Polyethylene pipeline defect detection device and detection method based on microwave reflection

Abstract

The invention relates to a microwave reflection-based polyethylene pipeline defect detection device which comprises a shell, a PCB (printed circuit board) and a waveguide antenna are arranged in the shell, a voltage-controlled oscillator, a signal amplifier, a band-pass filter, a bidirectional detector chip and a single chip microcomputer which are sequentially connected are arranged on the PCB, the bidirectional detector chip is connected with the waveguide antenna, and the waveguide antenna is connected with the single chip microcomputer. The shell is provided with a display, and the single-chip microcomputer is connected with the LCD screen. The detection method comprises the following steps: step 1, obtaining a calibration microwave signal attenuation amount; 2, cleaning or performing surface treatment on the polyethylene natural gas pipeline to be detected; step 3, acquiring an actual microwave signal attenuation amount; and step 4, comparing the actual microwave signal attenuation amount with the calibrated microwave signal attenuation amount, and determining the position as the defect part of the polyethylene natural gas pipeline if the difference value between the actual microwave signal attenuation amount and the calibrated microwave signal attenuation amount exceeds a preset threshold value. According to the invention, the polyethylene natural gas pipeline can be detected in real time, and the detected result can be displayed on the LCD.

Description

Technical Field

[0001] The invention belongs to the technical field of pipeline detection, and in particular relates to a polyethylene pipeline defect detection device and a detection method based on microwave reflection. Background Art

[0002] With the continuous growth of global energy demand, natural gas, as a clean and efficient energy source, has become particularly important in terms of its transportation and supply system safety and reliability. As the main carrier of natural gas transportation, the safety and integrity of natural gas pipelines are directly related to public safety, environmental protection and the stability of energy supply. However, during the operation of polyethylene natural gas pipelines, due to corrosion, wear, material aging, construction defects and other factors, safety accidents such as leakage are prone to occur, which will not only cause huge economic losses, but also cause serious consequences such as fire and explosion, posing a serious threat to the safety of life and property and the ecological environment. Defects may occur during the service of polyethylene natural gas pipelines, causing safety problems, especially at the welding joints of the pipelines. However, the installation of pipelines is usually closely arranged or buried underground. When conducting inspections, some excavation work is required to expose the area to be inspected. The inspection operation space is small, and small inspection equipment is required to adapt to the working environment. Traditional polyethylene natural gas pipeline inspection methods mainly include ultrasonic inspection, magnetic particle inspection, X-ray inspection, magnetic leakage inspection, pressure testing, etc. These methods have their own advantages and disadvantages, but most of them have problems such as low detection efficiency, complex equipment, high cost, and poor real-time performance, which are difficult to meet the needs of modern polyethylene natural gas pipeline inspection. Summary of the invention

[0003] Therefore, the present invention aims to solve the problems of low detection efficiency, complex equipment, high cost and real-time performance in the prior art.

[0004] To this end, the technical solution adopted is that a polyethylene pipeline defect detection device based on microwave reflection of the present invention comprises: a shell, a PCB circuit board and a waveguide antenna are arranged in the shell, a voltage-controlled oscillator, a signal amplifier, a bandpass filter, a bidirectional detector chip and a single-chip microcomputer are arranged on the PCB circuit board, the bidirectional detector chip is connected to the waveguide antenna, a display is arranged on the shell, the single-chip microcomputer is connected to the LCD screen, the voltage-controlled oscillator generates a microwave signal, the signal is amplified by the signal amplifier, the bandpass filter extracts the signal, and the microwave signal is transmitted to the polyethylene pipeline through the waveguide antenna. The reflected microwave signal is transmitted to the bidirectional detector chip through the waveguide antenna. The bidirectional detector chip records the transmitted microwave signal and the received microwave signal, and performs a comparison operation to obtain the microwave attenuation, and transmits the microwave attenuation to the single-chip microcomputer. The single-chip microcomputer compares the microwave attenuation with the stored calibrated microwave attenuation to obtain the microwave attenuation difference. When the microwave attenuation difference is greater than the preset threshold, the LCD screen will display a defect alarm. .

[0005] Preferably, the bidirectional detector chip is connected to one end of a coaxial cable, the other end of the coaxial cable is connected to an SMA interface, and the SMA interface is connected to a waveguide antenna.

[0006] Preferably, a comparison operator and a digital-to-analog conversion chip are provided on the PCB circuit board, the bidirectional detector chip is connected to the comparison operator, the comparison operator is connected to the digital-to-analog conversion chip, and the digital-to-analog conversion chip is connected to the single-chip microcomputer.

[0007] Preferably, the housing is provided with a power button, a microwave power adjustment knob, an amplification gain adjustment knob, a single-chip computer program reset button and a power-on indicator light.

[0008] Preferably, the waveguide antenna is a combination of a rectangular waveguide and a horn antenna.

[0009] Preferably, the PCB circuit board is connected to the housing via screws.

[0010] A detection method, applicable to the polyethylene pipe defect detection device based on microwave reflection as mentioned above, comprising the following steps:

[0011] Step 1: Calibrate the device using a polyethylene natural gas pipeline reference specimen to obtain a calibrated microwave signal attenuation;

[0012] Step 2: Clean or perform surface treatment on the polyethylene natural gas pipeline to be tested;

[0013] Step 3: The probe of the detection device scans the detection area of ​​the polyethylene natural gas pipe to obtain the actual microwave signal attenuation;

[0014] Step 4: Compare the actual microwave signal attenuation with the calibrated microwave signal attenuation. If the difference between the two exceeds a preset threshold, the location is determined to be a defective part of the polyethylene natural gas pipeline.

[0015] Preferably, in step three, the vertical distance between the probe of the detection device and the detection area is maintained at 3 to 5 mm, and the scanning speed is 15 to 25 mm / s.

[0016] The technical solution of the present invention has the following advantages:

[0017] The invention is simple to operate, convenient to obtain results, and low in price. It can perform portable quick scanning on complex urban polyethylene natural gas pipelines in a handheld manner. When detecting pipeline welds in a targeted manner, a mechanical auxiliary part can be added to fix the microwave radio frequency part to improve the detection accuracy. The invention can perform real-time detection on polyethylene natural gas pipelines, and display the detected results on an LCD or on a mobile phone / computer through a wireless transmission chip.

[0018] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings.

[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0021] Figure 1 It is a usage state diagram of the present invention;

[0022] Figure 2 It is a schematic diagram of the structure of the present invention;

[0023] Figure 3 It is a schematic diagram of the workflow of the present invention;

[0024] Description of reference numerals:

[0025] 1. Shell; 2. PCB circuit board; 3. Waveguide antenna; 4. Voltage-controlled oscillator; 5. Signal amplifier; 6. Bandpass filter; 7. Bidirectional detector chip; 8. Single-chip microcomputer; 9. LCD screen; 10. Coaxial cable; 11. SMA interface; 12. Comparator; 13. Digital-to-analog conversion chip; 14. Power button; 15. Microwave power adjustment knob; 16. Amplification gain adjustment knob; 17. Single-chip microcomputer program reset button; 18. Power-on indicator light; 19. Polyethylene natural gas pipeline; 20. Welding seam. DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0027] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it can be directly on the other component or indirectly on the other component. When a component is referred to as being "connected to" another component, it can be directly or indirectly connected to the other component.

[0028] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0029] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0030] The present invention provides a polyethylene pipe defect detection device based on microwave reflection, such as Figure 1-3 As shown, it includes: a housing 1, a PCB circuit board 2 and a waveguide antenna 3 are arranged in the housing 1, a voltage-controlled oscillator 4, a signal amplifier 5, a bandpass filter 6, a bidirectional detector chip 7 and a single-chip microcomputer 8 are arranged on the PCB circuit board 2, and the bidirectional detector chip 7 is connected to the waveguide antenna 3 respectively. A display 9 is arranged on the housing 1, and the single-chip microcomputer 8 is connected to the LCD screen 9. The voltage-controlled oscillator 4 generates a microwave signal, which is amplified by the signal amplifier 5, and the bandpass filter 6 extracts the signal. The microwave signal is transmitted to the polyethylene pipe through the waveguide antenna 3, and the reflected microwave signal is transmitted to the bidirectional detector chip 7 through the waveguide antenna 3. The bidirectional detector chip 7 records the transmitted microwave signal and the received microwave signal, and performs a comparison operation to obtain the microwave attenuation, and transmits the microwave attenuation to the single-chip microcomputer 8. The single-chip microcomputer 8 compares the microwave attenuation with the stored calibrated microwave attenuation to obtain the microwave attenuation difference. When the microwave attenuation difference is greater than the preset threshold, the LCD screen 9 will display a defect alarm. The bidirectional detector chip 7 can detect bidirectional (transmitting / receiving) signals.

[0031] The working principle and beneficial technical effects of the above technical solution are as follows: hold the housing 1, align one end of the waveguide antenna 3 with the weld 20 or the detection area of ​​the polyethylene natural gas pipeline 19, and perform mobile scanning. The voltage-controlled oscillator 4 transmits the microwave signal through the waveguide antenna 3. If a defect is encountered, the reflection situation will change. The reflected signal is transmitted to the bidirectional detector chip 7 through the waveguide antenna 3. The bidirectional detector chip 7 can record the emitted microwave signal and the received emitted microwave signal, and perform a comparison operation to obtain the microwave attenuation. The microwave attenuation is transmitted to the single-chip microcomputer 8. The single-chip microcomputer 8 compares the microwave attenuation with the stored calibrated microwave attenuation to obtain the microwave attenuation difference. When the microwave attenuation difference is greater than the preset threshold, the LCD screen 9 will display a defect alarm.

[0032] In one embodiment, the bidirectional detector chip 7 is connected to one end of the coaxial cable 10, and the other end of the coaxial cable 10 is connected to the SMA interface 11, and the SMA interface 11 is connected to the waveguide antenna 3, and the SMA interface is a type of interface of the coaxial cable. A comparison operator 12 and a digital-to-analog conversion chip 13 are provided on the PCB circuit board 2, and the bidirectional detector chip 7 is connected to the comparison operator 12, and the comparison operator 12 is connected to the digital-to-analog conversion chip 13, and the digital-to-analog conversion chip 13 is connected to the single-chip computer 8. The bidirectional detector chip 7 adopts a bidirectional bridge structure inside to make it an ultra-wideband bidirectional detector, so as to measure the forward and reverse return losses simultaneously in one signal path, and the comparison operator 12 calculates the voltage value of the incident and reflected microwave signals, calculates the attenuation thereof and inputs it into the digital-to-analog conversion chip 13, and converts the voltage analog signal into a digital signal and inputs it into the single-chip computer 8.

[0033] In one embodiment, the housing 1 is provided with a power button 14, a microwave power adjustment knob 15, an amplification gain adjustment knob 16, a single-chip program reset button 17, and a power-on indicator light 18. The power button 14 is used to control the power supply of the detection device. The microwave power adjustment knob 15 can be used to adjust the control voltage of the voltage-controlled oscillator source, thereby adjusting the microwave power and frequency; the amplification gain adjustment knob 16 can be used to adjust the control voltage of the variable gain amplifier VGA, thereby adjusting the amplification gain of the microwave power, and obtaining a microwave signal with a larger power range; the power-on indicator light 18 can indicate whether the power is turned on normally; the single-chip program reset button 17 can reset the control system program, which is convenient for resetting the detection program of the system during the test process, and can also be reset and re-detected when an error occurs during the detection process.

[0034] The waveguide antenna 3 is a combination of a rectangular waveguide and a horn antenna, with a gain of 17.3 dB and a return loss of -45.6 dB at 10 GHz. The microwave signal generated is sufficient to penetrate the polyethylene pipe wall, and the return signal loss is small, which can better reflect the true situation of the defect. The PCB circuit board 2 is connected to the housing 1 by screws, which is convenient for the installation and removal of the circuit board.

[0035] Data collection and analysis:

[0036] The signal processing part is mainly composed of a bidirectional detector chip 7, a comparison operator 12, and a digital-to-analog conversion chip 13. The bidirectional bridge structure used in the bidirectional detector chip 7 makes it an ultra-wideband bidirectional detector, which can simultaneously measure the forward and reverse power levels and return loss in one signal path. The comparison operator can calculate the voltage values ​​of the incident and reflected microwave signals, calculate their attenuation and input them into the digital-to-analog conversion chip, and convert the voltage analog signal into a digital signal and input it into the control part.

[0037] The control part is mainly composed of circuit structures such as the main control chip module, LCD display module, ESP8266 chip and WiFi module. The main control chip module uses the STM32F103ZET6 chip, which processes the input digital signal through built-in programming to obtain the corresponding microwave energy attenuation, which is displayed in real time on the LCD screen 9 and can be wirelessly transmitted to the host computer through the ESP8266 chip and WiFi module. The LCD display module is composed of LCD1602 and its peripheral circuits, which are used to measure the voltage value and the display of the attenuation. The ESP8266 chip and WiFi module are used to communicate with the host computer.

[0038] The main functions of the host computer system are: first, it mainly provides the wireless transmission entrance of the ESP8266 chip and the WiFi module to receive data; second, it can store the data after collection, expand the detection samples through a large number of experiments, summarize the rules for comparative analysis, and store data. Third, data playback reads the detected data in the host computer for post-processing.

[0039] A detection method, applicable to the polyethylene pipe defect detection device based on microwave reflection, comprises the following steps:

[0040] Step 1: Investigate the nominal diameter, wall thickness, material composition, process and surface quality of the object to be tested, prepare equipment, and evaluate the possibility and value of testing. Measure the nominal diameter and wall thickness of the object to be tested on site to determine its shape and location. The natural gas pipelines tested are generally made of polyethylene materials, with grades of PE80 and PE100, and a diameter of 60-300mm.

[0041] Step 2: Calibrate the device using a polyethylene natural gas pipeline reference specimen to obtain a calibrated microwave signal attenuation.

[0042] Step 3: Clean or surface treat the polyethylene natural gas pipeline to be tested; use special tools to remove welds or perform surface treatment on the outer surface of the object to be tested. The scanning area of ​​the detection surface probe should be free of protrusions, debris, dirt and other impurities that may interfere with microwave detection. If necessary, perform mechanical surface treatment technology to ensure surface quality and reduce detection errors.

[0043] Step 4: The probe of the detection device scans the detection area of ​​the polyethylene natural gas pipe to obtain the actual microwave signal attenuation; the vertical distance between the probe of the detection device and the detection area is maintained at 3 to 5 mm, and the scanning speed is 15 to 25 mm / s to obtain more accurate detection results.

[0044] Step 5: Compare the actual microwave signal attenuation with the calibrated microwave signal attenuation. If the difference between the two exceeds the preset threshold, the location is determined to be a defective part of the polyethylene natural gas pipeline. The microcontroller displays the detected microwave energy attenuation in the form of a digital / waveform graph on the LCD screen, or uploads it to a mobile phone / computer or other host computer through a wireless transmission chip for display.

[0045] Step 6: Evaluate the test results. It is necessary to distinguish the location, size and type of defects based on the test results. For areas with uncertain test results, repeated testing is required to determine whether the polyethylene natural gas pipeline can continue to serve.

[0046] Step 7. Save the sample data. Through a large amount of test data, collect and save the different test results presented by different defects. Compare and analyze them to calibrate the test results and distinguish the types of defects more clearly. With the horizontal axis as the distance unit (mm) and the vertical axis as the signal attenuation (V), peaks / troughs will appear in the defective area. The location of the defect can be determined by combining the horizontal axis distance and the initial position. The size / length of the defect can be determined by the duration of the peak / trough. The type of defect can be determined by comparing it with the result of step 2 calibration.

[0047] The beneficial technical effects of the above technical solution are as follows: the detection method can quickly scan polyethylene natural gas pipelines, obtain results conveniently, and effectively reduce the professional requirements for users. It has high social significance and economic value for the detection of large and complex polyethylene natural gas pipeline networks and the reduction of corresponding pipeline accidents. It can realize wireless transmission of detection data and storage in the upper computer, which is of great significance for increasing detection samples, summarizing detection results, and conducting comparative analysis and reliability evaluation of polyethylene natural gas pipelines.

[0048] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A polyethylene pipe defect detection device based on microwave reflection, characterized in that: include: A housing (1) is provided with a PCB circuit board (2) and a waveguide antenna (3) in the housing (1); a voltage-controlled oscillator (4), a signal amplifier (5), a bandpass filter (6), a bidirectional detector chip (7) and a single-chip microcomputer (8) which are connected in sequence are provided on the PCB circuit board (2); the bidirectional detector chip (7) is connected to the waveguide antenna (3); an LCD screen (9) is provided on the housing (1); the single-chip microcomputer (8) is connected to the LCD screen (9); the voltage-controlled oscillator (4) generates a microwave signal, the signal is amplified by the signal amplifier (5), and the bandpass filter (8) generates a microwave signal. 6) extracting the signal, transmitting the microwave signal to the polyethylene pipe via the waveguide antenna (3), transmitting the reflected microwave signal to the bidirectional detector chip (7) via the waveguide antenna (3), recording the transmitted microwave signal and the received microwave signal, performing a comparison operation to obtain the microwave attenuation, transmitting the microwave attenuation to the single-chip microcomputer (8), and comparing the microwave attenuation with the stored calibrated microwave attenuation to obtain the microwave attenuation difference. When the microwave attenuation difference is greater than a preset threshold, the LCD screen (9) will display a defect alarm.

2. A polyethylene pipe defect detection device based on microwave reflection according to claim 1, characterized in that: The bidirectional detector chip (7) is connected to one end of a coaxial cable (10), the other end of the coaxial cable (10) is connected to an SMA interface (11), and the SMA interface (11) is connected to a waveguide antenna (3).

3. The polyethylene pipe defect detection device based on microwave reflection according to claim 1 is characterized in that: A comparison operator (12) and a digital-to-analog conversion chip (13) are arranged on the PCB circuit board (2); the bidirectional detector chip (7) is connected to the comparison operator (12); the comparison operator (12) is connected to the digital-to-analog conversion chip (13); and the digital-to-analog conversion chip (13) is connected to the single-chip computer (8).

4. The polyethylene pipe defect detection device based on microwave reflection according to claim 1 is characterized in that: The housing (1) is provided with a power button (14), a microwave power adjustment knob (15), an amplification gain adjustment knob (16), a single-chip computer program reset button (17) and a power-on indicator light (18).

5. The polyethylene pipe defect detection device based on microwave reflection according to claim 1 is characterized in that: The waveguide antenna (3) is in the form of a combination of a rectangular waveguide and a horn antenna.

6. The polyethylene pipe defect detection device based on microwave reflection according to claim 1 is characterized in that: The PCB circuit board (2) is connected to the housing (1) via screws.

7. A detection method, applicable to a polyethylene pipe defect detection device based on microwave reflection as claimed in any one of claims 1 to 6, characterized in that: The steps include: Step 1: Calibrate the device using a polyethylene natural gas pipeline reference specimen to obtain a calibrated microwave signal attenuation; Step 2: Clean or perform surface treatment on the polyethylene natural gas pipeline to be tested; Step 3: The probe of the detection device scans the detection area of ​​the polyethylene natural gas pipe to obtain the actual microwave signal attenuation; Step 4: Compare the actual microwave signal attenuation with the calibrated microwave signal attenuation. If the difference between the two exceeds a preset threshold, the location is determined to be a defective part of the polyethylene natural gas pipeline.

8. A detection method according to claim 7, characterized in that: In step three, the vertical distance between the probe of the detection device and the detection area is maintained at 3 to 5 mm, and the scanning speed is 15 to 25 mm / s.

Images