JP2016050927A - Flow rate measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow rate measurement device, constructed to be simple and easily to assemble, with which it is possible to obtain an accurate output reliably.SOLUTION: A beam member 4 is provided along a direction crossing the direction of a measurement fluid 3 in a conduit line; a power generation sheet 5 of self-excitation type oscillating cyclically due to the flow of the measurement fluid 3 and generating electric power is attached to the beam member 4 in a cantilever posture; frequency detection means 6 for detecting the frequency of the electric power generated by the power generation sheet 5 is provided by connecting to the power generation sheet 5; and flow velocity derivation means 7 for deriving the flow velocity of the measurement fluid 3 on the basis of the frequency of the electric power detected by the frequency detection means 6 is provided.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a flow rate measuring device for measuring a flow rate of a measurement fluid flowing in a pipe line.

  Conventionally, there are various types of such flow rate measuring devices. As an example, there is a flow rate sensor that detects the flow rate of fluid based on the periodic behavior of Karman vortex, and is generally known as a Karman flow meter that detects the flow rate of fluid based on the detected flow rate ( For example, see Patent Document 1).

  However, the flow measurement device applied to the Karman flow meter adopts a configuration that detects the pressure at two locations where a pressure difference is caused by the behavior of the Karman vortex by guiding it to a pressure sensor via a pressure guiding path or the like. Therefore, the flow velocity is not directly detected in a state in accordance with the flow of the fluid, that is, in a state along the flow of the vortex in the fluid.

  Accordingly, the present inventors have provided a self-excited power generation sheet for detecting the flow rate of a fluid in order to provide a flow rate measuring device that can directly detect the flow rate of the fluid in a state in accordance with the flow of the fluid. And the power generation sheet vibrates along the vortex by the periodic behavior of the vortex generated by the vortex generator, and generates electric power, and the flow velocity of the fluid based on the frequency of the electric power Has been developed (see Patent Document 2).

JP-A-3-20618 JP 2012-173102 A

  However, since the flow rate measuring device described above needs to cause Karman vortices to act on the power generation sheet, it is necessary to provide vortex generating parts such as obstacles and grooves for forming Karman vortices. Only when the power generation sheet is attached under conditions suitable for Karman vortices, the desired output can be expected.

  Therefore, the output characteristics may vary greatly due to slight differences in the shape and size of the power generation sheet, slight displacement of the mounting position, etc., and accurate output can be obtained unless calibration is performed individually for each flow measurement device. There is a possibility that it cannot be used as a flow measuring device that can be used.

  In view of the above circumstances, an object of the present invention is to provide a flow rate measuring apparatus that can obtain an accurate output more reliably while having a simple and easily assembled structure.

[Configuration 1]
In order to achieve the above object, the characteristic configuration of the flow rate measuring device of the present invention is:
A flow rate measuring device for measuring a flow rate of a measurement fluid flowing through a pipeline,
A beam member is provided along a direction crossing a flow direction of the measurement fluid in the pipe;
A self-exciting power generation sheet that periodically vibrates and generates power by the flow of the measurement fluid is attached to the beam member in a cantilevered posture,
A frequency detection means for detecting the frequency of power generated by the power generation sheet is provided in connection with the power generation sheet,
A flow velocity deriving unit for deriving the flow velocity of the measurement fluid based on the frequency of the electric power detected by the frequency detection unit is provided.

[Operation effect 1]
According to the above configuration, since the power generation sheet is attached to the beam member in a cantilever posture, the power generation sheet is held in a posture separated from the inner peripheral surface of the pipeline. Here, even if the beam member provided along the direction crossing the flow direction of the measurement fluid in the pipe line does not generate Karman vortex, the measurement fluid is intermittently provided around the power generation sheet attached to the beam member. A new flow. Therefore, the intermittent flow of the measurement fluid moves the power generation sheet so that the flag flutters, and can periodically vibrate the power generation sheet. In other words, a self-excited power generation sheet is used, and the power generation sheet is detected by the frequency detection means by utilizing the generation of electric power by the periodic behavior that vibrates periodically by the flow of the measurement fluid. Based on the frequency of electric power, the flow velocity deriving means detects the flow velocity of the fluid. Therefore, the flow velocity of the fluid can be directly detected in a state corresponding to the fluid flow.

  Therefore, the power generation sheet vibrates in accordance with the flow of the measurement fluid, and a stable output is easily obtained.

  Therefore, the power generation sheet is simply attached to the beam member in a cantilever posture on the beam member provided along the direction crossing the flow direction of the measurement fluid in the pipe line, and stable output is achieved. An obtained flow rate measuring device can be obtained.

[Configuration 2]
In addition, a plurality of the power generation sheets can be provided on the beam member, and the power generation sheets can be connected in series.

[Operation effect 2]
In this way, the difference in vibration characteristics for each power generation sheet is due to the use of a plurality of the power generation sheets electrically connected in series, so that the output of a specific frequency is superimposed on each power generation sheet. High output. For this reason, the present inventors have proved through demonstration that the vibration characteristics of the power generation sheets connected in series are easily obtained as having stable output characteristics. Therefore, it is possible to obtain a flow rate measuring device that can obtain an accurate and high output without greatly complicating the configuration.

[Configuration 3]
Moreover, the said structure WHEREIN: It is preferable that the said several electric power generation sheet | seat is formed in the same shape and the same thickness.

[Operation effect 3]
According to such a configuration, the vibration characteristics of the respective power generation sheets can be standardized almost in advance. Therefore, large variations in vibration characteristics (natural frequencies) of the plurality of power generation sheets attached to the beam member are unlikely to occur, which contributes to obtaining a flow measurement device that can obtain a more accurate and high output.

  Since the output of the power generation sheet has an AC waveform, the combined output value as the sum of the output of each power generation sheet when a plurality of power generation sheets are electrically connected in series is the peak value of the output from each power generation sheet However, in the actual experimental results, the combined output value is obtained as a value close to the simple sum of the output values of the respective power generation sheets. This can be considered to be due to synchronization in such a manner that the vibrations of the respective power generation sheets resonate.

[Configuration 4]
In order to achieve the above object, the flow rate measuring device of the present invention includes:
The power generation sheet may be configured such that at least a part of the sheet surface is attached to the beam member in a cantilever position in a posture along the horizontal direction.

[Operation effect 4]
According to the above configuration, the power generation sheet can be easily induced to vibrate due to deformation and return of the power generation sheet by attaching the power generation sheet in a cantilevered position to at least a part of the sheet surface along the horizontal direction. The inventors have clarified through experiments that stable high output can be easily obtained.

  Specifically, by setting at least a part of the sheet surface along the horizontal direction, the power generation sheet is splashed upward by the movement of the power generation sheet to drop downward by its own weight and the flow of the measurement fluid. The movement appears as vibration due to the intermittent flow of the measurement fluid. This vibration is caused by a structure that can be attached to the beam member in a cantilevered posture. Since the attachment structure to the beam member can be easily obtained, this vibration state is also easily standardized, and individual differences due to the attachment structure occur. This is considered to be a cause of being difficult to obtain and having a stable output characteristic.

  In addition, since at least a part of the surface of the sheet is in the horizontal direction, the power generation sheet is unlikely to twist when it is moved downward by its own weight, and stable vibration is generated by the intermittent flow of the measurement fluid. It's easy to do.

  Therefore, an accurate and high output flow rate can be obtained simply by attaching the power generation sheet to the beam member provided along the direction crossing the flow direction of the measurement fluid in the pipe in the above-mentioned appropriate posture. It became easy to create a measuring device.

[Configuration 5]
Moreover, in the said structure, while fixing the one end part in a longitudinal direction to the said beam member, a weight member can be attached to the other end part as a free end.

[Operation effect 5]
Thus, if a weight is provided at the other end, the output from the power generation sheet can be increased, the separation characteristics of the output of the power generation sheet against noise and the like can be improved, and an accurate output frequency is obtained. Contribute to.

[Configuration 6]
Moreover, the said structure WHEREIN: It can be set as the strip shape which has the short side used as the one end part attached to the said beam member, and the long side more than the required length which a power generation sheet vibrates with respect to the one end part.

[Operation effect 6]
If comprised in this way, a power generation sheet can be fixed in the state where the short side used as one end part was along a beam member, and it contributes to assembling a flow measuring device with high workability and the same characteristic stably. . Further, since the power generation sheet has a long side longer than a necessary length with which the power generation sheet vibrates with respect to one end portion thereof, the other end portion in a cantilever posture is in a state where the one end portion is fixed, It is fixed to the beam member in a form that flutters and vibrates like a windsock provided at the tip of the rod. Then, the vibration of the power generation sheet can be easily detected, and a sufficiently high power can be output. Therefore, it is possible to create a flow measuring device that can obtain an accurate and high output.

  Therefore, it is possible to provide a flow rate measuring device that has a simple configuration, is easy to assemble, and can obtain an accurate output more reliably.

Schematic diagram of the flow measurement device of the present invention Graph showing output characteristics of power generation sheet Output example of power generation sheets connected in series Schematic of the flow measurement device in another embodiment

  Hereinafter, the flow rate measuring device of the present invention will be described. Preferred embodiments will be described below, but these embodiments are described in order to more specifically illustrate the present invention, and various modifications can be made without departing from the spirit of the present invention. The present invention is not limited to the following description.

As shown in FIG. 1, the flow rate measuring apparatus 1 according to the embodiment of the present invention measures, for example, the flow rate of city gas that is circulated in a city gas pipe supplied to each household or business office. It is provided by being attached to the pipeline 2.
The flow rate measuring device 1 is provided with a beam member 4 along a direction crossing the flow direction of the measurement fluid 3 in the pipe 2,
A plurality of self-exciting power generation sheets 5 that periodically vibrate to generate electric power due to the flow of the measurement fluid 3 are attached to the beam member 4 in a cantilever posture,
A frequency detection means 6 for detecting the frequency of power generated by the power generation sheet 5 is provided in connection with the power generation sheet 5;
A flow velocity deriving means 7 for deriving the flow velocity of the measurement fluid 3 based on the frequency of the electric power detected by the frequency detecting means 6 is provided.

  The beam member 4 is formed of a resin rod-like body that horizontally traverses the pipe line 2 in the pipe diameter direction, and is provided with both ends bonded and fixed to the peripheral wall of the pipe line 2. The power generation sheet 5 is made of, for example, a ferroelectric polymer typified by polyvinylidene fluoride, and more specifically, is made of, for example, a piezo film (trade name, manufactured by Tokyo Sensor Co., Ltd.) and vibrates. It has the characteristic of generating high voltage power by self-exciting. The power generation sheet 5 has, for example, a short side that is one end of a plurality of (four pieces in the figure) strip-shaped power generation sheets 5 that are excellent in flexibility due to thin film formation and that have water resistance, impact resistance, and the like. In a posture along the longitudinal direction of the beam member 4 and the longer side longer than the necessary length that the power generation sheet 5 vibrates is along the flow direction of the measurement fluid 3 flowing in the pipe line 2 on the downstream side of the beam member 4. The measuring fluid 3 is attached to the beam member 4 by bonding, and the measurement fluid 3 flows on both sides in the direction orthogonal to the sheet surface of the power generation sheet 5.

  Specifically, for a gas supply pipe having an inner diameter of 25 mm, the power generation sheet 5 made of a piezoelectric film with a thickness of 40 μm is formed in a strip shape having a short side of 5 mm and a long side of 30 to 50 mm, and the long side is measured. The beam member 4 is attached to the beam member 4 in a cantilever posture in a posture along the flow direction of the fluid 3 and in a posture in which at least a part of the sheet surface is in a horizontal direction. (In the configuration of FIG. 1, the sheet surface is attached so as to have a horizontal posture along the flow direction of the measurement fluid 3.)

  The power generation sheet 5 is electrically connected in series and connected to two lead wires 8, and the terminal 8 a of the lead wire 8 is provided in a state of being taken out of the pipe line 2. Further, the frequency detection means 6 is connected to the terminal 8 a of the lead wire 8 via two cables 9. That is, the frequency detection means 6 is provided by being electrically connected to the power generation sheet 5 via the two lead wires 8 and the cable 9, and the frequency detection means 6 has the frequency of the electric power generated by the power generation sheet 5. Based on this, the vibration frequency of the power generation sheet 5 is determined, and the flow velocity deriving means 7 is connected to the frequency detecting means 6.

  With such a configuration, when the measurement fluid 3 is caused to flow through the pipe line 2, the power generation sheet 5 jumps upward due to the movement of the power generation sheet 5 to drop downward due to its own weight and the flow of the measurement fluid 3. The observed movement appears as vibration due to the intermittent flow of the measuring fluid 3. And the electric power output by the electric power generation sheet | seat 5 is obtained based on the vibration.

  The flow velocity deriving means 7 stores relational data between the vibration frequency of the power generation sheet 5 and the fluid flow velocity measured in advance, and is based on the frequency of the power detected by the power generation sheet 5 transmitted from the frequency detection means 6. The flow velocity of the fluid (or the flow rate in consideration of the tube diameter) is derived.

〔Example〕
With respect to the gas supply pipe having an inner diameter of 25 mm, the power generation sheet 5 made of a strip-shaped piezo film having a thickness of 40 μm, a short side of 5 mm, and a long side of 30 mm is used. 2 and the output characteristics of the fluid measuring device 1 attached to the beam member 4 in a cantilevered posture so that at least a part of the sheet surface is in the horizontal direction are as shown in FIG. became. In the figure, L1 to L4 are obtained for output characteristics (dependence of output frequency on wind speed) of each of the four power generation sheets 5.

  That is, it can be read that the frequency of the electric power obtained from the power generation sheet 5 changes linearly according to the flow velocity (wind velocity) of the measurement fluid 3. In addition, the degree of change has a certain degree of variation for each power generation sheet 5, but the combined output (the combined output when the power generation sheets 5 are electrically connected in series) is the output for each power generation sheet 5. The frequency is collected into eigenvalues, and the output is superimposed to increase the output. In addition, the frequency dependence of the output of the combined output at this time is as shown in FIG. 3, which is obtained as an output that is extremely high and sharp compared to the noise of the commercial power supply and has high discriminability. Based on this, it can be read that the flow velocity of the measurement fluid 3 can be accurately obtained.

[Another embodiment]
In the said embodiment, although the electric power generation sheet 5 was formed in strip shape, the length of the one end part attached to the beam member 4 is a free end from the one end part in the state which attached the one end part to the beam member 4. The square may be longer than the length to the other end, and the dimensional ratio is not limited to that described above. Further, it may be a pennant type, not a square shape, and may be a three-dimensionally bent shape (see FIGS. 4A and 4B). By bending three-dimensionally, it is possible to adjust a suitable flow velocity range in which the power generation sheet 5 outputs electric power. For example, in the case of FIG. 4 (b), which is suitable for measuring the flow velocity of 3 and bent to the tactile shape of an insect, produces an output specifically when the flow velocity of the measurement fluid 3 exceeds a certain level. It can be said that it is useful in applications where it is desired to obtain output only during detection.

  Moreover, in the said embodiment, although the beam member 4 was provided in the attitude | position which crosses horizontally in a pipe diameter direction, and the electric power generation sheet | seat 5 was provided in the substantially horizontal attitude | position, the attitude | position of the electric power generation sheet | seat 5 is set arbitrarily not only in this. can do. For example, even when the beam member 4 is provided in a posture that vertically traverses the pipe diameter direction and the power generation sheet 5 is provided in a standing posture (see FIG. 4C), a plurality of power generation sheets 5 are connected in series. If it is provided, it is possible to sufficiently amplify the output even when the vibration of the power generation sheet 5 due to the measurement fluid 3 becomes minute, and to increase the discriminability. Can be sought. In addition, when attaching the strip-shaped power generation sheet 5 to the beam member 4 in a cantilever posture, it is preferable that a part of the sheet surface is attached in a posture along the horizontal direction, but the sheet surface is in a posture along the vertical direction, When the long side of the strip-shaped power generation sheet 5 is attached in a direction intersecting the flow direction of the measurement fluid 3 (see FIG. 4D, in this case, a hanging posture substantially orthogonal to the flow direction of the measurement fluid 3) However, if the posture of the part of the sheet surface can be in a posture along the horizontal direction by the action of the measurement fluid 3, an output can be obtained similarly. In the present invention, a part of the power generating sheet 5 is fixed to the beam member 4 and the other end opposite to the part is a free end. ".

  On the other hand, when the power generation sheet 5 is attached to the beam member 4 in a cantilevered posture in such a manner that at least a part of the surface of the sheet is in the horizontal direction, that is, the mounting posture of the power generation sheet 5 is When the measurement component 3 has a horizontal component, the movement of the power generation sheet 5 to drop downward due to its own weight and the movement of the power generation sheet 5 to return to a flat shape by the flow of the measurement fluid 3 are intermittent. Therefore, a sufficiently high output can be obtained by the output from at least one power generation sheet 5, and the flow velocity of the measurement fluid 3 can be accurately obtained.

Moreover, while fixing the one end part in the longitudinal direction of the said electric power generation sheet 5 to the said beam member 4, the weight member 5a can be attached to the other end part as a free end (refer FIG.4 (e)). In this way, the vibration characteristics of the power generation sheet 5 can be adjusted by the weight of the weight member 5a, and therefore, it is effective because it can be adjusted to obtain a highly discriminating power output in an appropriate flow rate range. Specifically, when power frequency noise from a commercial power source is mixed in the output from the power generation sheet 5 and the output discriminability is lowered, the output can be increased by attaching the weight member 5a. Therefore, it is possible to improve the distinguishability from commercial power supply noise. In the case of the power generation sheet 5 made of a strip-shaped piezo film having a thickness of 40 μm, a short side of 10 mm, and a long side of 65 mm, if an aluminum foil is pasted (attached) at a thickness of 200 μm in the range of 5 mm at the tip, a flow rate of 2.6 m / It has been found that the power output obtained in seconds is about 4 times after the FFT conversion.
Moreover, in the said embodiment, although the example which connects the several electric power generation sheet | seat 5 electrically in series was shown, it can also be electrically connected in parallel. Furthermore, it can also be used singularly. Further, instead of providing a plurality of power generation sheets 5 on one beam member 4, the power generation sheets 5 provided on each of the plurality of beam members 4 are connected to each other to obtain outputs, or outputs can be independently performed. It can also be set as the structure obtained. In the latter case, it is considered effective for the purpose of knowing the flow velocity distribution of the measurement fluid 3 in the pipe 2.

  In the above-described example, the flow rate measuring device 1 is configured to measure the flow rate of the city gas circulated through the gas heat pump using the measurement fluid 3 as the city gas, and the flow rate measuring device 1 is 0.5 m / second to 3.0 m / second. Although an example particularly suitable for measuring the flow velocity has been shown, the output characteristics of the power generation sheet 5 can be designed according to the type of the measurement fluid 3 and the flow velocity range.

  In addition, as an arrangement form of the flow rate measuring device 1, not only the laminar flow in the straight pipe portion is detected and the average flow rate is obtained, but also by providing a plurality of flow rate measuring devices 1 in a sectional view of the curved pipe portion, It can also be used to determine the flow velocity distribution in the curved pipe section.

  In the above embodiment, the output from the power generation sheet 5 is directly taken out from the terminal 8a of the lead wire 8 to the frequency detection means 6, but is taken out to the infrared light emitting element or the like via the output amplifier, and the infrared light emitting element. The frequency detection means 6 and the flow velocity deriving means 7 may be configured to derive the flow velocity of the measurement fluid 3 based on the frequency of the electric power via the wireless output from.

  Since the flow rate measuring device of the present invention is easy to assemble and an accurate output can be obtained more reliably, it can be used, for example, as a flow rate measuring device in a gas supply pipe.

1: Flow rate measuring device 2: Pipe line 3: Measurement fluid 4: Beam member 5: Power generation sheet 5a: Weight member 6: Frequency detecting means 7: Flow velocity deriving means 8: Lead wire 8a: Terminal 9: Cable

Claims (6)

A flow rate measuring device for measuring a flow rate of a measurement fluid flowing through a pipeline,
A beam member is provided along a direction crossing a flow direction of the measurement fluid in the pipe;
A self-exciting power generation sheet that periodically vibrates and generates power by the flow of the measurement fluid is attached to the beam member in a cantilevered posture,
A frequency detection means for detecting the frequency of power generated by the power generation sheet is provided in connection with the power generation sheet,
A flow rate measuring device provided with flow velocity deriving means for deriving the flow velocity of the measurement fluid based on the frequency of electric power detected by the frequency detecting means.   The flow rate measuring device according to claim 1, wherein a plurality of the power generation sheets are provided on the beam member, and the power generation sheets are connected in series.   The flow rate measuring device according to claim 2, wherein the plurality of power generation sheets have the same shape and the same thickness.   The flow rate measuring device according to any one of claims 1 to 3, wherein the power generation sheet is attached to the beam member in a cantilevered posture so that at least a part of the surface of the sheet is in a horizontal direction.   The flow rate measurement according to any one of claims 1 to 4, wherein the power generation sheet has one end in the longitudinal direction fixed to the beam member and a weight member attached to the other end as a free end. apparatus.   The said power generation sheet is a strip shape which has the short side used as the one end part attached to the said beam member, and the long side more than the required length which a power generation sheet vibrates with respect to the one end part. The flow measuring device according to claim 1.

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