CN102797979B - Device for detecting leakage points of underground pipeline and method thereof - Google Patents

Abstract

The present invention proposes a detection device and method for leakage points of underground pipelines. The device includes a housing and a functional circuit located in the housing. The functional circuit includes a digital signal processor connected to a human-machine control circuit, The display circuit and peripheral circuits also include a differential acoustic-electric sensor probe, which is connected to a digital signal processor through a signal conditioning circuit. The probe detects the vibration signal from the leakage point of the underground pipeline and transmits the signal to the digital signal processor. After determining the direction of the leak point, the scope of the leak point is gradually determined by comparing the signal characteristics through multiple detections. The detection device and method realize the detection of the leakage point of the underground pipeline without excavating the soil and being not affected by factors such as external noise, and can conveniently and accurately detect whether there is leakage in the groundwater and gas pipelines by directly detecting the land above the pipeline Point and leak point position, its structure is firm, performance is stable, durable, easy to operate.

Description

Device and method for detecting leak point of underground pipeline

technical field

The invention relates to the technical field of acoustic-electric sensors, in particular to a device and method for detecting leakage points of groundwater and gas pipelines based on coil-type acoustic-electric sensors.

Background technique

Ground water and gas pipelines have been widely used in today's urban infrastructure, and occupy an extremely important position in the country's economic development and people's production and life. However, due to its concealment, if the pipeline is damaged or leaked, it is difficult to observe it on the ground, which will cause serious waste of resources, seriously affect people's production and life, and even cause safety hazards. The serious consequences of pipeline leakage have attracted the attention of all walks of life, so a group of "leakage workers" specializing in groundwater and gas pipelines have emerged. However, this job requires too much experience of the staff, and the working hours can only be limited to late night with very little noise. In view of the above situation, after interviews with the "leak listener" and careful research on the characteristics of the leak point, the device and method for detecting the leak point of groundwater and gas pipelines have been designed and developed, which realizes the detection of the leakage point without being affected by working hours and external noise. , Fast, simple, and leak point detection without excavation and covering soil.

In the existing research results, the detection method of groundwater and gas pipeline leakage points is mainly based on simple physical leakage sticks, which requires too much experience and hearing of the staff, and the working hours can only be limited to late night when the noise is relatively small. It will affect the staff's eardrum and physical health for a long time; therefore, it is necessary to design a simple and practical detection method with low cost, which is not affected by working hours and external noise, and can be detected quickly without digging and covering soil. , Accurately detect the leakage point.

Contents of the invention

The object of the present invention is to provide a detection device and method for the leakage point of underground pipelines, without excavating and covering the soil, without being affected by external noise and other factors, by directly detecting the land above the surface of the pipeline to accurately detect the leakage points of underground water and gas pipelines and the purpose of its location.

The technical scheme that the present invention adopts for solving its technical problem is,

The detection device for the leakage point of the underground pipeline includes a casing and a functional circuit located in the casing. The functional circuit includes a digital signal processor connected to a man-machine control circuit, a display circuit and a peripheral circuit. A differential acoustic-electric sensor probe is connected with a digital signal processor through a signal conditioning circuit, and the probe detects the vibration signal from the leakage point of the underground pipeline and transmits the signal to the digital signal processor.

The bottom of the probe has a metal diaphragm, which has a magnet and a coil inside. The metal diaphragm is connected to the coil. The vibration signal from the underground pipeline makes the metal diaphragm resonate and drives the coil to vibrate in the magnetic field, thereby generating an induced voltage. The coil passes through The wire is connected with the signal conditioning circuit, and the induced voltage is passed into the signal conditioning circuit.

A telescopic detection rod is connected to the casing.

The man-machine control circuit is provided with vibration signal acquisition frequency bands, including: low frequency band 60-80 Hz, middle frequency band 80-250 Hz, high frequency band 250-600 Hz.

The signal conditioning circuit adjusts the amplitude of the induced voltage of the coil between 0 and 3V, and keeps its frequency between 60Hz and 250Hz.

The method for detecting the leakage point of the underground pipeline by using the above-mentioned device comprises the following steps:

1) Place the detection device near the underground pipeline to be tested, stick the probe on the ground, make the detection rod perpendicular to the ground, and collect the signals of low frequency, medium frequency and high frequency in sequence through the man-machine control circuit;

2) The digital signal processor processes and analyzes the signals collected three times. If the signals show the following characteristics: the signals of the three frequency bands are complete and stable, and the amplitude of the low frequency band is larger than that of the middle and high frequency bands, then judge the detection point. There is a leak nearby;

3) Along the direction of the underground pipeline, at a distance of 100 to 500 meters from the last detection point, select another detection point, repeat steps 1) and 2), and compare the collected signal with the last signal, if found If the amplitude of the low-frequency signal increases compared with the last time, it means that the distance between the detection point and the leak point is closer than the previous detection point, and the next detection should be carried forward; if the amplitude of the low-frequency signal is found to be relatively If it decreases last time, it means that the distance between the detection point and the leakage point is farther than the last detection point, and the detection point should be taken in the opposite direction;

4) After determining the direction of the leakage point, only save the latest signal data collected for comparison with the next detection, repeat steps 1), 2), and 3), and gradually determine the scope of the leakage point.

When the underground pipeline leaks water or air, under the action of water and air pressure, it impacts and rubs against the pipe wall and the external medium, which will produce a certain sound of water leakage and air leakage. The sound of water leakage is composed of three parts: 1. The length of water and air Time impacts the surrounding medium, forming a cavity outside the water and air leakage, forming a resonance cavity, where the sound amplitude is relatively large and the frequency is low, mainly concentrated between 60 and 80Hz; 2. Water and air impact the pipe wall, resulting in Vibration sound, its frequency is between 80 and 250 Hz; 3. After water and air rush out of the pipe wall, they impact the surrounding medium, such as clay, sand or loess, and produce sound with a wide frequency, mainly concentrated at 250 to 600 Hz. Based on the above principles, the man-machine control circuit of the detection device sets three acquisition frequency bands: low frequency band 60-80 Hz, middle frequency band 80-250 Hz, high frequency band 250-600 Hz.

The advantage of the present invention is that the detection device and method realize the detection of the leakage point of the underground pipeline without excavating the soil and being not affected by factors such as external noise, and the groundwater can be detected conveniently and accurately by directly detecting the land above the pipeline , Whether there is a leakage point in the air pipeline and its location, the structure is firm, the performance is stable, durable, and the operation is simple.

Description of drawings

Fig. 1 is the system structural diagram of the detection device that the present invention proposes;

Fig. 2 is a structural schematic diagram of the acoustic-electric probe of the detection device.

Detailed ways

In order to make the technical means, creative features, goals and effects achieved by the present invention easy to understand, the present invention will be further elaborated below in conjunction with illustrations and specific embodiments.

The detection device of the underground pipeline leak point proposed by the present invention includes a housing and a functional circuit located in the housing. As shown in Figure 1, the functional circuit includes a digital signal processor, and the digital signal processor is connected to a human-machine control circuit, The display circuit and the peripheral circuit also include a differential acoustic-electric sensor probe, which is connected to a digital signal processor through a signal conditioning circuit. The probe detects the vibration signal from the leakage point of the underground pipeline and transmits the signal to the digital signal processor.

As shown in Figure 2, the bottom of the probe has a metal diaphragm, which has a magnet and a coil inside, and the metal diaphragm is connected to the coil. The vibration signal sent by the underground pipeline makes the metal diaphragm resonate and drives the coil to vibrate in the magnetic field, thereby The induced voltage is generated, the coil is connected with the signal conditioning circuit through the wire, and the induced voltage is passed into the signal conditioning circuit.

In addition, in order to facilitate the detection work, a telescopic detection rod is connected to the casing, and the whole device is light in weight and easy to carry.

The man-machine control circuit is provided with vibration signal acquisition frequency bands, including: low frequency band 60-80 Hz, middle frequency band 80-250 Hz, high frequency band 250-600 Hz. The signal conditioning circuit adjusts the amplitude of the induced voltage of the coil between 0 and 3V, and keeps its frequency between 60Hz and 250Hz.

The digital signal processor chooses TMS320X281xDSP, and its peripheral circuit provides the power supply, reset, clock and other circuits required by the processor.

The device adopts the integration of data acquisition, analysis and processing, and result display, and can reproduce the pipeline operation in real time.

The method for detecting the leakage point of the underground pipeline by using the above-mentioned device comprises the following steps:

1) Place the detection device near the underground pipeline to be tested, stick the probe on the ground, make the detection rod perpendicular to the ground, and collect the signals of low frequency, medium frequency and high frequency in sequence through the man-machine control circuit;

2) The digital signal processor processes and analyzes the signals collected three times. If the signals show the following characteristics: the signals of the three frequency bands are complete and stable, and the amplitude of the low frequency band is larger than that of the middle and high frequency bands, then judge the detection point. There is a leak nearby;

3) Along the direction of the underground pipeline, at a distance of 100 to 500 meters from the last detection point, select another detection point, repeat steps 1) and 2), and compare the collected signal with the last signal, if found If the amplitude of the low-frequency signal increases compared with the last time, it means that the distance between the detection point and the leak point is closer than the previous detection point, and the next detection should be carried forward; if the amplitude of the low-frequency signal is found to be relatively If it decreases last time, it means that the distance between the detection point and the leakage point is farther than the last detection point, and the detection point should be taken in the opposite direction;

4) After determining the direction of the leakage point, only save the latest signal data collected for comparison with the next detection, repeat steps 1), 2), and 3), and gradually determine the scope of the leakage point.

The effect will be better if the detection device is placed in the reserved observation port of the pipeline (such as the pipeline exposed under the manhole cover).

The detection device and method realize the detection of the leakage point of the underground pipeline without excavating and covering the soil, without being affected by external noise and other factors, and can conveniently and accurately detect whether there is leakage in the groundwater and gas pipelines by directly detecting the land above the pipeline The location of the point and its leakage point, its structure is firm, its performance is stable, it is durable and easy to operate.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments, and that described in the above-mentioned embodiments and the description only illustrates the principles of the present invention, and the present invention also has various aspects without departing from the spirit and scope of the present invention. Variations and improvements all fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (1)

1. the detection method of underground pipeline leakage point, is characterized in that, comprises the following steps:

1) near underground pipeline to be measured, place sniffer, will pop one's head in and paste on the ground, make feeler perpendicular to the ground, gather successively the signal of low-frequency range, Mid Frequency and high band by man-machine control circuit;

2) digital signal processor carries out Treatment Analysis to the signal of three collections, if signal presents following features: three frequency band signals are complete and stable, the amplitude of the relative medium-high frequency section of amplitude of low-frequency range is larger, judges near this sensing point and has leakage point;

3) move towards along underground pipeline, apart from 100～500 meters of of sensing point last time, select again a sensing point, repeating step 1), 2) work, and the signal of the signal of collection and last time is compared, increase if the amplitude of discovery low-band signal is compared last time, illustrate that this sensing point is nearer than the sensing point of last time with the distance of leakage point, should continue to carry out forward next time and survey; If find that low-band signal amplitude reduced relative last time, the distance that this sensing point and leakage point be described than last time sensing point farther, should be along getting sensing point in the other direction;

4), after definite leakage point direction, only preserve the last signal data gathering, for comparing with surveying next time, repeating step 1), 2), 3) work, progressively determine the scope of leakage point.

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