CN111664364B - Buried pipeline leakage online monitoring system and monitoring method - Google Patents

Abstract

The invention relates to an on-line monitoring system and a monitoring method for leakage of a buried pipeline, wherein N buried pipeline leakage on-line monitoring devices are parallelly arranged at a slave station, at least one commercial signal transmission module 4G/5G server end is arranged at a master station, the slave station and the master station are in wireless communication, the commercial signal transmission module 4G/5G server end is connected with the commercial server, a strip piezoelectric wafer of the on-line monitoring device is arranged on the near end face of a strip wave guide rod, and an ultrasonic signal transmitting/receiving module is connected with the strip piezoelectric wafer through a positive wire and a negative wire. The ultrasonic signal transmitting/receiving module, the signal conditioning module, the signal sampling module and the microcontroller module are integrated on the circuit board and controlled by the microcontroller module. The distal end face of the ribbon waveguide extends out of the housing and is inserted into the soil surrounding the pipe. During leakage monitoring, signals generated by the monitoring device are transmitted to the commercial server, and the data processing module installed in the commercial server compares the change of the signals to judge the leakage degree of the pipeline.

Description

Buried pipeline leakage online monitoring system and monitoring method

Technical Field

The invention relates to an on-line monitoring system and a monitoring method for leakage of a buried pipeline, in particular to an on-line monitoring system and judgment for leakage conditions of a buried water pipe and an oil conveying pipe, and belongs to the field of structural health monitoring in the field of pipelines in petrochemical industry, urban public use and the like. The method is suitable for long-distance large-area online long-term monitoring of buried pipeline leakage or for occasions where the viscous property of surrounding environment media can be changed due to pipeline leakage.

Background

Buried pipelines are widely applied to the fields of petrochemical industry, urban public use and the like, and the buried pipelines as long as tens of thousands of kilometers inevitably suffer load impact, earthquake, aging, external accidental damage and the like, which are main reasons for inducing leakage. The buried pipeline leakage is difficult to locate and monitor, is a great problem in operation and maintenance of an intricate and complex pipe network, brings an inconceivable challenge to safe operation and maintenance of the buried pipeline, if leakage cannot be stopped in time, the leakage of the pipeline can cause great economic loss, a large amount of oil leakage can cause serious pollution to the environment, and serious leakage can cause serious accidents such as explosion and the like, and even social disasters.

At present, the detection of the buried pipeline mainly comprises methods such as manual detection, listening method, negative pressure wave, acoustic emission, optical fiber measurement and the like. In the manual monitoring method, no matter the observation is carried out by naked eyes or vehicle-mounted inspection is carried out, the workload is very heavy, the leakage cannot be detected in time, and the unmanned aerial vehicle can only detect the running condition of the surface pipeline by using a GPS positioning system for inspection; the listening method is limited to that when the pipeline leakage reaches a certain degree, the leakage condition can be judged through sound, and the leakage cannot be found in time in the early stage; the negative pressure wave method can effectively detect a large amount of instantaneous leakage, but normal pressure waves and leakage are difficult to distinguish, so that the positioning accuracy is poor, and false alarm is easily caused; the acoustic emission is a passive detection method, the leakage condition is judged by using the weak change of the acoustic wave caused by the pipeline leakage, and the leakage cannot be reliably detected because the leakage sound is easily covered by background noise and flowing sound in the pipeline; the optical fiber measurement mainly depends on the change of temperature to judge the leakage condition, and the condition that the temperature of the surrounding environment can not be obviously changed due to medium leakage of the water pipeline and the oil pipeline can not be measured.

In order to timely detect the leakage state of the buried pipeline and guarantee the production safety, a large amount of research is carried out at home and abroad. ZL201610088117.9 discloses a leakage detection system and method for water supply and drainage pipes, wherein a composite pipe of the system comprises an inner insulating layer and an outer insulating layer, and leakage is identified by using resistance change of a conducting layer between the inner insulating layer and the outer insulating layer. The technology cannot meet the requirement of rapid detection of large-range pipelines; KP 1020170005401 discloses a continuous leak location detection system that transmits acoustic signals of water leakage from water supply pipelines from the ground through a wireless network, and determines the possibility of water leakage using an acoustic information analysis operation terminal. The method effectively reduces the workload of detection personnel and enlarges the monitoring range, but the method still judges the water leakage condition based on the acoustic signal and cannot eliminate the interference of environmental noise; JP2018013407 discloses a water leakage detection system which works according to the principle that a water leakage detector and a detection belt are short-circuited due to water leakage around the water leakage detector, and detects the possibility of water pipe leakage. The method is more suitable for detecting the leakage of the water pipeline with a more definite leakage position, but the pipeline with an indefinite leakage position cannot be monitored; CN201510166892.7 discloses an oil-leakage detection device and method for an oil-conveying pipeline, which uses the liquid pressure change at the leakage and blockage position in the oil-conveying pipeline to locate the abnormal position in the pipe, compared with the negative pressure wave method, the method has no substantial improvement, and also has poor location accuracy, which is easy to cause false alarm; JP2017145036 discloses an underground pipe laying double-shell leakage detecting system and an underground tank double-shell structure, when the system monitors, a leakage detecting device is formed by using two layers of pipelines and a plurality of leakage detecting sensors at a position to be monitored, a Wi-Fi control alarm system is built, and related personnel are timely informed of oil leakage information, and the device is complex in structure, numerous in equipment and not suitable for pipelines with undefined leakage positions.

In order to make up for the defects, the invention designs an online monitoring device and an online monitoring method for leakage of a buried pipeline. The device is simple in structure and easy to install, long-distance efficient intelligent monitoring of oil and water pipelines can be achieved by the method, the difficulty that complex pipelines are difficult to locate and monitor in leakage is overcome, and the safety prevention capability of the pipelines is improved.

Disclosure of Invention

The invention aims to solve the technical problem of providing a reliable and quick online system and a monitoring method for buried oil pipelines or water pipeline leakage.

The invention is realized by the following technical scheme:

an online buried pipeline leakage monitoring system is characterized by comprising N sets of online buried pipeline leakage monitoring devices 22, a commercial signal transmission module 4G/5G server end 24 and a commercial server 25 with a data processing module 26, wherein the N sets of online buried pipeline leakage monitoring devices 22 are parallelly arranged at the positions of slave stations, at least one commercial signal transmission module 4G/5G server end 24 is arranged at the position of a master station, the slave stations and the master station are in wireless communication, the commercial signal transmission module 4G/5G server end 24 is connected with the commercial server 25, and N is greater than or equal to 2;

the buried pipeline leakage online monitoring device 22 comprises: the ultrasonic signal transmitting/receiving module 12, the signal conditioning module 3, the signal sampling module 4, the signal transmission module 4G/5G client 14 and the microcontroller module 13 are integrated on the circuit board 15, the microcontroller module 13 controls the working sequence of the ultrasonic signal transmitting/receiving module 12, the signal conditioning module 3, the signal sampling module 4 and the signal transmission module 4G/5G client 14, the battery 2 supplies power to the circuit board 15, the circuit board 15 is installed in the shell 10 and sealed by the left shell cover 16 and the right shell cover 1; the first clip 9 and the second clip 18 on the housing 10 fix the proximal end face 20 of the ribbon waveguide 7 in the housing 10 by means of the bolt 8, the strip piezoelectric wafer 6 is tightly fitted on the proximal end face 20 of the ribbon waveguide 7, the ultrasonic signal transmitting/receiving module 12 is connected to the strip piezoelectric wafer 6 via the positive wire 5 and the negative wire 11, and the distal end face 21 of the ribbon waveguide 7 protrudes out of the housing 10 and is inserted into the soil around the pipe.

The length l, the thickness d and the width w of the ribbon waveguide rod 7 need to satisfy the following conditions: the length l is in the range of (0.1m, 2m), the thickness d and the width w are related to the wavelength lambda of the ultrasonic signal of the ribbon waveguide rod 7, the width w is greater than 6 lambda, and the thickness d is less than 1.5 lambda.

The length lp and the width wp of the narrow strip piezoelectric wafer 6 need to satisfy the following conditions: the ratio of the length lp of the strip piezoelectric wafer 6 to the width w of the strip waveguide 7 should satisfy the relational expression that lp/w is 0.9-1, and the width wp of the strip piezoelectric wafer 6 should be equal to the thickness d of the strip waveguide 7.

The invention also provides an online monitoring method for leakage of the buried pipeline, which comprises the following steps:

distributing the N buried pipeline leakage online monitoring devices 22 at different monitoring points, wherein a signal acquired by the first online monitoring device 22 is a reference signal for leakage judgment, and measurement signals of the other N-1 online monitoring devices 22 are compared with the reference signal in real time to judge the leakage condition of a monitoring position, so that one set of online monitoring system realizes online monitoring of the N-1 leakage positions;

in each buried pipeline leakage on-line monitoring device 22, an ultrasonic signal transmitting/receiving module 12 transmits a pulse signal to excite a narrow strip piezoelectric wafer 6 to generate an ultrasonic signal, the ultrasonic signal is transmitted in a strip-shaped waveguide rod 7 and generates a reflected echo when encountering a far-end surface 21 of the waveguide rod, the reflected echo is filtered and amplified by a signal conditioning module 3, the reflected echo is sampled by a signal sampling module 4 and transmitted by a signal transmission module 4G/5G client 14, the ultrasonic echo signal is transmitted to a commercial server 25 by means of a commercial signal transmission module 4G/5G server end 24, and a data processing module 26 installed in the commercial server 25 operates according to a leakage calculation formula to judge the leakage degree of a pipeline at a monitoring position.

The leakage calculation formula is that A is K delta + a, wherein A is the humidity of the surrounding soil after the pipeline leaks, K is a test coefficient, a is an initial soil ultrasonic constant, and delta is an ultrasonic attenuation.

Advantageous effects

The invention has the advantages that:

the invention provides an installation and matching mode that a narrow strip piezoelectric wafer is installed on the end face of a strip waveguide rod, establishes a structural size design standard for exciting pure similar fundamental mode horizontal shear waves, and provides theoretical reference for the design of a waveguide rod type sensing device.

The on-line monitoring system for the leakage of the buried pipeline, provided by the invention, can excite pure quasi-fundamental mode horizontal shear waves in the waveguide rod. The single ultrasonic mode is characterized in that when the viscous damping force of soil changes, the changed signal parameters are correspondingly simplified, so that the burden of signal transmission is reduced, the difficulty of signal processing is reduced, and the measurement precision is improved.

Directly inserting the buried pipeline leakage on-line monitoring device into soil; or once excavation is carried out, the monitoring device is buried under the ground, and long-term monitoring of leakage can be achieved. Will effectively reduce the buried pipeline and overhaul tedious auxiliary work such as excavation. Low price, durable and strong practicability.

The invention provides an online monitoring method for leakage of buried pipelines, which provides a leakage amount calculation formula based on an ultrasonic guided wave technology and can quantitatively and timely detect leakage of pipelines for water transportation, oil transportation and the like. A plurality of monitoring devices can form a set of system, a plurality of positions are measured simultaneously, and long-term monitoring on a large scale can be realized on pipelines such as water delivery, oil delivery and the like. The intelligent pipeline leakage monitoring system is based on a powerful internet of things technology, and intelligent pipeline leakage monitoring is achieved. The pipeline monitoring system has the advantages that timely monitoring of the pipeline at the position difficult to reach is possible, labor is effectively reduced, and scientific management of safe operation of the pipeline is achieved.

Drawings

FIG. 1 is an on-line monitoring device for buried pipeline leakage

Wherein, 1: right housing cover, 2: battery, 3: signal conditioning module, 4: signal sampling module, 5: positive wire, 6: narrow strip piezoelectric wafer, 7: ribbon waveguide rod, 8: bolt, 9: first clip, 10: housing, 11: the wire is negative; 12: ultrasonic signal transmitting/receiving module, 13: microcontroller module, 14: signal transmission module 4G/5G client, 15: circuit board, 16: a left shell cover;

FIG. 2 shows the internal structure of the housing 10

Wherein, 17: battery interface, 18: second clip, 19: a through hole;

FIG. 3 is a diagram showing the distribution of the modules on the circuit board 15

Wherein, 3: signal conditioning module, 4: signal sampling module, 12: ultrasonic signal transmitting/receiving module, 13: microcontroller module, 14: the signal transmission module 4G/5G client;

FIG. 4 is a schematic view of the mounting of a piezoelectric wafer on a wave guide plate

Wherein, 6: narrow strip piezoelectric wafer, 7: ribbon waveguide rod, 20: proximal end face, 21: distal surface, l: length of the strip waveguide rod, w: strip waveguide rod width, lp: length of narrow strip piezoelectric wafer, wp: the width of the narrow strip piezoelectric wafer;

FIG. 5 is an installation example of an on-line monitoring device for leakage of buried pipeline

Wherein, 22: on-line monitoring device, 23: buried pipeline

FIG. 6 is an installation example of an on-line monitoring device for leakage of buried pipeline

Wherein, 22: on-line monitoring device, 23: buried pipeline

FIG. 7 is an installation example (III) of an on-line monitoring device for leakage of buried pipelines

Wherein, 22: on-line monitoring device, 23: buried pipeline

FIG. 8 is an installation example (IV) of an on-line monitoring device for leakage of buried pipelines

Wherein, 22: on-line monitoring device, 23: buried pipeline

FIG. 9 is a block diagram of an on-line monitoring system for leakage of buried pipelines

Wherein, 22: on-line monitoring device, 24: signal transmission module 4G/5G server, 25: commercial server, 26: a data processing module;

FIG. 10 is a test effect diagram of an on-line monitoring system for leakage of buried pipelines

Detailed Description

The invention is further described with reference to the following figures and detailed description:

as can be seen from the block diagram shown in fig. 1, the ultrasonic signal transmitting/receiving module 12, the signal conditioning module 3, the signal sampling module 4 and the signal transmission module 4G/5G client 14 are controlled by the microcontroller module 13, and they are all mounted on the circuit board 15 (fig. 3). The circuit board 15 is installed on the right side inside the housing 10 and sealed by the right housing cover 1, and the battery 2 is installed in the interface inside the left side of the housing 10 and sealed by the left housing cover 16, so that it is not affected by external conditions such as rainwater and corrosion. The battery 2 supplies power to the circuit board 15.

The circuit board 15 supplies power to the narrow strip piezoelectric wafer 6 through the positive wire 5 and the negative wire 11. The strip piezoelectric wafer 6 is closely attached to the proximal end face 20 of the ribbon waveguide 7. The strip piezoelectric wafer 6 and the proximal end face 20 of the ribbon waveguide 7 are both inside the housing 10, and the first clip 9 and the second clip 18, which is designed as one piece with the housing 10, tightly fix the ribbon waveguide 7 to the housing 10 by means of the bolt 8. The ribbon waveguide 7 extends out of the housing 10 through a through hole 19 in the housing 10, and the ribbon waveguide 7 extending out of the housing 10 is an effective length for leak monitoring.

The ultrasonic signal transmitting/receiving module 12 generates electric pulses, the narrow strip piezoelectric wafer 6 generates vibration under the excitation of the electric pulses to generate ultrasonic waves, the ultrasonic waves are transmitted in the strip wave guide rod 7, and the narrow strip piezoelectric wafer 6 can excite and receive pure basic mode-like horizontal shear waves in the wave guide rod.

When it encounters the distal end face 21 of the ribbon waveguide rod 7, a reflected echo is produced. The reflected echo acts on the strip piezoelectric wafer 6 through the strip waveguide rod 7, and the strip piezoelectric wafer 6 is forced to vibrate to cause deformation and convert the deformation into an electric signal. After the electric signal is conditioned by the signal conditioning module 3, the signal sampling module 4 collects the electric signal, and the signal is transmitted out of the monitoring device through the signal transmission module 4G/5G client 14.

The length l of the strip waveguide rod 7 extending out of the shell 10 can be within the range of [0.1m, 2m ]. The thickness d and the width w of the ribbon waveguide 7 are related to the wavelength λ of the ultrasonic signal propagating in the ribbon waveguide 7, the width w >6 λ, and the thickness d <1.5 λ. The proximal end face 20 of the ribbon waveguide 7 and the lower surface of the narrow piezoelectric wafer 6 are dimensioned to satisfy the following correspondence: the width w of the strip waveguide rod 7 and the length lp of the narrow strip piezoelectric wafer 6 need to satisfy a relational expression that lp/w is 0.9-1; the thickness d of the strip waveguide 7 and the width wp of the strip piezoelectric wafer 6 should satisfy wp/d of 1.

The online buried pipeline leakage monitoring device 22 (see fig. 1) can be wholly buried in soil (see fig. 5) or only part of a waveguide rod can be inserted into the soil (see fig. 6-8) in actual operation. The waveguide rods may be positioned parallel to the circumference of the pipe (see fig. 5) or perpendicular to the circumference of the pipe (see fig. 6-8). The waveguide rod may be wound around the pipe in one turn (see fig. 6) or in part (see fig. 7-8).

N (N is more than or equal to 2) online monitoring devices form a set of monitoring system (see figure 9), and the system comprises a buried pipeline leakage online monitoring device, a signal transmission module 4G/5G server end 24, a data processing module 26 and a commercial server 25. The first on-line monitoring device 22 may be configured as a reference signal device, installed in a location that is not affected by a pipe leak, and the surrounding environment is the same as the other devices. The ultrasonic waves transmitted in the waveguide rod are influenced by viscous damping of the viscosity of the soil surrounding the waveguide rod. When the viscosity of the soil around the strip waveguide rod 7 is changed due to pipeline leakage, the soil with different viscosity has different viscous damping forces on the ultrasonic wave transmitted in the strip waveguide rod 7, and the change of the viscosity of the soil causes the change of the ultrasonic signal in the strip waveguide rod 7. Ultrasonic signals collected by the online monitoring device are transmitted out of the monitoring device through the signal transmission module 4G/5G client 14, the ultrasonic signals are received by the signal transmission module 4G/5G server 24, and the received ultrasonic signals are calculated by the data processing module 26 to give a diagnosis result of the pipeline leakage degree. The data processing module 26 may be implemented as a software package installed on the commercial server 25. The data processing module 26 determines the degree of pipeline leakage according to a formula a, where a is a leakage amount, K is a test coefficient, δ is an acoustic attenuation amount, and a is an initial acoustic parameter of soil.

The implementation case is as follows:

an online leakage monitoring device 22 for a buried pipeline is designed, wherein a strip-shaped waveguide rod 7 is made of 316L stainless steel, the thickness of the strip-shaped waveguide rod is 1mm, the width of the strip-shaped waveguide rod is 20mm, and the length of the strip-shaped waveguide rod is 400 mm. The strip piezoelectric wafer 6 is made of 2-2 composite materials, and has the thickness of 1mm, the width of 1mm and the length of 18 mm. The shell 10, the first clamping piece 9 and the second clamping piece 18 are made of polytetrafluoroethylene. A battery 2, an ultrasonic signal transmitting/receiving module, an ADC (analog to digital converter) sampling module, a microprocessor and a 4G module which are commercially available are purchased, and the signal conditioning module adopts an amplifying and filtering circuit. The ultrasonic signal transmitting/receiving module, the ADC sampling module, the microprocessor, the 4G module and the amplifying and filtering circuit are integrated on the PCB 15, so that an online monitoring system consisting of two online monitoring devices is assembled.

Two on-line monitoring devices are inserted into the barrels filled with soil, water is continuously injected into one of the barrels during a test, and the other barrel is kept in an initial state. And recording the time domain signal waveforms acquired by the two online monitoring devices each time, and finding that the signals are very pure. Comparing the amplitude attenuation of the two sets of signals, a graph plotting the humidity of the soil in the tub and the sound wave attenuation is shown in fig. 10. According to the graph, the humidity of the soil and the attenuation of the ultrasonic wave present a single linear relationship A of 2.2 delta + 1.0. The maximum error is 7% when the humidity calculated by the method is compared with the measured value of the hygrometer, and the result proves that the method is reliable in detection result and can meet engineering requirements.

Claims (3)

1. An online monitoring system for leakage of a buried pipeline is characterized by comprising N online monitoring devices (22), a commercial signal transmission module 4G/5G server end (24) and a commercial server (25) with a data processing module (26), wherein the N online monitoring devices (22) are parallelly arranged at slave stations, at least one commercial signal transmission module 4G/5G server end (24) is arranged at a master station, the slave stations and the master station are in wireless communication, the commercial signal transmission module 4G/5G server end (24) is connected with the commercial server (25), and N is greater than or equal to 2;

the online monitoring device (22) comprises: the ultrasonic signal transmitting/receiving module (12), the signal conditioning module (3), the signal sampling module (4), the signal transmission module 4G/5G client (14) and the microcontroller module (13) are integrated on the circuit board (15), the microcontroller module (13) controls the working sequence of the ultrasonic signal transmitting/receiving module (12), the signal conditioning module (3), the signal sampling module (4) and the signal transmission module 4G/5G client (14), the battery (2) supplies power to the circuit board (15), the circuit board (15) is installed in the shell (10) and is sealed by the left shell cover (16) and the right shell cover (1); the first clamping piece (9) and the second clamping piece (18) on the shell (10) fix the near end face (20) of the ribbon waveguide rod (7) in the shell (10) by means of a bolt (8), the strip piezoelectric wafer (6) is tightly attached to the near end face (20) of the ribbon waveguide rod (7), the ultrasonic signal transmitting/receiving module (12) is connected with the strip piezoelectric wafer (6) through a lead (5) and a lead (11), and the far end face (21) of the ribbon waveguide rod (7) extends out of the shell (10) and is inserted into the soil around the pipeline;

wherein, the length l, the thickness d and the width w of the strip waveguide rod (7) need to satisfy the following conditions: the length l is within the range of 0.1 m-2 m, the thickness d and the width w are related to the wavelength lambda of the ultrasonic signal of the ribbon waveguide rod (7), the width w is more than 6 lambda, and the thickness d is less than 1.5 lambda;

the length lp and the width wp of the narrow strip piezoelectric wafer (6) need to meet the following conditions: the ratio of the length lp of the strip piezoelectric wafer (6) to the width w of the strip waveguide rod (7) is required to satisfy the relational expression that lp/w is 0.9-1, and the width wp of the strip piezoelectric wafer (6) is equal to the thickness d of the strip waveguide rod (7).

2. An on-line buried pipeline leakage monitoring system as claimed in claim 1, wherein said commercial signal transmission module 4G/5G server terminal (24) is connected to commercial server (25) through USB communication.

3. A monitoring method of an online leakage monitoring system of a buried pipeline according to claim 1, characterized in that N online monitoring devices (22) are distributed at different monitoring points, a signal collected by the first online monitoring device (22) is a reference signal for leakage judgment, measurement signals of other N-1 online monitoring devices (22) are compared with the reference signal in real time to judge the leakage condition of a monitoring position, and one set of online monitoring system realizes online monitoring of N-1 leakage positions;

in each online monitoring device (22), an ultrasonic signal transmitting/receiving module (12) transmits a pulse signal to excite a narrow strip piezoelectric wafer (6) to generate an ultrasonic signal, the ultrasonic signal is transmitted in a strip-shaped waveguide rod (7), a reflected echo is generated when the ultrasonic signal meets a far-end surface (21) of the waveguide rod, the reflected echo is filtered and amplified by a signal conditioning module (3), the reflected echo is sampled by a signal sampling module (4), the ultrasonic echo is transmitted by a signal transmission module 4G/5G client (14), the ultrasonic echo signal is transmitted to a commercial server (25) by a commercial signal transmission module 4G/5G server end (24), a data processing module (26) installed in the commercial server (25) performs operation according to a leakage calculation formula, and the leakage degree of a pipeline at a monitoring position is judged;

the leakage calculation formula is that A is K delta + a, wherein A is the humidity of the surrounding soil after the pipeline leaks, K is a test coefficient, a is an initial soil ultrasonic constant, and delta is an ultrasonic attenuation.

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