if not, reassign R2, if equal, add the reference number to the R2 value and assign it to R2, the digital filtering subroutine ends, and returns to the main program, and then further digitally filters the digital weak magnetic signal in the weak magnetic detection data storage area ADTURN1, and sends it to the R2 register after the reference numerical processing to wait for the system call.

[0036] like Figure 5As shown, the data judgment subroutine first defines the abnormal data address storage area ADTURN3 and the abnormal data value storage area ADTURN4, and points the R1, R3, and R4 pointers to the filter processing data storage area first address ADTURN2, the abnormal data address storage area ADTURN3, and the abnormal data value storage area ADTURN4, respectively, and the R5 register is cleared to complete the definition of the storage area and register. R5 counts plus one to determine whether the value pointed to by R1 is greater than the critical value; if greater, R1 is assigned to the position pointed to by R4 and the R5 value is assigned to the position pointed to by R3, and R3 and R4 are respectively pointed to the next storage unit to determine whether R5 is equal to 36. If not greater, directly determine whether R5 is equal to 36. Then, the detection data after filtering in the filter processing data storage area ADTURN2 is compared and analyzed with the preset critical value. If not equal, R1 is pointed to the next storage unit and R5 is counted again and added by one to perform critical value judgment. If equal, R3 and R4 are respectively pointed to the first address ADTURN3 of the abnormal data address storage area and the first address ADTURN4 of the abnormal data value storage area, thereby completing the storage of data in the abnormal data value storage area ADTURN4 and the abnormal data address storage area ADTURN3. It is judged whether the value pointed to by R4 is 0, and abnormal detection data analysis and corresponding sensor storage unit analysis are performed in the two storage areas. Finally, if the values ​​pointed to by the R3 and R4 pointers are both equal to 0, it means that there is no abnormal data, and the PC 10 is used to display "None", and return to the main program for a new round of data collection. If not 0, the PC 10 displays the address *R3 and the value *R4, and points R3 and R4 to the next storage unit respectively, and judges whether the value pointed to by the R4 pointer is 0 again. If not equal to 0, the new address *R3 and data *R4 are displayed again. If equal to 0, the alarm system 12 is started and returns to the main program for a new round of data collection. In this way, the detection data exceeding the critical value in the filtering processing data storage area ADTURN2 is found, and the detection data value and the detection probe position in the abnormal data value storage area ADTURN4 pointed to by R4 and the abnormal data address storage area ADTURN3 pointed to by R3 are used as stress damage degree and damage location information, which are displayed in real time through the PC 10, and when there is a probe exceeding the critical value, the alarm system 12 is turned on to form a real-time early warning function of the system.

[0037] like Figure 6As shown, multiple groups of weak magnetic sensors 5 adopt the HMC1021 model, and the circuit includes two comparators and multiple resistors and capacitors. The comparator is used to compare two input signals and judge the magnitude relationship of the input voltage, current or digital signal. In analog circuits, it is used for signal detection and shaping; in digital circuits, logical judgment can be realized. Resistors are used for voltage division and current limiting, and capacitors are used for charge storage, filtering and coupling AC signals. The specific connection method is: the HMC1021 type weak magnetic sensor is connected to the resistor R1 through the capacitor C1 and connected to the negative input port of the first comparator, the resistor R2 is connected in parallel at both ends of the comparator, the comparator output port is connected to the resistor R3 through the capacitor C2 and connected to the negative input port of the next comparator, the resistor R4 is connected in parallel at both ends of the comparator, and the positive input ports of the two comparators are connected to each other.

[0038] like Figure 7 As shown, the multi-group hardware filtering system 6 includes two parts: LM324 chip high-pass filtering and LM324 chip low-pass filtering. The LM324 operational amplifier is mainly used for signal amplification. The high-pass filtering attenuates signals below the cut-off frequency and allows signals above the cut-off frequency to pass through, which is used to remove low-frequency noise and extract rapidly changing signal components. The low-pass filtering attenuates signals above the cut-off frequency and allows signals below the cut-off frequency to pass through, which is used to remove high-frequency noise and smooth signals. The specific connection method is: the positive input end of the LM324 operational amplifier of the high-pass filtering is connected to the weak magnetic sensor signal output end Vout through a 100μF capacitor, and the next negative input end is connected to the high-pass filtering output end through a 24.7K resistor; the positive input end of the LM324 operational amplifier of the low-pass filtering is connected to the high-pass filtering output end through a 36K resistor, and the next negative input end is connected to the low-pass filtering output port Vout through a 24.7K resistor.

[0039] like Figure 8 As shown, the multi-group infrared transmission system 7 includes two parts: an 8050 chip infrared transmitting circuit and an LM386 chip infrared receiving circuit. The infrared transmitting circuit is used to convert the electrical signal into an infrared light signal and transmit it. The 8050 transistor is used for signal amplification and is also used for electronic switches to control the on and off of the circuit; the infrared receiving circuit is used to receive the infrared light signal emitted by the transmitting circuit, convert it into an electrical signal, and then amplify and filter it. The LM386 power amplifier is used to amplify the input low-power signal to enhance the driving ability. The specific connection method is: the infrared transmitting circuit is connected to the transistor through a 100K resistor as the input port Vin, and is connected to the diode VD1 through a 4.7μF capacitor and then grounded; the infrared receiving circuit is connected to the LM386 power amplifier 3 interface through a 0.22μF capacitor, 1 and 8 interfaces are connected through a 10μF capacitor, 7 interface is grounded through a 100μF capacitor, and 5 interface is connected to the infrared receiving circuit output terminal Vout through a 100μF capacitor and connected to the ground in parallel through a 0.1μF capacitor.

[0040] like Fig. 9 As shown, the analog / digital converter 8 includes an ADS1232 analog / digital conversion chip and a MAX4636 analog multiplexer. The ADS1232 analog / digital conversion chip is used to convert analog signals into digital signals, and quantize and encode the input analog quantities with high precision and high resolution. The clock module 9 provides a synchronization signal for the system, and finally the PC 10 displays the abnormal value and the probe position, and the power-off protection device 13 is always in a protection state; the MAX4636 analog multiplexer is used to realize the switching and routing of different analog signal sources; the clock module 9 is used to provide a synchronization signal for the digital system, and is also used for timing and controlling data transmission; the PC 10 is used to display the value of the final abnormal data and the probe position; the power-off protection device 13 is used to save data to prevent system program interruption and data loss due to power failure. The specific connection method is as follows: the INT0 port of the AT89S52 chip is connected to the INT port of the ADS1232 chip, the P2.0, P2.1, and P2.2 ports are respectively connected to the LBEN, HBEN, and CE ports of the ADS1232 chip, and the P1.0, P1.1, and P1.2 ports are respectively connected to the SDI, SDN, and CS ports of the MAX4636 analog multiplexer; the IN port of the ADS1232 chip is connected to the COM port of the MAX4636 analog multiplexer; the clock module 9 is connected to the XTAL1 and XTAL2 pins of the AT89S52 microcontroller 14; the PC 10 is connected to the P3.0 and P3.1 pins of the AT89S52 microcontroller 14 through a 232C\422A converter; the CEIN and RST pins of the power-off protection device 13 are correspondingly connected to the RST and P3.2 pins of the AT89S52 microcontroller 14.

[0041] like Fig.10 As shown, the external memory 11 includes a 74LS373 latch chip and a 628128 external memory chip. The 74LS373 chip is used to store and maintain input data under the control of an enable signal. The 628128 chip is used to meet the needs of storing and processing a large amount of data. The specific connection method is: the P0 port of the AT89S52 chip is respectively connected to the data input port of the 74LS373 chip, the chip data output port of the 74LS373 is respectively connected to the address input port of the 628128 chip, the WR and RD pins of the AT89S52 chip are respectively connected to the WR and OE pins of the 628128 chip, the P2.3, P2.4 and P2.5 ports of the AT89S52 chip are respectively connected to the A10, A9 and A8 address pins of the 628128 chip, and the ALE pin of the AT89S52 chip is connected to the LE pin of the 74LS373 chip.

[0042] like Fig.11As shown, the alarm system 12 includes a 3DG6 NPN transistor, a 3AX81 PNP transistor and a buzzer. The transistor is used to amplify the alarm signal, control the on and off of the alarm device, and realize the circuit logic control; the buzzer emits a sound alarm. When the system detects an abnormal or dangerous situation, the buzzer is driven to sound, which plays a warning role. The specific connection method is: the positive terminal of the buzzer is connected to the capacitor C1 and the power supply VCC, and the capacitor C1 is connected to the resistor R1. The connection end of the capacitor C1 and the resistor R1 is connected to the P3.4 port of the AT89S52 single-chip computer 14, and is connected to the base of the 3DG6 NPN transistor; the negative terminal of the buzzer is connected to the capacitor C2, and is respectively connected to the emitters of the two transistors, and the emitter of the NPN transistor is grounded, and the collector of the 3DG6 NPN transistor is connected to the base of the 3AX81 PNP transistor.

[0043] The operation process of the system of the present invention is:

[0044] The monitoring system first uses multiple groups of weak magnetic sensors 5 to collect weak magnetic signals on the surface of the monitored oil and gas pipeline, and after eliminating interference signals through multiple groups of hardware filtering systems 6, multiple groups of infrared transmission systems 7 transmit the detection signals to the signal receiving and processing part over a long distance. After the detection signals are converted into digital signals through analog / digital converters 8, they are handed over to the single-chip microcomputer 14 and the PC 10. Through system calls and numerical calculations, the determination of the degree of stress damage and the location analysis of the damage position are completed. The system call and data processing main program of this system first complete the collection, processing and storage of digital weak magnetic signals after collection, hardware filtering, infrared transmission, and analog / digital conversion through specific parameter settings and data acquisition subroutine calls; then, by calling the digital filtering subroutine, further digital filtering of the collected signals is completed; finally, through digital calculations and data judgment subroutine calls, based on the weak magnetic stress detection characteristics, the pipeline stress damage degree detection and damage location functions are completed, and real-time display and early warning are realized using the PC 10 and the alarm system 12.

[0045] 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 system for monitoring stress damage of oil and gas pipelines based on weak magnetic method. The system of the present invention includes two parts: an external structure and an internal circuit structure. The external structure includes a fixed pipe clamp, a bracket assembly, a protective shell, a detector substrate, and multiple groups of weak magnetic sensors. The fixed pipe clamp is used for installation and disassembly of the detection system; the bracket assembly is used for installation and fixation of the protective shell; the protective shell is used to protect the internal circuit structure and maintain the stability of the detector; the detector substrate is composed of packaging materials and a heat sink, and is used to fix multiple groups of weak magnetic sensor detection probes; multiple groups of weak magnetic sensors are used for weak magnetic signal acquisition at different test points on the surface of the oil and gas pipeline. The internal circuit structure includes multiple groups of weak magnetic sensors, multiple groups of hardware filtering systems, multiple groups of infrared transmission systems, analog / digital converters, clock modules, PCs, external storage, alarm systems, power-off protection devices, and single-chip microcomputers. The key points of the structure are as follows: the output ports of multiple groups of weak magnetic sensor circuits are connected to the input ports of multiple groups of hardware filtering systems, and then connected to the input ports of multiple groups of infrared transmission systems; the output ports of multiple groups of infrared transmission systems are connected to the detection signal input ports of analog / digital converters; the detection signal output ports of analog / digital converters are connected to the detection signal input ports of single-chip microcomputers; the signal output port of the clock module is connected to the signal input port of the single-chip microcomputer; the signal input and output ports of the PC are connected to the signal output and input ports of the single-chip microcomputer; the storage signal input port of the external memory is connected to the storage signal output port of the single-chip microcomputer; the signal input port of the alarm system is connected to the alarm signal output port of the single-chip microcomputer; the signal input port of the power-off protection device is connected to the power-off protection signal output port of the single-chip microcomputer; The system of the present invention contains a system call and data processing main program, which is responsible for the overall calculation analysis and subroutine call of the system; contains a data acquisition subroutine, which controls multiple groups of weak magnetic sensors, multiple groups of hardware filtering systems, multiple groups of infrared transmission systems, and analog / digital converters to collect, hardware filter, infrared transmit and digitally convert weak magnetic detection signals on the surface of oil and gas pipelines; contains a digital filtering subroutine, which can further digitally filter the collected digital weak magnetic signals to eliminate interference factors; contains a data judgment subroutine, which can complete the stress damage degree detection and damage location functions based on the weak magnetic stress detection characteristics, and use the display function and alarm system of the PC to display, locate and warn the stress damage of the oil and gas pipeline in real time. The system software sets ADTURN1 as the weak magnetic detection data storage area; ADTURN2 as the filter processing data storage area; ADTURN3 as the abnormal data address storage area; ADTURN4 as the abnormal data value storage area; The system calls and data processing main program, which first sets system parameters such as acquisition time setting, filter parameter setting and critical value setting, defines ADTURN1 as weak magnetic detection data storage area, and defines ADTURN2 as filter processing data storage area. The sensor is defined by for loop int i=0; i<1; i++ and N value int N=i. The sensor probe is started with int N=1, and R1 is used as a data pointer to point to the filter processing data storage area ADTURN2. The system can turn on the Nth probe with printf("%d probe has been turned on\n",N), and the N value changes from 1 to 36 cycles with the program, so as to complete the switching calculation of different probes in the main program. Call the data acquisition subroutine to control multiple groups of weak magnetic sensors, multiple groups of hardware filtering systems, multiple groups of infrared transmission systems, and analog / digital converters to complete the system functions of weak magnetic data acquisition, hardware filtering, infrared transmission, and analog / digital conversion, and store the collected and processed digital weak magnetic signals in the weak magnetic detection data storage area ADTURN1 to complete the preliminary acquisition of weak magnetic data. Then, the digital filtering subroutine is called to perform digital calculation and benchmark numerical processing on the digital weak magnetic signal in the weak magnetic detection data storage area ADTURN1, so as to realize further digital filtering of the digital weak magnetic signal, and store the filtered detection data in the filter processing data storage area ADTURN2 to wait for the system call. The R1 pointer points to the next storage space of the filter processing data storage area ADTURN2, and the N value count is increased by one, that is, the next detection probe is turned on, and the detection probe switching is further completed. Finally, the data judgment subroutine is called to use the matrix distribution equation to realize the location of oil and gas pipeline defect damage, compare the data in the filter processing data storage area ADTURN2 with the critical value set in the parameter setting, find out the weak magnetic detection probe that exceeds the critical value, and display the detection probe data and probe position in real time through the PC through the data group of the abnormal data address storage area ADTURN3 pointed by the R3 pointer and the abnormal data value storage area ADTURN4 pointed by the R4 pointer, so as to realize the stress damage degree detection and accurate damage positioning, and realize the synchronous warning of abnormal signals through the alarm system; The data acquisition subroutine first defines the high-intensity interference threshold High Value, the purpose is to directly eliminate the external large-value interference, so that the collected data is more reliable, assign 20 to R5, and use R0 as a data pointer to point to the first address ADTURN1 of the weak magnetic detection data storage area, and complete the definition of the interference threshold and the data storage area. Start the IN0 channel, and collect, filter, transmit and digitally convert the weak magnetic detection signal through multiple groups of weak magnetic sensors, multiple groups of hardware filtering systems, multiple groups of infrared transmission systems, and analog / digital converters. Then compare and analyze the R0 pointing value with the high-intensity interference threshold to determine whether the collected value is greater than the interference threshold. If the collected value is greater than the interference threshold, the data collected this time is abandoned, data collection is performed again, and the IN0 channel is restarted for analog / digital conversion. If the collected data is less than the interference threshold, the R5 count is reduced by one, and the R0 pointer points to the next storage unit, and the collected digital weak magnetic signal is judged for the interference threshold, and the collected data that meets the threshold is sent to the weak magnetic detection data storage area ADTURN1, so as to achieve the purpose of accurate collection and storage of the detection data. Finally, determine whether R5 is 0. If R5 is not 0, re-collect data and restart IN0 channel for analog / digital conversion. If R5 is 0, it means that the collection of digital weak magnetic signals has been completed, the data collection subroutine ends, and returns to the main program. Then, the collected data is subjected to hardware filtering, infrared transmission, and analog / digital conversion to form a digital weak magnetic signal, and the interference threshold is judged and sent to the weak magnetic detection data storage area ADTURN1 to wait for the system main program to call; The digital filtering subroutine first defines two maximum loop times and max loop2=60, clear registers R6 and R5, point R0 pointer to the first address ADTURN1 of the weak magnetic detection data storage area, and complete the definition of the maximum number of system cycles, registers and data storage areas. Assign the value pointed by R0 to R5 and point R0 to the next storage unit, judge the value pointed by R0 and the size of R5. If the value pointed by R0 is not greater than R5, the R5 value and the value pointed by R0 are swapped, and the counts of R5 and R6 are increased by one. If the value pointed by R0 is greater than R5, the counts of R5 and R6 are increased by one; judge whether R5 is equal to max loop2, if not, point R0 to the next storage unit, if equal, judge whether R6 is equal to max loop1; if not, clear R5, if equal, point R0 to the tenth value of the storage area, through the two cycles of max loop1 and max loop2, the digital weak magnetic signals collected by the weak magnetic detection data storage area ADTURN1 are arranged in order according to their numerical values. Define the reference number B to be equal to the value pointed to by R0, clear R2 and R5, point R0 to the first address ADTURN1 of the weak magnetic detection data storage area, subtract the reference number B from the value pointed to by R0 and add the value of R2, and assign it to R2. Use the weighted filtering and majority filtering mixed operations of a large amount of detection data to perform reference value processing on the sorted digital weak magnetic signal detection data through digital calculation, so as to achieve further digital filtering of the digital weak magnetic signal. Finally, point the R0 pointer to the next storage unit, add one to the R5 count, and determine whether R5 is equal to max loop2; if not, reassign R2; if equal, add the reference number to the R2 value and assign it to R2. The digital filtering subroutine ends and returns to the main program, and then further digitally filters the digital weak magnetic signal in the weak magnetic detection data storage area ADTURN1, and sends it to the R2 register after the reference value processing to wait for the system call; The data judgment subroutine first defines the abnormal data address storage area ADTURN3 and the abnormal data value storage area ADTURN4, and points the R1, R3, and R4 pointers to the filter processing data storage area first address ADTURN2, the abnormal data address storage area ADTURN3, and the abnormal data value storage area ADTURN4, respectively, and the R5 register is cleared to complete the definition of the storage area and the register. R5 counts plus one to determine whether the value pointed to by R1 is greater than the critical value; if greater, R1 is assigned to the position pointed to by R4 and the R5 value is assigned to the position pointed to by R3, and R3 and R4 are respectively pointed to the next storage unit to determine whether R5 is equal to 36. If not greater, directly determine whether R5 is equal to 36. Then compare and analyze the detection data after filtering in the filter processing data storage area ADTURN2 with the preset critical value. If not equal, R1 is pointed to the next storage unit and R5 is counted again and added by one to perform critical value judgment. If equal, R3 and R4 are respectively pointed to the first address ADTURN3 of the abnormal data address storage area and the first address ADTURN4 of the abnormal data value storage area, thereby completing the storage of data in the abnormal data value storage area ADTURN4 and the abnormal data address storage area ADTURN3. It is judged whether the value pointed to by R4 is 0, and abnormal detection data analysis and corresponding sensor storage unit analysis are performed in the two storage areas. Finally, if the values ​​pointed to by the R3 and R4 pointers are both equal to 0, it means that there is no abnormal data, and the PC is used to display "None" and return to the main program for a new round of data collection. If not 0, the PC displays the address *R3 and the value *R4, and points R3 and R4 to the next storage unit respectively. It is judged again whether the value pointed to by the R4 pointer is 0. If not equal to 0, the new address *R3 and data *R4 are displayed again. If equal to 0, the alarm system is started and returns to the main program for a new round of data collection. In this way, the detection data exceeding the critical value in the filtering processing data storage area ADTURN2 is found, and the detection data value and detection probe position in the abnormal data value storage area ADTURN4 pointed to by R4 and the abnormal data address storage area ADTURN3 pointed to by R3 are used as stress damage degree and damage location information, which are displayed in real time through a PC, and when there is a probe exceeding the critical value, the alarm system is turned on to form a real-time early warning function of the system.

2. According to claim 1, a weak magnetic method-based oil and gas pipeline stress damage monitoring system is characterized in that As described above, the multiple groups of weak magnetic sensors of the present invention adopt the HMC1021 model, and the circuit includes two comparators and multiple resistors and capacitors. The comparator is used to compare two input signals and judge the magnitude relationship of the input voltage, current or digital signal. In analog circuits, it is used for signal detection and shaping; in digital circuits, it can realize logical judgment. Resistors are used for voltage division and current limiting, and capacitors are used for charge storage, filtering, and coupling AC signals.

3. According to claim 1, a weak magnetic method-based oil and gas pipeline stress damage monitoring system is characterized in that The multi-group hardware filtering system of the present invention comprises two parts: a LM324 chip high-pass filter and a LM324 chip low-pass filter. The LM324 operational amplifier is mainly used for signal amplification. The high-pass filter attenuates signals below the cutoff frequency and allows signals above the cutoff frequency to pass through, thereby removing low-frequency noise and extracting rapidly changing signal components. The low-pass filter attenuates signals above the cutoff frequency and allows signals below the cutoff frequency to pass through, thereby removing high-frequency noise and smoothing signals.

4. According to claim 1, a weak magnetic method-based oil and gas pipeline stress damage monitoring system is characterized in that The multi-group infrared transmission system of the present invention comprises two parts: an 8050 chip infrared transmitting circuit and an LM386 chip infrared receiving circuit. The infrared transmitting circuit is used to convert the electrical signal into an infrared light signal and transmit it out, the 8050 transistor is used for signal amplification, and is also used for electronic switches to control the on and off of the circuit; the infrared receiving circuit is used to receive the infrared light signal emitted by the transmitting circuit, convert it into an electrical signal, and then amplify and filter it, and the LM386 power amplifier is used to amplify the input low-power signal to enhance the driving capability.

5. According to claim 1, a weak magnetic method-based oil and gas pipeline stress damage monitoring system is characterized in that The analog / digital converter of the present invention comprises an ADS1232 analog / digital conversion chip and a MAX4636 analog multi-way switch, wherein the ADS1232 analog / digital conversion chip is used to convert an analog signal into a digital signal, and quantize and encode the input analog quantity with high precision and high resolution, wherein a clock module is used to provide a synchronization signal for the system, and finally a PC displays an abnormal value and a probe position, and a power-off protection device is always in a protection state; the MAX4636 analog multi-way switch is used to realize switching and routing of different analog signal sources; the clock module is used to provide a synchronization signal for the digital system, and is also used for timing and controlling data transmission; the PC is used to display the value of the final abnormal data and the probe position; the power-off protection device is used to save data to prevent system program interruption and data loss due to power failure.

6. According to claim 1, a weak magnetic method-based oil and gas pipeline stress damage monitoring system is characterized in that The external memory of the present invention comprises a 74LS373 latch chip and a 628128 external memory chip. The 74LS373 chip is used to store and maintain input data under the control of an enable signal. The 628128 chip is used to meet large data storage and processing needs.

7. According to claim 1, a weak magnetic method-based oil and gas pipeline stress damage monitoring system is characterized in that The alarm system of the present invention comprises a 3DG6 NPN transistor, a 3AX81 PNP transistor and a buzzer. The transistor is used to amplify the alarm signal, control the on and off of the alarm device, and realize circuit logic control; the buzzer emits a sound alarm. When the system detects an abnormal or dangerous situation, the buzzer is driven to sound, which serves as a warning.

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