JP7048178B2 - Ultrasonic flow meter - Google Patents

Description

The present invention relates to an ultrasonic flow meter that measures a fluid flow rate using an ultrasonic sensor.

An ultrasonic flow meter is known to measure the flow rate of a fluid based on the time required from transmission to reception of ultrasonic waves by an ultrasonic sensor. As such a conventional ultrasonic flow meter, for example, Patent Document 1 discloses it.

Japanese Unexamined Patent Publication No. 2001-4416

Here, in the ultrasonic flow meter, if the mounting angle of the ultrasonic sensor is not correct, the propagation direction of the ultrasonic wave and the flow direction of the fluid do not match, and the measurement accuracy of the flow rate may decrease. In particular, when plate members such as a partition plate and a rectifying plate are installed in the flow path through which the fluid flows, the transmitted ultrasonic waves may collide with the plate members and the ultrasonic waves may not be sufficiently received. As a result, the mounting angle of the ultrasonic sensor affects the transmission / reception of ultrasonic waves, that is, the measurement accuracy of the flow rate.

The present invention has been made to solve the above-mentioned problems, and to provide an ultrasonic flow meter capable of preventing deterioration of measurement accuracy by mounting an ultrasonic sensor at a correct mounting angle. The purpose.

The ultrasonic flow meter according to the present invention is a pair of ultrasonic waves that measure the flow rate of the fluid flowing through the flow path based on the propagation time of the ultrasonic waves by transmitting and receiving ultrasonic waves to each other in the fluid flowing through the flow path. The ultrasonic sensor includes a sensor and a sensor accommodating portion provided in the flow path for accommodating a pair of ultrasonic sensors, and the ultrasonic sensor includes a support plate that supports a piezoelectric body that transmits and receives ultrasonic waves, and the support plate. It has a packing provided on the outer peripheral portion that seals between the ultrasonic sensor and the inner surface of the sensor housing portion, and a support plate side projecting portion that protrudes from the support plate. The sensor housing portion has a support plate side projecting portion. It is characterized by having a fitting portion for positioning the rotation angle position around the central axis of the ultrasonic sensor by being fitted.

According to the present invention, it is possible to prevent a decrease in measurement accuracy by mounting an ultrasonic sensor at a correct mounting angle.

It is external perspective view of the ultrasonic flow meter which concerns on Embodiment 1 of this invention. It is a top view of the ultrasonic flow meter which concerns on Embodiment 1 of this invention. It is a front view of the ultrasonic flow meter which concerns on Embodiment 1 of this invention. It is a side view of the ultrasonic flow meter which concerns on Embodiment 1 of this invention. FIG. 2 is a cross-sectional view taken along the line VV of FIG. FIG. 6A is an enlarged view of the sensor accommodating portion with the lid member removed. FIG. 6B is a sectional view taken along the line VI-VI of FIG. 6A. FIG. 7A is an external perspective view of another ultrasonic sensor. FIG. 7B is a plan view of another ultrasonic sensor. FIG. 7C is a cross-sectional view taken along the line VII-VII of FIG. 7B. FIG. 8A is an external perspective view of another ultrasonic sensor. FIG. 8B is a plan view of another ultrasonic sensor. FIG. 8C is a cross-sectional view taken along the line VIII-VIII of FIG. 8B.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1.
1 is an external perspective view of the ultrasonic flow meter according to the first embodiment, FIG. 2 is a plan view thereof, FIG. 3 is a front view thereof, and FIG. 4 is a side view thereof. FIG. 5 is a cross-sectional view taken along the line VV of FIG. 6A and 6B are views showing the positioning state of the ultrasonic sensor. 7A to 7C and FIGS. 8A to 8C are views showing the configuration of an ultrasonic sensor. The solid arrows shown in FIGS. 1, 3, and 5 indicate the flow direction of the fluid. Further, the arrow of the two-dot chain line shown in FIG. 5 indicates the propagation path of the ultrasonic wave.

As shown in FIGS. 1 to 5, the ultrasonic flow meter 1 according to the first embodiment includes a measuring tube 10, sensor housing portions 20a and 20b, and ultrasonic sensors 30a and 30b.

As shown in FIGS. 1 to 5, the measuring tube 10 has a flow path 11, a flow path inlet 12, a flow path outlet 13, and pocket portions 14a and 14b.

The flow path 11 extends in the axial direction of the measuring tube 10 and allows the fluid to flow along the axial direction thereof. Further, the upstream side opening end of the flow path 11 constitutes the flow path inlet 12, and the downstream side opening end of the flow path 11 constitutes the flow path outlet 13. That is, the measuring tube 10 passes the fluid supplied into the flow path 11 from the flow path inlet 12 through the flow path 11, and then discharges the fluid from the flow path outlet 13. At this time, the ultrasonic flow meter 1 measures the flow rate of the fluid as it passes through the flow path 11.

As shown in FIG. 5, the pocket portions 14a and 14b are provided on the upstream side and the downstream side of the flow path 11, respectively. Further, the pocket portions 14a and 14b extend from the flow path 11 toward the outside of the flow path 11 and communicate the inside of the flow path 11 with the inside of the sensor storage portions 20a and 20b.

As shown in FIGS. 1 to 5, the pair of sensor housing portions 20a and 20b have a cylindrical shape and house the pair of ultrasonic sensors 30a and 30b having a circular shape, respectively. Further, the sensor housing portions 20a and 20b communicate with the pocket portions 14a and 14b, respectively. As a result, the ultrasonic sensor 30a housed in the sensor housing portion 20a faces the flow path 11 via the pocket portion 14a. Similarly, the ultrasonic sensor 30b housed in the sensor housing portion 20b faces the flow path 11 via the pocket portion 14b.

As shown in FIG. 5, ultrasonic sensors 30a and 30b enable transmission and reception of ultrasonic waves between each other. Then, the ultrasonic flow meter 1 propagates the ultrasonic waves transmitted from the ultrasonic sensors 30a and 30b into the fluid flowing through the flow path 11 to cause a difference in the propagation time of the ultrasonic waves between the ultrasonic sensors 30a and 30b. Based on this, the flow rate of the fluid flowing through the flow path 11 is measured.

As a result, the ultrasonic sensors 30a and 30b are arranged on the upstream side and the downstream side of the flow path 11, respectively, and are located at the axis of the measuring tube 10 so that the transmitted ultrasonic waves intersect the fluid flow direction diagonally. On the other hand, it is provided at an angle. That is, the ultrasonic sensor 30a arranged on the upstream side is inclined so that the front surface of the sensor faces the downstream side. On the other hand, the ultrasonic sensor 30b arranged on the downstream side is inclined so that the front surface of the sensor faces the upstream side.

Therefore, the ultrasonic wave transmitted from the ultrasonic sensor 30a propagates diagonally from the upstream side to the downstream side in the fluid flowing through the flow path 11, is reflected on the bottom surface of the flow path 11, and then is an ultrasonic wave. Received by sensor 30b. On the other hand, the ultrasonic waves transmitted from the ultrasonic sensor 30b propagate diagonally in the fluid flowing through the flow path 11 from the downstream side to the upstream side, are reflected on the bottom surface of the flow path 11, and then are ultrasonic waves. Received by a sensor 30a.

Then, the ultrasonic sensors 30a and 30b obtain the propagation times of the two ultrasonic waves by alternately transmitting and receiving ultrasonic waves, and then measure the flow rate of the fluid flowing through the flow path 11 based on the difference between the propagation times. do.

Next, the configurations of the sensor housing portions 20a and 20b and the ultrasonic sensors 30a and 30b, and the mounting structure of the ultrasonic sensors 30a and 30b based on these configurations will be described with reference to FIGS. 1 to 7C. Since the sensor housing portions 20a and 20b have the same configuration and function, the corresponding constituent members are designated by a common reference numeral. Similarly, since the ultrasonic sensors 30a and 30b have the same configuration and function, the corresponding constituent members are designated by a common reference numeral.

As shown in FIGS. 1 to 5 and 7A to 7C, the ultrasonic sensors 30a and 30b have a support plate 31, a piezoelectric body 32, an acoustic matching body 33, and a packing 34.

The support plate 31 is a flat disk and is made of a conductive material. The circular support plate 31 supports the piezoelectric body 32 and the acoustic matching body 33, and has a protrusion 31a which is a support plate side protrusion. The protruding portion 31a protrudes radially outward from the outer peripheral portion of the support plate 31, and the details of the protruding portion 31a will be described later.

When a voltage is applied, the piezoelectric body 32 expands and contracts in the thickness direction of the support plate 31, that is, in the direction of the central axis of the ultrasonic sensors 30a and 30b (hereinafter referred to as the sensor central axis), thereby causing ultrasonic waves. Is an element that generates. Further, the piezoelectric body 32 generates a voltage when an ultrasonic wave (vibration) is applied from the outside. That is, the piezoelectric body 32 can transmit and receive ultrasonic waves. Such a piezoelectric body 32 has, for example, a rectangular parallelepiped shape, and is supported by the outer surface of a support plate 31 that does not face the flow path 11.

The acoustic matching body 33 is an element that matches the acoustic impedance of the piezoelectric body 32 with the acoustic impedance of the fluid and suppresses the reflection of ultrasonic waves between them in order to efficiently transmit and receive ultrasonic waves in the piezoelectric body 32. Is. Such an acoustic matching body 33 has, for example, a columnar shape, and is supported by the inner surface of the support plate 31 facing the flow path 11.

The packing 34 seals between the inner surface of the sensor housing portions 20a and 20a and the ultrasonic sensors 30a and 30b when the ultrasonic sensors 30a and 30b are housed in the sensor storage portions 20a and 20a. The packing 34 has an annular shape and is attached to the outer peripheral portion of the support plate 31. At this time, the protruding portion 31a of the support plate 31 penetrates the packing 34 in the radial direction and protrudes outward in the radial direction from the outer peripheral portion of the packing 34.

On the other hand, as shown in FIGS. 1 to 6B, the sensor housing portions 20a and 20b have an opening end 21, a lid member 22, and a notch portion 23 serving as a fitting portion. In addition, in FIGS. 1 to 5, the sensor accommodating portion 20a arranged on the upstream side is in a state in which the lid member 22 is attached, but the sensor accommodating portion 20b arranged on the downstream side has the lid member 22 attached. It is in a removed state.

The open end 21 serves as a storage work port used when the ultrasonic sensors 30a and 30b are stored in the sensor storage portions 20a and 20b.

When the ultrasonic sensors 30a and 30b are housed in the sensor storage parts 20a and 20b, the lid member 22 closes the opening end 21 of the sensor storage parts 20a and 20b and puts the ultrasonic sensors 30a and 30b in the sensor storage parts 20a. , 20b is pressed against the inner surface. Specifically, as shown in FIG. 5, the lid member 22 presses the upper end of the packing 34 of the ultrasonic sensors 30a and 30b, and the lower end of the pressed packing 34 is placed on the inner surface of the sensor housing portions 20a and 20b. Make them stick together.

The cutout portion 23 is formed at the open end 21, and is fitted through the protruding portions 31a of the ultrasonic sensors 30a and 30b. The notch direction of the notch portion 23 coincides with the sensor central axis direction when the ultrasonic sensors 30a and 30b are housed in the sensor housing portions 20a and 20b. That is, the ultrasonic sensors 30a and 30b are attached in the sensor central axis direction. Further, when the protruding portion 31a is fitted, the cutout portion 23 positions the rotation angle position of the protruding portion 31a around the sensor center axis.

Therefore, the ultrasonic sensors 30a and 30b are inserted into the sensor accommodating portions 20a and 20b from the open end 21 of the sensor accommodating portions 20a and 20b along the sensor central axis direction in a state where the protruding portions 31a are fitted into the notched portions 23. Simply, it sits on the inner surface of the sensor housing portions 20a and 20b and is attached to the sensor housing portions 20a and 20b. At this time, the ultrasonic sensors 30a and 30b are positioned at the correct rotation angle positions around the sensor center axis. In other words, the ultrasonic sensors 30a and 30b are always mounted at the correct mounting angle with the sensor center axis as the center of rotation.

The lid member 22 is further sealed between the sensor housing portions 20a and 20b and the ultrasonic sensors 30a and 30b by further pressing the positioned ultrasonic sensors 30a and 30b against the inner surfaces of the sensor housing portions 20a and 20b. Not only the performance is improved, but also the positions of the ultrasonic sensors 30a and 30b in the sensor central axis direction are positioned.

However, although the sensor housing portions 20a and 20b described above have the fitting portion as the notch portion 23, the fitting portion can position the rotation angle position of the protruding portion 31a around the sensor center axis. If so, it is not limited to that. The fitting portion may be, for example, a fitting recess recessed from the inner surface of the sensor housing portions 20a, 20b, a fitting hole penetrating the sensor housing portions 20a, 20b, or the like.

Further, in the ultrasonic sensors 30a and 30b, at least the support plate 31 of the support plate 31, the piezoelectric body 32, the acoustic matching body 33, and the packing 34 constituting the ultrasonic sensors 30a and 30b is attached to the fitting portion. If the sensor is fitted, the rotation angle position around the sensor central axis can be positioned, but the packing 34 may be fitted into the fitting portion together with the support plate 31.

Specifically, as shown in FIGS. 8A to 8C, the support plate 31 has the protrusion 31a, and the protrusion 31a is radially outward from the outer peripheral portion of the support plate 31. It is protruding. Correspondingly, the packing 34 has a protruding portion 34a which is a protruding portion on the packing side, and the protruding portion 34a protrudes radially outward from the outer peripheral portion of the packing 34.

At this time, although the packing 34 is attached to the outer peripheral portion of the support plate 31, the protruding portion 34a is not attached to the protruding portion 31a and closely overlaps with the protruding portion 31a in the sensor central axis direction. ing. That is, the protruding portion 31a is housed in the protruding portion 34a. In this way, the protrusion 31a is covered on both sides in the radial direction by the protrusions 34a, so that when it is fitted into the notch 23, it does not come into contact with the end face of the notch 23, and instead The protrusion 34a covering the protrusion 31a comes into contact with the end surface of the notch 23. As a result, the ultrasonic sensors 30a and 30b can prevent the position shift of the piezoelectric body 32 and the acoustic matching body 33 when the protruding portion 31a is fitted.

From the above, the ultrasonic flow meter 1 according to the first embodiment has an ultrasonic sensors 30a and 30b for measuring the flow rate of the fluid flowing through the flow path 11, and a sensor storage unit 20a for accommodating the ultrasonic sensors 30a and 30b. 20b is provided, and a protruding portion 31a protruding from the support plate 31 is formed on the support plate 31 of the ultrasonic sensors 30a and 30b, while the sensor center of the protruding portion 31a is formed on the opening end 21 of the sensor housing portions 20a and 20b. A notch 23 for positioning the rotation angle position around the axis is formed. As a result, the ultrasonic flow meter 1 can mount the ultrasonic sensors 30a and 30b at the correct mounting angle, so that it is possible to prevent a decrease in measurement accuracy.

Then, in the ultrasonic flow meter 1, the piezoelectric body 32 is formed by fitting the protruding portions 31a and 34a into the cutout portion 23 in a state where the protruding portion 31a of the support plate 31 is housed in the protruding portion 34a of the packing 34. And the misalignment of the acoustic matching body 33 can be prevented.

Further, in the ultrasonic flow meter 1, the fitting portion into which the protruding portion 31a is fitted is a notch portion 23, so that the attachment work of the ultrasonic sensors 30a and 30b can be performed by fitting the protruding portion 31a into the notch portion 23. Since it can be started from the crowded state, the installation workability can be improved.

Further, the ultrasonic flow meter 1 includes a lid member 22 that closes the open end 21 of the sensor housing portions 20a and 20b and presses the ultrasonic sensors 30a and 30b against the inner surfaces of the sensor housing portions 20a and 20b. As a result, in the ultrasonic flow meter 1, the packing 34 of the ultrasonic sensors 30a and 30b is strongly adhered to the inner surface of the sensor housing portions 20a and 20b, so that the sealing by the packing 34 can be improved. Further, since the ultrasonic flow meter 1 can position the positions of the ultrasonic sensors 30a and 30b in the sensor central axis direction, it is possible to further prevent the measurement accuracy from deteriorating.

In the present invention, it is possible to modify any component of the embodiment or omit any component of the embodiment within the scope of the invention.

1 Ultrasonic flow meter 10 Measuring tube 11 Flow path 12 Flow path inlet 13 Flow path outlet 14a, 14b Pocket part 20a, 20b Sensor storage part 21 Open end 22 Lid member 23 Notch part 30a, 30b Ultrasonic sensor 31 Support plate 31a Projection 32 Piezoelectric body 33 Acoustic matching body 34 Packing 34a Projection

Claims (6)

A pair of ultrasonic sensors that measure the flow rate of the fluid flowing through the flow path based on the propagation time of the ultrasonic waves by transmitting and receiving ultrasonic waves to each other in the fluid flowing through the flow path.
A sensor accommodating portion provided in the flow path and accommodating each of the pair of ultrasonic sensors is provided.
The ultrasonic sensor is
A support plate that supports the piezoelectric material that transmits and receives ultrasonic waves,
A packing provided on the outer peripheral portion of the support plate and sealing between the ultrasonic sensor and the inner surface of the sensor housing portion,
It has a support plate side protrusion that protrudes from the support plate, and has a support plate side protrusion.
The sensor storage unit is
An ultrasonic flow meter characterized by having a fitting portion for positioning a rotation angle position around a central axis of the ultrasonic sensor by fitting the protrusion on the support plate side. The protrusion on the support plate side is
The ultrasonic flow meter according to claim 1, wherein the packing is penetrated from the support plate and protrudes from the packing. The ultrasonic sensor is
The ultrasonic flow meter according to claim 1, further comprising a packing-side protruding portion that protrudes from the packing and is fitted into the fitting portion. The ultrasonic flow meter according to claim 3, wherein the support plate side protrusion is housed in the packing side protrusion. The fitting portion is
The ultrasonic flow meter according to any one of claims 1 to 4, wherein the ultrasonic flow meter is a notch formed at an open end of the sensor accommodating portion. The invention according to any one of claims 1 to 5, further comprising a lid member that closes the open end of the sensor accommodating portion and presses the ultrasonic sensor against the inner surface of the sensor accommodating portion. Ultrasonic flow meter.

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