JP2019184488A - Ultrasonic flowmeter - Google Patents

Abstract

To provide an ultrasonic flowmeter with which it is possible to expand a temperature range in which a damping function to suppress ultrasonic vibration is exhibited and use the ultrasonic flowmeter in a wide range of temperature regions.SOLUTION: The ultrasonic flowmeter comprises: ultrasonic sensors 21, 22 for propagating an ultrasonic wave through a fluid flowing in a passage 12 and measuring the flow rate of the fluid flowing in the passage 12 on the basis of the propagation time of the ultrasonic wave at the time the ultrasonic wave is transmitted and received; and multiple types of damping members 31, 32, mutually different in temperature range and provided between the passage 12 and the ultrasonic sensors 21, 22, which exhibit a damping function to suppress the vibrations of ultrasonic sensors 21, 22.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an ultrasonic flowmeter that measures the flow rate of a fluid.

  Conventionally, an ultrasonic flowmeter has been provided as a device for measuring the flow rate of a fluid flowing in a flow path. This ultrasonic flowmeter is equipped with a pair of ultrasonic sensors that can transmit and receive ultrasonic waves via a fluid flowing in the flow path, and based on the propagation time of ultrasonic waves between those ultrasonic sensors, The fluid flow rate can be measured.

  However, since the ultrasonic sensor is accompanied by generation of vibration when transmitting the ultrasonic wave, the generated vibration propagates as noise toward the ultrasonic sensor on the reception side, and the output of the ultrasonic sensor on the reception side May affect the signal.

  Therefore, in recent years, an ultrasonic flowmeter has been provided in which generation of noise propagating between ultrasonic sensors is suppressed. Such a conventional ultrasonic flowmeter is disclosed in, for example, Patent Document 1.

Japanese Patent No. 5979501

  In the conventional ultrasonic flowmeter, the ultrasonic sensor is fixed to the housing via a damping member. Generally, the temperature range in which the damping function can be exhibited is preset in the damping material used for the damping member. For this reason, in the above-mentioned conventional ultrasonic flowmeter, if the operating temperature when using the ultrasonic sensor deviates from the temperature range in which the damping member exhibits the damping function, the flow rate is measured with high accuracy. It may not be possible.

  The present invention has been made to solve the above-described problems, and extends the temperature range in which the vibration suppression function for suppressing the vibration of the ultrasonic wave is exhibited, and uses the ultrasonic sensor in a wide temperature range. An object of the present invention is to provide an ultrasonic flow meter capable of

  The ultrasonic flowmeter according to the present invention propagates ultrasonic waves into the fluid flowing in the flow path, and determines the flow rate of the fluid flowing in the flow path based on the propagation time of the ultrasonic waves at the time of transmission / reception of the ultrasonic waves. A pair of ultrasonic sensors to be measured, and a plurality of types of vibration control members provided between the flow path and the ultrasonic sensor and exhibiting a vibration suppression function for suppressing vibration of the ultrasonic sensor are different from each other. Is.

  According to the present invention, it is possible to use the ultrasonic sensor in a wide temperature range by expanding the temperature range in which the damping function for suppressing the vibration of the ultrasonic wave is exhibited.

It is the longitudinal cross-sectional view which showed schematic structure of the ultrasonic flowmeter which concerns on Embodiment 1 of this invention. It is the longitudinal cross-sectional view which showed schematic structure of the ultrasonic flowmeter which concerns on Embodiment 2 of this invention. It is the longitudinal cross-sectional view which showed schematic structure of the ultrasonic flowmeter which concerns on Embodiment 3 of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the white arrow described in FIG.1 and FIG.2 has shown the flow direction of the fluid. Moreover, the arrow of the dashed-two dotted line described in FIG.1 and FIG.2 has shown the propagation path of the ultrasonic wave.

Embodiment 1 FIG.
FIG. 1 is a longitudinal sectional view showing a schematic configuration of the ultrasonic flowmeter according to the first embodiment.

  As shown in FIG. 1, the ultrasonic flowmeter according to the first embodiment includes a housing 11, a pair of ultrasonic sensors 21 and 22, and vibration damping members 31 and 32.

  The housing 11 has a flow path 12 and a pair of openings 13a and 13b. The fluid flows in the flow path 12. The openings 13a and 13b extend in a cylindrical shape from the flow path 12 toward the outside. The openings 13a and 13b are arranged on the upstream side and the downstream side of the flow path 12, respectively, and are inclined so that the central axis intersects the fluid flow direction.

  The ultrasonic sensors 21 and 22 measure the flow rate of the fluid flowing through the flow path 12 using ultrasonic waves, and are attached to the outer opening ends of the openings 13a and 13b. The ultrasonic sensors 21 and 22 include mounting plates 21a and 22a, piezoelectric elements 21b and 22b, and acoustic elements 21c and 22c.

  The mounting plates 21a and 22a fix the piezoelectric elements 21b and 22b and the acoustic elements 21c and 22c, and are attached to the outer opening ends of the openings 13a and 13b. Specifically, the piezoelectric elements 21b and 22b are provided on the outer surfaces of the mounting plates 21a and 22a. On the other hand, the acoustic elements 21c and 22c are provided on the inner surfaces of the mounting plates 21a and 22a.

  The piezoelectric elements 21b and 22b expand and contract in the thickness direction of the mounting plates 21a and 22a, that is, in the axial direction of the openings 13a and 13b, by applying a voltage, and generate ultrasonic waves. In contrast, the acoustic elements 21c and 22c transmit the ultrasonic waves generated by the expansion and contraction of the piezoelectric elements 21b and 22b toward the fluid flowing in the flow path 12, and are transmitted from the other acoustic elements 22c and 21c. Receiving ultrasonic waves.

  Therefore, the ultrasonic wave transmitted from the ultrasonic sensor 21 propagates obliquely across the fluid flowing in the flow path 12 from the upstream side toward the downstream side and is reflected on the bottom surface of the flow path 12. Received by the ultrasonic sensor 22. On the other hand, the ultrasonic wave transmitted from the ultrasonic sensor 22 propagates obliquely across the fluid flowing in the flow channel 12 from the downstream side toward the upstream side and is reflected on the bottom surface of the flow channel 12. Received by the ultrasonic sensor 21.

  Then, the ultrasonic sensors 21 and 22 obtain the difference between the two propagation times by alternately transmitting and receiving ultrasonic waves, and then measure the flow rate of the fluid flowing in the flow path 12 based on the difference in the propagation times. To do.

  Moreover, the attachment plates 21a and 22a of the ultrasonic sensors 21 and 22 are attached to the outer opening ends of the opening portions 13a and 13b via the ring-shaped damping members 31 and 32, respectively. That is, the damping members 31 and 32 are provided between the flow path 12 and the ultrasonic sensors 21 and 22, and are superposed in the direction in which the ultrasonic sensors 21 and 22 are attached to the flow path 12. The damping members 31 and 32 have a damping function that suppresses vibrations generated by the ultrasonic sensors 21 and 22.

  Therefore, as described above, the ultrasonic sensors 21 and 22 generate ultrasonic waves by the expansion and contraction of the piezoelectric elements 21b and 22b, but the expansion and contraction of the piezoelectric elements 21b and 22b causes vibration. Further, the vibration propagates as noise from the ultrasonic sensors 21 and 22 on the transmission side to the ultrasonic sensors 22 and 21 on the reception side, and this noise is an output signal of the ultrasonic sensors 21 and 22 on the reception side. May be affected.

  On the other hand, the damping members 31 and 32 are provided between the openings 13 a and 13 b of the housing 11 and the mounting plates 21 a and 22 a of the ultrasonic sensors 21 and 22. Thereby, since the vibration propagating between the ultrasonic sensors 21 and 22 via the housing 11 is suppressed by the damping members 31 and 32, the vibration is generated as noise as the ultrasonic sensors 22 and 21 on the receiving side. Does not affect the output signal.

  Here, the damping members 31 and 32 are made of different types of damping materials. The damping material of the damping member 31 and the damping material of the damping member 32 have different temperature ranges in which the damping function can be exhibited. Thereby, since the damping members 31 and 32 can suppress the vibration generated from the ultrasonic sensors 21 and 22 in a wide temperature range, the operating temperature range of the ultrasonic sensors 21 and 22 is expanded.

  However, the damping members 31 and 32 are not required to have the same temperature range for exhibiting the damping function, and some of the temperature ranges overlap, or one of the temperature ranges is the other. The entire temperature range may be included. When the temperature range in which the damping members 31 and 32 exhibit the damping function is set, the temperature range of the damping member 31 and the temperature range of the damping member 32 do not overlap and have no gap. It is preferable that they are set continuously.

  As described above, the ultrasonic flowmeter according to the first embodiment includes a plurality of types of damping members 31 and 32 having different temperature ranges that exhibit a damping function for suppressing the vibration of the ultrasonic sensors 21 and 22. Thereby, the ultrasonic flowmeter can use the ultrasonic sensors 21 and 22 in a wide temperature range.

Embodiment 2. FIG.
FIG. 2 is a longitudinal sectional view showing a schematic configuration of the ultrasonic flowmeter according to the second embodiment.

  The ultrasonic flow meter according to the first embodiment shown in FIG. 1 includes damping members 31 and 32 as damping means for suppressing the vibrations of the ultrasonic sensors 21 and 22. On the other hand, the ultrasonic flowmeter according to the second embodiment shown in FIG. 2 includes damping members 31a and 31b as the vibration suppressing means.

  That is, although the damping members 31a and 31b are formed of the same damping material, the temperature ranges in which the damping function can be exhibited are different. Thereby, since the damping members 31a and 31b can suppress the vibration generated from the ultrasonic sensors 21 and 22 in a wide temperature range, the use temperature range of the ultrasonic sensors 21 and 22 is expanded.

  However, the vibration control members 31a and 31b may be configured so that the temperature ranges that exhibit the vibration suppression function do not completely coincide with each other, and some of the temperature ranges overlap, or either one of the temperature ranges has the other. The entire temperature range may be included. When setting the temperature range in which the damping members 31a and 31b exhibit the damping function, the temperature range of the damping member 31a and the temperature range of the damping member 31b do not overlap and have no gap. It is preferable that they are set continuously.

  As described above, the ultrasonic flowmeter according to Embodiment 1 includes a plurality of types of vibration damping members 31a and 31b having different temperature ranges that exhibit a vibration damping function for suppressing vibrations of the ultrasonic sensors 21 and 22. Thereby, the ultrasonic flowmeter can use the ultrasonic sensors 21 and 22 in a wide temperature range.

Embodiment 3 FIG.
FIG. 3 is a longitudinal sectional view showing a schematic configuration of the ultrasonic flowmeter according to the third embodiment.

  The ultrasonic flow meter according to the first embodiment shown in FIG. 1 includes damping members 31 and 32 as damping means for suppressing the vibrations of the ultrasonic sensors 21 and 22. On the other hand, the ultrasonic flowmeter according to the third embodiment shown in FIG. 3 includes a casing 11 and a damping member 31 as vibration suppression means. That is, the ultrasonic flowmeter according to the third embodiment includes a casing 11 formed of the same damping material as the damping material of the damping member 32, instead of the damping member 32, as damping means. ing.

  Specifically, as shown in FIG. 2, the openings 13 a and 13 b of the housing 11 are provided between the flow path 12 and the ultrasonic sensors 21 and 22, and the flow paths of the ultrasonic sensors 21 and 22. 12 is superposed on the damping member 31 in the direction of attachment to 12. And the housing | casing 11 has a damping function which suppresses the vibration generate | occur | produced by the ultrasonic sensors 21 and 22, and is comprised as one of the damping members.

  Here, the housing | casing 11 and the damping member 31 are formed with the damping material from which a kind differs. The damping material of the housing 11 and the damping material of the damping member 31 have different temperature ranges in which the damping function can be exhibited. Thereby, since the housing | casing 11 and the damping member 31 can suppress the vibration generate | occur | produced from the ultrasonic sensors 21 and 22 in a wide temperature range, the use temperature range of the ultrasonic sensors 21 and 22 is expanded. The

  However, the casing 11 and the damping member 31 may not have a completely matching temperature range for exhibiting the damping function, and some of the temperature ranges may overlap, or any one of the temperature ranges may be The other temperature range may be included. When the temperature range in which the casing 11 and the damping member 31 exhibit the damping function is set, the temperature range of the casing 11 and the temperature range of the damping member 31 do not overlap with each other and have a gap. It is preferable that they are set continuously without any problem.

  Further, when ultrasonic waves (sound waves) propagate through different media, the transmittance and reflectance at the medium interface change according to the magnitude of the difference in acoustic impedance between the media. In general, since the difference in acoustic impedance between the mounting plates 21a and 22a and the damping member 31 and the difference in acoustic impedance between the damping member 31 and the housing 11 are large, the propagation wave is The ratio of propagation from the mounting plates 21a and 22a to the housing 11 via the damping member 31 is reduced.

  Therefore, the ultrasonic flowmeter according to the third embodiment can also improve the damping performance by adjusting the difference in acoustic impedance between the damping member 31 and the mounting plates 21a, 22a or the housing 11. Can do. Specifically, the ultrasonic flowmeter according to the third embodiment can improve the vibration damping performance by separating the difference in acoustic impedance by MRayls or more. Similarly, in the first and second embodiments, the vibration damping performance can be improved by adjusting the difference in acoustic impedance.

  As described above, the ultrasonic flowmeter according to the third embodiment includes the casing 11 and the damping member 31 having different temperature ranges that exhibit the damping function for suppressing the vibration of the ultrasonic sensors 21 and 22. Thereby, the ultrasonic flowmeter can use the ultrasonic sensors 21 and 22 in a wide temperature range.

  In the present invention, within the scope of the invention, a free combination of each embodiment, a modification of any component in each embodiment, or omission of any component in each embodiment is possible. Is possible.

DESCRIPTION OF SYMBOLS 11 Housing | casing 12 Flow path 13a, 13b Opening part 21, 22 Ultrasonic sensor 21a, 22a Mounting plate 21b, 22b Piezoelectric element 21c, 22c Acoustic element 31, 31a, 31b, 32 Damping member

Claims (3)

A pair of ultrasonic sensors for propagating ultrasonic waves in the fluid flowing in the flow channel and measuring the flow rate of the fluid flowing in the flow channel based on the propagation time of the ultrasonic waves at the time of transmission and reception of the ultrasonic waves;
A plurality of types of damping members provided between the flow path and the ultrasonic sensor and having different temperature ranges that exhibit a damping function for suppressing vibration of the ultrasonic sensor. Sonic flow meter. The plurality of types of vibration damping members are:
The ultrasonic flowmeter according to claim 1, wherein the ultrasonic flowmeter is superimposed in a direction in which the ultrasonic sensor is attached to the flow path. A housing having the flow path;
The ultrasonic flowmeter according to claim 1, wherein the casing constitutes one damping member among the plurality of types of damping members.

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