JP2004279224A - Supersonic flowmeter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a compact design as well as a highly accurate measurement in a supersonic flowmeter to measure such fluid flow as air, gas, and water by using supersonic wave. <P>SOLUTION: Because the supersonic wave propagation distance becomes longer in spite of the same channel width, and also the supersonic oscillators 13, 14 can be attached on the same direction side; the enhancement of the space efficiency and the measurement with better accuracy can be achieved in the following way that the multilayer measurement channel 12 is constructed by dividing the narrow side of rectangular channel 2 with dashboard 11, at least a couple of supersonic oscillators 13, 14 are installed on the same wall of this measurement channel 12, the supersonic wave is reflected at the other side, and this reflected wave is received by the other oscillator. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ultrasonic flow rate measuring device that measures the flow rate and flow rate of a gas or a liquid using ultrasonic waves.
[0002]
[Prior art]
Conventionally, as shown in FIGS. 6 and 7, this type of ultrasonic flow meter is provided with a flow measuring section 53 having a laminar flow path 52 separated by a partition plate 51, and the flow measuring section 53 interposed therebetween. It is known that the first ultrasonic vibrator 54 and the second ultrasonic vibrator 55 are used and a flow rate calculating unit that calculates a flow rate based on the signal of the ultrasonic vibrator 5 is known. .
[0003]
Here, 56 is an upstream connection portion, 57 is a downstream connection portion, 58 is an entrance portion connected to the upstream connection portion 56, and 59 is an exit portion connected to the downstream connection portion 57.
[0004]
In the above-described configuration, a two-dimensional flow is generated in the laminar flow path 52 to realize highly accurate flow rate measurement (for example, see Patent Document 1).
[0005]
[Patent Document 1]
JP-A-9-43015
[Problems to be solved by the invention]
However, in the above-described conventional technology, the ultrasonic transducer is provided on the opposed wall surface with the measurement flow path interposed therebetween, so that it is necessary to increase the installation space. If the installation space is limited, it may not be possible to obtain a sufficient size for the mounting angle of the ultrasonic vibrator or the width of the flow path, and it may not be possible to optimize the ultrasonic wave propagation distance. There are also unavoidable situations.
[0007]
The present invention has been made to solve such a conventional problem, and has as its object to increase the degree of freedom of design and promote the downsizing of the device.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a rectangular flow path having a short side and a long side opposed to each other, and a measurement flow formed by dividing the short side of the rectangular flow path by a plurality of partition plates. A path, at least one pair of ultrasonic transducers provided on the same short side of the measurement flow path and reflecting ultrasonic waves on the facing surface and propagating in the measurement flow path, and an ultrasonic wave between the ultrasonic vibrators. Measurement control means for measuring the propagation time of the sound wave, and a calculation means for calculating the flow rate based on the signal from the measurement control means, whereby the degree of freedom of design of the flow path and the ultrasonic transducer is reduced Since the ultrasonic wave propagation distance becomes longer even with the same channel width and the ultrasonic transducers can be attached in the same direction, a compact design becomes possible.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
The embodiment of the present invention is a rectangular flow path having a short side and a long side facing each other, a measurement flow path formed by dividing the short side of the rectangular flow path by a plurality of partition plates, At least one pair of ultrasonic transducers provided on the same short side of the measurement flow path and reflecting the ultrasonic waves on the opposing surface and propagating in the measurement flow path, and propagation of ultrasonic waves between the ultrasonic transducers Measurement control means for measuring time, and arithmetic means for calculating a flow rate based on a signal from the measurement control means, which increases the degree of freedom in designing the flow path and the ultrasonic vibrator, and provides the same flow path Even with the width, the ultrasonic wave propagation distance is lengthened and the ultrasonic vibrator can be mounted in the same direction, so that a compact design is possible.
[0010]
As the ultrasonic wave propagation path between the ultrasonic transducers in the measurement flow path, a V-shaped shape or a W-shaped shape can be considered.
[0011]
If the material of the side wall surface of the measurement flow path is different between the ultrasonic vibrator mounting side and the ultrasonic reflecting side, for example, the ultrasonic vibrator mounting surface may be made of a material that does not easily reflect ultrasonic waves. Also, the vibration of the ultrasonic wave directly transmitted and received without being reflected between the ultrasonic transducers can be reduced, and a stable received signal with less noise can be obtained, and the measurement accuracy can be improved.
[0012]
In addition, if an ultrasonic reflecting member is provided on a wall surface on which ultrasonic waves are reflected, it is possible to perform reflection with less attenuation and less scattering, stabilize a received waveform, and enable more precise measurement.
[0013]
It is preferable that the divided layers inside the measurement channel are partitioned by a partition plate so that the layers have an equal height. In this case, since the amount of fluid flowing through each layer becomes equal, even if the propagation path of the ultrasonic wave varies due to a sensor mounting error or the like, a measurement error hardly occurs, and measurement accuracy can be easily secured.
[0014]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
1 and 2, a fluid to be measured such as a gas flows from an introduction path 1 to a flow path 2 and reaches a gas consumption device from an outflow path 3.
[0016]
The introduction path 1, the flow path 2, and the lead-out path 3 are connected at right angles to each other in a substantially U-shape in order to reduce the overall size, and at least the flow path 2 has at least one of the opposite short sides and It has a rectangular shape with long sides.
[0017]
The introduction path 1 has a valve seat 6 that is opened and closed by a valve element 5 on the way from the inlet 4 to the flow path 2.
[0018]
The valve element 5 is linked to a driving element 7 composed of an electromagnetic device or a stepping motor. For example, when an earthquake of a certain seismic intensity or more occurs, the driving element 7 closes the valve seat 6. 5 operates.
[0019]
Of course, the driving body 7 is located in a substantially U-shaped space formed by the introduction path 1, the flow path 2, and the extraction path 3, so as not to hinder the compactness of the apparatus.
[0020]
The introduction path 1 and the outflow path 3 are connected to the inflow chamber 8 and the outflow chamber 9 with a predetermined length margin from the ends of the flow path 2, so that the introduced fluid is once bypassed. The fluid reaches the flow path 2, and the fluid from the flow path 2 once flows around the outlet path 3, bypassing the outlet path 10.
[0021]
The reason for generating the bypass flow is that the flow is rectified as much as possible to reach the flow path 2 when a normal flow or a backflow occurs.
[0022]
In the main length portion of the flow path 2, a measurement flow path 12 whose short side is divided by a plurality of partition plates 11 is formed. In the present embodiment, the fluid is equally divided into four layers so that the fluid flows as a two-dimensional flow.
[0023]
At least one pair of ultrasonic transducers 13 and 14 are arranged on one short side wall of the measurement flow channel 12 at predetermined intervals in the flow direction of the fluid.
[0024]
The ultrasonic vibrators 13 and 14 are configured such that ultrasonic waves transmitted from one side are reflected by the opposite wall and received by the other side, that is, the ultrasonic wave propagation path is set to form a V-shape. It is.
[0025]
More specifically, the measurement control unit 15 causes the ultrasonic transducers 13 and 14 to alternately transmit and receive ultrasonic waves, and sets the difference between the ultrasonic wave propagation time in the forward direction and the ultrasonic wave propagation time in the reverse direction to the flow of the fluid at regular intervals. It is measured and output as a propagation time difference signal.
[0026]
The propagation time difference signal from the measurement control means 15 is input to the calculation means 16 to calculate the flow rate from the propagation time difference signal.
[0027]
The above ultrasonic propagation paths are set mainly at the center two of the divided measurement flow paths 12.
[0028]
Further, a power supply means 17 composed of a lithium battery or the like is connected to the measurement control means 15, the arithmetic means 16, and the like.
[0029]
Of course, the measurement control means 15, the calculation means 16, and the power supply means 17 are also located in the substantially U-shaped space formed by the introduction path 1, the flow path 2, and the derivation path 3, thereby promoting the compactness of the apparatus. Like that.
[0030]
The ultrasonic transducers 13 and 14 are housed in installation chambers 18 and 19 formed on the short side road wall of the measurement flow channel 12. Are provided with porous materials 20 and 21 for smoothing. The porous materials 20 and 21 are made of a screen, a punching metal or the like.
[0031]
The operation and operation of the ultrasonic flow measuring device configured as described above will be described below.
[0032]
First, the fluid to be measured flows from the inflow port 4 of the introduction path 1 via the external pipe. Further, since the valve element 5 is at the open position, the fluid flows through the valve seat 6 to the upstream chamber 8 of the flow path 2. The fluid in the upstream chamber 8 flows into the measurement flow channel 12 while taking a form of once bypassing.
[0033]
Since the measurement channel 12 is divided by the partition plate 11, the fluid becomes a two-dimensional flow, then flows into the downstream chamber 9, reaches the outlet channel 3 once again in a detour form, and exits therefrom. The data is sent to an external device (not shown) via the communication device 10.
[0034]
Next, the ultrasonic wave transmitted from one of the pair of ultrasonic transducers 14 and 15 provided in the measurement channel 12 is reflected by the facing wall surface and received by the other. Then, under the influence of the flow velocity of the fluid to be measured in the course of the flow of the ultrasonic wave in the measurement passage 12, the ultrasonic wave is received early when propagating in the forward direction with the flow, and is received late when propagating in the reverse direction with the flow.
[0035]
The time difference between the transmission and reception of the ultrasonic wave is measured by the measurement control means 15 and the result is output to the calculation means 16.
[0036]
The calculation means 16 calculates the flow rate at that time by calculating the signal from the measurement control means 15, the cross-sectional area of the measurement flow path stored therein, and the coefficient unique to the device.
[0037]
When performing this measurement, accurate measurement of the flow rate of the ultrasonic waves transmitted and received from the ultrasonic transducers 13 and 14 cannot be performed unless the ultrasonic waves propagate through the entire portion through which the fluid passes.
[0038]
In the ultrasonic flow rate measuring device of the present embodiment, the measurement flow path 12 is multi-layered, so that the flow path height per layer is reduced, and the ultrasonic wave is easily transmitted through the entire fluid passage portion.
[0039]
Further, by providing the reflecting portion in the ultrasonic wave propagation path, the ultrasonic oscillators 13 and 14 can be provided on the same side wall surface. Since the length of the ultrasonic wave propagation path can be made longer, the degree of freedom in the mounting angles of the ultrasonic transducers 13 and 14 and the size of the flow path width increases, and it is possible to provide a flow measuring device with excellent space properties. It is.
[0040]
As shown in FIG. 3, by forming the wall surface of the flow path on the mounting side of the ultrasonic vibrators 13 and 14 with an ultrasonic absorbing member 22 (for example, a resin having fine pores on the surface), the ultrasonic wave on the transmitting side can be obtained. The component of the ultrasonic wave transmitted from the vibrator does not directly travel along the wall surface and the vicinity of the wall surface and is reflected, so that it is possible to suppress the reception of other than the normal ultrasonic wave.
[0041]
Therefore, since the reflected wave mainly passing through the propagation path in the measurement channel 12 is received, a signal with little noise can be received, and the measurement accuracy can be improved.
[0042]
Also, as shown in FIG. 4, by providing an ultrasonic reflecting member 23 made of a material having a high acoustic wave reflectance, for example, a mirror-finished metal plate, on the ultrasonic reflecting surface in the ultrasonic wave propagation path, the ultrasonic wave is reflected. The attenuation and scattering at the time are reduced, and the propagation of the ultrasonic wave can be performed efficiently, and the noise component in the received wave is reduced, so that more accurate measurement can be performed.
[0043]
Further, in the above-described embodiment, the description has been made with respect to the V-type propagation path in which the reflection in the ultrasonic wave propagation path is performed once. There is an effect and can be used.
[0044]
Also in this embodiment, it goes without saying that the ultrasonic reflecting member 23 may be provided on the ultrasonic reflecting surface.
[0045]
Further, in the above-described embodiment, the channel is divided into four layers by the partition plate, but any number of layers can be used as long as the channels are equally divided. However, it is effective that the height per layer (dimension A in FIG. 1) is 3 mm or less in consideration of the influence of the boundary layer.
[0046]
As described above, in the embodiment, the ultrasonic wave transmitted from the ultrasonic transducer provided on the same wall side of the multi-layer measurement flow path in which the short side direction of the rectangular flow path is divided into a plurality of parts by the partition plate is applied to the opposing wall surface. By reflecting and receiving the ultrasonic wave, the ultrasonic wave propagation distance can be extended and the ultrasonic transducer can be attached in the same direction, so that measurement performance can be improved and a compact fluid measurement device design can be designed. Become.
[0047]
【The invention's effect】
As described above, according to the ultrasonic flow rate measuring device of the present invention, the ultrasonic wave propagation distance can be increased, the degree of freedom in the mounting angle of the ultrasonic transducer and the flow path width design increases, and the ultrasonic wave Since the vibrator can be attached, a design excellent in space property can be realized. Also, since the ultrasonic vibrator is attached from the same direction, the assembling workability is improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an ultrasonic flow measuring device according to an embodiment of the present invention. FIG. 2 is a transverse sectional view of an ultrasonic flow measuring device according to an embodiment of the present invention. FIG. 4 is a cross-sectional view showing still another embodiment of the apparatus. FIG. 5 is a cross-sectional view showing still another embodiment of the apparatus. FIG. 6 is a view of a conventional ultrasonic flow meter. Longitudinal cross section of flow path [Fig. 7] Cross sectional flow path of conventional ultrasonic flowmeter [Explanation of reference numerals]
2 flow path 11 partition plate 12 measurement flow paths 13 and 14 ultrasonic transducer 15 measurement control means 16 calculation means 23 ultrasonic reflection member

Claims (6)

A rectangular flow path having a short side and a long side facing each other, a measurement flow path formed by dividing the short side of the rectangular flow path by a plurality of partition plates, and the same short side of the measurement flow path Provided on the side, at least a pair of ultrasonic transducers for reflecting ultrasonic waves on the facing surface and propagating in the measurement flow path, and measurement control means for measuring the propagation time of ultrasonic waves between the ultrasonic transducers, And an arithmetic means for calculating a flow rate based on a signal from the measurement control means. The ultrasonic flow measuring device according to claim 1, wherein an ultrasonic wave propagation path between the ultrasonic transducers in the measurement flow path has a V-shape. The ultrasonic flow measuring device according to claim 1, wherein an ultrasonic wave propagation path between the ultrasonic transducers in the measurement flow path has a W-shape. 3. The ultrasonic flow measuring device according to claim 2, wherein the material of the side wall surface of the measurement flow path is different between the ultrasonic vibrator mounting side and the ultrasonic reflecting side. The ultrasonic flow measuring device according to any one of claims 1 to 4, wherein an ultrasonic reflecting member is provided on a wall surface that reflects the ultrasonic waves. The ultrasonic flow measuring device according to any one of claims 1 to 5, wherein the inside of the measurement flow path is partitioned to have a uniform height via a partition plate.

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