CN102182937A - Pipeline leakage vibration signal acquisition enhancing device - Google Patents

Abstract

The invention discloses a pipeline leakage vibration signal acquisition enhancement device, which is composed of a rigid amplitude-changing mechanism and a sensor; wherein, one end of the rigid amplitude-changing mechanism is a large end face, and the large end surface is connected with the outer wall of the pipeline or a valve handle of the pipeline; the rigid amplitude-changing mechanism The other end of the mechanism is a small end face, and the small end face is flat, and the small end face is connected to the sensor; the cross-sectional area of the rigid luffing mechanism changes from small end to large end face, from small to large. The beneficial technical effects of the present invention are: a new device for collecting vibration signals of pipeline leakage is provided, which can transmit the vibration to the sensor after converging, so that the input of the sensor is enhanced, the output signal-to-noise ratio is improved, and the detection and positioning of pipeline leakage is improved. The detection performance of the device is excellent, and the device is easy to install and move.

Description

Pipeline Leakage Vibration Signal Acquisition Enhancement Device

technical field

The invention relates to a pipeline leak detection technology, in particular to a pipeline leakage vibration signal collection enhancement device.

Background technique

In all kinds of pressure pipelines, such as water supply, oil and gas pipelines, due to various man-made or natural reasons, pipeline leakage occurs from time to time, causing a lot of waste of water, oil and gas resources. Therefore, it is necessary to find out in time And accurately locate these pipeline leaks, and take remedial measures.

At present, various types of leak detection and positioning equipment using acoustic signal processing methods have been widely used in the detection and positioning of pipeline leaks, such as listening instruments, digital correlators, etc., such equipment applications use vibration (acoustic) sensors to obtain leakage The pipeline vibration (acoustic) signal caused by the pipeline is analyzed and processed, and the leak detection and leak point location are performed according to the collected vibration signal, and various signal features are analyzed and extracted, and the phase of the signal is directly related to the leak point location.

The vibration signal caused by pipeline leakage will propagate far along the pipeline and the pipeline embedding medium (such as soil, sand, etc.). Vibration sensors are used to obtain pipeline vibration signals. Among the widely used detection devices at present, for metal pipelines, a magnetic base is usually connected with the sensor. The magnetic base can be directly adsorbed on the metal pipe wall or valve, and the pipeline vibration is transmitted through the magnetic base. to the vibration sensor. The function of the magnetic base is to ensure that the entire vibration acquisition device can be in good contact with the measured point, and to ensure that the pipeline vibration signal is transmitted to the sensor. For non-metallic pipes, relying on the gravity of the sensor itself, it is in close contact with the pipe wall. In this way, when the sensor collects pipeline vibration signals, it only collects the vibration of the pipeline in contact with the sensor or the sensor seat. When propagating to the detected position, the vibration may have become very weak, and the sensor only collects the vibration in a very limited area, so the signal-to-noise ratio of the output signal of the sensor is extremely low, making the detection performance greatly reduced or even impossible to detect.

Contents of the invention

In order to solve the problems existing in the background technology, the inventor, after painstaking research, proposed the pipeline leakage vibration signal acquisition enhancement device of the present invention, that is, one end of the rigid luffing mechanism is a large end face, and the large end face is connected to the outer wall of the pipeline or the valve handle of the pipeline; The other end of the rigid luffing mechanism is a small end surface, and the small end surface is a plane, and the small end surface is connected to the sensor; no matter what shape of the rigid luffing mechanism is, its shape must ensure that the vibration propagates from the large end surface to the small contact surface (it can also be It is considered to be transmitted to the sensor) is superimposed and enhanced, so the cross-sectional area of the rigid luffing mechanism must be changed from small to large from the small end to the large end.

Due to the difference in shape between the outer wall of the pipeline and the valve handle of the pipeline, the rigid luffing mechanism of the present invention also has two options when corresponding to the two positions of the outer wall of the pipeline and the valve handle of the pipeline:

1) When the rigid luffing mechanism is connected to the outer wall of the pipeline, the large end surface is an arc surface, and the longitudinal section of the rigid luffing mechanism is an axisymmetric figure. A straight line perpendicular to the plane. At this time, the size of the cross-sectional area of the rigid luffing mechanism gradually changes from small to large in a linear, exponential or stepwise manner from the small end to the large end.

2) When the rigid luffing mechanism is connected to the valve handle of the pipeline, the shape of the rigid luffing mechanism is a circular platform, the small end of the circular platform is connected to the sensor, and the large end of the circular platform is connected to the large end of the valve handle.

When the rigid luffing mechanism is connected with the outer wall of the pipeline or the valve handle of the pipeline, the rigid luffing mechanism can be bound to the outer wall of the pipeline or the position of the valve handle of the pipeline, or the rigid luffing mechanism and the metal strip can be wrapped around the outer wall of the pipeline together with bolts Fastening; using the aforementioned connection method requires additional binding tools, which is not conducive to the disassembly/installation and displacement of the device. Therefore, the inventor proposes to use a magnetic connection between the rigid luffing mechanism and the outer wall of the pipeline and the valve handle of the pipeline: Alternatively, the rigid luffing mechanism is made of magnetic material (the magnetic material itself is a good conductor of the acoustic signal); considering that the overall rigid luffing mechanism is made of magnetic material, the cost is too expensive, and good acoustic conductor materials other than magnetic materials can also be used Make a rigid luffing mechanism, set a groove on the large end surface of the bottom of the rigid luffing mechanism, set a permanent magnet in the groove, and use the permanent magnet to adsorb the rigid luffing mechanism on the surface of the pipe or valve, and the number of permanent magnets set is 1 When the number of permanent magnets is more than one, it is better to arrange the permanent magnets on the rigid luffing mechanism along the two sides of the pipeline.

When the rigid luffing mechanism is connected to the outer wall of the pipeline, the thickness of the rigid luffing mechanism along the axial direction of the pipeline is less than 1/6 of the vibration wavelength propagating in the pipeline.

The beneficial technical effects of the present invention are: a new device for collecting pipeline leakage vibration signals is provided, the device can transmit the vibration to the sensor after converging, so that the input of the sensor is enhanced, the output signal-to-noise ratio is improved, and the detection and positioning of pipeline leakage is improved The detection performance of the device is excellent, and the device is easy to install and move.

Description of drawings

Figure 1. Schematic diagram of the shape of a rigid luffing mechanism with a linearly changing cross section;

Fig. 2. Schematic diagram of the shape of the rigid luffing mechanism whose cross-section changes exponentially;

Figure 3. Schematic diagram of the appearance of a rigid luffing mechanism with a stepwise change in cross section;

Figure 4. Schematic diagram of the shape of the frustum-shaped rigid luffing mechanism;

Figure 5. Schematic diagram of the setting position of the rigid luffing mechanism when detecting the outer wall of the pipeline;

Figure 6. Schematic diagram of the setting position of the rigid luffing mechanism when testing the valve handle.

Detailed ways

In fact, the vibrations of the points at the intersection of the plane perpendicular to the radial direction of the pipe and the pipe wall are the same, and their phases are completely consistent. Suppression cancels out, and the result of superposition is vibration enhancement. If the vibrations of these points can be collected together, the signal energy collected by the sensor 2 can be increased, thereby improving the signal-to-noise ratio output by the sensor 2 .

It is precisely based on the aforementioned ideas that the inventors proposed the device of the present invention. The rigid luffing mechanism 1 of the present invention is actually a strain convergence amplification device. The wave propagating in the rigid luffing mechanism 1, along with the direction perpendicular to the wave propagation direction The cross-sectional area of the rigid luffing mechanism 1 changes from large to small, and the energy of the wave converges. Specifically, for the rigid luffing mechanism 1, its function is to converge the vibration displacement or amplitude of the large end face of the rigid luffing mechanism 1, and concentrate the vibration energy on the small On the end face, it plays the role of gathering energy. The large end surface is in contact with the outer wall 3 of the pipeline or other devices connected to the pipeline, such as fire hydrants, valve handles 4, etc., and the small end surface is connected with the sensor 2. When the pipeline leaks and causes pipeline vibration, the large end surface in contact with the pipeline surface First of all, it is excited to vibrate. Since the vibration phases of the points of the pipe wall in contact with the large end surface are basically the same, the vibrations are in the same phase, and they will not be suppressed and canceled each other. They are superimposed together and gradually converge to the small end surface and collected by the sensor 2. The vibration of the small end face area is enhanced relative to the large end face area, so that the input signal of the sensor 2 is enhanced.

If the area ratio of the large and small end faces of the rigid luffing mechanism 1 is set to N, and the vibration amplitude of the pipeline felt by the large end face is A, then according to the principle of the luffing mechanism, the vibration amplitude at the small end face should be g×A, where g is the magnified multiple of the amplitude A, and under ideal conditions, g is approximately equal to N, that is, the vibration amplitude felt at the small end face is g times that of the large end face, and this enhanced vibration is transmitted to Sensor 2, so as to achieve the purpose of enhancing the measured vibration signal.

In order to better collect the vibration signal of the pipeline, theoretically, the larger the area of the large end face of the rigid luffing mechanism 1, the better, but at the same time, it should be ensured that the vibration transmitted to the sensor 2 through the collection enhancement device is superimposed and enhanced, and the large end face must be ensured. The effective area is maximized. Therefore, when collecting the vibration signal at the outer wall 3 of the pipeline, in order to fit closely with the outer wall 3 of the pipeline, the large end surface of the rigid luffing mechanism 1 is an arc surface, and the radius of the arc surface is consistent with the radius of the outer wall 3 of the pipeline or They are basically the same, and the cross section of the rigid luffing mechanism 1 gradually changes from small to large, from the small end to the large end. In the previous analysis, the vibration and phase of each point at the intersection of the plane perpendicular to the radial direction of the pipe and the pipe wall are completely consistent, that is, the arc surface at the contact point between the rigid luffing mechanism 1 and the outer wall 3 of the pipe not only has no negative impact on signal transmission , and instead can increase the contact area between the rigid luffing mechanism 1 and the outer wall 3 of the pipeline, so that the effective area for receiving signals becomes larger. Referring to Figures 1 to 3, the structure of the rigid luffing mechanism 1 shown in Figure 1 is similar to a trapezoid whose lower surface is a curved surface. When we know the upper and lower bottom widths of the trapezoid, the height of the trapezoid and the arc After the arc length of the shaped surface, the multiplier by which the vibration signal received by the sensor 2 is enhanced can be calculated. Similarly, the structure of the rigid luffing mechanism 1 shown in Fig. 2 and Fig. 3 can also obtain the multiplier by which the vibration signal received by the sensor 2 is amplified through correlation calculations. Since the signal-to-noise ratio is greatly improved, subsequent detection sensitivity and positioning accuracy can also be improved accordingly.

When it is necessary to collect the vibration signal at 4 places of the valve handle of the pipeline, the principle of setting up the device is the same as that of collecting the vibration signal at 3 places on the outer wall of the pipeline. Enlarge the area of the large end surface as far as possible, and at this time design the large end surface to be circular, that is, the entire rigid luffing mechanism 1 is in the shape of a circular frustum, see Figure 4, the area of the bottom surface of the circular platform is the same or similar to the area of the large end surface of the valve handle 4, so that It not only meets the area requirement of the large end face, but also satisfies the principle of "from the small end to the large end face, gradually changing from small to large".

When the rigid luffing mechanism 1 is connected to the outer wall 3 of the pipeline, the thickness of the rigid luffing mechanism 1 along the axial direction of the pipeline, in theory, the smaller the thickness, the better the output signal effect of the device; because the vibration wave propagating in the pipeline, in the At the same section, the vibration phase along the circumferential direction of the pipe is the same, but there are differences between the phases at different sections along the axial direction of the pipe (the phase of the sections continuously distributed along the axial direction of the pipe changes gradually, if the axis between the sections If the distance is too large, the difference between the phases will also become larger), if the thickness is too thick, the device will receive and superimpose more vibrations of different phases at the same time and interfere with each other, which will reduce the effect of the output signal; the inventor proposes A preferred way is: under the premise that the thickness satisfies the condition "less than 1/6 of the vibration wavelength propagating in the pipe", it is only necessary to ensure that the device can be placed on the pipe smoothly, so that the device can output The signal-to-noise ratio of the signal has reached a better result. When the rigid luffing mechanism 1 is connected to the valve handle 4 of the pipeline, there is no aforementioned thickness limitation, which is based on the above-mentioned "vibration waves propagating in the pipeline, at the same section, the vibration phase along the circumference of the pipeline is the same ", and the valve handle 4 is disc-shaped, so the phases of the vibration waves transmitted to the end face of the valve handle 4 are the same, and there will be no problem that many vibrations of different phases are received simultaneously and superimposed to interfere with each other.

Figures 5 and 6 are schematic diagrams of rigid luffing mechanisms 1 with two structures when they are arranged on pipelines.

Claims (6)

1. pipe leakage vibration signals collecting intensifier, it is characterized in that: it is made up of rigidity jib lubbing mechanism (1) and sensor (2); Wherein, rigidity jib lubbing mechanism (1) one end is a large end face, and large end face is connected with the valve handle (4) of pipeline outer wall (3) or pipeline; Rigidity jib lubbing mechanism (1) the other end is a small end face, and small end face is the plane, and small end face is connected with sensor (2); The cross sectional area of rigidity jib lubbing mechanism (1), changes by from small to large mode to large end face from small end face.

2. pipe leakage vibration signals collecting intensifier according to claim 1, it is characterized in that: rigidity jib lubbing mechanism (1) and pipeline outer wall (3) are when being connected, large end face is a cambered surface, the longitudinal section of rigidity jib lubbing mechanism (1) is a zhou duicheng tuxing, symmetry axis is: intersect vertically with the circle core shaft of large end face cambered surface, and with the vertical straight line in plane, small end face place.

3. pipe leakage vibration signals collecting intensifier according to claim 2, it is characterized in that: the cross sectional area size of rigidity jib lubbing mechanism (1), to large end face, the version by linearity, index or ladder gradually changes from small to large from small end face.

4. pipe leakage vibration signals collecting intensifier according to claim 1, it is characterized in that: the valve handle (4) of rigidity jib lubbing mechanism (1) and pipeline is when being connected, rigidity jib lubbing mechanism (1) profile is a round platform, the small end face of round platform is connected with sensor (2), and the large end face of round platform is connected with the large end face of valve handle (4).

5. pipe leakage vibration signals collecting intensifier according to claim 1, it is characterized in that: adopt magnetic to be connected between the valve handle (4) of rigidity jib lubbing mechanism (1) and pipeline outer wall (3), pipeline: perhaps, rigidity jib lubbing mechanism (1) adopts the magnetic material making; Perhaps, the good conductor material of rigidity jib lubbing mechanism (1) employing sound is provided with groove at the large end face of rigidity jib lubbing mechanism (1), and permanent magnet (5) is set in the groove, and permanent magnet (5) number that is provided with is more than 1 or 1.

6. pipe leakage vibration signals collecting intensifier according to claim 1, it is characterized in that: rigidity jib lubbing mechanism (1) and pipeline outer wall (3) are when being connected, rigidity jib lubbing mechanism (1) is along the thickness of pipeline axial, and this thickness is less than 1/6 of the vibration wavelength of propagating in pipeline.

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