CN209876531U - Pipeline leakage acoustic emission signal detection system - Google Patents
Pipeline leakage acoustic emission signal detection system Download PDFInfo
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- CN209876531U CN209876531U CN201920785293.7U CN201920785293U CN209876531U CN 209876531 U CN209876531 U CN 209876531U CN 201920785293 U CN201920785293 U CN 201920785293U CN 209876531 U CN209876531 U CN 209876531U
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Abstract
The utility model discloses a pipeline leaks acoustic emission signal detecting system, this system mainly comprises following circuit module: the device comprises an acoustic emission sensor, a front-end amplifying circuit, a band-pass and band-stop filter circuit, a single-ended-to-differential signal circuit, a high-precision A/D conversion circuit, a Beidou time service module, 1# and 2# microprocessors, a double-port RAM (random access memory) memory, a PHY (physical layer) module, a wireless WIFI (wireless fidelity) module, a monitoring center server and the like. The system can realize the synchronous data acquisition and wireless transmission functions of the pipeline leakage acoustic emission signals, thereby timely, accurately and effectively positioning the pipeline leakage position.
Description
Technical Field
The utility model particularly relates to a pipeline leaks acoustic emission signal detecting system belongs to pipeline leakage detection technical field.
Background
The pipeline is used as a main channel for conveying liquid and gas media, and plays a great role in national economy. However, with the rapid increase of pipelines, the increase of the age of the pipelines, and inevitable natural or artificial damages such as corrosion and abrasion, pipeline leakage accidents happen successively, which poses serious threats to the life and property safety of people. Therefore, the timely and accurate positioning of the pipeline leakage position is of great significance to the actual engineering production.
At present, the means for detecting and checking the pipeline mainly comprise an in-pipeline detector, a pipeline manual inspection method, a portable instrument and meter and the like, but the methods cannot be well applied to pipeline leakage detection because the methods influence normal material conveying, or have high investment cost, poor real-time performance or cannot realize continuous detection. Although conventional nondestructive testing (such as ultrasonic testing, magnetic flux leakage testing, etc.) techniques are mature, these testing techniques have significant defects: the detection process is point-by-point scanning, the detected equipment must be stopped when being detected, the detection efficiency is low, and the method is difficult to be effectively applied to industrial pipelines.
Research shows that when the pipeline leaks, fluid is sprayed outwards through cracks or corrosion holes and interacts with the pipeline to form an acoustic emission source; by detecting the acoustic emission signals and processing the signal data, the pipeline leakage points can be positioned, so that the method is widely concerned by scientific and technical personnel as a dynamic nondestructive testing technology. However, the pipeline leakage detection system based on the acoustic emission signal in the prior art has the problems of low sensitivity, low data acquisition, processing and transmission speed, asynchronous data and the like, so that adverse effects are caused on timely and accurate positioning and judgment of a pipeline leakage point.
Disclosure of Invention
The utility model provides a not enough to prior art, the utility model provides a can detect pipeline leakage acoustic emission signal's system, this system can gather in real time and analysis processes the acoustic emission signal that the leakage arouses to the leakage position in the quick accurate positioning pipeline.
The technical scheme of the utility model as follows: the pipeline leakage acoustic emission signal detection system comprises an acoustic emission signal synchronous data acquisition module, a wireless transmission module and a monitoring center server; the acoustic emission signal synchronous data acquisition module comprises an acoustic emission sensor, a front-end amplification circuit, a band-pass and band-stop filter circuit, a single-end-to-differential signal circuit, a high-precision A/D conversion circuit, a first microprocessor and a Beidou time service module; the Beidou time service module is connected with the first microprocessor; the wireless transmission module comprises a double-port RAM memory, a second microprocessor, a PHY module and a wireless WIFI module which are sequentially connected; the output end of the first microprocessor is connected with the input end of the double-port RAM memory; the acoustic emission sensor converts a received acoustic emission signal into an analog voltage signal and sends the analog voltage signal to the front-end amplifying circuit, the front-end amplifying circuit outputs the amplified signal to the band-pass and band-stop filter circuit, the band-pass and band-stop filter circuit filters the amplified signal and then outputs a single-ended signal to the single-ended-to-differential signal circuit, the single-ended-to-differential signal circuit outputs a differential signal to the high-precision A/D conversion circuit to obtain a digital signal, the first microprocessor receives the digital signal and sends the digital signal to the dual-port RAM memory, and the second microprocessor reads data from the dual-port RAM memory in real time and sends the data to the monitoring center server through the PHY module and the wireless WIFI module for analysis and processing; the Beidou time service module receives satellite clock signals through an antenna and carries out time calibration on the data acquisition module.
Further, the model of the acoustic emission sensor is SR10B, and the range of detectable acoustic emission signals is 1Hz ~ 15 kHz.
Furthermore, the band-pass and band-stop filter circuit comprises a second-order band-pass filter and a double-T type active band-stop filter, wherein the second-order band-pass filter comprises a second-order voltage-controlled active high-pass filter and a second-order voltage-controlled active low-pass filter which are formed by a precise operational amplifier NEC5532, the pass band frequency of the second-order voltage-controlled active high-pass filter is 1Hz ~ 10kHz, and the center frequency of the double-T type active band-stop filter is 50 Hz.
Furthermore, the single-ended to differential signal conversion circuit adopts an AD8318 operational amplifier chip to convert the 0-5V single-ended signal into a +/-2.5V differential voltage signal.
Furthermore, the high-precision A/D conversion circuit adopts a 16-bit successive approximation ADS8422IPFBR as an A/D conversion chip.
Furthermore, the model of the Beidou time service module is SKG17 DT.
Further, the model of the first microprocessor and the model of the second microprocessor are STM32F407, and the model of the dual-port RAM memory is DT7024L20 GB.
Further, the chip model of the PHY module is DP83848, and is connected to the second microprocessor through an RMII interface.
Furthermore, the model of the WIFI wireless module is WF7233, and is connected with the PHY module through an RJ45 interface.
Has the advantages that: the utility model discloses a carry out acoustic emission signal detecting system that the optimal combination constitutes with high sensitive acoustic emission sensor and other each functional circuit module, mainly accomplish two functions, acoustic emission signal's synchronous acquisition and the wireless transmission function of data promptly, it can leak the pipeline that gathers acoustic emission data and send the surveillance center server in real time and carry out analysis and processing. Considering that the sampling rate of the acoustic emission signals is high and the data transmission amount is large, the design adopts two microprocessors to synchronously acquire the signals and wirelessly transmit the data respectively, so that the acoustic emission signals of the pipeline leakage can be timely and accurately acquired and sent to the monitoring center server; the Beidou time service module receives satellite clock signals through the antenna and carries out time calibration on the data acquisition modules, and synchronous acquisition of data is achieved.
Drawings
FIG. 1 is a general block diagram of a pipe leakage acoustic emission signal detection system.
Figure 2 is a schematic diagram of a bandpass filter circuit.
FIG. 350 Hz band stop filter circuit schematic.
Fig. 4 is a schematic diagram of a single-ended to differential signaling circuit.
FIG. 5 is a connection diagram of the A/D converter and the 1# microprocessor.
FIG. 6 is a clock synchronization error test chart of two Beidou time service modules.
Fig. 7 is a WIFI-based wireless data transmission hardware connection diagram.
Detailed Description
The invention will be explained and explained in detail with reference to the drawings attached to the specification.
The pipeline leakage acoustic emission signal detection system mainly comprises three parts: the system comprises an acoustic emission signal synchronous data acquisition part, a wireless transmission part and a monitoring center server, and the overall block diagram of the system is shown in figure 1. The core of the acoustic emission signal synchronous data acquisition part is an acoustic emission signal synchronous acquisition module; the core of the wireless transmission part is a wireless data transmission module.
Each functional module of the system mainly comprises the following circuit modules: the system comprises an acoustic emission signal sensor, a front-end amplifying circuit, a band-pass and band-stop filter circuit, a single-end-to-differential signal circuit, a high-precision A/D conversion circuit, a Beidou time service module, 1# and 2# microprocessors, a double-port RAM (random access memory) memory, a PHY (physical layer) module, a wireless WIFI (wireless fidelity) module, a monitoring center server and the like. The method comprises the steps that firstly, an acoustic emission signal sensor converts an acoustic emission signal into a weak analog voltage signal, then the signal is amplified through a front-end amplifier, then the signal is filtered through a band-pass and band-stop filter circuit, the filter circuit is used for filtering other noise signals except the frequency of the acoustic emission signal, a filtered single-ended signal is converted into a differential signal through a single-ended to differential signal circuit, then the differential signal is input into a high-precision A/D converter for conversion, and then a 1# microprocessor is used for transmitting the digital signal after A/D conversion to a double-port RAM storage buffer area in real time through a left port of the double-port RAM. After the 1# microprocessor sends 4k × 16 bit data, a data reading control command is sent to the 2# microprocessor, and the 2# microprocessor can read the data. After the 2# microprocessor reads data from the dual-port RAM port in real time, the data are sent to the PC server end of the monitoring center through the PHY module and the wireless WIFI module to be stored and analyzed. The Beidou time service module receives satellite clock signals through the antenna and carries out time calibration on the data acquisition modules, and synchronous acquisition of data is achieved.
(1) Acoustic emission sensor and preceding stage amplifier circuit selection
According to the frequency characteristic of an acoustic emission signal when the pipeline leaks, the system selectively uses an SR10B acoustic emission sensor, the sensor belongs to an ultra-low frequency acoustic emission sensor, the range of the acoustic emission signal which can be detected is 1Hz ~ 15kHz, and the acoustic emission signal when the pipeline leaks is in the range, because the SR10B acoustic emission sensor adopts a high-quality stainless steel shell shielding design, the external interference can be effectively reduced, and the contact surface of the sensor adopts a ceramic material coated film, the shell and a measured object are effectively isolated electromagnetically.
The voltage signal output by the acoustic emission sensor is a microvolt level signal, which cannot be directly collected and transmitted, and needs to be amplified. The sensor is provided with a universal front-end amplifier, and the amplifier has gains selectable in three stages of 20dB, 40dB and 60 dB; the signal input mode can be selected to be single-ended input or differential input.
(2) Acoustic emission signal conditioning circuit design
The signal output by the preamplifier contains external noise and 50Hz power frequency noise, and the external noise needs to be filtered by a band-pass filter circuit, and the 50Hz power frequency noise is filtered by a band-elimination filter circuit; in addition, the a/D converter adopted in the design is an a/D conversion chip for inputting differential signals, so that the filtered single-ended signal needs to be converted into a differential signal.
The filter in the design adopts a second-order band-pass filter, and the circuit schematic diagram of the filter is shown in FIG. 2.
The designed band-pass filter circuit is composed of a precise operational amplifier NEC5532, because the frequency of a pipeline leakage acoustic emission signal is mainly concentrated on about 1Hz ~ 10kHz, the frequency band is wide, in order to obtain a better effect, a second-order filter with better attenuation characteristic is adopted, the attenuation slope of a transition band is increased, and the performance of the filter is closer to an ideal condition, therefore, the NEC5532 is adopted to form a second-order voltage-controlled active high-pass filter and a second-order voltage-controlled active low-pass filter, and the pass-band frequency is 1Hz ~ 10 kHz.
Wherein, the first-order filter is a high-pass filter, and the high-pass cut-off frequency is:
the second-stage filter is a low-pass filter, and the low-pass cut-off frequency is as follows:
the 50Hz interference of the commercial power supply is the main interference of the pipeline leakage acoustic emission signal, so the design adopts a band elimination filter with the center frequency of 50 Hz. The schematic circuit diagram is shown in fig. 3.
The circuit is an active band elimination filter with double T types, and the double T type active band elimination filter has good frequency selection characteristics. To reduce the width of the stop band and improve the selectivity, the center frequency should be adjustedf 0The nearby amplitude is increased, so the band elimination filter introduces positive feedback in the circuit and obviously improves the notch characteristic, which is different from the prior double T filter. R22And C22Can be determined by the center frequencyTo be determined. When in usef 0R at 50Hz22And C22680k Ω and 4.7nF were taken, respectively. The varistor RV is used to regulate the value of the quality factor Q.
Because the A/D converter chip selected in the system is used as differential signal input, and the output of the filter circuit is single-ended signal. So that the filtered pipe leakage acoustic emission signal needs to be further processed before a/D conversion. The design adopts a circuit for converting a single-ended signal into a differential signal based on AD8318, and a schematic diagram of the circuit is shown in FIG. 4.
The AD8318 is an operational amplifier chip specially used for converting a single-end signal into a differential signal, the differential output of the operational amplifier chip is helpful for balancing the input of a differential A/D converter, and the A/D conversion performance is maximized, in the circuit, a resistor R11 takes 499 omega, a resistor R13 takes 523 omega, and a resistor R18 takes 49.9 omega, and the circuit can convert the single-end signal of 0 ~ 5V into a differential voltage signal of plus or minus 2.5V.
(3) High precision A/D conversion circuit design
The A/D conversion circuit can convert the acoustic emission voltage analog signal of the pipeline leakage into a digital signal, which is an important component in a signal detection system, the conversion speed and the conversion precision of the analog signal determine the real-time performance and the accuracy of the detected signal, the frequency range of the acoustic emission signal of the pipeline leakage is 1Hz-10kHz, the conversion speed of an A/D converter should reach more than 100kHz according to the sampling theorem and the requirement of the system precision, the conversion precision is determined by the number of bits of the A/D converter, a 16-bit A/D conversion chip can meet the requirement of the system precision, ADS8422IPFBR of TI company is finally selected as the A/D conversion chip of the design by comparing the performances of various types of A/D converters, the chip is a 16-bit successive approximation type A/D converter, the differential input voltage range is-4V ~ +4V, and the sampling rate can reach 4MHz, and a connection diagram of the A/D converter and a 1# microprocessor in the design is shown in FIG. 5.
The regulated acoustic emission signal of the pipeline leakage is a differential signal, the regulated acoustic emission signal is input by + IN and-IN of the ADS8422IPFBR, and the converted 16-bit digital quantity is transmitted to a parallel interface of the 1# microprocessor through a DB0 ~ DB15 pin, other control pins are connected with corresponding pins of the 1# microprocessor, it is noted that a reference voltage output pin REFUT of the ADS8422IPFBR needs to be connected to a reference voltage input pin REFIN, a 0.1 muf capacitor and a 1 muf capacitor are connected between the REFUT pin and GND to filter the influence of high-frequency noise, so that the reference voltage is more stable, meanwhile, the REFM is connected to an analog ground, a +5V single power supply is used for an analog power supply pin + VA and a regulated power supply + VAADSG of the ADSFBR 2, a 3.3V voltage is used for the digital power supply pin VBD, and a 10 muf capacitor and a 0.1 muf capacitor are connected to filter the noise of each group of power supply to stabilize the power supply and the high-frequency noise.
(4) Data synchronous acquisition control module design
The data synchronous acquisition control function is completed by adopting a Beidou time service module, and after the Beidou time service module receives satellite signals, pulse per second signals and UTC time are output, so that the data synchronous acquisition of a plurality of acoustic emission signal acquisition modules is realized. According to the design, the SKG17DT high-performance Beidou time service module is adopted to realize synchronous acquisition of pipeline leakage acoustic emission signal data. Through pulse per second 1PPS signal of big dipper time service module output, can realize gathering the signal data synchronization of a plurality of collection passageways. The synchronous error between the pulse per second signals of the two Beidou time service modules is tested and compared. Tests show that the clock synchronization errors of the two Beidou time service modules are within 1 mu s, the data synchronization acquisition requirements of system design are met, and a test chart is shown in fig. 6.
(5) Data cache circuit design
Considering that the sampling rate of the pipeline leakage acoustic emission signal is high and the data transmission amount is large, the design adopts two microprocessors to synchronously acquire the signal and wirelessly transmit the data respectively, the 1# microprocessor is mainly used for acquiring the data, and the 2# microprocessor is mainly used for sending the data. Both the 1# and 2# microprocessors employ STM32F 407. In the process of collecting and sending the pipeline leakage acoustic emission signals at high speed in real time, the requirement on the stability of data is very high; the system requires high data transmission speed and high real-time requirement. In order to enable 2 microprocessors to exchange data rapidly and stably, a data buffer memory DT7024L20GB, which is a high-speed 4K 16-bit static RAM, is connected between the 1# microprocessor and the 2# microprocessor.
(6) Wireless data transmission circuit design
The key of the acquisition and data transmission system of the pipeline leakage acoustic emission signal lies in the high-speed acquisition of the signal and the rapid transmission of mass data. According to the technical requirements of pipeline leakage detection, the system needs to adopt a data transmission mode of wireless communication, and has higher requirements on data transmission bandwidth, data transmission speed and stability. Therefore, the system adopts a wireless WIFI mode to transmit data, and the hardware connection mode is as shown in fig. 7.
The # 2 microprocessor is mainly used for data transmission, and adopts an STM32F407 chip, an Ethernet module is carried in the chip, and an RMII interface is supported to connect an external PHY chip to realize data transmission. The DP83848 is adopted as a PHY chip in the design, and is connected with the 2# microprocessor through an RMII interface to realize the network communication function. The DP83848 acquires the clock source through an external crystal oscillator, and the pins TXP, TXN, RXP, RXN realize the transmission and reception of data in network communication. Because this design adopts WIFI wireless communication mode to transmit data, consequently these four interfaces are used for connecting outside wireless module. The wireless module adopts an RJ 45-to-WIFI module, the model is WF7233, and due to the fact that hardware such as a WLAN MAC, a baseband processor and a radio frequency front end are integrated in the WF7233 wireless module, complete protocols such as an 802.11b/g/n WLAN protocol, a TCP/IP protocol and configuration management are provided, and the use is very convenient. The 2# microprocessor can conveniently access to a WIFI wireless network by using the PHY chip and the WF7233 wireless module, and wireless transmission of the pipeline leakage acoustic emission signal data is realized.
The WF7233 module is directly connected with the PHY chip through an RJ45 interface, and pipeline leakage acoustic emission signal data are uploaded to a monitoring center server in a wireless communication mode so that the server can analyze and process signals and accurately position leakage points.
In summary, the system mainly achieves two functions, namely synchronous acquisition of acoustic emission signals and wireless data transmission, and can transmit acquired pipeline leakage acoustic emission data to a monitoring center server in real time for analysis and processing. Considering that the sampling rate of the acoustic emission signals is high, and the data transmission amount is large, the two microprocessors are adopted in the design to synchronously acquire the signals and wirelessly transmit the data respectively, so that the pipeline leakage acoustic emission signals can be timely and accurately acquired and sent to the monitoring center server, and the pipeline leakage position can be timely, accurately and effectively positioned.
Claims (9)
1. Pipeline leaks acoustic emission signal detecting system, its characterized in that: the system comprises an acoustic emission signal synchronous data acquisition module, a wireless transmission module and a monitoring center server; the acoustic emission signal synchronous data acquisition module comprises an acoustic emission sensor, a front-end amplification circuit, a band-pass and band-stop filter circuit, a single-end-to-differential signal circuit, a high-precision A/D conversion circuit, a first microprocessor and a Beidou time service module; the Beidou time service module is connected with the first microprocessor; the wireless transmission module comprises a double-port RAM memory, a second microprocessor, a PHY module and a wireless WIFI module which are sequentially connected; the output end of the first microprocessor is connected with the input end of the double-port RAM memory; the acoustic emission sensor converts a received acoustic emission signal into an analog voltage signal and sends the analog voltage signal to the front-end amplifying circuit, the front-end amplifying circuit outputs the amplified signal to the band-pass and band-stop filter circuit, the band-pass and band-stop filter circuit filters the amplified signal and then outputs a single-ended signal to the single-ended-to-differential signal circuit, the single-ended-to-differential signal circuit outputs a differential signal to the high-precision A/D conversion circuit to obtain a digital signal, the first microprocessor receives the digital signal and sends the digital signal to the dual-port RAM memory, and the second microprocessor reads data from the dual-port RAM memory in real time and sends the data to the monitoring center server through the PHY module and the wireless WIFI module for analysis and processing; the Beidou time service module receives satellite clock signals through an antenna and carries out time calibration on the data acquisition module.
2. The system for detecting pipe leakage acoustic emission signals of claim 1, wherein said acoustic emission sensor is model SR10B, and the detectable acoustic emission signal is in the range of 1Hz ~ 15 kHz.
3. The pipeline leakage acoustic emission signal detection system according to claim 1, wherein the band-pass and band-stop filter circuit comprises a second-order band-pass filter and a double-T type active band-stop filter, the second-order band-pass filter comprises a second-order voltage-controlled active high-pass filter and a second-order voltage-controlled active low-pass filter which are formed by a precision operational amplifier NEC5532, the pass-band frequency of the second-order voltage-controlled active high-pass filter is 1Hz ~ 10kHz, and the center frequency of the double-T type active band-stop filter is 50 Hz.
4. The pipe leak acoustic emission signal detection system of claim 1, wherein: the single-ended to differential signal circuit adopts an AD8318 operational amplifier chip to convert a 0-5V single-ended signal into a +/-2.5V differential voltage signal.
5. The pipe leak acoustic emission signal detection system of claim 1, wherein: the high-precision A/D conversion circuit adopts a 16-bit successive approximation ADS8422IPFBR as an A/D conversion chip.
6. The pipe leak acoustic emission signal detection system of claim 1, wherein: the model of the Beidou time service module is SKG17 DT.
7. The pipe leak acoustic emission signal detection system of claim 1, wherein: the model of the first microprocessor and the model of the second microprocessor are STM32F407, and the model of the double-port RAM memory is DT7024L20 GB.
8. The pipe leak acoustic emission signal detection system of claim 1, wherein: the chip model of the PHY module is DP83848, and the PHY module is connected with the second microprocessor through an RMII interface.
9. The pipe leak acoustic emission signal detection system of claim 1, wherein: the type of the WIFI wireless module is WF7233, and the WIFI wireless module is connected with the PHY module through an RJ45 interface.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114460177A (en) * | 2022-01-24 | 2022-05-10 | 北京科技大学 | Sensor array pressure vessel leakage wireless monitoring method and system based on 5G |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114460177A (en) * | 2022-01-24 | 2022-05-10 | 北京科技大学 | Sensor array pressure vessel leakage wireless monitoring method and system based on 5G |
| CN114460177B (en) * | 2022-01-24 | 2023-12-12 | 北京科技大学 | 5G-based sensor array pressure vessel leakage wireless monitoring method and system |
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