CN107707151B - A Piezoelectric Energy Harvester Applied to Pipeline Fluid Monitoring - Google Patents

Abstract

The invention relates to a piezoelectric energy harvester used in pipeline fluid monitoring, which belongs to the field of new energy and piezoelectric power generation. The inner wall of the pipe is equipped with an impeller at one end of the warp shaft, which is located in the center of the pipe. The other end of the shaft is equipped with a bar-shaped permanent magnet, which is located on the outer wall of the pipe. The shaft is supported by bearings and bearing housings and installed vertically above the pipeline. The piezoelectric vibrator is made of a metal substrate, a piezoelectric sheet and a bar-shaped permanent magnet. One end of the metal substrate is connected to the inside of the metal shell, and the free end is connected to the permanent magnet. The piezoelectric sheet is glued on the surface. The circuit board is installed in the center of the shell, and the shell is installed on the upper part of the pipeline. Features and advantages: Use the interaction force between permanent magnets to form a stable piezoelectric energy harvester. The structure and process are simple, the cost is low, there is no acceleration mutation, the vibration stability is strong, the power generation capacity is strong, and the reliability is high; the power generation can be increased by increasing the number and length of piezoelectric vibrators.

Description

A Piezoelectric Energy Harvester Applied to Pipeline Fluid Monitoring

technical field

The invention belongs to the field of new energy and piezoelectric power generation, and in particular relates to a piezoelectric energy harvester applied to pipeline fluid monitoring, which is used in a fluid pipeline monitoring system.

Background technique

Pipeline fluid (including oil and gas pipelines, South-to-North Water Diversion Project, West-East Gas Transmission Project.) is the lifeblood of national energy and economic construction. Due to natural corrosion, natural force majeure, and especially man-made theft, pipeline fluid leakage incidents occur from time to time, which not only cause huge economic losses, but also cause serious pollution to the surrounding natural environment. In the past, regular manual inspections were often used to maintain fluid pipelines. However, due to the long laying distance and often in inaccessible or inconvenient places, regular inspections are difficult to find leaks and repair them in time. Therefore, many people have proposed Types of pipeline leak detection or anti-theft systems. Although some pipeline leakage or anti-theft monitoring and alarm methods proposed are relatively mature at the technical level, the application of anti-theft monitoring systems for long-distance pipelines in my country is still in its infancy and has not been widely used. One of the reasons is that its power supply problem has not been solved. Get well resolved. The method of laying cables is costly, and has been cut off by criminals, which affects the normal operation of the monitoring system; while using batteries for power supply, the use time is limited and needs to be replaced frequently. Once the battery is insufficient and not replaced in time, the monitoring information cannot be completed. teleportation. Therefore, in order to make the fluid pipeline leakage and anti-theft system practical, the self-power supply problem of the monitoring system must be solved first.

Contents of the invention

Aiming at the power supply problem of the fluid pipeline monitoring system, the invention discloses a magnetically excited piezoelectric energy harvester applied to pipeline fluid monitoring. The embodiment adopted by the present invention is: the inner wall of the pipeline is equipped with an impeller at one end of the shaft, and is horizontally located in the center of the pipeline. The shaft is vertically installed in the pipe hole, and the other end of the shaft is equipped with two poles (including N and S poles) bar-shaped permanent magnets, which are located on the outer wall of the pipe. The shaft is vertically installed above the pipeline supported by bearings and bearing housings, and is fastened to the outer wall of the pipeline with screws. The piezoelectric vibrator is made of a metal substrate, a piezoelectric sheet and a unipolar strip permanent magnet. One end of the metal substrate is connected to the inside of the metal shell by screws, the piezoelectric sheet is bonded to the surface, and the free end is connected to a unipolar strip permanent magnet. Magnets, the end of the metal substrate of the piezoelectric vibrator I is connected with a unipolar (N) bar-shaped permanent magnet, and the end of the metal substrate of the piezoelectric vibrator II is connected with a unipolar (S) bar-shaped permanent magnet, and the piezoelectric vibrator is suspended vertically. The two permanent magnets are located at the same horizontal position, with a certain distance from each other. The circuit board is installed in the center of the casing through screws, and the metal casing is installed on the upper part of the pipeline with screws.

After the energy harvester is assembled and there is no fluid flow in the non-working state, the state of the piezoelectric vibrator I and the piezoelectric vibrator II is statically balanced. Since the magnets at the free ends of the two piezoelectric vibrators have the same magnetic moment, in the non-working state that is When the permanent magnet on the shaft is placed vertically, the force balance of the two piezoelectric vibrators is in a static equilibrium state, showing a vertical suspension state.

When there is a fluid pipeline in the work, there is an interaction force between the fluid and the impeller. The hydrodynamic pressure pushes the impeller to the right, forcing the shaft supported by rolling bearings to turn clockwise. The rotation of the shaft drives the other end with the two-pole bar-shaped permanent magnet to rotate clockwise, and the unipolar bar-shaped permanent magnet at the free end of the piezoelectric vibrator on the left will be deflected to the left by the repulsive force of the permanent magnet on the shaft. The electric vibrator generates disturbance, so that the piezoelectric sheet deforms. When the axis rotates 90°, the deformation of the piezoelectric sheet is the largest. Similarly, when the right piezoelectric vibrator rotates clockwise on the axis, the piezoelectric vibrator moves to the right Deflection, when the shaft rotates 90°, the piezoelectric vibrator produces the maximum disturbance, and the deformation of the piezoelectric sheet is the largest. When the shaft rotates between 90° and 180°, the left piezoelectric vibrator and the right piezoelectric vibrator are gradually reduced by the repulsive force of the permanent magnets on the two poles on the shaft, and the piezoelectric vibrator slowly deflects to the middle. When the shaft rotates to 180° °, the left and right piezoelectric vibrators return to a new state of static equilibrium. At this time, the piezoelectric vibrator is not deformed, and no disturbance is generated. When the shaft rotates through 180°, the poles of the permanent magnet at the shaft end and the permanent magnet at the free end of the piezoelectric vibrator change, and the two piezoelectric vibrators are attracted to the middle, so that the two piezoelectric vibrators are deflected inward. When the shaft rotates 270°, the piezoelectric vibrator produces the maximum disturbance, and the deformation of the piezoelectric sheet is the largest. When the shaft rotates between 270° and 360°, the left piezoelectric vibrator and the right piezoelectric vibrator are gradually reduced by the attraction of the permanent magnets on the two poles on the shaft, and the piezoelectric vibrator slowly deflects to the outside. When the shaft rotates to At 360°, the left and right piezoelectric vibrators return to the initial static equilibrium state. At this time, the piezoelectric vibrator is not deformed, and no disturbance is generated. When the shaft rotates, the repulsive force and attractive force on the above-mentioned piezoelectric vibrator change alternately, so that the piezoelectric vibrator deflects and vibrates left and right. During the vibration process, the vibration energy of the piezoelectric vibrator is converted into electrical energy through the piezoelectric sheet, and the generated electrical energy is passed The energy conversion and storage circuits transmitted by the wires to the circuit board.

In order to improve the power generation capacity and reliability of the piezoelectric vibrator, the permanent magnet is a NdFeB magnet, which has strong magnetism; the piezoelectric chip is made of 0.2mm PZT-51 material, and the metal substrate is made of beryllium bronze. The thickness of the metal substrate and the piezoelectric chip is The ratio is 1 to 2.5.

Advantages and features: ① Using the interaction force between permanent magnets to form a stable piezoelectric energy harvester, the structure and manufacturing process are simple, the cost is low, and the power generation capacity is strong. ②Under the action of the permanent magnet, the piezoelectric vibrator has a gradual increase in the exciting force without a sudden increase, and there is no sudden change in the exciting acceleration, so the reliability is high; ③The power generation can be increased by increasing the number and length of the piezoelectric vibrator.

Fig. 1 is the structural representation of energy harvester in a preferred embodiment of the present invention;

Figure 2 is a schematic diagram of a static equilibrium structure in a non-working state;

Fig. 3 is a structural schematic diagram of a state in which the central axis of the present invention has been rotated by 90°;

Fig. 4 is a schematic structural view of the state where the central axis of the present invention has been rotated by 270°;

The characteristic curve of the voltage of the energy harvester and the rotating speed of the shaft in the preferred example among Fig. 5 of the present invention;

Fig. 6 is the characteristic curve of the power of the energy harvester and the rotational speed of the shaft in the preferred example of the present invention.

Detailed ways:

One end of the inner wall of the pipe a through the axis b is equipped with an impeller c, which is horizontally located in the center of the pipe. The shaft b is vertically installed in the hole of the pipe a, and the other end of the shaft b is equipped with two poles (including N and S poles) bar-shaped permanent magnet g, which is located on the outer wall of the pipe a. The bearing j and the bearing seat i are installed directly above the pipe a, and are fastened to the outer wall of the pipe a with screws. Piezoelectric vibrator 1 is formed by bonding metal substrate e2, piezoelectric sheet e3 and unipolar (N) bar-shaped permanent magnet e1. One end of metal substrate e2 is connected to the inside of metal shell d by screws, and piezoelectric sheet e3 is bonded on the surface , the piezoelectric vibrator II is made of a metal substrate h2, a piezoelectric sheet h3 and a unipolar (N) strip permanent magnet h1. One end of the metal substrate h1 is connected to the inside of the metal shell d by screws, and the piezoelectric sheet is bonded on the surface. h3, the free end of the metal substrate is connected with a unipolar (S) bar-shaped permanent magnet h1, the piezoelectric vibrator is suspended vertically, and the three permanent magnets g, h1, and e1 are located at the same horizontal position with a certain distance from each other. The circuit board f is The screw is installed in the center of the shell d, and the metal d shell is installed on the upper part of the pipe a with screws.

After the energy harvester is assembled and there is no fluid flow in the non-working state, the state of the piezoelectric vibrator I and the piezoelectric vibrator II is statically balanced. Since the magnets at the free ends of the two piezoelectric vibrators have the same magnetic moment, in the non-working state that is When the permanent magnet g on the axis b is vertically placed, the force balance of the two piezoelectric vibrators is in a static equilibrium state, showing a vertical suspension state.

When there is a fluid pipeline a in the work, there is an interaction force between the fluid and the impeller c. The hydrodynamic pressure causes the impeller c to bear the thrust to the right, thereby forcing the shaft b supported by the rolling bearing j to rotate clockwise. The rotation of the shaft b drives the other end with the bipolar bar-shaped permanent magnet g to rotate clockwise, and the unipolar bar-shaped permanent magnet h1 at the free end of the piezoelectric vibrator I will be deflected to the left by the repulsive force of the permanent magnet g on the shaft , the piezoelectric vibrator produces disturbance, and thus the piezoelectric sheet h3 deforms. When the axis rotates 90°, the deformation of the piezoelectric sheet h3 is the largest. Similarly, when the piezoelectric vibrator II rotates clockwise on the axis, the piezoelectric vibrator moves to the right Deflection, when the axis b rotates 90°, the piezoelectric vibrator produces the maximum disturbance, and the deformation of the piezoelectric sheet e3 is the largest. When the shaft rotates between 90° and 180°, the piezoelectric vibrator I and the piezoelectric vibrator II are gradually reduced by the repulsive force of the two-pole permanent magnet g on the axis b, and the piezoelectric vibrator slowly deflects to the middle. When the axis b rotates to At 180°, the two piezoelectric vibrators return to a new state of static equilibrium. At this time, the piezoelectric vibrator is not deformed, and no disturbance is generated. When the shaft rotates through 180°, the magnetic poles of the permanent magnet g at the end of the shaft b and the permanent magnet at the free end of the piezoelectric vibrator change, and the two piezoelectric vibrators are attracted to the middle, so that the two piezoelectric vibrators are deflected inward. When the axis rotates to 270°, the piezoelectric vibrator produces the maximum disturbance, and the deformation of the piezoelectric sheet is the largest. When the shaft rotates between 270° and 360°, the piezoelectric vibrator I and the piezoelectric vibrator II are gradually reduced by the attraction of the two-pole permanent magnet g on the axis b, and the piezoelectric vibrator slowly deflects to the outside. When the shaft rotates to At 360°, the two piezoelectric vibrators return to the initial static equilibrium state. At this time, the piezoelectric vibrator is not deformed, and no disturbance is generated. When the shaft rotates, the repulsive force and attractive force on the above-mentioned piezoelectric vibrator change alternately, so that the piezoelectric vibrator deflects and vibrates left and right. During the vibration process, the vibration energy of the piezoelectric vibrator is converted into electrical energy through the piezoelectric sheet, and the generated electrical energy is passed The energy conversion and storage circuits transmitted by the wires to the circuit board.

Claims (2)

1. a kind of piezoelectric harvester applied to pipeline fluid monitoring, it is characterised in that: one end of inner wall of the pipe warp beam is equipped with leaf Wheel, impeller are positioned horizontally in pipeline center, and axis is vertically arranged in pipe hole, and the other end of axis is equipped with the bar shaped containing the pole N, S forever Long magnet；The bar permanent magnet is located at pipeline outer wall, and axis is by bearing and bearing seat supports and is vertically arranged to above pipeline, It is connected between bearing block and pipeline with fastened by screw；

Piezoelectric vibrator is bonded by metal substrate, piezoelectric patches and monopole bar permanent magnet；Metal substrate one end warp For screw connection inside metal shell, the surface of metal substrate is bonded with piezoelectric patches, and the free end of metal substrate is connected with monopole Bar permanent magnet；There are two piezoelectric vibrators, and the free end of the metal substrate of the first piezoelectric vibrator is connected with monopole (N) bar shaped forever Long magnet, the free end of the metal substrate of the second piezoelectric vibrator are connected with monopole (S) bar permanent magnet；Two piezoelectric vibrators are equal Vertical suspension, three permanent magnets are located at the same horizontal position, and three permanent magnets have certain equidistance, circuit board each other Through the cased portion center of screw, metal shell is mounted on conduit upper with screw；

After piezoelectric harvester assembling and under the off working state without fluid flowing, the shape of the first piezoelectric vibrator and the second piezoelectric vibrator State is static balancing, the magnet of the free end of two piezoelectric vibrators magnetic moment having the same, on off working state, that is, axis forever When long magnet is disposed vertically, two piezoelectric vibrator stress balances are in equipoise, and vertical hanging state is presented；

When piezoelectric harvester works, hydrodynamic pressure makes the thrust of impeller receiving to the right, forces the axis hair by roller bearings Life rotates clockwise；The rotation of axis drives the other end equipped with the two poles of the earth bar permanent magnet to rotate clockwise, the pressure of left The monopole bar permanent magnet of the free end of electric tachometer indicator by permanent magnet on axis repulsion and deflect to the left, piezoelectric vibrator produce Raw degree of disturbing, so that piezoelectric patches deforms；

When axis rotates 90 °, the deformation of piezoelectric patches is maximum, the piezoelectric vibrator of right when axis rotates clockwise, piezoelectric vibrator to Right avertence turns, and when axis rotates 90 °, piezoelectric vibrator generates maximum degree of disturbing, and the deformation of piezoelectric patches is maximum；

When axis rotation is between 90 ° and 180 °, left piezoelectric vibrator and right piezoelectric vibrator are by the two poles of the earth permanent magnet on axis Repulsion gradually become smaller, piezoelectric vibrator slowly toward centre deflect；

When axis turns to 180 °, two piezoelectric vibrators of left and right return to new static balancing state；Piezoelectric vibrator does not deform at this time, The not generation for degree of disturbing；

When axis turns over 180 °, the variation of the permanent magnet poles of shaft end permanent magnet and piezoelectric vibrator free end, the vibration of two piezoelectricity Son is by the gravitation to middle part, so that two piezoelectric vibrators be made inwardly to generate deflection；

When axis rotates 270 °, piezoelectric vibrator generates maximum degree of disturbing, and the deformation of piezoelectric patches is maximum；

When axis rotation is between 270 ° and 360 °, left piezoelectric vibrator and right piezoelectric vibrator are by the two poles of the earth permanent magnet on axis Gravitation gradually become smaller, piezoelectric vibrator is slowly toward deflecting between external；

When axis turns to 360 °, two piezoelectric vibrators of left and right return to initial static balancing state, and piezoelectric vibrator does not become at this time Shape, the not generation for degree of disturbing；

When axis rotation, repulsion suffered by above-mentioned piezoelectric vibrator replaces variation with gravitation, to keep piezoelectric vibrator or so inclined Rotational oscillation is dynamic, and vibration processes convert electric energy by piezoelectric patches for the vibrational energy of piezoelectric vibrator, and generated electricity is arrived through wire transmission The energy of circuit board is transformed in storage circuit.

2. piezoelectric harvester according to claim 1, it is characterised in that: permanent magnet selects ndfeb magnet, has strong It is magnetic；PZT-51 material that piezoelectric patches is 0.2mm, metal substrate are beryllium-bronze, the ratio between metal substrate and the thickness of piezoelectric chip It is 1~2.5.