JPH05209766A - Ultrasonic transmitter-receiver - Google Patents

Abstract

PURPOSE:To prevent the release of an internal piezoelectric vibrator from a shoe (or a wedge) even when an ultrasonic transmitter-receiver receives a heat shock from an object to be measured. CONSTITUTION:An ultrasonic transmitter-receiver is constituted by bonding a piezoelectric vibrator to a shoe 4 and transmits and receives ultrasonic waves in the direction oblique with respect to a mounting surface. A synthetic material having many grooves 8, 9 provided thereto at a predetermined interval is provided to the entire area of the surface bonded to the piezoelectric vibrator 3 of the shone 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic wave transmitter / receiver for converting between electricity and ultrasonic waves, and particularly to a relatively high or low temperature such as LPG (liquefied petroleum gas) or LNG (liquefied natural gas). The present invention relates to an ultrasonic wave transmitter / receiver which is attached to a pipeline through which a low temperature fluid flows and which is used for measuring the flow velocity or flow rate of the fluid.

[0002]

2. Description of the Related Art Conventionally, for measuring the flow velocity or flow rate of a fluid flowing in a pipe, a pair of ultrasonic wave transmitters / receivers are mounted so as to face each other in an oblique direction with respect to the pipe axis of the pipe. To do. Then, the ultrasonic wave is propagated in an oblique direction with respect to the mounting surface of the transducer, and in a forward direction or a reverse direction to the flow of the fluid, and a propagation time difference or a singaround frequency difference of the ultrasonic wave is measured, It was carried out based on.

[0003]

However, in the ultrasonic transmitter / receiver mounted on the conduit, the structure is such that the piezoelectric vibrator is bonded to the shoe (or also referred to as a wedge) made of a synthetic resin material. With this, ultrasonic waves are propagated in an oblique direction with respect to the fluid in the conduit.

Usually, when the fluid to be measured does not flow in the pipe, the temperature of the pipe wall is close to the ambient temperature, but when a low temperature fluid such as LPG or LNG begins to flow in the pipe, The temperature of the tube wall drops sharply. Then, the ultrasonic transmitter / receiver receives a large thermal shock, and the internal temperature thereof is significantly lowered.

Therefore, in the ultrasonic wave transmitter / receiver, the piezoelectric vibrator and the shoe bonded to each other have different coefficients of thermal expansion, so that excessive stress is generated between them, and There is a problem that part or all of the piezoelectric vibrator is separated from the shoe.

Therefore, the joint area between the piezoelectric vibrator and the shoe is reduced, the ultrasonic transmission efficiency between them is reduced, and the performance as an ultrasonic transmitter / receiver is finally lost. Sound waves cannot be transmitted or received. That is,
There is a risk that the flow velocity or flow rate of the fluid may not be measured.

The present invention has been made in view of the above points,
The purpose is to eliminate the above-mentioned problems, and even if the internal piezoelectric vibrator and the shoe (or wedge) are subjected to thermal shock by a fluid having a relatively high temperature or a low temperature to be measured, such as low temperature LPG or LNG. An object of the present invention is to provide an ultrasonic wave transmitter / receiver that prevents separation between the two.

[0008]

The structure of the present invention for achieving the above object is as follows. (1) In an ultrasonic wave transmitter / receiver in which a piezoelectric vibrator is bonded to a shoe and which transmits and receives ultrasonic waves in an oblique direction with respect to a mounting surface, the entire area of the surface where the shoe is bonded to the piezoelectric vibrator And is made of a synthetic resin material provided with a plurality of grooves at predetermined intervals.

(2) The plurality of grooves in (1) above are grooves that are orthogonal to each other.

(3) The synthetic resin material in (1) is a high heat resistant engineering plastic.

(4) In an ultrasonic wave transmitter / receiver in which a piezoelectric vibrator is joined to a shoe and which transmits / receives ultrasonic waves in an oblique direction with respect to a mounting surface, the piezoelectric vibrators are provided at a plurality of predetermined intervals. An electrode which is divided into a plurality of transducer elements by a cutting line, each of the transducer elements is arranged at a position before the division with the cut line width, and each of the transducer elements has the same polarity. Therefore, it is characterized in that they are simultaneously excited by a conductive member.

(5) The plurality of cut lines in (4) are cut lines that are orthogonal to each other.

[0013]

Since the present invention is configured as described above, the joint surface of the shoe with the piezoelectric vibrator is divided into a plurality of parts over the entire area thereof, or the piezoelectric vibrator is cut into a plurality of parts at predetermined intervals. Even if there is a difference in the coefficient of thermal expansion between the piezoelectric vibrator and the shoe due to a thermal shock from the outside, the stress generated between them is significantly reduced. Prevents peeling of the joint surface.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be illustratively described in detail below with reference to the drawings. (First Embodiment) FIGS. 1 and 2 show a first embodiment of an ultrasonic wave transmitter / receiver according to the present invention, FIG. 1 is a sectional view of the structure of the ultrasonic wave transmitter / receiver, and FIG. It is a figure by the II line arrow.

In the figure, 1 is an ultrasonic wave transmitter / receiver, 2 is a case whose bottom surface is opened, 3 is a piezoelectric vibrator made of ceramic material, and 4 is a shoe (or wedge) to which the piezoelectric vibrator 3 is joined. , A signal cable arranged in the case 2, and 5 for transmitting and receiving electric pulses to and from the piezoelectric vibrator 3, 6
Is a filler that fills the space inside the case 2 and absorbs harmful vibration energy of the piezoelectric vibrator 3. The shoe 4 has a relatively high temperature to a relatively low temperature (for example, LPG or L
It is a high heat resistant engineering plastic that has little thermal deformation in the range of up to about NG freezing temperature) and has stable electrical characteristics in the frequency range used, such as polyetherimide resin or polyimide resin.

The shoe 4 has the piezoelectric vibrator 3
A plurality of groove groups 8 which are orthogonal to each other and have a predetermined interval and a predetermined depth over the entire joining surface 7 of
9 is provided, and the piezoelectric vibrator 3 is bonded to the surface of each split shoe 4a divided by the groove groups 8 and 9 with an adhesive.

The adhesive used for this bonding is preferably an elastic adhesive such as a modified silicone which can maintain the adhesive performance in the above temperature range.

Now, each of the plurality of groove groups 8 and 9 provided on the shoe 4 has, for example, an interval of 3 mm and a groove width of 50 μm.
In the case of m, the difference in thermal expansion coefficient between the piezoelectric vibrator 3 and the shoe 4 is within the groove width of the groove groups 8 and 9 even if the expansion difference is about 38 μm when the temperature difference is 200 ° C. The strain due to the difference in expansion is absorbed. Therefore, the stress generated between the piezoelectric vibrator 3 and the shoe 4 is remarkably relieved, and the occurrence of peeling at the joint surface between them can be prevented.

Furthermore, the change in the area of the joint between the shoe 4 provided with the groove groups 8 and 9 and the piezoelectric vibrator 3 corresponds to the area of the groove groups 8 and 9 and is 4% or less of the total area. Therefore, the influence on the ultrasonic wave transmission efficiency between the piezoelectric vibrator 3 and the shoe 4 can be reduced.

Therefore, the ultrasonic wave transmitter / receiver 1 retains its original performance and can exhibit a predetermined performance in a range of relatively high temperature to relatively low temperature.

FIG. 3 shows an example of mounting the ultrasonic transmitter / receiver of the present invention. In the figure, a cryogenic fluid such as LPG or L
NG10 to the pipeline 11 using the steel pipe flowing in the direction of the arrow,
A pair of ultrasonic wave transmitters / receivers 1, 1 are attached to the tube shaft 12 in an oblique direction so as to face each other. The conduit 11 including the ultrasonic transmitters / receivers 1 and 1 is covered with a cold insulating material 13 such as glass wool.

In FIG. 3, the one ultrasonic wave transmitter / receiver 1 is used.
The ultrasonic waves transmitted from the device in an oblique direction with respect to the mounting surface are received by the other ultrasonic wave transmitter / receiver 1 via the conduit 11 and vice versa. Therefore, the ultrasonic waves alternately pass through the path 14 shown by the solid line.

In FIG. 3, LPG or L is provided in the conduit 11.
When the NG 10 starts to flow, the conduit 11 and the ultrasonic wave transmitters / receivers 1, 1 are cooled by thermal shock depending on the fluid temperature. At this time, stress is generated in the joint 7 between the piezoelectric vibrator 3 and the shoe 4 in the ultrasonic transmitter / receiver 1 due to the difference in thermal expansion coefficient between the two, but the shoe 4 covers the entire joint 7. Since a plurality of grooves at a predetermined interval, particularly a plurality of orthogonal groove groups 8 and 9, are provided, the generated stress is remarkably relieved, and the piezoelectric vibrator 3 and the shoe 4 are prevented from being separated from each other.

Further, since the ultrasonic transmission efficiency between them is small, the ultrasonic transmitter / receiver 1 exhibits a predetermined performance. Similar performance can be exhibited even when a relatively high-temperature fluid flows in the passage 11.

(Second Embodiment) FIGS. 4 to 6 show a second embodiment of the ultrasonic transmitter / receiver of the present invention, FIG. 4 is a sectional view of the structure of the ultrasonic transmitter / receiver, and FIG. 5 is FIG. 5 is a view taken along the line V-V in FIG. 6, and FIG. 6 is a sectional view taken along the line VI-VI in FIG. In the figure, the same members as those in FIGS. 1 and 2 are designated by the same reference numerals and the description thereof will be omitted.

In the figure, reference numeral 21 denotes an ultrasonic wave transmitter / receiver, and 23
Is a piezoelectric vibrator element group made of a ceramic material, 24 is a shoe (or wedge) to which the piezoelectric vibrator element group 23 is joined, and 25a and 25b are the piezoelectric vibrator element group 23,
Conductive members that are simultaneously excited by the same electric pulse via the conductors 26, and these are arranged in the case 2.

A plurality of piezoelectric vibrator element groups 23 are formed by a plurality of cut lines 27, 28 which are orthogonal to each other and have a predetermined interval and a predetermined width over the entire region of the piezoelectric vibrator element 23 which is joined to the shoe 24. The transducer elements 23a are divided into the transducer elements 23a, and the respective transducer elements 23a are arranged at positions before the division with the line widths of the cut lines 27 and 28 separated from each other, and are joined to the shoe 24.

The vibrator elements 23a are electrically connected to each other by the conductive members 25a and 25b joined to the electrodes having the same polarity so as to be simultaneously excited.

The shoe 24 is a high heat resistant engineering plastic similar to the shoe 4, and is, for example, a polyetherimide resin or a polyimide resin, and is joined to each of the transducer elements 23a by an adhesive 29.

The adhesive 28 used for this bonding is preferably an elastic adhesive such as a modified silicone-based adhesive having an elongation of 300% or more which can maintain the adhesive performance in the above temperature range.

Now, the plurality of cut lines 27 and 28 for obtaining the plurality of piezoelectric vibrator elements 23a are arranged, for example, at intervals of 3
mm, the line width is 50 μm, the vibrator elements 23a, 23
Due to the difference in the coefficient of thermal expansion between a and the shoe 24, the temperature difference is 20
Even if the expansion difference at 0 ° C is about 38 μm, the score line 27
Since it is within the line width of, the strain due to the difference in expansion is absorbed. Therefore, the stress generated between each of the transducer elements 23a and 23a and the shoe 24 is remarkably relieved, and the occurrence of peeling at the joint surface between them can be prevented.

Furthermore, the change in the area of the joint portion between each of the transducer elements 23a, 23a and the shoe 24 depends on the cut line 2.
This corresponds to the area of 7 and 28, which is 4% or less of the whole, so that the influence on the ultrasonic wave transmission efficiency between the piezoelectric vibrator element group 23 and the shoe 24 can be reduced. Therefore, the ultrasonic transmitter / receiver 21 retains its original performance and can exhibit a predetermined performance in a range of relatively high temperature to relatively low temperature.

FIG. 7 shows another mounting example of the ultrasonic transmitter / receiver of the present invention. In the figure, in addition to the ultrasonic wave transmitter / receiver 21, the same members as those in FIG.

In FIG. 7, LPG or L is provided in the conduit 11.
When the NG 10 starts to flow, the pipe line 11 and the ultrasonic wave transmitters / receivers 21, 21 are cooled by thermal shock depending on the fluid temperature. At this time, at the joint 7 between the piezoelectric vibrator element group 23 and the shoe 24 in the ultrasonic transmitter / receiver 21,
Although a stress is generated based on the difference in thermal expansion coefficient between the two, a plurality of cut lines 27 at predetermined intervals, particularly a plurality of cut lines 27, 28 orthogonal to each other are provided in the piezoelectric vibrator element group 23. Therefore, the generated stress is remarkably relaxed, and the piezoelectric vibrator element group 23
The peeling between the shoe and the shoe 24 is prevented. Moreover, since the influence on the ultrasonic transmission efficiency between the two is small, the ultrasonic transmitter / receiver 2
1 shows a predetermined performance. Similar performance can be exhibited even when a relatively high temperature fluid flows through the pipe 11.

Others are the same as those in the first embodiment described above.

Note that the technique of the present invention is not limited to the technique in the above-described embodiment, and may be implemented by means of another aspect having the same function, and the technique of the present invention is various within the scope of the above configuration. Can be changed or added.

[0037]

As is apparent from the above description, according to the ultrasonic transmitter / receiver of the present invention, the bonding surface of the shoe with the piezoelectric vibrator has a plurality of grooves formed at predetermined intervals over the entire area thereof. , Or the piezoelectric vibrator is divided into a plurality of vibrating elements by a plurality of cut lines at predetermined intervals, so that thermal shock can be used to determine the difference in the coefficient of thermal expansion between the piezoelectric vibrator and the shoe. The stress generated as a result is remarkably relieved, and it is possible to prevent the occurrence of peeling of the joint surface between the two.

Therefore, even when a fluid having a relatively high temperature or a low temperature flows in the pipe line and is subjected to a thermal shock, the ultrasonic transducer of the present invention can exhibit its original performance, and the fluid is stable. Can be used for measuring the flow velocity or flow rate of

[Brief description of drawings]

FIG. 1 is a structural cross-sectional view showing a first embodiment of an ultrasonic wave transmitter / receiver of the present invention.

FIG. 2 is a view taken along the line II-II of FIG.

FIG. 3 is a cross-sectional view showing a mounting example of the ultrasonic transmitter / receiver of the first embodiment.

FIG. 4 is a sectional view showing the configuration of a second embodiment of the ultrasonic transmitter / receiver of the present invention.

5 is a view taken along the line VV of FIG.

6 is a cross-sectional view of a main part taken along the line VI-VI of FIG.

FIG. 7 is a cross-sectional view showing an example of mounting the ultrasonic wave transmitter / receiver of the second embodiment.

[Explanation of symbols]

 1,21 Ultrasonic wave transmitter / receiver 3 Piezoelectric vibrator 4 Shoes 8,9 Groove 14 Ultrasonic wave transmitting / receiving path 23 Piezoelectric vibrator element group 23a Piezoelectric vibrator element 24 Shoes 25a, 25b Conductive member 27, 28 Cut line

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukiko Suzuki 2-16-46 Minami Kamata, Ota-ku, Tokyo Within Tokimec Co., Ltd. (72) Inventor Akio Ansai 3-14-3 Temple Kamata, Ayase City, Kanagawa Prefecture

Claims (5)

[Claims] 1. A piezoelectric vibrator is joined to a shoe, and ultrasonic waves are transmitted and received in an oblique direction with respect to a mounting surface, and a predetermined area is provided over the entire area where the shoe is joined to the piezoelectric vibrator. An ultrasonic transducer comprising a synthetic resin material provided with a plurality of grooves at intervals. 2. The ultrasonic transducer according to claim 1, wherein the plurality of grooves are grooves orthogonal to each other. 3. The ultrasonic transducer according to claim 1, wherein the synthetic resin material is a high heat resistant engineering plastic. 4. A piezoelectric vibrator which is joined to a shoe and which transmits and receives ultrasonic waves in an oblique direction with respect to a mounting surface, wherein a plurality of the piezoelectric vibrators are provided by a plurality of score lines at predetermined intervals. Of the vibrator elements, the vibrator elements are arranged at the cut line widths, and the electrodes of the same polarity are simultaneously excited by a conductive member. And ultrasonic transducer. 5. The ultrasonic transducer according to claim 4, wherein the plurality of cut lines are cut lines orthogonal to each other.