JPH11325992A - Ultrasonic oscillator, support structure thereof and ultrasonic flow rate measuring apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a high-reliability ultrasonic oscillator which is capable of transmitting/receiving ultrasonic pulses with a short reverberation and reduces the transmission of the oscillation to the pipe line wall. SOLUTION: A top-closed tubular case 7 having a top part 8, side wall 9 and opening 10, a piezoelectric body 12 fixed to the inner wall of the top part 8, an acoustic matching layer 11 provided on the outer wall of the top part 8, and support 13 provided on the outer wall of the side wall are provided. The support 13 has a shape increasing the rigidity, the oscillation of the piezoelectric body 12 is suppressed from propagating to the mounting side, and ultrasonic pulses with a short reverberation can be transmitted/received.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic flow rate measuring device for measuring a flow rate and a flow rate of a gas or liquid by ultrasonic waves.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. Hei 4-309817 is known as an ultrasonic vibrator used for this type of ultrasonic flow rate measuring device. As shown in FIG. 2 and the metal diaphragm 2 was welded to the metal housing 3. Also, 6-7
No. 8821 is known, and as shown in FIG. 11, a piezoelectric ceramic 1 is joined to a bottom surface 4a of an inner surface of a metal housing 4 which shields the piezoelectric ceramic 1 from a measurement fluid by a pressing means 5 or the like.
The metal housing 4 was attached by welding or the like in a state of being inclined with respect to the pipe axis of the pipe 6 through which the measurement fluid flows.

[0003]

However, in the conventional structure, since the vibration suppression of the metal housing is not taken, the vibration of the piezoelectric ceramic transmitted to the metal housing is hardly attenuated and returns to the piezoelectric ceramic. It does not fit easily and becomes an ultrasonic pulse with a long reverberation. This reverberation causes noise, deteriorating the S / N, and reducing the measurement accuracy of the flow rate and the flow velocity. Further, in another conventional configuration, since the ultrasonic vibrator is directly attached to the conduit through which the measuring fluid flows, when the piezoelectric ceramic is vibrated on the transmitting side, the vibration propagates through the measuring fluid and is transmitted to the receiving side. In addition to the vibration, the vibration transmitted to the metal housing through the metal diaphragm or the bottom surface is transmitted to the receiving side through the pipe wall, and the vibration that propagates through the pipe wall interferes with the signal propagated in the measurement fluid and becomes noise. In addition, there is a problem that the measurement ranges of the flow rate and the flow velocity cannot be expanded because the S / N is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has realized a highly reliable ultrasonic vibrator capable of transmitting and receiving an ultrasonic pulse having a short reverberation and reducing the propagation of vibration to a pipeline wall. An object of the present invention is to improve the measurement characteristics of a sound wave flow measurement device.

[0005]

According to the present invention, in order to solve the above-mentioned problems, a piezoelectric body constituting an ultrasonic vibrator is enclosed in a case which shields from a fluid to be measured, and rigidity is increased on a side wall portion of the case. A supporting portion is provided to reduce the propagation of vibration from the supporting portion to the mounting side. According to the above invention, the vibration of the piezoelectric body can be attenuated by the support portion of the case and made difficult to be transmitted to the mounting side, and an ultrasonic pulse having a short reverberation can be transmitted and received, and the vibration propagation to the mounting side can be reduced. A possible ultrasonic transducer can be obtained. As a result, the generation of noise due to reverberation and the propagation of vibration to the mounting side can be reduced, and the S / N is improved, and the measurement characteristics such as the measurement accuracy of the flow rate and flow velocity of the fluid to be measured and the expansion of the measurement range can be improved. . Further, the mounting state can be stabilized over a long time by the supporting portion with reduced vibration, and the reliability of measurement can be improved.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a cylindrical case having a top, a side wall, and an opening, a piezoelectric body fixed to an inner wall surface of the top, and an outer wall of the top. An acoustic matching layer is provided, and a support provided on the side wall is provided, wherein the support has a shape that increases rigidity. Then, the rigidity of the support portion is increased to reduce the propagation of the vibration of the piezoelectric body to the mounting side, and an ultrasonic vibrator capable of transmitting and receiving ultrasonic pulses with short reverberation can be obtained.

Further, the support portion has a configuration in which a flange provided at an end portion of the side wall portion and a sealing member closing the opening portion are overlapped. Since the supporting portion can be reinforced by the sealing member, the thickness of the case can be further reduced, and the sensitivity of the ultrasonic transducer can be increased. In addition, the sealed body that hermetically stores the piezoelectric body can be used as a rigidity strengthening member for the support part to increase productivity, and the case-side flange can be easily molded and sealed to a flange with an expanded joint surface. Since the body is joined, the airtightness can be improved and the reliability can be improved.

[0008] The thickness of the sealing body of the supporting portion is larger than that of the flange. By increasing the thickness of the sealing body, deformation of the support portion is prevented, and a seal portion for sealing the measured fluid so as not to leak from the mounting portion of the ultrasonic transducer to the outside can be secured in the support portion. Furthermore, since the thickness of the sealing body can be increased, it is possible to easily form a terminal electrically connected to the piezoelectric body and an insulating portion for insulating the terminal, thereby improving productivity.

In addition, a vibration transmission suppressor for reducing transmission of vibration of the ultrasonic vibrator to the fluid passage wall side is provided, and an ultrasonic vibrator is provided in a mounting hole provided in the fluid passage wall via the vibration transmission suppressor. Is attached. Then, the acoustic impedance mismatch is provided to make it difficult for the vibration of the ultrasonic vibrator to be transmitted to the mounting side, and the measurement accuracy can be improved. Further, a projection is provided at least on the fluid passage wall side of the vibration transmission suppressing body, and the vibration transmission suppressing body and the fluid passage wall are partially contacted. Then, the vibration of the ultrasonic transducer can be hardly transmitted to the mounting side due to the partial contact, and the measurement accuracy can be further improved.

[0010] The vibration transmission suppressing member is made of an elastic material.
A deformation preventing body for preventing deformation of the elastic body is provided in contact with the vibration transmission suppressing body. The vibration transmission suppressor not only reduces the transmission of vibration, but also prevents leakage of the fluid to be measured and can be hermetically sealed.The deformation preventing body prevents deformation of the elastic body and can maintain the hermetic seal for a long time. The reliability of the hermetic seal can be improved.

The deformation preventing member is made of a material having a lower acoustic impedance than at least the case or the sealing member which cools the opening of the case. And, even if the deformation preventing body and the ultrasonic vibrator come into contact with each other, it is difficult for the vibration to be transmitted to the mounting side. Therefore, the deformation preventing body is placed in contact with the ultrasonic vibrator, so that the deformation can be reliably deformed over the entire area of the vibration transmission suppressing body. Can be prevented, and the reliability of the hermetic seal can be further improved.

Further, the mounting hole is a stepped mounting hole provided with a stepped portion which comes into contact with the vibration transmission suppressing body. Fix the vibration transmission suppressor with the fixed body provided outside the mounting hole,
The ultrasonic transducer does not contact the fluid passage wall and the fixed body. The ultrasonic vibrator can be mounted on the mounting side in a non-contact manner, and its mounting position can be set with high accuracy. Therefore, the measurement accuracy can be improved by reducing the propagation of vibration and ensuring the mounting position accuracy.

The opening of the mounting hole into the fluid passage has a smaller cross-sectional area than the storage portion for storing the side wall of the ultrasonic vibrator. By reducing the area of the opening, the disturbance of the flow of the fluid to be measured due to the opening can be reduced, and the measurement accuracy can be improved.

A measuring section through which a fluid to be measured flows, a pair of ultrasonic transducers provided in the measuring section for transmitting and receiving ultrasonic waves, and a pair of ultrasonic transducers between the ultrasonic transducers. 10. A measurement control unit for measuring a propagation time of a signal, and a calculation unit for calculating a flow rate based on a signal from the measurement control unit, wherein the ultrasonic vibrator is any one of claims 4 to 9. The supporting configuration described in (1). And an ultrasonic vibrator having a case for shielding the piezoelectric body from the fluid to be measured and capable of transmitting and receiving an ultrasonic pulse having a short reverberation,
Flow rate measuring device that can maintain the measurement characteristics over a long period of time by increasing the measurement accuracy and maintaining the measurement characteristics for a long period of time with the support structure of the ultrasonic transducer that can reduce the vibration propagation to the mounting side and the airtight seal structure that prevents the leakage of the fluid to be measured Can be realized.

The cross section in the direction perpendicular to the flow of the measuring section is rectangular, and the opening of the mounting hole for mounting the ultrasonic vibrator on the fluid passage side is rectangular. Since the opening area is constant in the height direction of the measuring unit, it is possible to transmit and receive ultrasonic waves evenly in the height direction of the fluid passage, and the average is obtained by ultrasonic propagation according to the flow distribution in the height direction. The flow velocity can be accurately detected.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a sectional view of an ultrasonic transducer according to Embodiment 1 of the present invention. In FIG. 1, 7 is a case, 8 is a top part of the case 7, 9 is a side wall part of the case 7, 1
Reference numeral 0 denotes an opening of the case 7, and the case 7 has a topped cylindrical shape having a top portion 8, a side wall portion 9, and an opening portion 10. 11
Is an acoustic matching layer fixed to the outer wall surface of the top part 8 of the case 7,
Reference numeral 12 denotes a piezoelectric member fixed to the inner wall surface of the top portion 8, reference numeral 13 denotes a support portion provided on the outer wall of the side wall portion 9, and the support portion 13 has a bent portion 14 and is folded to increase the thickness to increase rigidity. Is increasing. Reference numeral 15 denotes a sealing body for closing the opening 10, 16 a and 16 b denote terminals provided in the sealing body 15,
7 is an insulating portion for insulating the terminal 16a from the terminal 16b;
Reference numeral 18 denotes a lead wire for electrically connecting the piezoelectric body 12 to the terminal 16a, and 19 denotes a plurality of grooves provided in the piezoelectric body 12. As described above, the ultrasonic vibrator 20 has the case 7
A piezoelectric body 12 is provided inside the housing 7 and sealed by a sealing body 15, and an acoustic matching layer 11 and a support portion 13 are provided outside the case 7.

An example of a method for manufacturing the ultrasonic transducer configured as described above will be described. Ultrasonic vibrator 20 is LP
Case 7 for use in gas or natural gas
, And a material made of a mixture of epoxy resin and hollow glass spheres is selected for the acoustic matching layer 11. Case 7
In consideration of mass productivity, a forming method such as drawing is selected instead of cutting. The thickness of the stainless steel of the case 7 is selected to be about 0.1 to 0.5 mm from the viewpoint of the sensitivity, structural strength, and moldability of the ultrasonic vibrator 20. In order to form the case 7 from such a thin material, the support portion 13 is bent from the side wall portion 9 of the case 7 to the bent portion 14.
Are protruded and folded so as to be equivalent to a plurality of plate thicknesses to increase rigidity. Further, since the piezoelectric body 12 is bonded and fixed to the ceiling portion 8 made of stainless steel, vibration in the spreading direction is inhibited. In order to increase the sensitivity of the ultrasonic vibrator 20, it is more advantageous to use the thickness longitudinal vibration in the main mode than the spread vibration. However, the main mode of vibration of the piezoelectric body 12 is determined by its shape, and the allowable range for the shape and the working frequency of the piezoelectric body 12 is narrow. Therefore, as a structure in which the piezoelectric body 12 is divided by providing a groove 19 in, for example, a cross shape, the thickness vibration can be set to the main mode with a practically small size.

As a specific manufacturing procedure for such a material and shape, first, a stainless steel plate having a thickness of 0.2 mm is formed into a hollow cylindrical case 7 having a circular top portion 8, and then the case 7 is formed. An annular bead is formed on the side wall portion 9 of the above, and the bead is crushed in the cylindrical axis direction and compressed so as to overlap to form the support portion 13. The thickness of the support 13 can be arbitrarily increased by molding and compressing a plurality of beads. Next, a disc-shaped acoustic matching layer 11 is fixed to the outer wall surface of the top portion 8 and a piezoelectric body 12 is fixed to the inner wall surface by using an epoxy-based adhesive. At this time, the electrode (not shown) divided by the groove 19 and the top portion 8 are bonded and fixed via a thin adhesive layer having a thickness of 10 μm or less, thereby electrically connecting the divided electrode (not shown) and the top portion 8. Conduction can also be taken. The lead wires 18 are soldered to the electrodes (not shown) of the piezoelectric body 12 and the terminals 16a, respectively. Finally,
A sealing body 15 made of a stainless steel plate of about 1 mm is fixed to the opening 10 by electric resistance welding or the like, and sealing and electrical conduction are simultaneously performed. Since the piezoelectric body 12 shares the case 7 as a ground and is covered with the case 7 and the sealing body 15, the effect of noise can be reduced. When dry nitrogen or an inert gas is replaced and sealed in the case 7 during sealing, deterioration of the electrodes of the piezoelectric body 12 and the adhesive layer between the piezoelectric body 12 and the case 7 due to long-term use can be prevented. .

Next, the operation of the ultrasonic transducer will be described. First, on the transmission side, a drive electric input is applied, and the piezoelectric body 12 vibrates. This vibration is not only emitted as an ultrasonic pulse to the fluid to be measured through the acoustic matching layer 11 but also causes the case 7 to vibrate. And On the receiving side, the received ultrasonic pulse is converted into an electric signal by the piezoelectric body 12 and at the same time, the case 7 is caused to vibrate. If the case 7 vibrates here, a long reverberation of the piezoelectric body 12 is observed on both the transmitting side and the receiving side, and the reverberation on the transmitting side becomes electric noise with respect to a measurement circuit (not shown). Since the reverberation on the receiving side is combined with the received ultrasonic pulse, the reverberation affects the amplitude and phase and causes an error in measurement. Further, when the case 7 vibrates, the vibration of the case 7 is transmitted to the ultrasonic vibrator on the receiving side via the fluid passage wall, and the receiving side combines the vibration via the fluid passage wall with the received ultrasonic pulse. Therefore, it affects the amplitude and phase and causes an error in measurement.

In this embodiment, the case 7 is provided with the bent portion 14 and the rigidity of the side wall portion 9 is increased by the support portion 13 which is folded and increased in thickness, so that the side wall portion 9 and the support portion 13 are hardly vibrated. Has become. Therefore, the vibration of the case 7 can be suppressed, and the propagation of the vibration from the support portion 13 to the mounting side can be reduced. Furthermore, since the vibration of the support portion 13 is small, it is possible to prevent a deviation from the mounting side and a change in the propagation method of the vibration over a long period of time.
Therefore, it is possible to transmit and receive an ultrasonic pulse having a short reverberation, and obtain an ultrasonic vibrator capable of reducing the propagation of vibration to the mounting side, thereby reducing the generation of noise due to reverberation and transmitting the vibration to the mounting side. The measurement characteristics can be improved, such as reduction of the S / N, improvement of the measurement accuracy of the flow rate and flow velocity of the fluid to be measured, and expansion of the measurement range. Further, the mounting state can be stabilized over a long time by the supporting portion with reduced vibration, and the reliability of measurement can be improved.

Further, since the ultrasonic vibrator of the present embodiment is detachable from the mounting side, the maintainability can be improved with respect to what is welded to the mounting side, and furthermore, when the ultrasonic vibrator is discarded due to the end of its service life. Since the ultrasonic transducer can be easily separated from the fluid passage, recyclability can be ensured.

The supporting portion 13 is not limited to the form shown in the figure, but may be constituted by providing, for example, a vertically extending protruding rib on the measuring wall section 9, and various forms are conceivable. .

(Embodiment 2) FIG. 2 is a sectional view of an ultrasonic transducer according to Embodiment 2 of the present invention. 2, the same members and the same functions as those in the embodiment of FIG. 1 are denoted by the same reference numerals, detailed description thereof will be omitted, and different points will be mainly described. Reference numeral 21 denotes an annularly extending flange provided at the end of the side wall 9 of the case 7 on the opening 10 side, and the support portion 13
And a sealing body 15 for closing the opening 10 are overlapped and joined.

Here, the flange 21 is formed by drawing of the case 7, and by overlapping the sealing body 15, it is possible to obtain the support portion 13 having increased structural strength. Further, since the support portion 13 is reinforced by the sealing body 15, the case 7 can be formed of a material having a smaller thickness, and the sensitivity of the ultrasonic transducer can be further increased. Furthermore, the sealing body 15 can be used as a sealing member of the case 7 and a rigidity reinforcing member of the support portion 13 to increase productivity, and the flange 21 can be easily formed at the same time as the case 7 is formed. Flange 21
Since the joining surface of the sealing body 15 and the sealing body 15 are joined by a wide annular surface, sealing with improved airtightness can be achieved, and the reliability of the members housed inside can be improved.

The thickness T1 of the sealing body 15 is
1 (T1> T2). By increasing the thickness of the sealing body 15, the deformation of the support portion 13 can be prevented, and when the sealing body 15 and the flange 21 are sealed, they are deformed toward the flange 21 side of the thin plate when they are joined by electric resistance welding or the like. Since the sealing member 15 on the thick plate side is not deformed even if this occurs, a seal portion for sealing the measured fluid so as not to leak from the mounting portion of the ultrasonic transducer to the outside can be secured in the support portion 13. Further, since the thickness of the sealing body 15 can be increased, the terminal 1 electrically connected to the piezoelectric body 12 is formed.
6a, 16b and an insulating part 1 for insulating the terminal 16a
(Embodiment 3) FIG. 3 is a cross-sectional view showing an attached state of an ultrasonic transducer according to Embodiment 3 of the present invention. In FIG. 3, the same members and the same functions as those in the embodiment of FIGS. 1 and 2 are denoted by the same reference numerals, detailed description thereof will be omitted, and different portions will be mainly described.

Numeral 22 denotes a vibration transmission suppressor which is held in contact with the support portion 13 of the ultrasonic vibrator 20.
Numeral 0 is attached to a mounting hole 24 which opens in the fluid passage wall 23 provided on the fluid passage wall 23 through which the fluid to be measured flows. Reference numeral 25 denotes the fluid transmission wall 23 which accommodates the vibration transmission suppressing body 22.
The positioning body 25 is detachably fixed to the fluid passage wall 23 by coupling means such as screws (not shown). 26 is an airtight packing provided between the fluid passage wall 23 and the positioning body 25 for airtight sealing, 27a,
27b is a connection terminal connected to the terminals 16a and 16b of the ultrasonic vibrator 20, and 28 is an insulating part for insulating the connection terminals 27a and 27b from each other. In addition, the vibration transmission suppressing body 22 is divided in the supporting portion 13 into a pressing side 22a on the sealing body 15 side and a supporting side 22b on the flange 21 side.
3 and both planes (upper and lower surfaces of the support portion 13 in the figure)
Holding.

Here, the vibration transmission suppressing body 22 is
The acoustic impedance is made of a material smaller than the acoustic impedance of the material forming the case 7 or the sealing body 15 so as to form a mismatched portion in which the vibration of the case 7 is hardly acoustically transmitted to the fluid passage wall 23. Metal such as stainless steel (acoustic impedance of 30 to 50)
X 103 kg / m2 s), resin (acoustic impedance 3 to
5 × 103 kg / m 2 s) or an elastic body (acoustic impedance 1 to 2 × 103 kg / m 2 s) can be used. The ultrasonic vibrator 20 is positioned by the vibration transmission suppressing body 22 and the positioning body 25 so that the side wall 9 does not contact the wall surface of the mounting hole 24, and is sealed by an airtight packing 26 provided on the positioning body 25. The fluid to be measured is prevented from leaking outside.

Next, the operation will be described. First, on the transmission side, a drive electric input is applied, and the piezoelectric body 12 vibrates,
This vibration is not only emitted as an ultrasonic pulse to the fluid to be measured through the acoustic matching layer 11, but also causes the case 7 to vibrate. However, the vibration of the case 7 is reduced by the support portion 13 having increased rigidity, and the case 7 is mounted in the mounting hole 24 provided in the fluid passage wall 23 via the vibration transmission suppressing body 22. Transmission of vibration to the fluid passage wall 23 side is reduced.

Therefore, on the receiving side, the influence on the amplitude and phase due to the combination of the vibration via the fluid passage wall 23 and the received ultrasonic pulse can be prevented, factors that cause errors in measurement can be eliminated, and measurement accuracy can be improved. be able to.

The vibration transmission suppressor 22 is mounted on the ultrasonic vibrator 20 by using the support portion 13. However, the present invention is not limited to this. For example, a protrusion that does not increase the rigidity of the case 7 is provided. May be provided and attached thereto. In short, it is sufficient that the ultrasonic vibrator 20 is held so that the vibration of the case 7 is not transmitted to the outer wall 23 of the fluid surface. It is.

(Embodiment 4) FIG. 4 is a cross-sectional view showing an attached state of an ultrasonic vibrator according to Embodiment 4 of the present invention. In FIG. 4, the same members and the same functions as those in the embodiment of FIGS. 1 to 3 are denoted by the same reference numerals, detailed description is omitted, and different portions will be mainly described.

Reference numeral 29 denotes a projection provided on the vibration transmission suppressing body 22. The projection 29 is provided not only on the fluid passage wall 23 side but also on the positioning body 25 side. For this reason, at least the protrusion 29 provided on the fluid passage wall 23 makes the vibration transmission suppressing body 22 a partial contact with the fluid passage wall 23 with a reduced contact area.

Here, when the driving body input is applied and the piezoelectric body 12 vibrates, the vibration is radiated as an ultrasonic pulse to the fluid to be measured via the acoustic matching layer 11. At this time, the vibration of the case 7 is reduced by the support portion 13 having increased rigidity, and the case 7 is attached to the attachment hole 24 provided in the fluid passage wall 23 through the vibration transmission suppressor 22 by partial contact. Propagation of the vibration of the ultrasonic transducer 20 to the fluid passage wall 23 is further reduced.

Therefore, on the receiving side, the vibration transmitted through the fluid passage wall 23 can be greatly reduced, so that the influence on the amplitude and phase due to the combination with the received ultrasonic pulse can be prevented, and the factor causing an error in the measurement can be eliminated. The measurement accuracy can be further improved. By providing the protrusions 29 not only on the fluid passage wall 23 side but also on the positioning body 25 side, it is possible to prevent vibration from propagating to the fluid passage wall 23 side through the positioning body 25, Propagation to the 23 side can be further reduced.

(Embodiment 5) FIG. 5 is a cross-sectional view showing an attached state of an ultrasonic vibrator according to Embodiment 5 of the present invention. 5, the same members and the same functions as those in the embodiment of FIGS. 1 to 4 are denoted by the same reference numerals, detailed description is omitted, and different portions will be mainly described.

Numeral 30 denotes a vibration transmission suppressor having an annular inner peripheral groove 30a formed of an elastic material such as rubber and holding the support portion 13 of the ultrasonic vibrator 20 on the inner peripheral side. It is a deformation preventing body provided in contact with the inner peripheral side of the transmission suppressing body 30 to prevent the vibration transmission suppressing body 30 from being deformed in the inner diameter direction. The deformation preventing body 31 is formed in an annular shape so that the inner peripheral side thereof has a gap without contacting the side wall 9 of the case 7, and has a gap in the axial direction (vertical direction in the figure) to provide a support portion 13. Try not to apply force. The deformation preventing body 32 is formed in an annular shape so as not to contact the terminals 16a and 16b. Reference numeral 33 denotes an annular projection provided on the lower surface of the vibration transmission suppressing body 30, and reference numeral 34 denotes an annular projection provided on the outer peripheral surface of the vibration transmission suppressing body 30. 35 is a vibration transmission suppressor 30
A stepped mounting hole provided with a stepped portion 36 serving as a contact portion, and has a flat surface 33a with which the annular lower projection 33 contacts and a cylindrical surface 33b with which the annular outer projection 34 contacts. ing. Reference numeral 37 denotes a fixed body for holding the vibration transmission suppressing body 30 provided outside the stepped mounting hole 35, and the fixed body 37 is a terminal 16
An extraction hole 38 through which a and 16b penetrate without contact is provided, and is fixed to the fluid passage wall 23 by a coupling means such as a screw.

Here, the mounting method will be described. The vibration transmission suppressor 30 formed of an elastic material such as rubber is stretched to fit the support portion 13 of the ultrasonic vibrator 20 into the inner circumferential groove 30a to hold the support portion 13 without any gap and to prevent the deformation preventing member 3 from being deformed.
1 and 32 are inserted into the inner periphery of the vibration transmission suppressing body 30. In this assembled state, the vibration transmission suppressing body 30 is inserted into the stepped portion 36 of the stepped mounting hole 35, and the vibration transmission suppressing body 30 is pressed down by the fixed body 37 to mount the ultrasonic transducer 20. Here, the external dimensions (including the protrusions 33 and 34) such as the height and the length of the vibration transmission suppressing body 30 are slightly larger than the stepped part 36 so that the vibration transmission suppressing body 30 can be inserted into the stepped part 36 or fixed by the fixed body 37. At the time of pressing, the vibration transmission suppressing body 30 of the elastic body is bent, and the airtight sealing property can be ensured so that the fluid to be measured does not leak from the mounting hole. By the way, when the deformation preventing members 31 and 32 are mounted without being provided, the vibration transmission suppressing member 30 tends to deform to the inner circumferential side with the lapse of time because the outer peripheral side is restricted by the mounting hole and the fixed body. However, in this case, since the deformation preventing bodies 31 and 32 are inserted into the inner peripheral side and restrained from being deformed, the deformation is prevented from inward, so that the hermetic sealing can be ensured for a long period of time. Further, since the elastic body has a sufficiently smaller acoustic impedance than the metal material of the case 7 of the ultrasonic vibrator 20 as described above, the propagation of vibration to the fluid passage can be reduced.

As described above, the vibration transmission suppressing body 30 not only reduces the transmission of vibration but also prevents leakage of the fluid to be measured and can be hermetically sealed. The deformation preventing body prevents deformation of the elastic body for a long period of time. The hermetic seal can be maintained, and the reliability of the hermetic seal can be improved.

(Embodiment 6) FIG. 6 is a cross-sectional view showing an ultrasonic vibrator according to Embodiment 6 of the present invention in a mounted state. 6, the same members and the same functions as those in the embodiment of FIGS. 1 to 5 are denoted by the same reference numerals, detailed description thereof will be omitted, and different portions will be mainly described.

Reference numeral 39 denotes a deformation preventing member which is provided in contact with the inner peripheral side of the vibration transmission suppressing member 30 to prevent the case 7 side of the vibration transmission suppressing member 30 from being deformed in the inner diameter direction. The inner peripheral side is arranged without a gap so as to contact the side wall portion 9 of the case 7, and abuts on the support portion 13 and the step portion 36 of the stepped mounting hole 35 in the axial direction (vertical direction in the figure). The vibration transmission suppressing body 30 is prevented from being deformed inward in the entire vertical direction in the drawing. Reference numeral 40 denotes a deformation preventing body which is provided in contact with the inner peripheral side of the vibration transmission suppressing body 30 to prevent the sealing body 15 side of the vibration transmission suppressing body 30 from deforming in the radial direction. Its inner peripheral side is formed in an annular shape so as to have a gap without contacting the terminals 16a and 16b, and to contact the sealing body 15 and the fixed body 37 in the axial direction (vertical direction in the figure). It is arranged without a gap, and the inward deformation of the vibration transmission suppressing body 30 is prevented over the entire area in the vertical direction in the figure. Here, the deformation preventing body 39 or the deformation preventing body 40 is made of a material having a smaller acoustic impedance than the material of the case 7 or the sealing body 15 forming the support portion 13 of the ultrasonic vibrator 20. The vibration of the case 7 is prevented from propagating to the fluid passage 23 even when the passage 23 is in contact with the deformation preventing member 39, and the support portion 13 and the sealing member 1
The vibration of the case 7 is prevented from propagating to the fluid passage 23 even when the case 5 is in contact with the fixed body 37 via the fixed body 37. Here, as the material of the deformation preventing members 39 and 40, a resin having an acoustic impedance sufficiently smaller than that of the metal material of the case 7 of the ultrasonic vibrator 20 as described above is used, so that an elastic body such as rubber (deformation preventing material) is used. (The acoustic impedance is smaller than that of the resin of the bodies 39 and 40).

As described above, even if the deformation preventing body and the ultrasonic vibrator are in contact with each other, it is difficult for the vibration to be transmitted to the mounting side. Therefore, the deformation preventing body is arranged in contact with the ultrasonic vibrator, and the entire area of the vibration transmission suppressing body is arranged. Over time, the deformation can be reliably prevented, and the reliability of the hermetic seal can be further improved.

(Embodiment 7) An embodiment 7 of the present invention will be described with reference to FIG. In FIG. 5, a method of attaching the ultrasonic vibrator 20 will be described. First, the support portion 13 of the ultrasonic vibrator 20
The vibration transmission suppressor 30 is mounted on the fluid passage wall 23, and the mounted vibration transmission suppressor 30 is inserted into the stepped mounting hole 35 provided in the fluid passage wall 23. At this time, the end face of the vibration transmission suppressing body 30 is
The outer peripheral portion of the vibration transmission suppressing body 30 is brought into contact with the flat surface 33a of the
To make radial positioning. after this,
By screwing a fixed body 37 provided outside the stepped mounting hole 35 to the fluid passage wall 23, the vibration transmission suppressing body 30 is pressed down to prevent the vibration transmission suppressing body 30 from coming off, and the axial positioning is ensured. With such attachment, the ultrasonic vibrator 20 is supported by the vibration transmission suppressing body 30 without contact with the fluid passage wall 23 and the fixed body 37.

Therefore, the ultrasonic vibrator 20 is connected to the fluid passage wall 2.
When the pair of ultrasonic transducers on the receiving side and the transmitting side are mounted on the flow path, the distance between the ultrasonic transducers is fixed and the fluid is accurately determined. Speed can be detected, and by aligning the centers of the central axes of the pair of ultrasonic transducers, a decrease in sensitivity due to misalignment can be prevented, and high-sensitivity measurement can be performed. Further, since the non-contact between the ultrasonic vibrator and the fluid passage wall is maintained, the measurement accuracy can be improved or the measurement range can be expanded by preventing the propagation of vibration to the fluid passage wall and increasing the S / N.

For this reason, the ultrasonic vibrator can be mounted on the mounting side in a contacted manner, and the mounting position can be set with high accuracy in both the radial direction and the axial direction, so that the propagation of vibration is reduced and the mounting position accuracy is ensured. Can improve the measurement accuracy.

(Eighth Embodiment) An eighth embodiment of the present invention will be described with reference to FIG. In FIG. 5, reference numeral 41 denotes an opening of the mounting hole 24 to the fluid passage, and reference numeral 42 denotes a storage portion provided in the mounting hole 24 for storing the side wall 9 of the ultrasonic vibrator 20.
Is the length D1 of the storage section 42 in the cross section direction.
2 (D1 <D2) so that the cross-sectional area of the opening 41 is smaller than the cross-sectional area of the storage section 42.

Therefore, even when the size of the ultrasonic transducer 20 is large, the opening 41 to the fluid passage through which the non-measuring fluid flows is provided.
Can be reduced, the turbulence of the flow due to the opening 41 acting as a depression with respect to the flow can be reduced, and a more accurate flow velocity can be measured. In addition, by increasing the size of the storage portion 42 with respect to the side wall 9 of the ultrasonic vibrator 20, the distance between the ultrasonic vibrator 20 and the fluid passage wall 23 can be increased, thereby improving lightning surge characteristics. Can be further increased.

For this reason, by reducing the area of the opening, the disturbance of the flow of the fluid to be measured due to the opening can be reduced and the measurement accuracy can be improved, and the withstand voltage characteristic can be improved to improve the reliability.

(Embodiment 9) FIG. 7 is a configuration diagram of an ultrasonic flow rate measuring apparatus showing Embodiment 9 of the present invention. In FIG.
The same members and the same functions as those of the embodiment of FIGS. 1 to 6 are denoted by the same reference numerals, detailed description is omitted, and different portions will be mainly described.

Reference numeral 43 denotes a measuring unit surrounded by the fluid passage wall 23, and reference numerals 44 and 45 denote ultrasonic transducers mounted on the mounting hole 24 of the fluid passage wall 23 via the vibration transmission suppressing body 30 so as to face each other. The ultrasonic transducer 44 on the upstream side and the ultrasonic transducer 45 on the downstream side are arranged at a distance L and at an angle θ with respect to the flow of the fluid to be measured at the velocity V. 46 is a measurement control unit for transmitting and receiving ultrasonic waves to and from the connected ultrasonic transducers 44 and 45, and 47 is a calculation unit for calculating the flow rate based on the signal from the measurement control unit 46 and calculating the flow rate. is there.

Next, the operation of the ultrasonic flow measuring device will be described. When the fluid to be measured flows through the measuring unit 43, the ultrasonic wave is transmitted and received between the ultrasonic transducers 44 and 45 so as to cross the measuring unit 43 by the operation of the measurement control unit 46.
That is, the elapsed time T1 until the ultrasonic wave emitted from the upstream ultrasonic vibrator 44 is received by the downstream ultrasonic vibrator 45 is measured. On the other hand, the ultrasonic wave emitted from the ultrasonic transducer 45 on the downstream side is transmitted to the ultrasonic transducer 4 on the upstream side.
4, the elapsed time T2 until the reception is measured. Based on the elapsed times T1 and T2 measured in this way, the flow rate is calculated by the calculation unit 47 by the following calculation formula.

Assume that the angle between the flow of the fluid to be measured and the ultrasonic wave propagation path is θ, and the ultrasonic vibrator
Assuming that the distance between the fluids 4 and 45 is L and the sound velocity of the fluid to be measured is C, the flow velocity V is calculated by the following equation.

T1 = L / (C + Vcosθ) T2 = L / (C−Vcosθ) The sound velocity C is eliminated from the formula of subtracting the reciprocal of T2 from the reciprocal of T1 and V = (L / 2cosθ) ((1 / T1) − (1 / T2)) Since θ and L are known, the flow velocity V is calculated from the values of T1 and T2.
Can be calculated. Now, considering the flow rate of air, the angle θ = 45 degrees, the distance L = 70 mm, and the sound velocity C = 340 m /
s and flow velocity V = 8 m / s, T1 = 2.0 × 1
0-4 seconds, T2 = 2.1 × 10−4 seconds, so that instantaneous measurement can be performed.

Here, based on the cross-sectional area s orthogonal to the flow direction of the measuring section 43, the flow rate Q is Q = kVs, where k is a conversion coefficient in consideration of the flow velocity distribution in the cross-sectional area s.

In this way, the flow rate can be obtained by the arithmetic unit 47. In the flow rate measurement by the ultrasonic wave, the time T1,
It is important to measure T2 with high accuracy. That is,
It is important that the transmitting side emits ultrasonic vibrations with little reverberation only in the fluid to be measured, while the receiving side eliminates ultrasonic vibrations that have propagated through the fluid passage walls and only the ultrasonic vibrations that have propagated through the fluid to be measured. It is important to receive low reverberation.
In the ultrasonic flow measurement device of the present invention, in the ultrasonic vibrator 20, the reliability is improved by blocking the piezoelectric body 12 from the fluid to be measured by the case 7, and reverberation is caused by the shape of the support portion 13 having increased rigidity. It is possible to improve the sensitivity by reducing the noise and the measurement accuracy by reducing the noise. Further, by attaching the support portion 13 for reducing vibration to the fluid passage wall 23 through the vibration transmission suppressing body 30 in a non-contact manner, the vibration transmitted through the fluid passage wall 23 is further reduced and the fluid to be measured is propagated. Since the signal detection accuracy can be improved, a very small flow rate of about 1 mm / s can be detected. In addition, the case 7 separates the piezoelectric body 12 from the fluid to be measured, and the vibration transmission suppressing body 30 is used both for suppressing vibration transmission and as a seal member for keeping the fluid to be measured airtight so as not to leak outside.
It can be applied to various fluids such as flammable gas such as city gas and LP gas in addition to air, and the range of use can be expanded. further,
By reducing the size of the opening, the turbulence caused by the opening can be reduced, and the measurement range at high flow rates (at high flow rates) can be expanded, and the rangeability (ratio of minimum flow rate to maximum flow rate) can be expanded to further enhance practicality. be able to. As described above, the ultrasonic vibrator having the case for shielding the piezoelectric body from the fluid to be measured and capable of transmitting and receiving the ultrasonic pulse having a short reverberation, the support structure of the ultrasonic vibrator capable of reducing the vibration propagation to the mounting side, and the ultrasonic vibrator. With a hermetic seal configuration that prevents leakage of the measurement fluid, a flow measurement device that can increase measurement accuracy, expand the measurement range, and maintain measurement characteristics for a long period of time can be realized.

The sound velocity C is calculated by the following formula, which is obtained by adding the reciprocal of the elapsed time T1 and the reciprocal of T2 in the calculation unit 47, and C = L ((1 / T1) + (1 / T2)) / 2 The type of the fluid to be measured can be determined based on the calculated sound speed C, and the measurement conditions as an ultrasonic flowmeter suitable for the sound speed or the type of the fluid to be measured can be set. The measurement conditions for the ultrasonic flow rate measuring device include a driving power such as a driving frequency and a driving voltage of the ultrasonic vibrator or a number of repetitions of how many times the elapsed times T1 and T2 are measured to calculate the flow velocity. . By registering the fluid that is assumed to be used in advance, the accuracy of determining the type of the fluid to be measured can be increased, and the temperature of the fluid to be measured is detected because the sound speed C changes depending on the temperature. It goes without saying that the accuracy of discriminating the type of the fluid to be measured can be further increased by providing a temperature sensor (not shown).

(Embodiment 10) FIGS. 8 and 9 are partial cross-sectional views of an ultrasonic flow rate measuring apparatus showing Embodiment 10 of the present invention.
8 is a sectional view taken along the line AA of FIG. 7, and FIG. 9 is a sectional view taken along the line BB of FIG. In the drawings, the same members and the same functions as those in the embodiment of FIGS. 1 to 7 are denoted by the same reference numerals, detailed description is omitted, and different portions will be mainly described.

As shown in the figure, the cross section in the direction perpendicular to the flow of the measuring section 43 is a rectangle having a width W and a height H, and the fluid passage wall 23a having a concave portion and the fluid passage wall 23b having a convex portion are fitted. In addition, the measuring section 43 is formed by the fluid passage wall 23 having the rectangular cross section. The shape of the opening 41 on the fluid passage side of the mounting hole 24 for mounting the ultrasonic vibrator is a rectangle having a length D1 in the left-right direction and a length D3 in the up-down direction (the height direction of the measuring section 43) in FIG. Yes, here, it is assumed that D1 = D3. The cross section in the direction orthogonal to the flow of the measuring unit 43 is rectangular, so that the flow in the measuring unit 43 is a two-dimensional flow, and the ultrasonic waves can be transmitted in the entire height H direction. Further, by making the shape of the opening portion 41 rectangular, the opening width becomes the dimension of D1 at any position in the height H direction, so that the ultrasonic wave can be transmitted and received uniformly in the height H direction of the measuring portion 43. Can be. As described above, the measuring section 4 is formed by the rectangular section of the measuring section 43 and the rectangular section of the opening.
Ultrasonic waves can be applied to the entire area of the flow 3 and by transmitting and receiving uniform ultrasonic waves in the height H direction, the flow velocity or flow rate can be measured with high accuracy by uniformly measuring the entire area of the flow.

As described above, since the opening area is constant in the height direction of the measuring section, it is possible to transmit and receive ultrasonic waves evenly in the height direction of the fluid passage, and to respond to the flow distribution in the height direction. The average flow velocity can be accurately detected by ultrasonic wave propagation.

The opening 41 is made uniform in the height direction of the fluid passage by making the length D1 in the left-right direction smaller than the length D3 in the up-down direction (height direction of the measuring unit 43) (D1 <D3). In addition to transmitting and receiving ultrasonic waves, the occurrence of flow disturbance due to the depression of the opening 41 can be further reduced, and the measurement accuracy can be further improved.

[0061]

As is apparent from the above description, the following effects can be obtained according to the flow rate measuring device of the present invention.

The piezoelectric body is contained in a case that shields from the fluid to be measured, an acoustic matching layer is provided on the top of the case, and a rigid support is provided on the side wall of the case. It has the effect of being able to transmit and receive short ultrasonic pulses and to obtain an ultrasonic transducer that can reduce the propagation of vibrations to the mounting side, and has measurement characteristics such as measurement accuracy of flow rate, flow velocity, and expansion of measurement range. There is an effect that the mounting state can be stabilized over a long period of time by the supporting portion with reduced vibration, and the reliability of measurement can be improved.

Further, since the supporting portion is formed by overlapping the flange provided at the end of the side wall portion and the sealing member for closing the opening, the thickness of the case is further increased by reinforcing the supporting portion with the sealing member. There is an effect that the sensitivity of the ultrasonic vibrator can be increased by making it thinner, and there is an effect that productivity can be improved by using the sealing body as a rigidity strengthening member of the support portion. Further, by joining the sealing body to the flange having an enlarged joining surface, there is an effect that internal airtightness can be increased and reliability can be improved.

Further, since the thickness of the sealing body of the supporting portion is thicker than that of the flange, there is an effect that deformation of the supporting portion is prevented, and airtightness of the fluid to be measured to the outside can be ensured. Since the thickness of the body is increased and the terminal and the insulating portion of the terminal can be easily formed, there is an effect that productivity can be improved.

Further, a vibration transmission suppressing member for reducing transmission of vibration of the ultrasonic vibrator to the fluid passage wall side is provided, and the ultrasonic vibrator is provided in a mounting hole provided in the fluid passage wall through the vibration transmission suppressing member. Is attached, acoustic impedance mismatch is provided, so that the vibration of the ultrasonic transducer can be hardly transmitted to the attachment side, and the measurement accuracy can be improved.

Further, since the projection is provided at least on the fluid passage wall side of the vibration transmission suppressing body and the vibration transmission suppressing body and the fluid passage wall are in partial contact, the vibration of the ultrasonic transducer is further transmitted to the mounting side. There is an effect that the measurement accuracy can be further improved. Further, since the vibration transmission suppressor is made of an elastic body, and a deformation prevention body for preventing deformation of the elastic body is provided in contact with the vibration transmission suppressor,
The vibration transmission suppressor has the effect of not only reducing vibration transmission, but also being able to be used together with the hermetic seal of the fluid to be measured, and the deformation prevention body prevents deformation of the elastic body and maintains the hermetic seal for a long period of time to maintain hermetic seal There is an effect that the reliability of the device can be improved.

Further, since the deformation preventing body is made of a material having a smaller acoustic impedance than at least the case or the sealing body which cools the opening of the case, even if the deformation preventing body and the ultrasonic vibrator come into contact with each other, the mounting side is not attached. Because vibration is difficult to be transmitted to
By arranging the deformation preventing body in contact with the ultrasonic vibrator, there is an effect that the deformation can be reliably prevented over the entire area of the vibration transmission suppressing body, and the reliability of the hermetic seal can be further improved.

Further, the mounting hole is a stepped mounting hole provided with a stepped portion which comes into contact with the vibration transmission suppressing body. Fix the vibration transmission suppressor with the fixed body provided outside the mounting hole,
Since the ultrasonic transducer is not in contact with the fluid passage wall and the fixed body, there is an effect that vibration propagation due to the non-contact can be reduced, and there is an effect that measurement accuracy can be improved by securing mounting position accuracy.

Since the opening of the mounting hole to the fluid passage has a smaller cross-sectional area than the storage portion for storing the side wall of the ultrasonic vibrator, the disturbance of the flow of the fluid to be measured due to the opening is reduced. Measurement accuracy can be improved.

A measuring section through which a fluid to be measured flows, a pair of ultrasonic transducers according to any one of claims 1 to 3 provided in the measuring section for transmitting and receiving ultrasonic waves, and 10. A measurement control unit for measuring a propagation time of a signal, and a calculation unit for calculating a flow rate based on a signal from the measurement control unit, wherein the ultrasonic vibrator is any one of claims 4 to 9. The ultrasonic vibrator has a case that shields the piezoelectric body from the fluid to be measured, so that it can transmit and receive ultrasonic pulses with short reverberation. This has the effect of reducing propagation and preventing leakage of the fluid to be measured, improving measurement accuracy, and expanding the measurement range. Further, there is an effect that the measurement characteristics can be maintained for a long time.

Also, since the cross section in the direction perpendicular to the flow of the measuring section is rectangular, and the shape of the opening on the fluid passage side of the mounting hole for mounting the ultrasonic vibrator is rectangular, the opening area in the height direction of the measuring section is large. The effect is that ultrasonic waves can be transmitted and received evenly in the height direction of the fluid passage because the pressure is constant, and the average flow velocity can be detected accurately by ultrasonic wave propagation according to the flow distribution in the height direction. effective.

[Brief description of the drawings]

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

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

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

FIG. 4 is a sectional view of a support structure of an ultrasonic transducer according to a fourth embodiment of the present invention.

FIG. 5 is a cross-sectional view of a support structure of an ultrasonic transducer according to Examples 5, 7, and 8 of the present invention.

FIG. 6 is a sectional view of a support structure of an ultrasonic transducer according to a sixth embodiment of the present invention.

FIG. 7 is a configuration diagram of an ultrasonic flow measurement device according to a ninth embodiment of the present invention.

FIG. 8 is a sectional view taken along the line AA of the ultrasonic flow measuring device of FIG. 7, showing a tenth embodiment of the present invention.

FIG. 9 is a sectional view taken along the line BB of the ultrasonic flow rate measuring apparatus shown in FIG. 7 showing the tenth embodiment of the present invention.

FIG. 10 is a sectional view of a conventional ultrasonic transducer.

FIG. 11 is a sectional view of another conventional ultrasonic transducer.

[Explanation of symbols]

 7 Case 8 Top part 9 Side wall part 10 Opening 11 Acoustic matching layer 12 Piezoelectric body 13 Supporting part 15 Sealing body 20, 44, 45 Ultrasonic vibrator 21 Flange 22, 30 Vibration transmission suppressor 23 Fluid passage wall 24 Mounting hole 29 Projection part 31, 32, 39, 40 Deformation prevention body 35 Stepped mounting hole 36 Stepped part 37 Fixed body 41 Opening part 42 Storage part 43 Measurement part 46 Measurement control part 47 Calculation part

Claims (12)

[Claims] 1. A topped cylindrical case having a top, a side wall, and an opening, a piezoelectric body fixed to an inner wall surface of the top, and an acoustic matching layer provided on an outer wall of the top. And a support part provided on the side wall part, wherein the support part is shaped to increase rigidity. 2. The ultrasonic vibrator according to claim 1, wherein the support portion is formed by overlapping a flange provided at an end portion of the side wall portion with a sealing member closing the opening. 3. The ultrasonic transducer according to claim 2, wherein the thickness of the sealing body of the supporting portion is larger than that of the flange. 4. An ultrasonic vibrator is provided in a mounting hole provided in the fluid passage wall through the vibration transmission suppressor, the vibration transmitting suppressor being configured to reduce transmission of vibration of the ultrasonic vibrator to the fluid passage wall side. A support structure for an ultrasonic vibrator to which the ultrasonic vibrator according to any one of claims 1 to 3 is attached. 5. The ultrasonic vibrator supporting structure according to claim 4, wherein a projection is provided at least on the side of the fluid passage wall of the vibration transmission suppressor, and the vibration transmission suppressor and the fluid passage wall are in partial contact. 6. The ultrasonic vibration according to claim 4, wherein said vibration transmission suppressing member is made of an elastic body, and a deformation preventing body for preventing deformation of said elastic body is provided in contact with said vibration transmission suppressing body. Child support configuration. 7. The support structure for an ultrasonic vibrator according to claim 6, wherein the deformation preventing member is made of a material having a smaller acoustic impedance than at least the case or the sealing member that cools the opening of the case. 8. The mounting hole is a stepped mounting hole provided with a stepped portion which comes into contact with the vibration transmission suppressing body, and a vibration transmission suppressing body having an ultrasonic vibrator mounted therein is inserted into the stepped mounting hole. The ultrasonic vibration according to any one of claims 4 to 7, wherein the vibration transmission suppressing body is fixed by a fixed body provided outside the mounting hole, and the ultrasonic vibrator is not in contact with the fluid passage wall and the fixed body. Child support configuration. 9. The ultrasonic vibrator according to claim 4, wherein an opening of the mounting hole to the fluid passage has a smaller cross-sectional area than a storage portion for storing the side wall of the ultrasonic vibrator. Support configuration. 10. A measuring part through which a fluid to be measured flows, a pair of ultrasonic transducers provided in the measuring part for transmitting and receiving ultrasonic waves, and the ultrasonic transducer according to claim 1. An ultrasonic surveying and measuring apparatus comprising: a measurement control unit that measures a propagation time between the two; and a calculation unit that calculates a flow rate based on a signal from the measurement control unit. 11. An ultrasonic flow rate measuring apparatus according to claim 10, wherein said ultrasonic transducer has a support structure according to any one of claims 4 to 9. 12. The ultrasonic flow rate measuring device according to claim 10, wherein a cross section in a direction orthogonal to the flow of the measuring section is rectangular, and a shape of an opening on a fluid passage side of a mounting hole for mounting the ultrasonic vibrator is rectangular. apparatus.