JPH10246658A - Flowmeter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flowmeter which achieves a higher measuring accuracy by using an ultrasonic sensor free from the adhesion of any acoustic bond sticking onto the side or the rear of an ultrasonic element without fine control of the amount of a bond such as acoustic bond. SOLUTION: A plurality of recessed parts 17 which have a portion located outside a part contacting the facade 10 of an ultrasonic element through an acoustic bond 16 are arranged on the surface 15 of a diaphragm along the outer circumference of the surface 15 of the diaphragm. As a result, the acoustic bond 16 spilling from between the ultrasonic element 9 and the diaphragm 14 flows into the recessed parts 17 and none thereof 16 adheres to the side and the rear side of the ultrasonic element 9. This achieves highly efficient transmission or reception of ultrasonic waves thereby improving the measuring accuracy of the flow rate and reliability of a flowmeter with a larger S/N ratio of the ultrasonic wave.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow meter for measuring a flow rate of a fluid to be measured using an ultrasonic sensor.

[0002]

2. Description of the Related Art Conventionally, ultrasonic flow meters, vortex flow meters and the like are known as flow meters for measuring the flow rate of a fluid to be measured using an ultrasonic sensor. Here, taking the vortex flow meter A as an example,
This will be described with reference to FIG. 4 showing a vertical cross section of the vortex flowmeter A and FIG. 5 showing a radial cross section of the vortex flowmeter A.

The vortex flow meter A is provided with a pipe 3 through which a fluid to be measured flows.
The vortex generator 2 is provided therein, and a pair of ultrasonic sensors 22 opposed to the pipe 3 downstream of the vortex generator 2 are provided.
The ultrasonic sensor 22 includes an ultrasonic transmitter 22a and an ultrasonic receiver 22b, and these ultrasonic transmitter / receivers 22a,
22b have the same structure. One of the ultrasonic sensors 22 is connected to an oscillator 23 and functions as an ultrasonic transmitter 22a for transmitting ultrasonic waves, and the other is connected to a detector 24 and functions as an ultrasonic receiver 22b.

The ultrasonic waves transmitted from the ultrasonic transmitter 22a are phase-modulated by Karman vortices generated alternately in the fluid to be measured by the vortex generator 2 when propagating in the pipe 3,
It is received by the ultrasonic receiver 22b. The generation frequency of the Karman vortex is obtained from the received ultrasonic waves, and the flow rate of the fluid to be measured is measured using the fact that the generation frequency of the Karman vortex is proportional to the flow rate.

Next, the structure of the ultrasonic sensor 22 will be described.
This will be described with reference to the cross-sectional view of the ultrasonic sensor 22 shown in FIG. The ultrasonic sensor 22 (22a, 22b) has a bottomed cylindrical shape having a flange 6 (6a, 6b) fitted into a hole 4 (4a, 4b) formed in the pipe 3 of the vortex flowmeter A main body. Sensor holder 8 (8a, 8b) and an ultrasonic element 9 (9) composed of a piezoelectric element housed in the sensor holder 8.
a, 9b) and a lid 13 (13a, 13b) for enclosing the ultrasonic element 9 in the sensor holder 8. The bottom surface of the sensor holder 8 is a vibration plate 25 (25a, 25b) that vibrates by the ultrasonic wave transmitted from the ultrasonic element 9, and the thickness thereof is 1 / the best in the propagation characteristic of the ultrasonic wave.
It is set to 2 lambdas.

[0006] In the sensor holder 8, the element holder 11 (11 a, 11 b) for positioning the ultrasonic element 9 at a predetermined position on the diaphragm surface 26 (26 a, 26 b) and by applying back pressure to the element holder 11. A disc spring 12 (12a, 12b) for pressing the ultrasonic element 9 against the diaphragm surface 26 is provided, and between the ultrasonic element 9 and the sensor holder 8 to improve the propagation characteristics of ultrasonic waves. Acoustic bonding agent 16 (16) such as grease, silicone gel, RTV rubber, etc.
a, 16b) are applied.

[0007] The acoustic bonding agent 16 has fluidity and a certain degree of viscosity, and can be made viscous or hardened by performing a treatment with heating, a chemical, or the like. Materials (eg, silicon gel, RTV
Rubber). Therefore, the ultrasonic element 9 and the diaphragm 26
When the ultrasonic sensor 22 is attached to the main body of the vortex flowmeter A, it has sufficient viscosity or hardens when it is applied between the vortex flowmeter A and the main body. Therefore, it does not flow out from between the ultrasonic element 9 and the diaphragm 26.

Next, the operation of the ultrasonic sensor 22 configured as described above will be described. First, a drive signal for instructing transmission of ultrasonic waves at a frequency substantially equal to the resonance frequency of the ultrasonic element 9a is supplied from the oscillator 23 to the ultrasonic element 9a of the ultrasonic transmitter 22a. The ultrasonic element 9a to which the driving signal is supplied from the oscillator 23 transmits an ultrasonic wave, and the ultrasonic wave propagates from the acoustic bonding agent 16a to the diaphragm 25a. In the portion of the ultrasonic element 9a where the acoustic bonding agent 16a is not attached,
Since a minute air layer is formed, the ultrasonic wave hardly propagates, so that the ultrasonic wave propagates only to the diaphragm 25a joined by the acoustic bonding agent 16a. If the drive signal supplied from the transmitter 23 has a frequency far from the resonance frequency of the ultrasonic element 9a, almost no ultrasonic waves are transmitted from the ultrasonic element 9a.

The ultrasonic wave transmitted from the ultrasonic element 9a propagates to the diaphragm 25a, and the diaphragm 25a vibrates at the frequency of the ultrasonic wave, so that the vibration of the diaphragm 25a is transmitted through the fluid in the pipe 3. The vibration propagates and vibrates the diaphragm 25b of the ultrasonic receiver 22b. The vibration of the vibration plate 25b of the ultrasonic receiver 22b propagates through the acoustic bonding agent 16b to the ultrasonic element 9b having the same vibration characteristics as the ultrasonic element 9a of the ultrasonic transmitter 22a and is received. It is detected by the detector 24 connected to the sound wave element 9b. When the frequency of the ultrasonic wave propagating to the ultrasonic element 9b is far from the resonance frequency of the ultrasonic element 9b, almost no ultrasonic waves are received by the ultrasonic element 9b.

[0010]

In the ultrasonic transmitter 22a of the ultrasonic sensor 22 of the conventional flowmeter, the surface of the ultrasonic element 9a which is not on the diaphragm 25a side, that is, the surface 10a on the diaphragm 25a side is used. If the acoustic bonding agent 16a adheres to the side surface or the rear surface when it is set to the front, the resonance frequency of the ultrasonic element 9a itself changes and shifts from the frequency of the drive signal supplied from the oscillator 23. There are problems that the sound wave is not transmitted or that the propagation characteristics of the ultrasonic wave are reduced and the transmission efficiency of the ultrasonic wave is reduced.
In addition, there is a problem that when the ultrasonic wave propagates to the side surface or the rear surface, energy is lost correspondingly, and the ultrasonic wave cannot be transmitted efficiently.

Also, on the ultrasonic receiver 22b side,
Like the ultrasonic transmitter 22a, the diaphragm 2 of the ultrasonic element 9b
If the acoustic bonding agent 16b adheres to the surface other than the 5b side, that is, the side surface or the back surface when the surface 10b on the diaphragm 25b side is the front, the resonance frequency of the ultrasonic element 9b itself changes and the ultrasonic element 9b becomes There are problems such as the inability to receive a sound wave and the deterioration of the propagation characteristics of the ultrasonic wave, thereby reducing the ultrasonic wave reception efficiency.

Further, in order to solve the above-mentioned problem, the amount of the acoustic bonding agent 16 is reduced so that the portion other than the bonding portion of the ultrasonic element 9 with the diaphragm 25 (between the front surface 10 of the ultrasonic element and the surface 26 of the diaphragm). It is conceivable to prevent the acoustic bonding agent from adhering to the surface. However, if the amount of the acoustic bonding agent 16 is reduced and the bonding between the front surface 10 of the ultrasonic element 9 and the surface 26 of the diaphragm 25 becomes insufficient, the ultrasonic transmitter 22a
In such a case, there is a possibility that a problem that the ultrasonic wave transmitted by the ultrasonic element 9a does not propagate to the diaphragm 25a or the propagation characteristic is deteriorated may occur. In the ultrasonic receiver 22b, the vibration of the diaphragm 25b There is a possibility that a problem that the light does not propagate to the sound wave element 9b or the propagation characteristics are deteriorated may occur.

Therefore, when the acoustic bonding agent 16 is not applied in an appropriate amount, the ultrasonic transmitter 22a has:
Even if the ultrasonic element 9a is supplied with energy enough to transmit an ultrasonic wave at a level necessary for detecting the flow rate of the fluid to be measured, only an ultrasonic wave below the required level can be transmitted, and the ultrasonic receiver 22b side Since the ultrasonic element 9b does not receive the ultrasonic wave at the level required for detecting the flow rate of the fluid to be measured, the flow rate measurement cannot be performed accurately, and the ultrasonic element 9b may not function as a flow meter.

Therefore, the acoustic bonding agent 16 is
It is conceivable to apply only an appropriate amount that is enough to join the vibration plate 25 and the surface, and does not flow out or adhere to a surface of the ultrasonic element 9 that is not on the vibration plate 25 side. It was very difficult to apply an appropriate amount to the varnish.

The present invention has been made in view of the above-mentioned problems, and uses an ultrasonic sensor which does not cause the above-mentioned problems without finely controlling the application amount of a bonding agent such as an acoustic bonding agent. An object of the present invention is to provide a flow meter with improved measurement accuracy.

[0016]

According to the present invention, there is provided an ultrasonic transmitter which is attached to a pipe through which a fluid to be measured flows and transmits ultrasonic waves toward the fluid to be measured, and an ultrasonic transmitter which transmits the ultrasonic wave to the fluid to be measured. An ultrasonic receiver comprising: an ultrasonic receiver that receives ultrasonic waves through the fluid to be measured; and the piping based on a modulation of an ultrasonic signal by a flow of the fluid to be measured detected by the ultrasonic sensor. Measuring means for measuring the flow rate of the fluid to be measured, and at least one of the ultrasonic transmitter and the ultrasonic receiver that constitute the ultrasonic sensor is configured to transmit ultrasonic waves. An ultrasonic element for transmitting or receiving, a vibration plate vibrated by the ultrasonic wave, and a bonding agent for bonding between the vibration plate and the ultrasonic element, comprising: The surface has a recess into which the bonding agent flows. It is characterized in that is.

Therefore, the ultrasonic sensor has a configuration in which the excessively applied bonding agent flows into the concave portion of the diaphragm.

Further, the invention according to claim 2 is characterized in that at least a part of the concave portion of the vibration plate is located outside a portion in contact with the ultrasonic element via the bonding agent. I do.

Therefore, when the bonding agent flows into the concave portion of the vibrating plate, the air reservoir is prevented from being formed in the concave portion.

Further, the invention according to claim 3 is characterized in that the concave portion of the diaphragm is an annular groove.

Accordingly, the diaphragm is provided with a concave portion into which a bonding agent excessively applied to the surface of the diaphragm flows, and the thickness of the joint between the periphery of the diaphragm and the diaphragm is reduced.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a vortex flowmeter using an ultrasonic sensor 1 according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a cross section of the ultrasonic sensor 1 according to the present embodiment, and FIG. 2 shows a surface 15 of a diaphragm 14 of the ultrasonic sensor 1. The description of the entire configuration is the same as that of the conventional vortex flow meter A shown in FIGS. Further, the ultrasonic transmitter 1a and the ultrasonic receiver 1b constituting the ultrasonic sensor 1 of the present embodiment have the same configuration.

As shown in FIGS. 1 and 2, the ultrasonic sensor 1
The ultrasonic transmitter 1a and the ultrasonic receiver 1b constituting
Two holes 4 (4a, 4b) provided opposite to the flow meter pipe 3 downstream of the vortex generator 2 are fitted to each other. In order to prevent the ultrasonic waves transmitted from the ultrasonic transmitter 1a from propagating to the pipe 3 (or to prevent the ultrasonic waves from the pipe 3 from propagating to the ultrasonic receiver 1b), The size of the holes 4a, 4b is
a and slightly larger than the size of the ultrasonic receiver 1b, and slightly between the inner peripheral surface of the hole 4 (4a, 4b) and the outer peripheral surface of the ultrasonic sensor 1 (1a, 1b). Space 5
(5a, 5b) are formed. Ultrasonic sensor 1 (1
a, 1b) are pipes 3 at the flange portions 6 (6a, 6b).
, And a seal member 7 (7a, 7b) is provided between the flange portion 6 (6a, 6b) and the pipe 3.

The ultrasonic sensor 1 has a bottomed cylindrical sensor holder 8 having a flange portion 6 for fixing to the pipe 3.
(8a, 8b), an ultrasonic element 9 (9a, 9b) composed of a piezoelectric element for transmitting or receiving an ultrasonic wave, and an element oscillator 11 for positioning the ultrasonic element 9 in the sensor holder 8 ( 11a, 11b) and a coned disc spring 12 (12a, 12a) for pressing the ultrasonic element 9 against the bottom surface of the sensor holder 8.
12b) and a lid 13 (13a, 13b).

The bottom of the sensor holder 8 has a disk-shaped portion surrounded by a cylinder serving as a vibration plate 14 (14a, 4b). The acoustic bonding agent 16 (16
a, 16b) are applied. As shown in FIG. 2, a surface 15 (15a, 15b) of the vibration plate 14 on the ultrasonic element 9 side.
(Hereinafter referred to as the diaphragm surface 15) than a portion which is in contact with the surface 10 (10 a, 10 b) (hereinafter referred to as the ultrasonic element front surface 10) of the ultrasonic element 9 via the acoustic bonding agent 16. A plurality of recesses 17 (17
a, 17b) are provided side by side along the outer periphery of the diaphragm surface 15.

In the ultrasonic sensor 1 configured as described above, the acoustic bonding agent 16 is applied to the diaphragm surface 15, the ultrasonic element 9 is positioned by the element elastic 11, and the disc spring 12 applies an appropriate pressing force. By pressing, the ultrasonic element 9 is pressed to a predetermined position of the diaphragm 14, and the diaphragm surface 1
A thin film of the acoustic bonding agent 16 is formed between 5 and the ultrasonic element front surface 10. At this time, in the ultrasonic sensor 1 of the present embodiment, the acoustic bonding agent 16 that has protruded from between the ultrasonic element 9 and the diaphragm 14 flows into the concave portion 17, so that the acoustic bonding agent 16 The protruding acoustic bonding agent 16 does not adhere.

Accordingly, in the ultrasonic transmitter 1a, since the ultrasonic wave does not propagate to the side surface and the back surface of the ultrasonic element 9a, it is possible to prevent the energy from being lost. Further, in the ultrasonic transmitter 1a and the ultrasonic receiver 1b, the ultrasonic wave does not stop propagating and the ultrasonic wave propagation characteristics do not deteriorate.

Further, in the present embodiment, the concave portion 17 serving as a fluid reservoir into which the excess acoustic bonding agent 16 flows is opened outside the portion of the diaphragm surface 15 which is in contact with the ultrasonic element 9. Therefore, when the acoustic bonding agent 16 flows in, no air is trapped in the concave portion 17, and therefore, it is possible to prevent the propagation of ultrasonic waves from being hindered by the air trap.

Therefore, the vortex flowmeter according to the present embodiment can efficiently transmit and receive ultrasonic waves at a level necessary for detecting Karman vortices, so that the S / N ratio (signal / Noise ratio) is increased, the detection accuracy of Karman vortex is improved, and the flow measurement accuracy and reliability of the flow meter are improved.

The concave portion 17 of the present embodiment has a portion located outside the portion of the diaphragm surface 15 which is in contact with the front surface 10 of the ultrasonic element via the acoustic bonding agent 16. Even if the entire concave portion 17 is located inside the portion of the front surface 15 that comes into contact with the ultrasonic element front surface 10 via the acoustic bonding agent 16, it protrudes from between the ultrasonic element 9 and the diaphragm 14. The acoustic bonding agent 16 that has flowed into the concave portion 17 does not adhere to the side or back surface of the ultrasonic element 9.

Next, an ultrasonic sensor 18 of an ultrasonic vortex flowmeter according to a second embodiment of the present invention will be described with reference to FIG. Note that the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted. As for the ultrasonic sensor 18, the ultrasonic transmitter 18a and the ultrasonic receiver 18b have the same configuration.

The ultrasonic sensor 18 of this embodiment differs from the ultrasonic sensor 1 of the first embodiment in that the sensor holder 8
Grooves 21 (21a, 21b) are provided outside the portion of the bottom diaphragm 19 (19a, 19b) that contacts the ultrasonic element 9.
b) is provided annularly along the outer periphery of the diaphragm surface 20 (20a, 20b).

As in the first embodiment, the acoustic bonding agent 16 is applied to the surface 20 of the diaphragm, and the ultrasonic element 9 is connected to the element oscillator 1.
The ultrasonic element 9 is pressed to a predetermined position on the diaphragm 19 by positioning the plate 1 and pressing the disc spring 12 with an appropriate pressing force, and an acoustic wave is generated between the diaphragm surface 20 and the ultrasonic element front 10. A thin film of the bonding agent 16 is formed. At this time,
In the ultrasonic sensor 18 of the present embodiment, the acoustic bonding agent 16 protruding from the ultrasonic element front face 10 is applied to the diaphragm surface 20.
Flows into the groove 21 provided outside the contact portion with the ultrasonic element 9, so that the protruding acoustic bonding agent 16 does not adhere to the side surface or the back surface of the ultrasonic element 9.

Therefore, in the ultrasonic transmitter 18a, since the ultrasonic wave does not propagate to the side surface and the back surface of the ultrasonic element 9a, it is possible to prevent the loss of the energy. Further, the ultrasonic transmitter 18a and the ultrasonic receiver 18b
In this case, the ultrasonic wave does not stop propagating and the ultrasonic wave propagation characteristics do not deteriorate.

A groove 21 serving as a fluid reservoir into which excess acoustic bonding agent 16 flows is formed on the ultrasonic element 9 on the diaphragm surface 20.
Is opened outward from the abutting portion, so that air does not accumulate in the groove 21 when the acoustic bonding agent 16 flows in. Even if air accumulates in the groove 21, Since the pool is located outside the portion of the diaphragm 20 that contacts the ultrasonic element 9, it is possible to prevent the propagation of ultrasonic waves from being hindered by the air pool.

In addition, a groove 21 is provided at a joint portion between the side surface portion of the sensor holder 8 and the bottom surface portion which is the vibration plate 19, so that the thickness is reduced. Therefore, the vibration plate 19 vibrates with the groove 21 as a node, so that the vibration plate 19 easily vibrates, and the ultrasonic wave propagation characteristics are improved. further,
By setting the diaphragm 19 to have a thickness of ラ ム lambda, which allows ultrasonic waves to propagate most easily, ultrasonic waves can be transmitted efficiently.

Accordingly, the vortex flowmeter according to the present embodiment improves the propagation characteristics of ultrasonic waves and the vibration efficiency of the diaphragm 19, and transmits and receives ultrasonic waves at a level necessary for detecting Karman vortices. Since it can be performed efficiently, the S / N ratio of the ultrasonic wave is increased, the detection accuracy of Karman vortex is improved, and the flow measurement accuracy and reliability of the flow meter are improved.

Although the vortex flowmeter has been described as an example in both the first embodiment and the second embodiment, the ultrasonic sensors 1 and 18 used in each embodiment are used for the vortex flowmeter. For example, a pair of ultrasonic sensors are provided opposite to the pipe, and the ultrasonic wave transmitted from the ultrasonic transmitter until the ultrasonic wave is received by the ultrasonic receiver. It can also be used for an ultrasonic sensor used in an ultrasonic flowmeter that performs flow measurement by utilizing that the change in speed is proportional to the flow rate of the fluid to be measured. In this case as well, the reliability of the ultrasonic sensor is improved and the S
Since the / N ratio is increased, it is possible to efficiently transmit and receive ultrasonic waves at a level required for measuring the flow rate of the fluid to be measured, thereby improving the reliability and measurement accuracy of the flow meter.

Further, the annular groove 21 of the second embodiment
Is a diaphragm surface 20 outside the portion of the diaphragm surface 20 that abuts on the ultrasonic element front face 10 via the acoustic bonding agent 16.
Although located above, the position of the annular groove 21 provided on the diaphragm surface 20 is not limited to this. That is, the groove 21 may be provided so as to be located inside the contacting portion of the diaphragm surface 20 contacting the ultrasonic element front face 10 via the acoustic bonding agent 16. Since the bonding agent 16 flows into the groove 21, the amount of the acoustic bonding agent 16 protruding from the ultrasonic element 9 can be reduced,
Accordingly, the amount of the acoustic bonding agent 16 sticking out to the side surface and the back surface of the ultrasonic element 9 can be reduced as compared with the conventional one.

[0040]

According to the flowmeter of the present invention, since the concave portion is provided on the surface of the ultrasonic sensor diaphragm on the side of the ultrasonic element, the excessively applied bonding agent flows into the concave portion of the diaphragm and the ultrasonic wave The bonding agent can be prevented from adhering to the side and back surfaces of the element. As a result, since the ultrasonic wave does not propagate to the side surface or the back surface of the ultrasonic element of the ultrasonic transmitter, it is possible to prevent loss of energy corresponding to the ultrasonic wave. In addition, since the resonance frequency does not shift, it is possible to prevent the ultrasonic wave from not propagating, and further, it is possible to efficiently transmit and receive the ultrasonic wave by improving the propagation characteristics of the ultrasonic wave.

Accordingly, in the flow meter of the present invention, the reliability of the ultrasonic sensor is improved, and the S / N ratio of the ultrasonic wave is increased. The transmission and reception of ultrasonic waves can be performed efficiently, and the reliability and measurement accuracy of the flowmeter are improved.

Further, the flow meter according to the second aspect of the present invention comprises:
Since at least a part of the concave portion is located outside a portion in contact with the ultrasonic element, there is no possibility that an air pool is formed in the concave portion, and the propagation of the ultrasonic wave is prevented from being hindered by the air pool. can do.

Therefore, in the flow meter according to the present invention, the reliability of the ultrasonic sensor is improved, and the reliability as the flow meter is improved.

Further, the flow meter according to the third aspect of the present invention comprises:
The grooves provided on the diaphragm of the ultrasonic sensor ensure the required thickness of the diaphragm, while reducing the thickness of the joint between the sensor holder side and the diaphragm. Since the vibration is generated, the vibration efficiency is improved, and the ultrasonic wave can be transmitted efficiently.

Therefore, the flowmeter of the present invention improves the ultrasonic wave propagation characteristics and the vibration efficiency of the diaphragm, and can efficiently transmit and receive ultrasonic waves at a level required for detecting the flow rate of the fluid to be measured. Since it can be performed well, the S / N ratio of the ultrasonic wave increases, and the flow rate measurement accuracy of the flow meter improves.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross section of an ultrasonic sensor 1 according to a first embodiment of the present invention.

FIG. 2 is a view showing a diaphragm surface 15 of the ultrasonic sensor 1;

FIG. 3 shows an ultrasonic sensor 18 according to a second embodiment of the present invention.
FIG.

FIG. 4 is a view showing a vertical cross section of a conventional vortex flow meter A.

FIG. 5 is a diagram showing a radial cross section of the vortex flow meter A viewed from a downstream side.

FIG. 6 is a diagram showing a cross section of an ultrasonic sensor 22 of the vortex flowmeter A.

[Explanation of symbols]

A vortex flow meter 1 ultrasonic sensor 1a ultrasonic transmitter 1b ultrasonic receiver 2 vortex generator 3 piping 4 hole 4a (ultrasonic transmitter 1a is fitted) hole 4b (ultrasonic receiver 1b is fitted Hole 5 space 5a (formed between the inner peripheral surface of hole 4a and the outer peripheral surface of ultrasonic transmitter 1a) space 5b (the inner peripheral surface of hole 4b and the outer peripheral surface of ultrasonic receiver 1b) 6) Flange 6a (of sensor holder 8a) 6b Flange (of sensor holder 8b) 7 Seal member 7a Seal (provided between hole 4a and ultrasonic transmitter 1a) Member 7b Sealing member (provided between hole 4b and ultrasonic receiver 1b) 8 Sensor holder 8a Sensor holder (of ultrasonic transmitter 1a) 8b Sensor holder (of ultrasonic receiver 1b) 9 Ultrasonic element 9a (Ultrasonic transmitter 1 Ultrasonic element 9b (provided in the ultrasonic receiver 1b) Ultrasonic element 10 (provided in the ultrasonic receiver 1b) Ultrasonic element front 10a (of the ultrasonic element 9a) Ultrasonic element 10b (of the ultrasonic element 9b) Element front 11 Element elastic 11a Element elastic 11b (provided in ultrasonic transmitter 1a) Element elastic 11 (provided in ultrasonic receiver 1b) 12 Disc spring 12a Disc spring (provided in ultrasonic transmitter 1a) 12b Belleville spring (provided in ultrasonic receiver 1b) 13 Lid 13a Lid (of ultrasonic transmitter 1a) 13b Lid (of ultrasonic receiver 1b) 14 Vibration plate 14a Vibration plate (of ultrasonic transmitter 1a) 14b Diaphragm (of the ultrasonic receiver 1b) 15 Diaphragm surface 15a Diaphragm surface (of the diaphragm 14a) 15b Diaphragm surface (of the diaphragm 14b) 16 Acoustic bonding agent 16 a Acoustic bonding agent 16b (applied to diaphragm 14a) Acoustic bonding agent 16b (applied to diaphragm 14b) 17 concave portion 17a concave portion (provided on diaphragm surface 15a) 17b concave portion (provided on diaphragm surface 15b) 18 Ultrasonic sensor 18a Ultrasonic transmitter 18b Ultrasonic receiver 19 Vibration plate 19a Vibration plate 19b (of ultrasonic receiver 18b) Vibration plate 20 (of ultrasonic receiver 18b) 20 Vibration plate surface 20a (of vibration plate 19a) Diaphragm surface 20b Diaphragm surface 21 (of diaphragm 19b) 21 Groove 21a Groove 21b (provided on diaphragm surface 20b) Groove 22 Ultrasonic sensor 22a Ultrasonic transmitter 22b Ultrasonic reception Instrument 23 Oscillator 24 Detector 25 Diaphragm 25a Diaphragm 25b (of ultrasonic transmitter 22a) Diaphragm (of ultrasonic receiver 22b) 6 diaphragm surface 26a (the diaphragm 25a) diaphragm surface 26b (the diaphragm 25b) diaphragm surface

Claims (3)

[Claims] 1. An ultrasonic transmitter attached to a pipe through which a fluid to be measured flows and transmitting an ultrasonic wave toward the fluid to be measured, and an ultrasonic wave transmitted from the ultrasonic transmitter is transmitted to the fluid to be measured. An ultrasonic sensor including an ultrasonic receiver that receives the measured fluid through the sensor, and the flow rate of the fluid to be measured in the pipe based on the modulation of the ultrasonic signal due to the flow of the fluid to be measured detected by the ultrasonic sensor. In a flowmeter comprising: a measuring unit for measuring, at least one of the ultrasonic transmitter and the ultrasonic receiver constituting the ultrasonic sensor, an ultrasonic element for transmitting or receiving an ultrasonic wave; A vibration plate that vibrates by the ultrasonic wave; a bonding agent that bonds the vibration plate and the ultrasonic element;
A flowmeter, wherein a concave portion into which the bonding agent flows is provided on a surface of the vibration plate on the ultrasonic element side. 2. The flow meter according to claim 1, wherein at least a part of the concave portion of the diaphragm is located outside a portion that comes into contact with the ultrasonic element via the bonding agent. 3. The flowmeter according to claim 1, wherein the concave portion of the diaphragm is an annular groove.