CN110646032A - Water flow measuring device driven by piezoelectric motor - Google Patents

Abstract

The invention discloses a water flow measuring device driven by a piezoelectric motor, comprising: a shell with a hollow inside, a telescopic body capable of expanding and contracting in the shell, a base for fixing the top of the telescopic body, and a folding body rotatably mounted on the base. body, PVDF piezoelectric film sensor, water level sensor and temperature sensor set on the folded body, piezoelectric motor and control device installed in the base; PVDF piezoelectric film sensor generates voltage signal through the pressure exerted by water flow, and data The transmission line is transmitted to the acquisition data processor and displayed in real time; the voltage signal of the PVDF piezoelectric film sensor provides power to the piezoelectric motor through the energy storage capacitor. The invention utilizes the piezoelectric effect of the piezoelectric smart material to realize the measurement of the flow velocity information of the water flow and to drive the measuring device to move in the water flow, thereby realizing the mobile measurement of the water flow information, and realizing the real-time monitoring of the water level and the water flow speed of the river, so that the Water monitoring work can be better carried out.

Description

A piezoelectric motor-driven water flow measuring device

technical field

The invention relates to the field of water flow detection, in particular to a water flow measurement device driven by a piezoelectric motor.

Background technique

At present, smart materials mainly include piezoelectric materials, shape memory alloys, electromagnetic stretching materials, electromagnetic rheological materials, etc. Among them, piezoelectric materials are the most widely used smart materials, and are increasingly used in aerospace, aviation, and national defense. , automotive, civil construction and other fields. Piezoelectric materials can be used not only in sensors but also in actuators. Specifically, the positive piezoelectric effect of the piezoelectric material makes it act as a strain sensor to realize the self-sensing of the structure of the smart material, which is mainly used to measure the external force exerted on the piezoelectric body; the inverse piezoelectric effect uses the active It can realize self-adjustment of smart material structure.

Piezoelectric motor is a motor that uses the inverse piezoelectric effect of piezoelectric body for electromechanical energy conversion. It has the characteristics of compact structure, easy miniaturization, low processing cost, simple modal excitation, and high energy density. down detection and the semiconductor industry.

The existing water flow velocity detection devices usually measure the water flow velocity by means of a fixed measuring rod. Therefore, usually only the flow velocity parameters at a fixed point can be measured. At the same time, the current water flow velocity detection devices are mostly suspended or fixed. The power device that moves in the water, and the fixed water flow velocity detection device cannot reduce the impact force of the water flow on the measuring rod when in use, it is difficult to provide effective protection for it, and the service life of the measuring rod cannot be prolonged. In addition, the current water flow velocity device cannot measure information such as water temperature and depth of the corresponding water area at the same time.

Therefore, those skilled in the art are committed to developing a piezoelectric motor-driven water flow measuring device, so that the device can dynamically measure the water flow velocity under the driving of the piezoelectric motor, and integrate a water level sensor and a temperature sensor at the same time. Measure the water flow velocity parameters, but also provide the depth and temperature of the measurement point.

SUMMARY OF THE INVENTION

In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is how to solve the problem of driving and power supply of the measuring device under water, measure multiple parameters such as flow velocity, water level and temperature in the water area, and how to prolong the service life.

In order to achieve the above purpose, the present invention provides a piezoelectric motor-driven water flow measurement device, which is characterized in that it includes:

a shell, the shell is hollow inside;

a telescopic body, the telescopic body is slidably mounted on the casing, extends from the casing to the outside of the casing or retracts from the outside of the casing to the outside of the casing;

a base, the base is fixed on the top end of the telescopic body;

a folding body, one end of the folding body is rotatably mounted on the base, and unfolds or folds along the base;

a sensor module, the sensor module includes a PVDF piezoelectric film sensor, a water level sensor and a temperature sensor;

The PVDF piezoelectric film sensor is coated on the folded body, and the water level sensor and the temperature sensor are arranged on the folded body;

a piezoelectric motor installed in the base for driving the measurement device;

a control device installed in the base for controlling the piezoelectric motor;

a data transmission line, the data transmission line is connected with the acquisition data processor, and is used for real-time transmission of the data acquired by the sensor module;

The control device is provided with an energy storage capacitor, and the energy storage capacitor stores the electrical energy generated by the PVDF piezoelectric film sensor for driving the piezoelectric motor.

Further, the bottom end of the telescopic body is fixed on a connecting block, a driver is installed in the connecting block, and the driver drives the connecting block to slide along the inner wall of the casing.

Further, when the measuring device is not measuring, the telescopic body is retracted into the casing, the base is located on the surface of the casing, and the folded body is folded; when the measuring device is measuring, The telescopic body protrudes out of the casing, and the foldable body is unfolded.

Further, the number of the folded bodies is three.

Further, the three folded bodies are located on the same plane after being unfolded.

Further, the PVDF piezoelectric thin film sensors are coated on the folded body at equal intervals.

Further, the driver is a piezoelectric motor.

Further, the collection data processor is disposed outside the water flow, and the collection data processor is connected to a display device, and the display device displays the data of the water flow in real time.

Further, the PVDF piezoelectric thin film sensor is connected to the data transmission line through a charge amplifier.

Further, the PVDF piezoelectric thin film sensor is coated on the telescopic body.

The piezoelectric motor-driven water flow measurement device provided by the present invention utilizes the positive piezoelectric effect and the inverse piezoelectric effect of the piezoelectric smart material, which can not only realize the measurement of the flow velocity information of the water flow, improve the measurement accuracy, but also drive the measurement device. Move in the water flow, and then realize the mobile measurement of water flow information. At the same time, a water level sensor and a temperature sensor are integrated on the device to realize real-time monitoring of the water level and water flow speed of the river, so that the water conservancy monitoring work can be better carried out. In addition, when the measurement device does not need to be measured, each component is folded, which can effectively prevent obstacles such as weeds from adhering to the measurement device, thereby improving the measurement stability and prolonging the service life.

The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings, so as to fully understand the purpose, characteristics and effects of the present invention.

Description of drawings

1 is a schematic structural diagram of a preferred embodiment of the present invention when unfolded;

2 is a schematic structural diagram of a preferred embodiment of the present invention when it is folded;

FIG. 3 is a schematic structural diagram of a control device according to a preferred embodiment of the present invention.

Among them, 1-water flow measuring device, 2-shell, 3-stretching body, 4-base, 5-folding body, 51-PVDF piezoelectric film sensor, 6-connecting block, 7-data transmission line, 81-master control module, 82-voltage storage module, 83-motor control module, 84-signal processing unit.

Detailed ways

The following describes a preferred embodiment of the present invention with reference to the accompanying drawings to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned herein.

In the drawings, structurally identical components are denoted by the same numerals, and structurally or functionally similar components are denoted by like numerals throughout. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present invention does not limit the size and thickness of each component. In order to make the illustration clearer, the thicknesses of components are appropriately exaggerated in some places in the drawings.

As shown in FIG. 1 , the piezoelectric motor-driven water flow measuring device 1 in the embodiment of the present invention includes a casing 2 , a telescopic body 3 , a base 4 and a folding body 5 . The casing 2 is hollow inside, the bottom end of the telescopic body 3 is mounted on the casing 2 , the base 4 is fixed on the top of the telescopic body 3 , and one end of the folding body 5 is mounted on the base 4 .

The telescopic body 3 can slide along the casing 2 so as to retract into the casing 2 or protrude from the casing 2 . Specifically, a connecting block 6 is fixed at the bottom end of the telescopic body 3 , and the connecting block 6 cooperates with the inner wall of the casing 2 and slides along the inner wall of the casing 2 , thereby driving the telescopic body 3 to retract or extend. A driver, such as a piezoelectric linear motor, is installed inside the connection block 6 to drive the telescopic body 3 to move.

One end of the foldable body 5 is mounted on the base 4 and can be rotated around the base 4 to complete the unfolded or folded state.

As shown in FIG. 2 , when the water flow measuring device 1 in this embodiment does not perform detection, the water flow measuring device 1 can be folded. Specifically, the telescopic body 3 is retracted into the casing 2 , and the base 4 follows the telescopic body 3 . Moving and staying on the surface of the casing 2 , the folded body 5 rotates around its fixed axis on the base 4 , so as to be folded and attached to or close to the side of the casing 2 . When the water flow measuring device 1 is not measuring, the whole device is folded, which can effectively prevent obstacles such as weeds from adhering to the water flow measuring device 1 and improve the measurement stability of the device. The housing 2 can be cylindrical or spherical, and is preferably cylindrical in this embodiment.

The water flow measuring device 1 also includes a piezoelectric motor for driving the device to move in different directions, a control device for controlling the piezoelectric motor, a sensor module for collecting water flow data, and a data processor for data transmission and acquisition on the ground or on board Communication data transmission line 7.

The sensor module is used to collect data such as flow rate, water level, and temperature of the water flow, including a flow rate sensor, a water level sensor, and a temperature sensor. Among them, the flow velocity sensor adopts PVDF piezoelectric film sensor 51, which is coated on the folded body 5, and the water level sensor (not shown in the figure) and the temperature sensor (not shown in the figure) are arranged on the folded body 5. body 5.

In order to improve the measurement effect, the number of folded bodies 5 can be set to three, and the three folded bodies 5 are in the same plane after being unfolded. The PVDF piezoelectric film sensor 51 on the folded body 5 can measure the water pressure on its upstream surface, and then convert it into the water flow velocity.

The relationship between the voltage between the two polar plates of the PVDF piezoelectric film sensor 51 and the flow velocity of the river caused by the pressure of the water flow can be expressed as:

Among them, U is the converted voltage value, d ₃₃ is the piezoelectric strain constant, ε ₀ is the vacuum dielectric constant, ∈ _r is the relative dielectric constant of the PVDF piezoelectric film sensor 51 , and t is the thickness of the PVDF piezoelectric film sensor 51 , δ is the bulk density of water, generally 10KN/m ³ , g is the acceleration of gravity, and v is the velocity of the water flow. The voltage value collected by the PVDF piezoelectric film sensor 51 is proportional to its thickness t and inversely proportional to the square of the water flow velocity v.

According to the collected voltage value of the PVDF piezoelectric film sensor 51 and the water conditions such as temperature and water level, the flow rate of the detected water area is converted in real time according to the measured voltage value. The relationship between flow rate, temperature and water level provides test data.

A piezoelectric motor (not shown in the figure) is used to drive the water flow testing device 1 to move in different directions, and the PVDF piezoelectric film sensor 51 provides energy. Specifically, the PVDF piezoelectric thin film sensor 51 is connected to a rectifier filter circuit, which is converted into a DC signal by the rectifier filter circuit, and then stored by a super capacitor, and the stored electrical signal is used as a power source for driving the piezoelectric motor.

As shown in FIG. 3 , the control device is used to control the piezoelectric motor and transmit the collected data, including a main control module 81 , a voltage storage module 82 , a motor control module 83 , and a signal processing unit 84 . The main control module 81 is respectively connected with the motor control module 83 and the signal processing unit 84, the motor control module 83 is connected with the voltage storage module 82, and the signal processing unit 84 is connected with the sensor module, including the flow rate signal processing module, the water level signal processing module, the temperature signal Modules such as processing modules can also be expanded according to actual needs. The signal processing unit 84 transmits the processed data to the acquisition data processor through the data transmission line 7 . The main control module 81 adopts a single-chip microcomputer.

The piezoelectric motor and the control device for controlling the movement of the water flow testing device 1 are installed in the base 4 .

Because the PVDF piezoelectric thin film sensor 51 is pressurized by the water flow, the amount of charge generated is very small, the electrical signal is relatively weak, and it needs a very high insulation resistance. The voltage output by the electric thin film sensor 51 is amplified. Preferably, the pre-charge amplifier is AD8067. The voltage output by the PVDF piezoelectric film sensor 51 amplified by the amplifier is:

Among them, C ₀ is the inherent capacitance of the PVDF piezoelectric thin film sensor 51, and C _f is the feedback resistance connected to the AD8067.

The acquisition data processor is located on the shore or on the boat, not in the current. The collected water flow data is received through the data transmission line 7 . The acquisition data processor is connected with the display device to display the measurement results in real time. The display device is preferably an LED screen.

The working principle of the water flow test device 1 of this embodiment is: when measuring unknown waters, the water flow test device 1 is thrown into the water, and when the water flow test device 1 enters the water and stabilizes, the folding body 5 is unfolded, and the telescopic body 3 is removed from the casing 2 . Extends out, pushes the base 4 to leave the shell 2; detects the water level, flow rate and temperature information through the PVDF piezoelectric film sensor 51, the water level sensor and the temperature sensor; at the same time, a data transmission line 7 is provided at the The data is transmitted to the acquisition data processor outside the water flow in real time, and the measured temperature, water level and flow rate values are displayed in real time through the LED screen.

The preferred embodiments of the present invention have been described in detail above. It should be understood that many modifications and changes can be made according to the concept of the present invention by those skilled in the art without creative efforts. Therefore, any technical solutions that can be obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the prior art according to the concept of the present invention shall fall within the protection scope determined by the claims.

Claims (10)

1. A piezoelectric motor driven water flow measuring device, comprising:

a housing, the housing being hollow inside;

a telescopic body slidably mounted on the housing, extending from within the housing to outside the housing or retracting from outside the housing to outside the housing;

the base is fixed at the top end of the telescopic body;

one end of the folding body is rotatably arranged on the base and can be unfolded or folded along the base;

the sensor module comprises a PVDF piezoelectric film sensor, a water level sensor and a temperature sensor;

the PVDF piezoelectric film sensor is coated on the folding body, and the water level sensor and the temperature sensor are arranged on the folding body;

the piezoelectric motor is arranged in the base and used for driving the measuring device;

the control device is arranged in the base and used for controlling the piezoelectric motor;

the data transmission line is connected with the data acquisition processor and is used for transmitting the data acquired by the sensor module in real time;

and the control device is provided with an energy storage capacitor, and the energy storage capacitor stores electric energy generated by the PVDF piezoelectric film sensor and is used for driving the piezoelectric motor.

2. The water flow rate measuring device of claim 1, wherein the bottom end of the telescopic body is fixed to a connecting block, and a driver is installed in the connecting block and drives the connecting block to slide along the inner wall of the housing.

3. The device for measuring the flow rate of water flow of claim 1, wherein when the measuring device is not measuring, the telescopic body is retracted into the shell, the base is positioned on the surface of the shell, and the foldable body is folded; when the measuring device measures, the telescopic body extends out of the shell, and the folding body is unfolded.

4. The water flow rate measuring device of claim 1, wherein the number of said folded bodies is 3.

5. The water flow velocity measuring device of claim 4, wherein three of said folded bodies are located in the same plane after being unfolded.

6. The water flow rate measuring device of claim 1, wherein said pleated body is coated with said PVDF piezoelectric film sensor at equal intervals.

7. The water flow rate measuring device of claim 2, wherein the actuator is a piezoelectric motor.

8. The water flow rate measuring device according to claim 1, wherein the data acquisition processor is disposed outside the water flow, and the data acquisition processor is connected to a display device, and the display device displays the data of the water flow in real time.

9. The water flow rate measuring device of claim 1, wherein the PVDF piezoelectric film sensor is connected to the data transmission line via a charge amplifier.

10. The system of claim 1, wherein said PVDF piezoelectric film sensor is coated on said telescopic body.

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