Clamp-on type ultrasonic transceiver

Abstract

This invention provides a clamp-on type ultrasonic transceiver that prevents the base from shifting or sliding horizontally. [Solution] The base portion 4 consists of a base portion 4a on which the measuring tube P is placed, and an ultrasonic transmitting and receiving portion 4b connected to the base portion 4a. The base portion 4a, which is an acoustic matching layer, is in close contact with the piezoelectric transducer 4c and consists of a main body portion 4d extending diagonally upward and a rib portion 4e extending axially below the main body portion 4d. A first fixed portion 4f, which is a screw hole in the housing portion 2c, extends axially from the center of the bottom surface of the rib portion 4e. After aligning the first fixed portion 4f with a third fixed portion 2d, which is a through hole located inside the housing portion 2c, a screw body is screwed into the second fixed portion 4o from below, sandwiching the third fixed portion 2d, thereby preventing the base portion 4a from moving or sliding horizontally.

Description

Technical Field

[0006]

[0001] The present invention relates to a clamp-on type ultrasonic transmitting and receiving device that fixedly attaches an ultrasonic transmitting and receiving unit to a measuring tube made of synthetic resin in a post-attached manner.

Background Art

[0002] Patent Document 1 discloses a clamp-on type ultrasonic transmitting and receiving device that transmits and receives a guided wave by ultrasonic waves propagating through a measuring tube through which a fluid flows, using a pair of piezoelectric vibrators.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such a clamp-on type ultrasonic flowmeter that propagates such a guided wave through a measuring tube, ultrasonic waves transmitted from and incident on a pair of piezoelectric vibrators need to be propagated obliquely from an acoustic matching layer that is assembled and arranged in an oblique direction to a measuring tube held horizontally. However, when holding the measuring tube, the pressing force from above on the measuring tube may shift and move the acoustic matching layer arranged obliquely, and the positional relationship between the acoustic matching layers with respect to the measuring tube may easily fluctuate, which may affect the measurement accuracy.

[0005] An object of the present invention is to solve the above problems, arrange the piezoelectric vibrator to transmit and receive in an obliquely upward direction, prevent the base portion from escaping or slipping horizontally due to the acoustic matching layer being arranged obliquely with respect to the measuring tube, and provide a clamp-on type ultrasonic transmitting and receiving device capable of ensuring measurement accuracy.

Means for Solving the Problems

[0006] The clamp-on ultrasonic transmitting and receiving device according to the present invention for achieving the above-mentioned objectives comprises a holding part that clamps and holds a straight tubular measuring tube, and a pair of piezoelectric transducers that transmit and receive ultrasonic waves, wherein the holding part is provided on the main body and comprises a base part on which the measuring tube is placed, and a pressing piece provided on the lid part connected to the main body and pressing the measuring tube on the base part from above, wherein the base part comprises a base part made of an acoustic matching layer and an ultrasonic transmitting and receiving part connected to the base part, wherein the base part is in close contact with the piezoelectric transducers that transmit and receive ultrasonic waves and comprises a cylindrical main body part that extends diagonally upward in the direction of the central axis of the piezoelectric transducer, and a rib part that extends perpendicular to the axis below the main body part, and the upper end surface of the main body part is a curved surface that is in close contact with the measuring tube. [Effects of the Invention]

[0007] According to the clamp-on ultrasonic transmitting and receiving device of the present invention, the piezoelectric transducer is arranged to transmit and receive in an oblique upward direction, and the base portion, which has an acoustic matching layer positioned obliquely upward relative to the measuring tube, is fixed to the housing portion via the rib portion in a direction perpendicular to the axis, that is, perpendicular to the central axis of the measuring tube. As a result, even when the measuring tube is strongly pressed by the holding portion during clamp-on, the base portion remains immobile.

[0008] Therefore, even if the pressing force is applied from an oblique direction to the central axis of the base, the position of the piezoelectric vibrator is not affected, and horizontal displacement or slippage of the base can be prevented. As a result, there is no risk of the relative positions of the piezoelectric vibrators changing, and stable measurements can be achieved. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view showing a clamp-on type ultrasonic transceiver attached to a measuring tube. [Figure 2] This is a perspective view showing the lid opened from the state shown in Figure 1. [Figure 3] This is a cross-sectional view along the line A-A' in Figure 1. [Figure 4]This is an exploded perspective view of the base and the housing. [Figure 5] This is a perspective view of the assembled ultrasonic transmitter / receiver unit. [Figure 6] This is a perspective view of the assembled ultrasonic transmitting and receiving unit, seen from below. [Figure 7] This is a perspective view of the housing with a pair of bases attached. [Figure 8] This is a perspective view from below of the housing with a pair of bases attached. [Modes for carrying out the invention]

[0010] The present invention will be described in detail based on the illustrated embodiments. Figure 1 is a perspective view of a measuring tube made of synthetic resin with a clamp-on ultrasonic transceiver attached, Figure 2 is a perspective view of the state in Figure 1 with the lid opened, and Figure 3 is a cross-sectional view along the line A-A' in Figure 1.

[0011] The clamp-on ultrasonic transceiver 1, which is roughly rectangular in shape, consists of a main body 2 on which a measuring tube P is placed and to which a connecting cable can be connected at the bottom, and a lid 3 that is connected to the main body 2 so as to be openable and closable via an opening / closing part 2a. The main body 2 has a pair of piezoelectric transducers arranged at two locations in the longitudinal direction for transmitting and receiving ultrasonic waves to and from the measuring tube P.

[0012] The holding portion that clamps and holds the straight tubular measuring tube P consists of a base portion 4 provided on the main body portion 2, a side wall portion 2b, and a pressing piece 3b provided on the lid portion 3. The base portion 4 is mounted inside the housing portion 2c which is installed inside the main body portion 2. As shown in Figures 2 and 3, the housing portion 2c is installed inside the main body portion 2 and is fixed to the main body portion 2 by a screw body.

[0013] Figure 4 is an exploded perspective view of the base 4 and the housing 2c, Figure 5 is a perspective view of the base 4, and Figure 6 is a perspective view of the base 4 from below. Figure 7 is a perspective view of the housing 2c with the pair of base 4 attached, and Figure 8 is a perspective view of the housing 2c with the pair of base 4 attached from below.

[0014] The pedestal portion 4 is composed of a base portion 4a on which the measurement tube P is placed on the upper surface, and an ultrasonic transmitting and receiving portion 4b composed of a plurality of components connected to the base portion 4a. The upper surface of the base portion 4a has a dish shape with an arcuate cross section for placing the measurement tube P.

[0015] The base portion 4a, which is an acoustic matching layer for propagating ultrasonic waves, is made of synthetic resin, and the piezoelectric vibrator 4c is in close contact. The base portion 4a is composed of a columnar main body portion 4d extending in the obliquely upward direction, which is the central axis direction of the piezoelectric vibrator 4c, and a rib portion 4e extending in the axial direction below the main body portion 4d and having a horizontal bottom surface.

[0016] On the horizontal bottom surface of this rib portion 4e, a first fixed portion 4f in the shape of a screw hole is formed in the axial direction from the center of the bottom surface, that is, in a direction orthogonal to the central axis of the measurement tube P to be placed.

[0017] The length of the screw hole of the first fixed portion 4f is set to a length that does not reach the main body portion 4d. This is because if the screw hole reaches the main body portion 4d, the ultrasonic waves transmitted and received by the piezoelectric vibrator 4c will be interfered by, for example, the first fixed portion 4p of a metal body screwed into the screw hole, significantly reducing the propagation efficiency.

[0018] The measurement tube P can be placed on the base portion 4a through a thin film protective film portion 4h that covers the upper side of the main body portion 4d. This protective film portion 4h is made of a thin film-like rubber sheet material having waterproof properties, and the measurement tube P can be made to adhere more closely to the base portion 4a.

[0019] Also, at the end of the main body portion 4d on the side of the piezoelectric vibrator 4c, a flange portion 4g that is substantially annular and protrudes outward is provided. The ultrasonic transmitting and receiving portion 4b includes a piezoelectric vibrator 4c that is in close contact with the end surface of the base portion 4a provided with the flange portion 4g, a piezoelectric vibrator holding portion 4i that holds the piezoelectric vibrator 4c from the rear, and a connecting portion 4j that closely adheres and fixes the base portion 4a, the piezoelectric vibrator 4c, and the piezoelectric vibrator holding portion 4i.

[0020] The connecting section 4j consists of a storage section 4k with an opening at the top and a fixing plate section 4l extending horizontally from the bottom of the storage section 4k. The storage section 4k is designed to accommodate the flange section 4g, the piezoelectric vibrator 4c, and the piezoelectric vibrator holder section 4i in that order from the tip.

[0021] The storage compartment 4k is positioned diagonally and is a roughly cylindrical body with a bottom, with its top surface and part of its slanted side open. A bottom screw hole 4m is provided in the center of the bottom of the storage compartment 4k.

[0022] The fixing plate portion 4l is a plate-like body for fixing the storage portion 4k to the housing portion 2c, and is provided with a through hole 4n whose central axis is in an oblique direction, and a second fixing portion 4o which is a U-shaped notch cut out at the rear end.

[0023] Furthermore, in order to firmly attach the piezoelectric vibrator 4c to the central flat surface of the flange portion 4g of the main body portion 4d, an adjustment screw (not shown) is inserted into the through hole 4n from the back surface of the fixing plate portion 4l, and this adjustment screw is screwed into the bottom screw hole 4m and screwed in. By adjusting the screwing in of this adjustment screw, the piezoelectric vibrator 4c is pressed by the adjustment screw that passes through the bottom hole (not shown) of the piezoelectric vibrator holding portion 4i, thereby firmly attaching the piezoelectric vibrator 4c to the contact surface of the main body portion 4d.

[0024] When fixing the base portion 4 to the housing portion 2c, the flange portion 4g, piezoelectric transducer 4c, and piezoelectric transducer holding portion 4i are housed in the storage portion 4k as described above, and the base portion 4a and the ultrasonic transmitting / receiving portion 4b are connected and integrated. Furthermore, the pressing force of the piezoelectric transducer 4c against the main body portion 4d is adjusted using an adjustment screw (not shown) on the integrated base portion 4.

[0025] Next, the first fixing portion 4f of the rib portion 4e is aligned with the third fixing portion 2d, which is a through hole located inside the housing portion 2c. Then, the first fixing portion 4p, which is a screw, is screwed into the first fixing portion 4f from below, sandwiching the third fixing portion 2d.

[0026] Similarly, after aligning the second fixing portion 4o of the fixing plate portion 4l with the fourth fixing portion 2e, which is a screw hole located outside the third fixing portion 2d, the second fixing portion 4q, which is a screw body, is screwed onto the fourth fixing portion 2e from above, sandwiching the second fixing portion 4o.

[0027] Figure 7 is a perspective view of the housing 2c with the pair of bases 4 attached in this manner, and Figure 8 is a perspective view of the housing 2c in this state viewed from below. In this way, the housing 2c with the bases 4 attached is placed on the base 2f of the main body 2, and as shown in Figure 2, the measuring tube mounting section 2g with side walls 2b is placed on top of the housing 2c and fixed with multiple fixing screws 2h, thereby completing the assembly of the main body 2.

[0028] Furthermore, the lid portion 3 is provided with a pressing piece 3b positioned on its closing surface 3a, which presses the measuring tube P with an even force distribution, forming a polyhedron with multiple small faces, and pressing the measuring tube P on the base portion 4 from above; a hook-shaped locking portion 3d positioned on the outer surface 3c, which locks the lid portion 3 to a locking portion 2i also positioned on the outer surface 3c when the lid portion 3 is closed; and an unlocking button 3f positioned on the top surface 3e, which unlocks the locking portion 3d by pressing it.

[0029] An elastic body 3i, made of a compression coil spring, is embedded in the gap 3h within the lid portion 3 between the pressing piece 3b provided on the closing surface 3a and the elastic body fixing part 3g provided on the top surface 3e. As a result, the pressing piece 3b is constantly subjected to a downward pressing force due to the repulsive force of the elastic body 3i. When the measuring tube P is placed on the base portion 4 and the lid portion 3 is closed and locked, the pressing piece 3b presses the measuring tube P against the base portion 4 with an appropriate pressing force from above.

[0030] In particular, in conventional structures that mechanically press and clamp from above without using pressing force from springs or the like, variations in pressing strength occurred due to variations in the dimensions of the parts. In contrast, in this embodiment, the pressing force by the elastic body 3i reduces the variation in pressing strength due to variations in the parts of the pressing piece 3b.

[0031] When attaching the clamp-on ultrasonic transceiver 1 to the measuring tube P, the lid 3 is opened as shown in Figure 2, the measuring tube P is placed on the front and rear bases 4, and the lid 3 is closed. When closing the lid 3, the locking part 3d of the lid 3 is locked to the locking part 2i on the side of the main body 2, and the lid 3 is locked as shown in Figures 1 and 3. This locked state cannot be released unless the unlocking button 3f, which is linked to the locking part 3d, is pressed.

[0032] In this manner, the straight-tube measuring tube P is held by the holding portion, which consists of the base portion 4 and side wall portions 2b of the main body portion 2, and the pressing piece 3b of the lid portion 3. The measuring tube P, held by the holding portion of the clamp-on ultrasonic transceiver 1, originally has a circular cross-section. As shown in Figure 2, when the measuring tube P is placed on the base portion 4, the movement of the measuring tube P in the width direction is restricted by the side wall portions 2b on both sides of the base portion 4.

[0033] The piezoelectric transducers 4c, which are ultrasonic transmitting and receiving units, are positioned on a pair of base units 4 and alternately transmit and receive ultrasonic waves to measure the propagation state of guided waves in each direction of fluid flow in the measuring tube P. The various data obtained by the pair of piezoelectric transducers 4c are transmitted to an external device, the processing unit, via a connecting cable 2j connected to the main unit 2.

[0034] In this processing apparatus, the flow rate of the fluid flowing through the measuring tube P is measured by a known calculation based on the flow velocity calculated based on the time difference in the propagation time of the guided wave in the measuring tube P, and the cross-sectional area of ​​the measuring tube P.

[0035] The processing unit for calculating the fluid flow rate may be installed inside the main unit 2. In this case, the fluid velocity, flow rate information, etc., calculated by the processing unit consisting of an IC chip or the like, will be transmitted to an external device via the connection cable 2j.

[0036] In this embodiment, the flow velocity and flow rate of the fluid flowing through the measuring tube P are measured based on the time difference in the propagation time of ultrasonic waves propagating as guide waves through the measuring tube P. However, it is also possible to employ an appropriate flow rate measurement method using ultrasonic beams propagating through the fluid from a pair of piezoelectric transducers 4c.

[0037] Thus, according to the clamp-on ultrasonic transceiver of the present invention, the piezoelectric transducer 4c is arranged to transmit and receive signals in an oblique upward direction, and the base portion 4a, on which the acoustic matching layer is positioned obliquely upward relative to the measuring tube P, is fixed to the housing portion 2c via the rib portion 4e in a direction perpendicular to the axis, that is, perpendicular to the central axis of the measuring tube P. As a result, even when the measuring tube P is strongly pressed by the holding portion during clamping, the base portion 4a remains immobile.

[0038] Therefore, even if the pressing force is applied from an oblique direction to the central axis of the base portion 4a, the position of the piezoelectric vibrator 4c is not affected, and horizontal displacement or slippage of the base portion 4a can be prevented. As a result, there is no risk of the relative positions of the piezoelectric vibrators 4c changing, and stable measurement can be achieved. [Explanation of symbols]

[0039] 1. Clamp-on type ultrasonic transceiver 2 Main body 2c Enclosure 2d Third fixed part 2e Fourth fixed part 3 Lid 4. Base 4a Base 4b Ultrasonic Transceiver Unit 4c piezoelectric vibrator 4d main body 4e Rib section 4f First fixed part 4g flange section 4i Piezoelectric vibrator holder 4j connection part 4K storage compartment 4l Fixed plate part 4o Second part to be fixed 4p First fixing part 4q Second fixing part P measurement tube

Claims

1. It comprises a holding part that clamps and holds a straight tubular measuring tube, and a pair of piezoelectric transducers that transmit and receive ultrasonic waves. In a clamp-on type ultrasonic transmitting and receiving device, the holding part is provided on the main body and consists of a base portion on which the measuring tube is placed and a pressing piece provided on the lid portion connected to the main body and pressing the measuring tube on the base portion from above. The base portion consists of a base portion made of an acoustic matching layer and an ultrasonic transmitting and receiving portion connected to the base portion. The base portion is in close contact with the piezoelectric transducer that transmits and receives ultrasonic waves and consists of a cylindrical main body that extends diagonally upward in the direction of the central axis of the piezoelectric transducer, and a rib portion that extends perpendicular to the axis below the main body. A clamp-on type ultrasonic transmitting and receiving device characterized in that the upper end surface of the main body is curved so as to be in close contact with the measuring tube.

2. The clamp-on type ultrasonic transmitting and receiving device according to claim 1, characterized in that the ultrasonic transmitting and receiving unit comprises a piezoelectric vibrator that is in close contact with one end of the base unit, a piezoelectric vibrator holding unit that holds the piezoelectric vibrator from the rear, and a connecting unit that brings the base unit, the piezoelectric vibrator, and the piezoelectric vibrator holding unit into close contact and fixed.

3. The end of the main body on the piezoelectric vibrator side is provided with a flange portion that protrudes outward. The aforementioned connecting section consists of a storage section with an opening at the top and a fixing plate section that is continuous with the bottom of the storage section. The clamp-on type ultrasonic transmitting and receiving device according to claim 2, characterized in that the housing portion houses the flange portion, the piezoelectric vibrator, and the piezoelectric vibrator holding portion in that order from the tip.

4. The bottom surface of the rib portion is provided with a first attachment portion which is fixed to the main body portion by a first fixing portion. The clamp-on type ultrasonic transmitting and receiving device according to claim 3, characterized in that the rear end of the fixing plate portion is provided with a second attachment portion which is fixed to the main body portion by a second fixing portion.

5. The clamp-on type ultrasonic transmitting and receiving device according to claim 4, characterized in that the first and second fixing parts are screw bodies.

6. The clamp-on type ultrasonic transmitting and receiving device according to claim 5, characterized in that the first fixed portion is a screw hole extending in the axial direction from the center of the bottom surface.

7. The clamp-on type ultrasonic transmitting and receiving device according to claim 5, characterized in that the second fixed portion is a notched piece.

8. The clamp-on type ultrasonic transmitting and receiving device according to claim 6, characterized in that the length of the screw hole is such that it does not reach the main body.

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