JPH0926342A - Ultrasonic oscillator and ultrasonic flowmeter using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the directional control of an ultrasonic oscillator and the measuring accuracy of an ultrasonic flowmeter. SOLUTION: A columnar osicillator 5 is divided into a plurality of oscillating parts 6, 7 and 8, and they are driven at a phase difference of at most a half of wavelength so as to control its directivity. If an ultrasonic flowmeter is compared of an ultrasonic oscillator capable of controlling directionality, the reduction of reception sensitivity of ultrasonic waves can be prevented and the measuring accuracy of flow can be also improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic flowmeter for measuring the flow rate of fluids such as gas and water using ultrasonic waves.

[0002]

2. Description of the Related Art A conventional ultrasonic flowmeter of this type is shown in FIG.
As shown in FIG. 2, a pair of ultrasonic transducers 2 and 3 are provided upstream and downstream of the flow path 1 so as to face each other in the flow direction (indicated by an arrow in the figure), and The ultrasonic wave is transmitted in the direction, the ultrasonic wave is received by the vibrator 3 on the downstream side, and the propagation time of the ultrasonic wave from the vibrators 2 to 3, Tdn, is measured. On the contrary, an ultrasonic wave is transmitted from the vibrator 3 on the downstream side against the flow, the ultrasonic wave is received by the vibrator 2 on the upstream side, and the propagation time of the ultrasonic wave from the vibrator 3 to Tup is Tup. measure. The average flow velocity of the fluid flowing through the flow channel 1 is calculated from the difference between the two propagation times, and the flow rate of the fluid is detected from the cross-sectional area of the flow channel 1 which is known in advance.

[0003]

However, in the above-mentioned conventional ultrasonic flowmeter, the propagation direction of the ultrasonic wave propagating in the flow path 1 is determined by the installation direction of the vibrators 2 and 3, and therefore, for example, the vibrator 2 is used. If 3 and 3 are installed so as to be displaced from the respective center lines 4, the reception sensitivity of ultrasonic waves is extremely lowered. As a result, the S / N ratio decreases, and the measured flow rate value contains an error.
It sometimes malfunctioned. Therefore, the oscillators 2 and 3 are
Each was mechanically adjusted to increase the reception sensitivity. Further, since the ultrasonic waves propagating between the vibrators 2 and 3 are caused to flow in the downstream direction by the fluid flowing in the flow path 1, the propagation direction of the ultrasonic waves is bent. That is, since the propagating ultrasonic wave propagates in the downstream direction of the receiving-side transducer,
The reception intensity of the ultrasonic waves received by the transducer on the receiving side changes depending on the flow velocity of the fluid, which causes an error when measuring the propagation time, and the measured flow rate value includes an error, which may cause malfunction. there were.

The present invention solves the above problems and provides an ultrasonic transducer capable of controlling the direction of transmission of ultrasonic waves and an ultrasonic flow meter capable of highly accurate flow rate measurement over a wide flow rate range. Is.

[0005]

In order to achieve the above object, the ultrasonic vibrator of the present invention has the following constitution.

That is, the structure is made up of a plurality of vibrating parts, each of which is capable of transmitting an ultrasonic wave having a phase difference within a half wavelength independently of each other.

Further, it is constituted such that it comprises a plurality of vibrating portions, each of which is driven independently of each other and with an electrical phase difference within a half wavelength so that ultrasonic waves can be transmitted independently of each other.

Further, it is constituted such that it comprises a plurality of vibrating parts, each of which is driven independently of each other and with a physical phase difference within a half wavelength, and can transmit ultrasonic waves independently of each other.

In order to achieve the above object, the ultrasonic flowmeter of the present invention has the following configuration. That is, a pair of ultrasonic transducers, each of which is composed of a plurality of vibrating parts, is capable of transmitting and receiving ultrasonic waves independently of each other and with a phase difference within a half-wavelength is provided facing the upstream and downstream of the flow path. It was configured to let.

A pair of ultrasonic transducers, each of which is composed of a plurality of vibrating portions, can transmit and receive ultrasonic waves independently of each other and with a phase difference within a half wavelength, is provided at the upstream and downstream sides of the flow path. The ultrasonic wave propagation direction and the fluid flow direction are parallel to each other.

Further, a pair of ultrasonic transducers, each of which is composed of a plurality of transducers, capable of transmitting and receiving ultrasonic waves independently of each other and with a phase difference within a half wavelength, is provided upstream of the flow path. The structure is made to face the downstream side, and the propagation direction of the ultrasonic wave and the direction of the fluid flow are made to cross obliquely.

In addition, a pair of ultrasonic transducers, which are composed of a plurality of vibrating portions arranged in the flow direction, are capable of transmitting and receiving ultrasonic waves independently of each other and with a phase difference within a half wavelength, The upstream side and the downstream side of the passage are faced to each other, and the ultrasonic wave is propagated in the longitudinal direction of the rectangular flow path, and is oblique to the direction of the fluid flow.

In addition, a pair of ultrasonic transducers, which are composed of a plurality of vibrating portions arranged in the flow direction, are capable of transmitting and receiving ultrasonic waves independently of each other and with a phase difference within a half wavelength, The ultrasonic transducer composed of the plurality of vibrating portions is made to face the upstream side and the downstream side of the passage, while the propagation direction of the ultrasonic wave is set in the longitudinal direction of the rectangular flow path, and is obliquely intersected with the flow direction of the fluid. , A configuration in which each vibrating part is driven by sequentially changing the phase difference within a half wavelength, and a plurality of vibrating parts are driven by the phase difference at which the maximum receiving sensitivity is obtained to measure the flow rate of the fluid. did.

[0014]

According to the present invention, since the ultrasonic transducer is divided into a plurality of vibrating portions, and each of them can be independently driven with a phase difference within a half wavelength, it is transmitted from the ultrasonic transducer. The propagation direction of ultrasonic waves, that is, the directivity can be controlled. The ultrasonic waves transmitted from multiple vibrating parts are
Since the phase difference is within a half wavelength, ultrasonic waves interfere with each other in a certain direction (direction with sharp directivity), resulting in mutual strengthening.

Further, when the transducers are installed opposite to each other in a channel such as a pipe line, even if a mechanical displacement occurs in the central axis of the transducers and the reception sensitivity decreases, the By applying a phase difference to the oscillating portion and driving the same, it is possible to correct the deterioration of the ultrasonic wave reception sensitivity due to the mechanical displacement.

Further, even if the ultrasonic wave propagation direction and the fluid flow direction are oblique to each other and the ultrasonic wave is flowed by the fluid and the reception sensitivity of the ultrasonic wave is lowered, the directivity of the vibrator is controlled. Thus, the reception sensitivity of ultrasonic waves can be corrected.

Therefore, the S / N ratio of the ultrasonic wave reception sensitivity is
It is possible to provide an ultrasonic flowmeter which can be kept constant without depending on the positional displacement between the oscillators and the flow velocity of the fluid and which has a small error.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a perspective view of a cylindrical ultrasonic transducer 5 according to an embodiment of the present invention. Three vibrating parts 6,
It is divided into 7 and 8. Vibrating part is PZT, PC
It is composed of a piezoelectric material such as M or PVDF. On top of each part, a baked silver electrode with a thickness of about 10 μm,
Electrodes 6a, 7a, 8a such as vapor-deposited aluminum electrodes are formed. In addition, the same electrode, 6
b, 7b, 8b, (not shown) are formed. In order to be able to supply power to each upper electrode independently,
The lead wires 6c, 7c, 8c are connected to the lower electrodes by 6d, 7c.
d and 8d (not shown) are connected. Reference numeral 5a denotes a partially broken storage container for storing the vibrating portion, which is made of metal such as aluminum or SUS. Reference numeral 5b denotes an electrically insulating spacer for holding the distance between the vibrating portions 6, 7, and 8, which is one half or less of the height of the vibrating portion and is made of epoxy,
It is made of resin such as silicon or rubber, or plastic. In addition, a similar spacer is
It was also provided between the vibrating part and the storage container.

FIG. 2 is a perspective view of a rectangular vibrator 9 according to the second embodiment of the present invention. Three vibrating parts 10,
It is divided into 11 and 12. Vibration part is PZT, P
It is composed of a piezoelectric material such as CM or PVDF. Electrodes 10a, 11a and 12a similar to those of the ultrasonic transducer 5 shown in FIG. 1 are formed on the upper part of each part. Also, an electrode such as a baked silver electrode is also provided on the bottom of each of them.
0b, 11b, 12b, (not shown) are formed. Lead wires 10c, 11c, 12c and 10d, 11d, so as to be able to independently supply power to each electrode,
12d (not shown) are formed. Reference numeral 9a denotes a partially broken container that houses the vibrating portion, such as aluminum, SU
It is composed of a metal such as S. 9b is a vibrating part 10, 1
An electrically insulative spacer for holding the intervals of 1 and 12 is shown, which is one half or less of the height of the vibrating portion and is made of resin such as epoxy or silicon or rubber, or plastic. A similar spacer was also provided between the vibrating portion and the storage container.

Similarly, FIG. 3 is a perspective view of a rectangular vibrator 13 according to the third embodiment of the present invention. The vibrating part is divided into six parts. The vibrating portion is stored and fixed in the storage container 13a. Moreover, an electrically insulating spacer 1 is provided between the vibrating parts and between the vibrating part and the storage container.
3b is provided. For each vibrating part,
As shown in FIG. 2 and FIG. 2, electrodes and lead wires (not shown) for supplying power are formed.

For example, the cylindrical vibrator 5 shown in FIG.
When the three vibrating portions 6, 7, 8 are driven simultaneously, that is, in the same phase, the directional characteristic of the ultrasonic wave transmitted from the cylindrical vibrator 5 is the diameter of the cylinder and the ultrasonic wave transmitted. Shows the directional characteristic determined by the wavelength of, i.e., the spatial intensity distribution, and the central axis of the cylindrical vibrator 5 is the reference axis in that case. However, as shown in FIG. 4, when three independent driving power sources 14, 15, 16 are used to sequentially drive the three vibrating portions 6, 7, 8 with a certain phase difference within one-half wavelength. As described above, the spatial intensity distribution is the same as that when driven in the same phase, but the reference axis can be controlled and the reference axis can be deviated from the central axis of the cylinder. Therefore, it is possible to control the directivity,
Ultrasonic waves can be transmitted in any direction. In this case, the oscillator used was one that was completely separated at each oscillating portion, but the directivity of the present invention can be controlled even if the oscillator is coupled at a portion of the lower end half or less. Become. That is, it is possible to slit one half or more of the vibrator from the top or bottom of one vibrator. The deeper the slit depth, the better the degree of vibration isolation. In addition, the rectangular vibrator 9 shown in FIG.
When 11 and 12 are driven at the same time, that is, in the same phase, the directional characteristics of the ultrasonic waves transmitted from the rectangular transducer 9 are
That is, the spatial intensity distribution shows a directional characteristic that is determined by the length of the rectangular side and the wavelength of the transmitted ultrasonic wave. But,
As shown in FIG. 4, by using three independent driving power sources, the three vibrating parts 1 with a phase difference within a half wavelength are used.
When 0, 11, and 12 are sequentially driven, the spatial intensity distribution is the same as that when driven in the same phase described above, but its reference axis can be freely shifted in any direction, The directional characteristics can be controlled. In this case, the controllable directions are the left and right directions in FIG. The intensity distribution in the vertical direction in FIG. 2 is the same as when driven in phase,
Can't control. Further, the central vibration portion 11
If the phase for driving is delayed a little more than the vibration parts 10 and 12 on both sides thereof, the ultrasonic wave transmitted from the vibrator 9 can be converged, so that a stronger ultrasonic wave that does not spread so much is transmitted. You can also

Further, in the case of the rectangular vibrator 13 shown in FIG. 3, for example, when 6 vibrating parts are driven by using 6 independent driving power sources, the reference axis of the transmitted ultrasonic wave is arbitrarily set. Can be controlled. That is, the control can be performed in the horizontal direction or the vertical direction in FIG. Therefore, in this case, by combining these, the ultrasonic wave transmission direction can be controlled in an arbitrary direction.

FIG. 5 is a diagram for explaining the directivity of ultrasonic waves according to the fourth embodiment. FIG. 5A is a view seen from the upper surface of the rectangular vibrator 9 shown in FIG. 2, and FIG. 5B is a front view thereof. The storage container 9b is omitted. The vibrator 9 has a vibrating part divided into three parts of 18, 19, and 20.
The thickness of the top and bottom of each vibrating part is about 10μ.
electrodes 18a, 18b, 19 made of baked silver of about m
a and 19b and 20a and 20b are formed. The lead wire for power supply is omitted. As shown in FIG. 5B, each vibrating part has a stepwise shape in the vertical direction. When the rectangular oscillator 9 is driven by the drive power source 21 shown in FIG. 6, the vibrating units 18, 19 and 20 simultaneously transmit ultrasonic waves, but as shown in FIG.
Since 8, 19, 20 are vertically stepped,
For example, when waiting for the propagation of ultrasonic waves at a certain point in the upper part of FIG. 5B, the ultrasonic waves from the vibrating unit 18 arrive first, and then from 19 to 20. You will arrive in order. Therefore, in the right direction of FIG. 5A, that is, in the upper right direction of FIG.
The strongest ultrasonic wave is obtained in the direction equidistant from 9, 20. Thus, by mechanically adjusting the distance of the vibrating portion in the vertical direction, even if a plurality of vibrating portions are driven in the same phase, the strongest direction of ultrasonic waves can be controlled.

FIG. 7 is a sectional view of the sonic flow meter 22 in which the cylindrical ultrasonic transducer 5 described in FIG. 1 is installed on the upstream side 51 and the downstream side 52. The fluid flows in the flow path 1 in the direction of the arrow. In this case, since the ultrasonic wave propagation paths are located upstream and downstream of the flow path 1 and obliquely intersect with the flow path, it is extremely difficult to make the central axes 23 exactly coincident with each other in practice. Met. Therefore, in the past, the oscillator 51,
Alternatively, the geometrical inclination of 52 is adjusted so as to increase the ultrasonic wave reception sensitivity. However, when the ultrasonic transducer of the present invention is used, it is possible to set the ultrasonic wave reception sensitivity to a large value simply by electrically delaying or advancing the phase, which is very simple. Also,
As described with reference to FIG. 5, the ultrasonic wave reception sensitivity can be easily increased simply by sliding each vibrating part back and forth without tilting the ultrasonic vibrator. Therefore, the adjustment work is simple and easy.

FIG. 8 is a cross-sectional view of the sonic flow meter 24 in which the cylindrical ultrasonic transducer 5 described in FIG. 1 is installed on the upstream side 51 and the downstream side 52. The fluid flows in the flow path 1 in the direction of the arrow. In this case, the ultrasonic wave propagation path is arranged in parallel with the flow path. In addition, the ultrasonic transducer 5a1,
Since 5a2 and 5a2 are arranged in the center of the flow path, it was practically very difficult to accurately match the central axes 25 with each other. Therefore, in the past, the oscillator 51 or the
Although the inclination of 52 was adjusted to set the ultrasonic wave reception sensitivity to be high, the workability was extremely poor because the transducer was installed in the center of the flow path. When the ultrasonic transducer of the present invention is used, it is possible to easily and easily set a large ultrasonic wave reception sensitivity simply by electrically delaying or advancing the phase. Further, as described with reference to FIG. 5, the ultrasonic wave reception sensitivity can be easily increased simply by sliding each vibrating part back and forth without tilting the ultrasonic vibrator. For this reason, it is possible to work after it is securely fixed. Therefore, the adjustment work becomes easy. When the phase is electrically adjusted, the ultrasonic transducer can be easily and externally adjusted even if it is located in the center of the flow path.

FIG. 9 is a diagram showing an ultrasonic flowmeter 26 according to the seventh embodiment. As the ultrasonic transducer, a rectangular transducer 9 is used, where the upstream side is 91 and the downstream side is 92. The horizontal direction shown in FIG. 2 was made to coincide with the flow direction (arrow) of the fluid in the channel 1. Therefore, the arrangement is such that the directivity can be controlled in the direction in which the fluid flows. The ultrasonic wave propagation path 27 is oblique to the flow direction of the fluid. In such an arrangement, for example, when there is no fluid flow, that is, when the fluid is in a stationary state, the reception sensitivity of the ultrasonic waves transmitted / received to / from the transducers 91 and 92 is the electrical phase difference or the physical difference. It is assumed that the optimum value is set by adjusting the physical phase difference. When the fluid flows in such a state, for example, the ultrasonic waves transmitted from the transducer 91 on the upstream side are flown by the fluid, and when reaching the transducer 92 on the downstream side, the ultrasonic reception sensitivity is maximized. Is flowed to the downstream side of the optimum position. On the contrary, the ultrasonic waves transmitted from the transducer 92 on the downstream side are made to flow to the fluid, and when reaching the transducer 91 on the upstream side, the ultrasonic waves are located on the downstream side of the optimum position where the ultrasonic wave reception sensitivity is maximum. Shed Therefore, the reception sensitivity of ultrasonic waves is the flow rate of the fluid, that is,
Depending on the flow velocity, the flow rate may decrease or the flow rate may be erroneously measured, resulting in malfunction. In the present invention, the oscillator 9 whose directivity can be controlled in the direction of fluid flow
Since 1 and 92 are used, by adjusting the electrical phase difference, the optimum directivity that maximizes the reception sensitivity of ultrasonic waves can always be ensured regardless of the flow rate of the fluid. Therefore, an error does not occur in the flow rate measurement, and stable and accurate flow rate measurement can be performed.

FIG. 10 is a diagram showing an ultrasonic flowmeter 28 according to the eighth embodiment, and FIG. 10A is a sectional view thereof.
(B) shows the AA 'cross section of (a). As the ultrasonic transducer, a rectangular transducer 9 is used, with 91 on the upstream side and 9 on the downstream side.
Let it be 2. The left-right direction shown in FIG. 2A was made to coincide with the flow direction (arrow) of the fluid in the channel 1. Therefore, the arrangement is such that the directivity can be controlled in the direction in which the fluid flows.
The ultrasonic wave propagation path 29 crosses the flow direction of the fluid obliquely. The cross-sectional shape 30 of the flow channel 1 was rectangular. The short side 31 of the rectangular flow path has a size of about 5 to 20 mm, which is about the size of the ultrasonic transducer used. In addition, the long side 32 of the rectangular channel
Is calculated from the pressure loss at the maximum flow rate, and is generally 3 to 1 on the short side.
It was set to about 0 times. A strong ultrasonic wave was obtained by setting the short side 31 of the flow path to about the size of the transducer used. That is, since the ultrasonic wave transmitted from the vibrator 91 or 92 propagates in the width about the size of the vibrator, the ultrasonic wave in the short side direction (3
In the direction 1), almost no diffusion is possible. That is, since the ultrasonic wave transmitted from the short side 31 side is reflected by the long side 32, it does not diffuse. Further, in the flow direction of the fluid, both the upstream-side transducer 91 and the downstream-side transducer 92 can converge the ultrasonic waves to be transmitted and can control the directivity, so that the transmitted ultrasonic waves are Even if it is made to flow in the stream, it is possible to easily optimize the reception sensitivity of ultrasonic waves by adjusting the electrical phase difference. Therefore, in the ultrasonic flowmeter of the present invention, particularly in the ultrasonic flowmeter of the present invention having a rectangular cross-sectional flow path, strong ultrasonic waves are always transmitted and received, so that the ultrasonic wave reception sensitivity is large and the error A small amount of flow can be measured.

FIG. 11 shows the ultrasonic flowmeter 2 shown in FIG.
8 is a block diagram for explaining the operation of FIG. 33 is a phase variable transmitter, 34 is its output terminal, and the transmitter 9
1, 92 are connected. Reference numeral 35 is a variable phase receiver, 36 is an input terminal thereof, and receiving side oscillators 92 and 9 are provided.
1 is connected. Reference numeral 37 is an amplifier circuit, and 38 is a microcomputer, which performs arithmetic processing and generates a transmission command. For example, by connecting the upstream oscillator 91 to the output terminal 34 of the phase variable transmitter 33 and sequentially changing the phase between the plurality of terminals, the oscillator 9
1 is transmitted, and ultrasonic waves are transmitted along the propagation path 29.
The signal received by the downstream oscillator 92 is input to the variable phase receiver 35 via the input terminal 36. The output from 35 is amplified by the amplifier circuit 37 to such an extent that it can be easily processed by the microcomputer 38. The microcomputer 38 calculates and determines the optimum transmission phase and reception phase of ultrasonic waves from the phase relationship between the transmission side and the reception side. After that, the transducer 92 on the downstream side is connected to the output terminal 34, and the transducer 91 on the upstream side is connected to the input terminal 36, and the optimum transmission phase and reception phase of the ultrasonic waves are determined in the same manner as described above. The respective transmission / reception conditions are stored in the microcomputer 38, and accurate flow rate measurement is performed under the conditions. In addition, when a large change is not recognized in the flow rate value of the measurement result, the flow rate is measured under the same condition.

When a large change is found in the measured flow rate value, the optimum transmission / reception conditions are obtained before measuring the flow rate again.
The flow rate is measured under the new optimum condition. In addition, the optimum transmission / reception conditions are repeatedly obtained many times, and the microcomputer 3
In 8, the optimum phase condition corresponding to the measured flow rate value can be easily obtained by storing each time.

When obtaining the optimum transmission / reception conditions, if the phase difference of the phase variable type receiver is set to zero phase difference, the reception sensitivity is slightly lowered, but the optimum condition can be more easily found.

[0032]

As is apparent from the above description, according to the ultrasonic transducer of the present invention and the ultrasonic flowmeter using the same, the following effects can be obtained.

(1) Since it is composed of a plurality of vibrating parts, each of which has a function of transmitting ultrasonic waves having a phase difference within a half wavelength independently of each other, the directivity of the ultrasonic waves to be transmitted is changed. Can be controlled.

(2) It is composed of a plurality of vibrating parts, each of which is driven independently of each other and with an electrical phase difference within a half wavelength, and has a function of transmitting ultrasonic waves independently of each other. Therefore, the directivity of the transmitted ultrasonic wave can be electrically controlled.

(3) It comprises a plurality of vibrating parts, each of which is driven independently of each other and with a physical phase difference within a half wavelength, and has a function of transmitting ultrasonic waves independently of each other. Therefore, the directivity of the ultrasonic waves to be transmitted can be physically controlled.

(4) A pair of ultrasonic transducers, each of which is composed of a plurality of vibrating portions, is capable of transmitting and receiving ultrasonic waves independently of each other and with a phase difference within a half wavelength, upstream of the flow path, Because it is configured to face the downstream, even if the ultrasonic transducer is displaced, by controlling the directivity,
The position can be adjusted easily and the adjustment is easy. Therefore, the ultrasonic wave reception sensitivity is high, and the flowmeter has few malfunctions.

(5) A pair of ultrasonic transducers, each of which is composed of a plurality of vibrating portions and is capable of transmitting and receiving ultrasonic waves independently of each other and with a phase difference within a half wavelength, is provided upstream of the flow path. Since the ultrasonic wave is directed to the downstream side and the propagation direction of the ultrasonic wave is parallel to the flow direction of the fluid, even if the vibrator is located in the center of the flow path, it is possible to use the Since the directivity can be controlled, the alignment between the transducers can be easily performed and the adjustment becomes easy. Therefore, the ultrasonic wave reception sensitivity is high, and the flowmeter has few malfunctions.

(6) A pair of ultrasonic transducers, each of which is composed of a plurality of transducer portions and is capable of transmitting and receiving an ultrasonic wave independently of each other and with a phase difference within one-half wavelength, is provided upstream of the flow path. , The downstream is faced, and the propagation direction of the ultrasonic wave and the direction of the flow of the fluid are obliquely crossed. Therefore, even if the transmitted ultrasonic wave is flowed by the flow of the fluid, the directivity is not changed. Since it can be controlled, the optimum ultrasonic wave reception sensitivity can always be obtained, and the flowmeter has few malfunctions.

(7) A pair of ultrasonic transducers, each of which is composed of a plurality of vibrating portions arranged in the flow direction and which can transmit and receive ultrasonic waves independently of each other and with a phase difference within a half wavelength, The transmitted ultrasonic waves are rectangular because the configuration is such that they face the upstream and downstream of the flow path, the propagation direction of the ultrasonic wave is in the longitudinal direction of the rectangular flow path, and it intersects with the flow direction of the fluid. Is confined in the height direction of the flow path, and
The ultrasonic waves are converged in the flow direction of the fluid by controlling the directivity, so that the reception sensitivity of the ultrasonic waves is increased and the flow meter has less malfunctions.

(8) A pair of ultrasonic transducers, each of which is composed of a plurality of vibrating portions arranged in the flow direction and which can transmit and receive ultrasonic waves independently of each other and with a phase difference within a half wavelength, An ultrasonic transducer composed of a plurality of vibrating portions, which face the upstream side and the downstream side of the flow path, set the propagation direction of ultrasonic waves in the longitudinal direction of the rectangular flow path, and obliquely intersect with the flow direction of the fluid. , Each vibrating part is driven by sequentially changing the phase difference within a half wavelength, and the plurality of vibrating parts are driven by the phase difference obtained with the maximum receiving sensitivity to measure the fluid flow rate. With this configuration, regardless of the flow rate of the fluid, the reception sensitivity of ultrasonic waves can always be optimized,
The flow meter has few malfunctions.

[Brief description of drawings]

FIG. 1 is a perspective view of an ultrasonic transducer according to a first embodiment of the present invention.

FIG. 2 is a perspective view of an ultrasonic transducer according to a second embodiment of the present invention.

FIG. 3 is a perspective view of an ultrasonic transducer according to a third embodiment of the present invention.

FIG. 4 is a circuit diagram for driving the ultrasonic transducer of the present invention.

FIG. 5 (a) is a top view of an ultrasonic oscillator according to a fourth embodiment of the present invention, and (b) is a front view of the same oscillator.

FIG. 6 is another circuit diagram for driving the ultrasonic transducer of the present invention.

FIG. 7 is a sectional view of an ultrasonic flowmeter according to a fifth embodiment of the present invention.

FIG. 8 is a sectional view of an ultrasonic flowmeter according to a sixth embodiment of the present invention.

FIG. 9 is a sectional view of an ultrasonic flowmeter according to a seventh embodiment of the present invention.

FIG. 10 (a) is a sectional view of an ultrasonic flowmeter according to an eighth embodiment of the present invention. (B) is a sectional view taken along the line AA ′ of the same flowmeter.

FIG. 11 is a drive circuit block diagram of the ultrasonic flowmeter according to the embodiment of the present invention.

FIG. 12 is a sectional view of a conventional ultrasonic flowmeter.

[Explanation of symbols]

 5 Cylindrical ultrasonic transducers 6, 7, 8 Vibrating portions 6a, 7a, 8a Electrodes 6b, 7b, 8b Electrodes 9, 13, 17 Rectangular ultrasonic transducers 14, 15, 16 Drive power supply

Claims (8)

[Claims] 1. An ultrasonic transducer comprising a plurality of vibrating parts, each of which transmits an ultrasonic wave having a phase difference within a half wavelength independently of each other. 2. An ultrasonic vibration system comprising a plurality of vibrating parts, each of which is driven independently of each other and with an electrical phase difference within a half wavelength, and which transmits ultrasonic waves independently of each other. Child. 3. An ultrasonic vibration system comprising a plurality of vibrating parts, each of which is driven independently of each other and with a physical phase difference within a half wavelength, and which transmits ultrasonic waves independently of each other. Child. 4. A pair of ultrasonic transducers comprising a plurality of vibrating portions, each of which is capable of transmitting and receiving ultrasonic waves independently of each other and with a phase difference within a half wavelength, upstream of a flow path,
An ultrasonic flow meter facing downstream. 5. A pair of ultrasonic transducers comprising a plurality of vibrating portions, each of which is capable of transmitting and receiving ultrasonic waves independently of each other and with a phase difference within a half wavelength, upstream of the flow path,
An ultrasonic flowmeter, which faces the downstream side and in which the propagation direction of ultrasonic waves and the direction of fluid flow are parallel. 6. A pair of ultrasonic transducers comprising a plurality of transducer portions, each of which is capable of transmitting and receiving an ultrasonic wave independently of each other and with a phase difference within a half wavelength, upstream of a flow path, An ultrasonic flowmeter, which is arranged so as to face downstream and in which the propagation direction of ultrasonic waves and the direction of fluid flow are crossed obliquely. 7. A pair of ultrasonic transducers, each of which is composed of a plurality of vibrating portions arranged in the flow direction, capable of transmitting and receiving ultrasonic waves independently of each other and with a phase difference within a half wavelength, An ultrasonic flowmeter which is arranged so as to face the upstream side and the downstream side of the passage, the propagation direction of the ultrasonic wave is set in the longitudinal direction of the rectangular flow path, and is oblique to the direction of the fluid flow. 8. A pair of ultrasonic transducers, each of which is composed of a plurality of vibrating portions arranged in the flow direction, capable of transmitting and receiving an ultrasonic wave independently of each other and with a phase difference within a half wavelength, The ultrasonic transducer composed of the plurality of vibrating portions is made to face the upstream side and the downstream side of the passage, while the propagation direction of the ultrasonic wave is set in the longitudinal direction of the rectangular flow path, and is obliquely intersected with the flow direction of the fluid. , Each vibration part is driven by sequentially changing the phase difference within a half wavelength, and the flow rate of the fluid is measured by driving the plurality of vibration parts with the phase difference with the maximum receiving sensitivity. Ultrasonic flow meter.