JP2010071812A - Ultrasonic flowmeter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic flowmeter for efficiently and accurately measuring a flow rate by suppressing a pressure loss and a power loss of an ultrasonic beam during a measurement and using a transmit-receive oscillator, reducing a running zone in front of the transmit-receive oscillator, and simply constituted. <P>SOLUTION: Two plate partition walls 40 are disposed in parallel along the flow direction within a linear intermediate flow path 21a. An aperture width W as a long side of the linear intermediate flow path 21a is equally divided into three layers of aperture widths W' of divided flow paths 21a' in the width direction. Each partition wall 40 is formed with one circular communication hole 41 in the width direction which corresponds to a traverse line of the ultrasonic beam and penetrates through the partition wall 40. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ultrasonic flowmeter that measures the flow rate of fluid such as LP gas, city gas, air, and water.

  2. Description of the Related Art Conventionally, an ultrasonic flowmeter that measures a flow velocity using ultrasonic waves is known as a flow measurement device that measures the flow rate of a fluid such as LP gas, city gas, air, and water. In such an ultrasonic flowmeter, for example, ultrasonic waves are directed toward the upper side or lower side in the fluid flow direction on the wall portion (mounting wall surface) of the measurement flow channel (straight flow channel for measurement) for allowing fluid to pass therethrough. A pair of transmission / reception transducers (ultrasonic sensors) that receive ultrasonic waves coming from the upper side or lower side in the flow direction are attached to constitute a flow rate measuring unit. In addition, between the introduction-side channel and the measurement channel, the introduction-side channel located on the upper side in the flow direction is curved on the outer peripheral side and the inner peripheral side to change the direction of the fluid flow, and lower in the flow direction. A direction changing portion for reducing the cross-sectional area of the flow path as it goes toward the side and communicating with the measurement flow path located on the lower side in the flow direction is arranged. With such a flow path configuration, pressure loss is suppressed, and measurement accuracy in the flow rate measurement unit is improved and a measurement range is expanded.

  However, it opens in a rectangular shape with the width direction of the measurement flow path as the long side and the height direction as the short side, and the long side wall portion of the measurement flow path on the outer peripheral side and the inner peripheral side at the outlet side end portion of the direction changing portion In the case of connection to, in the width direction and height direction of the measurement flow path, the flow velocity distribution of the fluid flowing through the flow path becomes uneven or asymmetric depending on the flow rate. Of course, if the run-up section (the section in front of the flow rate measuring unit) is long, the flow velocity distribution in the width direction and the height direction in the measurement channel can be sufficiently equalized, symmetrized and smoothed.

Specifically, when the flow rate is small (low speed; laminar flow area), the maximum flow velocity (peak value) appears near the center position in the width direction and height direction of the measurement flow path (or arc shape or parabolic shape). In the case of a large flow rate (high speed; turbulent flow region), the average flow velocity is almost the same as the maximum flow velocity (peak value) in the width direction and height direction of the measurement channel. Presents a flow velocity distribution. The length of the run-up section necessary for equalizing and symmetrizing (smoothing) the flow velocity distribution is generally 10 × (W × H) ^1/2 when the opening width W and the opening height H are set. More than needed. Therefore, it is desired to simply configure the ultrasonic flowmeter by shortening the running section in front of the transmitting / receiving transducer. In some cases, it is desirable to smooth the flow velocity distribution so that it becomes a bathtub-like shape at the time of a small flow rate as in the case of a large flow rate.

  Thus, in the measurement flow path that opens in a rectangular shape with the width direction of the flow path as the long side and the height direction as the short side in this way, the transmission / reception vibrator is attached to the attachment wall surface of the short side wall portion, and the short side and It is disclosed that a partition plate (partition section) that forms a plurality of layered channels (divided channels) by dividing the height of the opening in the height direction is arranged along the flow direction (see Patent Document 1). ). A transmitter / receiver vibrator is attached to the wall surface of the measurement channel, and a partition plate (partition) with a beam restricting hole that forms a plurality of layered channels (divided channels) is arranged in the measurement channel along the flow direction. (See Patent Document 2).

Japanese Patent No. 3528347 JP 2004-251653 A

  Among these, according to Patent Document 1, it is possible to equalize and symmetrize (smooth) the flow velocity distribution mainly in the height direction for each layered flow path divided by the partition plate. However, since the partition plate is arranged in a shape that crosses (blocks) the transmission / reception vibrator, the ultrasonic beam is divided by the partition plate, the power is dispersed and attenuated, and the efficiency and accuracy of the ultrasonic flowmeter are lowered. In addition, because the measurement channel is divided into narrow (thin) layers in the height direction by the partition plate, the pressure loss during measurement increases, and the flow velocity distribution in the width direction and height direction is not sufficiently smoothed. Therefore, there is a possibility that the stable flowmeter side in a wide measurement range is obstructed. In particular, the flow velocity distribution in the width direction of each layered flow path may become uneven or asymmetric.

  On the other hand, according to Patent Document 2, the flow velocity distribution is distributed in one of the width direction and the height direction of the flow path for each divided flow path while narrowing the ultrasonic beam with the beam restriction hole of the partition plate. Can be equalized and symmetrized (smoothed). However, in Patent Document 2, the flow velocity distribution in the other direction may become uneven or asymmetric, and it is difficult to adjust (set) the beam aperture diameter to suppress the power loss of the ultrasonic beam. It may accompany.

  An object of the present invention is to enable high-efficiency and high-accuracy flow measurement by a transmitter / receiver transducer by suppressing pressure loss during measurement and power loss of an ultrasonic beam, An object of the present invention is to provide an ultrasonic flowmeter that can be shortened and configured simply. Specifically, a direction changing part, an adjusting part and an increasing part are provided on the upper side in the flow direction of the measurement linear flow channel to change the opening height of the flow channel, and the measurement linear flow channel is changed in the width direction by the partitioning unit. By dividing into two and forming multiple divided flow paths, the flow velocity distribution in the width direction and height direction can be equalized and / or symmetrized, enabling a stable flow meter side in a wide measurement range And

Means for Solving the Problems and Effects of the Invention

In order to solve the above problems, an ultrasonic flowmeter according to the present invention is
An introductory side channel having a predetermined channel cross-sectional area for allowing fluid to pass through, and a linear communication crossing the introductory side channel, and the width direction of the channel to measure the fluid flow rate Open in a rectangular shape having a long side and a short side in the height direction, and having a channel cross-sectional area smaller than that of the introduction-side channel, the fluid flow direction upper side or lower side on the mounting wall surface of the short side wall portion An ultrasonic flowmeter including a measurement linear flow channel to which a transmission / reception transducer is attached that oscillates an ultrasonic beam toward the side and / or receives an ultrasonic beam arriving from the upper side or the lower side in the flow direction Because
Following the outlet-side end of the introduction-side flow path, at least the outer peripheral side of the outer peripheral side and the inner peripheral side is formed in a curved shape to change the direction of fluid flow, and parallel to the mounting wall surface at the center in the width direction. In a simple cross-section, the direction changing portion having a decreasing portion that decreases as the opening height of the flow path goes toward the lower side in the flow direction,
An adjustment part that is connected to the outlet side end of the direction changing part and that aligns the flow direction of the fluid;
Following the adjustment part, the increasing part where the opening height of the flow path increases and changes stepwise in the height direction on the outer peripheral side and the inner peripheral side,
The ultrasonic linear beam is arranged along the flow direction in the measurement linear flow path, and a plurality of divided flow paths are formed by dividing an opening width as a long side of the measurement linear flow path in the width direction. One or a plurality of partitioning portions having communication holes formed in the width direction so as to correspond to the line of measurement,
The fluid flowing through the measurement linear flow path in the cross-section orthogonal to the flow direction in the width direction and the height direction by flowing through the direction change section, the adjustment section, and the increase section and divided into the divided flow paths. The flow velocity distribution is equalized and / or symmetrized, respectively.

  In such an ultrasonic flow meter, the flow direction of the fluid to be measured (for example, LP gas or city gas) is flowing while flowing through the direction changing portion (decreasing portion) located on the upper side in the flow direction of the measurement linear flow path. There is a tendency that the flow velocity is relatively faster on the outer peripheral side than on the inner peripheral side. However, the flow velocity in the height direction in the cross section perpendicular to the fluid flow direction is obtained while the opening height of the flow path increases and decreases in a stepwise manner in the height direction on the outer peripheral side and the inner peripheral side. The effects of distribution bias are mitigated and equalized and / or symmetrized. In other words, the drift generated in the direction changing part (decreasing part) (the flow in which the direction and the position of the maximum flow velocity are biased toward the outer periphery) is released by the increasing part via the adjusting part, and thus the center in the height direction. The flow is corrected to have a flow velocity peak (maximum flow velocity) near the position (the flow velocity distribution in the height direction is equalized and / or symmetrized). Therefore, the measurement line (for example, a pair of transmission / reception transducers) is arranged at the middle position (for example, the center position) of the flow velocity distribution in the height direction, and the fluid to be measured flowing through the measurement straight flow path (flow measurement section) The maximum flow rate can be measured stably.

  In other words, the opening height of the flow path is reduced toward the lower side in the flow direction at the reduction part (direction changing part), and a rectifying means such as a rectifying element needs to be arranged in the flow path on the lower side in the flow direction such as the adjustment part. Therefore, the pressure loss is suppressed, and the measurement range at the flow rate measurement unit can be expanded. Further, since no rectifying means is provided, the cost of the ultrasonic flowmeter can be reduced.

  In the ultrasonic flowmeter, a linear flow channel for measurement (for example, a linear intermediate flow channel) is divided in the width direction by a partition portion (for example, a partition wall) to form a plurality of divided flow channels. By forming the communication hole so as to penetrate, fluid flow (movement) between the adjacent divided flow paths is allowed. As described above, since the ultrasonic beam is not divided by the partition portion, the power is not dispersed or attenuated, and the flow rate measurement by the transmission / reception vibrator can be performed with high efficiency and high accuracy. In addition, since the measurement linear flow path is divided in the width direction by the partition, pressure loss during measurement is suppressed, and the flow velocity distribution in the width direction is equalized and / or symmetrized. The stable flowmeter side is possible.

  As a result, even if the viscosity changes with the type of fluid and temperature, and the kinematic viscosity coefficient fluctuates, fluid symmetry is always secured from the laminar flow region (small flow rate) to the turbulent flow region (large flow rate). The flow rate can be measured with high accuracy.

  Specifically, in such an ultrasonic flowmeter, the flow direction and the maximum flow velocity of the fluid are reduced between the outer peripheral side and the inner peripheral side of the reducing portion due to the centrifugal force when the fluid flows along the outer peripheral side of the direction changing portion. The flow direction is made uniform by the adjusting unit. By the rectifying action at the increasing part (no need to arrange a rectifying member such as a rectifying element), the increase in pressure loss is suppressed, and the flow velocity distribution in the height direction is equalized in the cross section perpendicular to the fluid flow direction. And / or symmetrized and led to a straight flow path for measurement.

  Next, at the beginning of the measurement straight flow path (flow rate measurement section), when the flow rate is small (low speed; laminar flow area), the maximum flow velocity (peak value) is near the center position in the width direction of each divided flow path. Appearing fan-shaped (or arc-shaped or parabolic) flow velocity distribution. On the other hand, in the case of a large flow rate (high speed; turbulent flow region), a bathtub-shaped (or U-shaped) flow velocity distribution in which the average flow velocity substantially matches the maximum flow velocity (peak value) in the width direction of each divided channel Present. Therefore, the straight section for measurement is divided in the width direction by the partition portion to form a plurality of divided flow passages, and the running section in front of the transmission / reception vibrator is shortened by a simple configuration in which the communication hole is formed through the partition portion. Can be planned.

In order to solve the above-mentioned problem, an ultrasonic flowmeter according to the present invention is
An introductory side channel having a predetermined channel cross-sectional area for allowing fluid to pass through, and a linear communication crossing the introductory side channel, and the width direction of the channel to measure the fluid flow rate Open in a rectangular shape having a long side and a short side in the height direction, and having a channel cross-sectional area smaller than that of the introduction-side channel, the fluid flow direction upper side or lower side on the mounting wall surface of the short side wall portion An ultrasonic flowmeter including a measurement linear flow channel to which a transmission / reception transducer is attached that oscillates an ultrasonic beam toward the side and / or receives an ultrasonic beam arriving from the upper side or the lower side in the flow direction Because
Following the outlet-side end of the introduction-side flow path, at least the outer peripheral side of the outer peripheral side and the inner peripheral side is formed in a curved shape to change the direction of fluid flow, and parallel to the mounting wall surface at the center in the width direction. In a simple cross-section, the direction changing portion having a first reduction portion that decreases as the opening height of the flow path decreases toward the lower side in the flow direction;
It is connected to the outlet side end of the direction changing portion so as to align the flow direction of the fluid, and in the cross section perpendicular to the flow direction, the opening height of the flow path decreases as it goes to the end in the width direction. An adjustment portion having a second reduction portion;
Following the adjustment portion, at least on the outer peripheral side, the opening height of the flow path increases in a stepwise manner in the height direction, and an increasing portion,
The ultrasonic linear beam is disposed along the flow direction in the measurement linear flow path, and a plurality of divided flow paths are formed by dividing an opening width, which is a long side of the measurement linear flow path, in the width direction. One or a plurality of partitioning portions having communication holes formed in the width direction so as to correspond to the line of measurement,
The fluid flowing through the measurement linear flow path in the cross-section orthogonal to the flow direction in the width direction and the height direction by flowing through the direction change part, the adjustment part, and the increase part and divided into the divided flow paths. The flow velocity distribution is equalized and / or symmetrized, respectively.

  Even in such an ultrasonic flowmeter, while the fluid to be measured (for example, LP gas or city gas) flows through the direction changing portion (first decreasing portion) located on the upper side in the flow direction of the measurement linear flow path, The flow direction is biased, and the flow velocity tends to be relatively faster on the outer peripheral side than on the inner peripheral side. However, the width direction in the cross section perpendicular to the fluid flow direction while passing through the increasing portion where the opening height of the flow path increases stepwise in the height direction on at least the outer peripheral side of the outer peripheral side and the inner peripheral side. And the flow velocity distribution in the height direction is equalized and / or symmetrized. That is, the drift (the flow in which the direction and the position of the maximum flow velocity are biased toward the outer periphery) generated in the direction change section (first decrease section) is corrected by the adjustment section (second decrease section) and the increase section. (The flow velocity distribution in the width direction and the height direction is equalized and / or symmetrized). Therefore, the measurement line (for example, a pair of transmission / reception transducers) is arranged at the middle position (for example, the center position) of the flow velocity distribution in the height direction, and the fluid to be measured flowing through the measurement straight flow path (flow measurement section) The maximum flow rate can be measured stably.

  In the ultrasonic flowmeter, a measurement linear flow path (for example, a linear intermediate flow path) is divided in the width direction by a partition portion (for example, a partition wall) to form a plurality of divided flow paths. By forming the communication hole so as to penetrate, fluid flow (movement) between the adjacent divided flow paths is allowed. As described above, since the ultrasonic beam is not divided by the partition portion, the power is not dispersed or attenuated, and the flow rate measurement by the transmission / reception vibrator can be performed with high efficiency and high accuracy. In addition, since the measurement linear flow path is divided in the width direction by the partition, pressure loss during measurement is suppressed, and the flow velocity distribution in the width direction is equalized and / or symmetrized. The stable flowmeter side is possible.

  As a result, even if the viscosity changes with the type of fluid and temperature, and the kinematic viscosity coefficient fluctuates, fluid symmetry is always secured from the laminar flow region (small flow rate) to the turbulent flow region (large flow rate). The flow rate can be measured with high accuracy.

  Specifically, in such an ultrasonic flow meter, the flow direction of the fluid on the outer peripheral side and the inner peripheral side of the first decreasing portion by the centrifugal force when the fluid flows along the outer peripheral side of the direction changing portion and The flow direction is aligned by the adjusting unit so that the maximum flow velocity is biased. Further, the second reducing portion prevents or suppresses the fluid from diffusing and moving toward the width direction end portion side at the first decreasing portion. By the rectifying action at the increasing part (no need to arrange a rectifying member such as a rectifying element), the increase in pressure loss is suppressed, and the flow velocity distribution in the height direction is equalized in the cross section perpendicular to the fluid flow direction. And / or symmetrized and led to a straight flow path for measurement.

  Next, at the beginning of the measurement straight flow path (flow rate measurement section), when the flow rate is small (low speed; laminar flow area), the maximum flow velocity (peak value) is near the center position in the width direction of each divided flow path. Appearing fan-shaped (or arc-shaped or parabolic) flow velocity distribution. On the other hand, in the case of a large flow rate (high speed; turbulent flow region), a bathtub-shaped (or U-shaped) flow velocity distribution in which the average flow velocity substantially matches the maximum flow velocity (peak value) in the width direction of each divided channel Present. Therefore, the straight section for measurement is divided in the width direction by the partition portion to form a plurality of divided flow passages, and the running section in front of the transmission / reception vibrator is shortened by a simple configuration in which the communication hole is formed through the partition portion. Can be planned.

  And as for the 2nd reduction part in the said ultrasonic flowmeter, the opening width of the flow path is continuous as it goes to the inner peripheral side or outer peripheral side from the intermediate position (for example, center position) of the height direction of a flow path. You may form so that it may reduce.

  As the opening height of the flow path decreases in the first decreasing portion, the fluid in the direction changing portion tries to diffuse and move toward the end in the width direction. It is blocked or suppressed by the second decreasing portion in which the opening width decreases. Thus, the flow velocity distribution in the width direction can be smoothly equalized (symmetrized) by the second decreasing portion. In addition, the channel wall surface in the 2nd reduction | decrease part can be formed in planar shape or curved surface shape. For example, the channel wall surface in the second decreasing portion can be formed in a cross section orthogonal to the flow direction, such as a triangular shape such as an isosceles triangular shape, a quadrangular shape such as a trapezoidal shape, an arc shape, an elliptical shape, or the like.

  At that time, in the second decreasing portion, the opening width of the flow path is continuously reduced from the intermediate position in the height direction of the flow path (for example, the center position) toward the inner peripheral side. Is desirable. As a result, it is possible to reduce the length of the second reduction portion required for equalization (symmetrization) of the flow velocity distribution in the width direction, that is, the section length (length in the flow direction) of the direction change portion and the adjustment portion.

  Alternatively, the second decreasing portion in the ultrasonic flowmeter has a continuous opening width of the flow path from the intermediate position (for example, the central position) in the height direction of the flow path toward the inner peripheral side and the outer peripheral side. It may be formed so as to decrease.

  In response to the opening height of the flow path decreasing at the first decreasing portion, the fluid in the direction changing portion tries to diffuse and move toward the end in the width direction. It is blocked or suppressed (suppressed) by the second decreasing portion where the opening width decreases, and is collected in the middle portion (central portion) in the height direction of the flow path. As described above, the second decreasing portion in which the opening width decreases on the inner peripheral side and the outer peripheral side smoothly equalizes (symmetrizes) the flow velocity distribution in the width direction with a short section length (length in the flow direction). Can do. In this case as well, the channel wall surface in the second reduction portion can be formed in a flat shape or a curved shape. For example, the channel wall surface in the second reduction portion can be formed in a half cross section perpendicular to the flow direction, in a triangular shape such as an isosceles triangular shape, a quadrangular shape such as a trapezoidal shape, an arc shape, an elliptical shape, or the like.

  At that time, in the second decreasing portion where the opening width decreases on the inner peripheral side and the outer peripheral side, the decreasing rate of the opening width from the intermediate position (for example, the central position) in the height direction of the flow path toward the inner peripheral side is It is desirable that it is larger than the decreasing rate of the opening width toward the outer peripheral side.

  As described above, the reduction rate of the opening width in the second reduction portion is smaller on the outer circumferential side than on the inner circumferential side, and is asymmetrical on the inner and outer sides, so that the fluid on the outer circumferential side where fluid bias is likely to occur due to centrifugal force. A relatively large diffusion movement capacity toward the end in the width direction can be ensured. As a result, the disturbance (unevenness and / or asymmetry) of the flow velocity distribution in the width direction that occurs in the direction change portion can be made relatively small, and therefore the first required for equalization (symmetrization) of the flow velocity distribution in the width direction. It is possible to further shorten the section length (length in the flow direction) of the second decreasing portion and thus the direction changing portion and the adjusting portion. If the flow path wall surface is flat, the magnitude of the reduction rate of the opening width corresponds to the reciprocal of the gradient, and if it is curved, the magnitude of the reduction ratio of the opening width corresponds to the magnitude of the reciprocal of the curvature (curvature radius). .

In the flow meter described above, the inner and outer flow path wall surfaces of the adjustment unit are arranged in parallel with the wall surfaces of the long side wall part of the measurement linear flow channel (flow measurement section), respectively.
The center in the height direction of the flow path of the increasing portion can be arranged (offset; lean) toward the outer peripheral side or the inner peripheral side with respect to the center in the height direction of the flow path of the adjusting portion.

  A straight line for measurement after smoothing the flow velocity distribution in the height direction at the increase part by arranging the center part in the height direction of the increase part toward the outer peripheral side or the inner peripheral side from the center position in the height direction of the adjustment part The maximum flow velocity to be measured in the flow path (flow rate measurement section) is likely to appear on an extension line at the center position in the height direction of the adjustment unit. Therefore, the section length (length in the flow direction) of the increased portion required for equalization (symmetrization) of the flow velocity distribution in the height direction can be shortened. Note that whether the center in the height direction of the increasing portion is offset to the outer peripheral side or the inner peripheral side with respect to the center position in the height direction of the adjusting portion depends on the shape (height, etc.) of the adjusting portion and the increasing portion. Can be determined. At that time, if the measurement line position of the measurement unit (for example, a pair of transmission / reception transducers) in the measurement straight flow path (flow rate measurement section) is arranged (matched) on the extension line of the center position in the height direction of the adjustment unit, measurement It is possible to stably measure the maximum flow velocity of the fluid to be measured flowing through the straight flow path (flow measurement section).

In addition, the increase portion, the opening height of the flow path is increased and changed stepwise in the height direction on the outer peripheral side and the inner peripheral side,
In the adjusting portion, at least the rear end portion on the inner peripheral side in the height direction of the flow path can extend to the lower side in the flow direction at the increasing portion to form an extending portion.

  As described above, the rear end portion on the inner peripheral side of the adjustment portion forms the extension portion, so that smoothing of the flow velocity distribution in the height direction in the cross section perpendicular to the fluid flow direction is short in the increase portion. It is performed quickly with the section length (length in the flow direction). At the same time, when the front end portion on the outer peripheral side in the height direction of the flow path in the increasing portion rushes to the upper side in the flow direction in the adjusting portion to form a rush portion, the above centrifugal force causes On the outer peripheral side where fluid bias is likely to occur, fluid can be partially (and temporarily) retained in the intrusion part formed in the adjusting part to delay the flow velocity, and smoothing the above-mentioned flow velocity distribution in the height direction Can be performed more quickly.

  For example, the flow path wall surface of the extending portion can be formed into a curved surface shape that gradually contacts the inner peripheral side and / or the outer peripheral side wall of the increasing portion as it goes toward the lower side in the flow direction.

  As a result, the wall portion on the inner peripheral side and the wall portion on the outer peripheral side and the extending portion in the increasing portion are smoothly connected and do not hinder the flow of fluid from the adjusting portion to the increasing portion. The flow velocity distribution can be smoothly smoothed.

  Alternatively, the flow path wall surface of the extending portion can be formed in a curved surface shape that gradually contacts the short side wall surface (short side wall portion) of the increasing portion as it goes toward the lower side in the flow direction.

  Thereby, the short side wall portion (short side wall portion) in the increasing portion and the extending portion are smoothly connected and do not hinder the flow of fluid from the adjusting portion to the increasing portion. The flow velocity distribution can be smoothly smoothed.

  Furthermore, at least one of the direction changing portion and the adjusting portion may be arranged along the flow direction with at least one adjusting portion that divides the opening height of the flow path in the height direction.

  By dividing the opening height of the flow path of the adjustment section in the height direction by the partition section, disturbance (unevenness and / or asymmetry) of the flow velocity distribution in the height direction can be relatively reduced. The flow rate can be measured with high accuracy over a wide range from the basin (small flow rate) to the turbulent flow range (large flow rate).

  The partition portion is disposed across the direction changing portion and the adjustment portion by a single plate having a smooth surface, and is at least offset (offset) on the outer peripheral side in the height direction of the adjustment portion. Can be located).

  Since the partition part is biased to the outer peripheral side in the adjustment part, the disturbance (unevenness and / or asymmetry) of the flow velocity distribution in the height direction is further reduced on the outer peripheral side where the fluid tends to be biased by the centrifugal force. can do. For example, the partition portion can be located near the center in the height direction in the direction conversion portion, and can be located biased toward the outer peripheral side in the adjustment portion.

  In such an ultrasonic flowmeter, the partition portion is made of a mesh-like material so as to be superposed on the communication hole while allowing the passage of the ultrasonic beam and the flow of the fluid and reducing the opening area of the communication hole. It can have a superposition part.

  By superposing the overlapping part composed of a mesh-like material on the communication hole and relatively reducing the opening area of the communication hole, the flow (movement) of fluid between the adjacent divided flow paths can To a limited range. Therefore, the influence of the overlapping portion on the equalization and symmetrization (smoothing) of the flow velocity distribution mainly in the width direction in the measurement straight flow path (flow rate measurement section) is reduced.

By the way, the “network-like material” constituting the superposition part includes the following.
(1) A woven fabric made of a polymer material such as gauze (for example, a synthetic resin such as polypropylene (PP));
(2) a perforated plate made of a metal such as punching metal (for example, stainless steel);
(3) Mesh fabric made of polymer material such as sieve cloth, sieve mesh or metal;
For example, in the case of a woven fabric or mesh fabric made of a polymer material, the mesh portion that forms the framework of the mesh material is a yarn (filament) in which a plurality of single yarns made of polymer materials (for example, synthetic resin) are bundled or joined together Or fiber) is knitted as weft yarn and warp yarn, and has a hole area ratio of about 30 to 80% (for example, 55%). By using a mesh-like material having such flexibility and elasticity, components with different phases in the ultrasonic beam are absorbed by the mesh-like material, and the receiving-side transducer can easily receive only the same-phase beam. As a result, the S / N ratio is improved.

  In such an ultrasonic flowmeter, the opening area of the communication hole may be equal to or less than the beam projection cross-sectional area in which the ultrasonic beam passing through the communication hole is projected onto a plane parallel to the communication hole. it can.

  As a result, the peripheral portion of the ultrasonic beam that expands after oscillation by the transducer on the transmitting side is eliminated at the peripheral portion of the communication hole, and components with different phases are difficult to reach by the transducer on the receiving side. Since it becomes easy to receive, S / N ratio improves. When the communication hole is circular and the ultrasonic beam is oscillated from a circular transmission / reception transducer, the circular opening area of the communication hole is the elliptical projection cross-sectional area of the ultrasonic beam (or transmission / reception transducer). Equal to or less than

  In these ultrasonic flowmeters, it is desirable that a plurality of partitioning portions are arranged in parallel with each other in the width direction, and that the opening widths of the divided flow paths are equal to each other.

  Since the measurement linear flow path is divided in the width direction by the equally-spaced partitions, the flow velocity distribution in the width direction in each divided flow path can be quickly equalized and symmetrized. In addition, when the opening widths of the respective divided flow paths are not equal, for example, a plurality of partition portions are arranged in parallel with each other in the width direction, and the opening width is made smaller as the divided flow path is closer to the center position in the width direction. Good. Since the flow rate of the fluid flowing through the divided flow path tends to decrease toward the center in the width direction (short side wall side) and decrease (particularly when the flow rate is small), the divided flow path in the central portion rather than the peripheral portion. By reducing the opening width (capacity), the flow rate in the peripheral part can be increased, and the flow velocity distribution in the width direction of the measurement linear flow path can be smoothed.

  The introduction-side flow path and the measurement straight flow path (flow rate measurement section) are arranged orthogonally, and the opening height and the opening width of the measurement straight flow path (flow measurement section) are formed constant with respect to the flow direction. If so, the ultrasonic flowmeter can be formed in a compact box shape. Further, since the flow velocity distribution equalized (symmetrized) at the increasing portion is stably maintained even in the measurement straight flow path (flow rate measurement section), the accuracy of flow rate measurement is improved. Furthermore, the running section in front of the transmitting / receiving transducer can be shortened.

(overall structure)
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an overall perspective view of an embodiment of an ultrasonic flow meter used as a general residential gas meter or the like. The ultrasonic flowmeter 100 includes a main body unit 10, an intermediate flow path forming unit 20, and a shut-off valve 30, and the main body unit 10 includes a main body portion 11 and a lid portion 17.

  FIG. 2 is a front sectional view of the ultrasonic flowmeter 100, and the AA sectional view of FIG. 2 is shown in FIG. As shown in FIG. 2, the main body 11 has a rectangular parallelepiped shape as a whole, and an inlet 12 connected to the upstream gas pipe and an outlet 13 connected to the downstream gas pipe are formed on the upper surface thereof. Each is open. In addition, a main body flow path 14 for allowing a gas (fluid) to pass between the inflow port 12 and the outflow port 13 is formed therein. A main body flow path cutting portion 15 is formed in the lower part of the main body portion 11 from the back side in FIG. 2 toward the front side (fitting direction). The main body flow path cutting portion 15 is provided with a packing 17a (seal material). It is covered from the outside by the cover part 17 (refer FIG. 3). A pair of window holes 16, 16 (see FIG. 1) communicating with the main body flow path cutting portion 15 are opened on the outer surface of the main body portion 11 on the front side in the fitting direction (front side in FIG. 2).

  As shown in FIG. 3, when the intermediate flow path forming unit 20 is fitted into the main body flow path cutting section 15 of the main body section 11 from a direction (fitting direction) perpendicular to the gas flow direction, An intermediate flow path 21 connected to the path 14 is formed through. The intermediate flow path 21 is connected to the main body flow path 14 in a vertically continuous inlet-side connection flow path 21b (introduction-side flow path) and outlet-side connection flow path 21c (outflow-side flow path). Consists of a horizontal linear intermediate flow channel 21a (measurement linear flow channel) that is continuous with the flow channels 21b and 21c and is disposed along the lower surface of the main body 11 in a form substantially orthogonal to the main body flow channel 14. (See FIG. 2). Further, the intermediate flow path forming unit 20 is integrally formed with a pair of projecting portions 22 and 22 on the front side in the fitting direction corresponding to the pair of window holes 16 and 16 opened in the main body portion 11.

  Further, the pair of projecting portions 22 and 22 of the intermediate flow path forming unit 20 includes ultrasonic waves for measuring the flow rate of the gas passing through the ultrasonic measurement section 21a1 (flow measurement section) in the linear intermediate flow path 21a. A pair of transmission / reception vibrators 23a and 23b of the sensor 23 are detachably attached. In this linear intermediate flow path 21a, on the upstream side (upper side in the flow direction) of the ultrasonic measurement section 21a1, a running section 21a2 (see FIG. 2) for adjusting the flow of the gas whose flow rate is measured by the transmission / reception vibrators 23a and 23b. Reference) is provided. The axial orthogonal cross-sectional area (flow-path cross-sectional area) of the straight intermediate flow path 21a is made smaller (throttle) than the axial-perpendicular cross-sectional area (flow-path cross-sectional area) of the main body flow path 14 and the inlet-side connecting flow path 21b. Are formed in a certain size. As a result, the flow rate of the gas flowing through the linear intermediate flow path 21a is increased and kept constant, and the measurement accuracy of the flow rate (flow rate) by the ultrasonic sensor 23 is increased. The main body flow path 14 between the inlet 12 and the intermediate flow path 21 is provided with a shut-off valve 30 that blocks the gas flow in the main body flow path 14 (see FIG. 2).

  Therefore, in FIG. 3, when the intermediate flow path forming unit 20 is fitted to the main body flow path cutting portion 15 of the main body portion 11 so that the intermediate flow path 21 communicates with the main body flow path 14, the protrusions 22, 22 become the main body. Projecting from the window holes 16 and 16 of the portion 11 to the outside. And each protrusion part 22 and 22 seals each window hole 16 and 16 via packing 16a (sealing material), respectively. Further, the transmission / reception transducers 23a and 23b of the ultrasonic sensor 23 are inserted from the outside into the receiving holes 22a and 22b of the protrusions 22 and 22, respectively, and are attached to a mounting screw (a mounting member; not shown) or a pressing plate (pressing). It is detachably fixed by a member (not shown).

  As shown in FIGS. 2 and 3, the straight intermediate flow path 21 a (the ultrasonic measurement section 21 a 1 and the run-up section 21 a 2) is in the width direction of the flow path (the fitting direction to the body flow path cutting section 15; the depth direction). Is formed in a rectangular shape with a long side L and a height direction (vertical direction) of the flow path as a short side S. The ultrasonic sensor 23 is configured in the following reflective V-shaped arrangement. That is, in the orthogonal cross section in the flow direction of the ultrasonic measurement section 21a1 (linear intermediate flow path 21a), the transmitting / receiving vibrators 23a and 23b are attached to the mounting wall surface of the short side wall portion 21d that forms the short side S on the front side in the fitting direction. Are attached at a predetermined distance W0 in the flow direction, and the wall surface of the short side wall part forming the short side S on the rear side in the fitting direction is defined as a reflection surface 21e.

  Returning to FIG. 1, the output signals obtained by the transmission / reception transducers 23 a and 23 b (sensor elements) of the ultrasonic sensor 23 are transmitted to the flow rate calculation processing circuit 24 via the lead wires 25 and 25 to calculate the gas flow rate. The notification is made using a flow rate display unit (not shown) or the like. The transmission / reception vibrators 23a and 23b, the flow rate calculation processing circuit 24, the lead wires 25 and 25, the flow rate display unit, and the like constitute a flow rate measurement unit M. Since the lead wires 25 and 25 are drawn out from the ultrasonic sensor 23 (transmission / reception transducers 23a and 23b) provided to project outside from the window holes 16 and 16, the measurement gas leaks to the outside through the core wire portion and is airtight. Therefore, there is no insufficiency and measurement accuracy is not lowered. Thus, the airtightness of the three parts of the main body part 11, the lid part 17, and the intermediate flow path forming unit 20 is ensured, and the lead wires 25 and 25 are located outside the flow path. There will be no fire caused by sparks. Note that a rectifying element (rectifying member) is provided between the inlet-side connecting flow path 21b and the straight intermediate flow path 21a to suppress the disturbance of the measurement gas flow in the flow path and make the speed distribution uniform. (See FIGS. 2 and 3).

(Arrangement modification of ultrasonic sensor)
In the overall configuration described above, a case has been described in which a reflective V-shaped array is employed as an arrangement of ultrasonic sensors (transmission / reception units) and a path (referred to as a survey line) through which ultrasonic beams pass. In the reflective V-shaped arrangement, the pair of transmission / reception units can be concentrated on the same side along the flow direction, so that there is an advantage that the transmission / reception units can be attached and detached from the same direction. In addition to the reflective V-shaped array, many types are known for the line measuring method of the ultrasonic sensor (transmission / reception unit) in the ultrasonic flowmeter. Examples of application of the present invention to other line survey methods will be described below.

(1) Transmission type Z arrangement (FIG. 4A)
In this method, ultrasonic waves emitted from one transmission / reception unit 123a are received by the other transmission / reception unit 123b arranged at a predetermined distance in the flow direction. In this method, one transmission / reception unit 123a and the other transmission / reception unit 123b are arranged separately on both sides in the flow direction.

(2) Transmission type V-shaped array (FIG. 4B)
In this method, ultrasonic waves emitted from one transmitter 223a are received by a pair of receivers 223b and 223b arranged at a predetermined distance in the flow direction. In this method, the transmission unit 223a and the reception units 223b and 223b are arranged separately on both sides in the flow direction.

(3) Crossed X array (FIG. 4 (c))
The ultrasonic waves emitted from the pair of transmission units 323a and 323a arranged at a predetermined distance along the flow direction are received by the pair of reception units 323b and 323b arranged at a predetermined distance along the flow direction. It is a method. This method corresponds to the method of FIG. 4 (b) described above in which one transmission unit is added as a pair.

  Since the flowmeter of the present invention is equivalent to any ultrasonic sensor arrangement method (measurement line method), in the following embodiments, description will be made using a transmission Z array.

  In the overall configuration and the ultrasonic sensor arrangement modification described above, the main body unit 10 includes the main body portion 11 having the main body flow path 14 therein and the lid portion 17 that covers the main body portion 11 from the outside. Although only the case has been described, the main unit 10 may be configured as follows. In other words, the main body unit may be configured such that the first main body portion and the second main body portion each having a half-shaped main body flow path are combined. However, in this case, the window hole is provided in at least one of the first main body and the second main body, and the lid may or may not be provided.

Example 1
Next, FIG. 5 is a partially broken perspective view and a front view showing a first embodiment of the flow path configuration of the intermediate flow path in FIG. In the intermediate flow path 21 shown in FIG. 5, a direction changing section 211 and an adjustment section 212 are provided between the inlet-side connection flow path 21b (main body flow path 14) and the straight intermediate flow path 21a that are arranged substantially orthogonally. And the increasing part 213 is connected and formed in this order from the upper side to the lower side in the flow direction. The direction changing section 211 and the adjusting section 212 are connected and formed so that the opening height of the flow path is smaller than that of the inlet side connecting flow path 21b.

  The direction changing portion 211 is curved at the outer peripheral side and the inner peripheral side so as to change the direction of the gas flow by about 90 ° following the outlet side end portion of the inlet side connecting flow path 21b arranged substantially downward. Is formed. The direction changing portion 211 has a decreasing portion 211a in which the opening height of the flow path decreases toward the lower side in the flow direction, and the outer peripheral side and the inner peripheral side of the flow path are linear intermediate flow paths 21a (ultrasonic measurement section). 21a1) is connected to the long side wall portion 21f. Moreover, the adjustment part 212 is connected and formed in the form which follows the exit side terminal part of the direction change part 211, and aligns the flow direction of a gas in a substantially horizontal direction. Further, following the adjusting portion 212, an increasing portion 213 in which the opening height of the flow path increases and changes in a stepwise manner in the height direction is connected and formed on the outer peripheral side and the inner peripheral side. It is connected to the flow path 21a (ultrasonic measurement section 21a1). Note that the center position O1 in the height direction of the flow path of the increasing portion 213 coincides with the center position O2 in the height direction of the flow path of the adjusting portion 212. Further, the central position O1 of the increasing portion 213 coincides with the measurement position of the transmission / reception transducers 123a and 123b of the ultrasonic sensor 23 and the central position in the height direction of the ultrasonic measurement section 21a1 (linear intermediate flow path 21a). ing. Furthermore, the inner and outer flow path wall surfaces of the adjustment unit 212 are arranged in parallel with the wall surface of the long side wall part 21f of the linear intermediate flow path 21a (ultrasonic measurement section 21a1).

  The flow rate distribution mainly in the height direction is equalized and symmetrized in the ultrasonic measurement section 21a1 (linear intermediate flow path 21a) by the direction changing unit 211 (particularly the decreasing unit 211a), the adjusting unit 212, and the increasing unit 213. (Smoothed).

  As described above, the adjusting unit is configured to cause the gas flow direction and the maximum flow velocity to be biased between the outer peripheral side and the inner peripheral side of the reducing unit 211a due to the centrifugal force acting when the gas flows along the outer peripheral side of the direction changing unit 211. By 212, the flow direction is made substantially horizontal. Further, the rectifying action in the increasing portion 213 (since it is not necessary to arrange a rectifying member such as a rectifying element) suppresses an increase in pressure loss, and the flow velocity distribution in the height direction is equalized and symmetrized (smoothed). Then, it is guided to the ultrasonic measurement section 21a1 (linear intermediate flow path 21a).

  6 is a plan sectional view and a side sectional view of the straight intermediate flow path in FIG. As shown in FIG. 6, a plurality of (for example, two) plate-like partition walls 40 (partition portions) are arranged in parallel along the flow direction in the straight intermediate flow path 21 a, and the straight intermediate flow path An opening width W that becomes the long side L of 21a is divided in the width direction to form a plurality (for example, three layers) of divided flow paths 21a ′ having the same opening width W ′. In each partition wall 40, one communication hole 41 (for example, a circular shape) is formed penetrating in the width direction so as to correspond to the measurement line of the ultrasonic beam.

  The circular opening area A1 of the communication hole 41 is an ellipse in which an ultrasonic beam transmitted from the circular transmission / reception surfaces of the transmission / reception transducers 123a and 123b and passing through the communication hole 41 is projected on a plane parallel to the communication hole 41. It is set to be slightly smaller than the beam projection sectional area A2 (see FIG. 5). Thereby, for example, even if the ultrasonic beam transmitted by the transmission / reception vibrator 123a expands after oscillation, the peripheral portion of the ultrasonic beam is excluded at the peripheral portion of the communication hole 41. Therefore, it is difficult for components having different phases to be mixed in the ultrasonic beam that reaches the transmitting / receiving transducer 123b, and it becomes easier to receive only the beams having the same phase, so that the S / N ratio is improved.

  In this way, the linear intermediate flow path 21a is divided and formed into three layers of divided flow paths 21a 'by the two partition walls 40. As a result, the flow velocity distribution in the width direction (secondarily the flow velocity distribution in the height direction) in each divided flow path 21a 'is equalized and symmetrized (smoothed).

  Since the intermediate flow path 21 is configured as described above, the gas flow in this flow path is as shown in the flow velocity distribution in the height direction shown in FIG. 7 and the flow velocity distribution in the width direction shown in FIG. .

  As shown in FIG. 7, the gas that has flowed into the direction changing portion 211 is in the process of changing direction from the downward (vertical direction) inlet-side connecting flow path 21 b to the horizontal (horizontal direction) linear intermediate flow path 21 a. The speed component of slanting downward (intermediate direction) is large. Since the gas having such a velocity component moves to the downstream side in the flow direction along the outer peripheral side of the direction changing portion 211 (decreasing portion 211a), the flow direction reaches the end position of the direction changing portion 211. Are still uneven and unstable. Further, the flow velocity distribution in the height direction at the end position of the direction changing portion 211 has a non-uniform (asymmetric) state in which the flow velocity increases toward the outer peripheral side. Thus, in the direction change part 211 (decrease part 211a), the flow direction is unstable and the flow rate is uneven (asymmetric) (uneven flow) is generated.

  For example, when the flow rate is small (low speed; laminar flow region), the centrifugal force when the gas flows along the outer peripheral side of the direction changing portion 211 is relatively small. Accordingly, as shown in FIG. 7A, the flow velocity distribution at the time of a small flow rate has a pseudo isosceles triangle shape that protrudes in the vicinity of the central position O2 in the height direction in the adjustment unit 212, but in the increase unit 213, the comparison is made. It becomes a fan shape (or arc shape or parabolic shape) equalized and symmetrized in the height direction quickly. On the other hand, at the time of a large flow rate (at high speed; turbulent flow region), the centrifugal force when the gas flows along the outer peripheral side of the direction changing portion 211 is relatively large. Accordingly, as shown in FIG. 7B, the flow velocity distribution at the time of a large flow rate has a pseudo right triangle shape that protrudes below the central position O2 in the height direction in the adjustment unit 212. It becomes a bathtub shape (or U-shape) that is equalized and symmetric in the height direction with a slight delay.

  As described above, the flow rate distribution in the height direction has an influence while the opening height of the flow path passes through the increasing portion 213 where the opening height of the flow path increases and decreases stepwise in the height direction on the outer peripheral side and the inner peripheral side. Relaxed, equalized and symmetrized (smoothed). That is, the drift generated in the direction changing unit 211 (decreasing unit 211a) is released by the increasing unit 213 via the adjusting unit 212, so that the peak of the flow velocity distribution (maximum flow velocity) is near the central position O1 in the height direction. ) Is corrected to the flow with. Therefore, the measurement line of the pair of transmission / reception vibrators 123a and 123b is arranged at the center position O1 of the flow velocity distribution in the height direction at the increasing portion 213, and the maximum amount of gas flowing through the ultrasonic measurement section 21a1 (linear intermediate flow path 21a). The flow rate can be measured stably.

  That is, in the reduction part 211a (direction changing part 211), the opening height of the flow path decreases toward the lower side in the flow direction, and a rectifying means such as a rectifying element is placed in the flow path on the lower side in the flow direction such as the adjustment part 212. Since it is not necessary to arrange, pressure loss is suppressed and the measurement range in the turbulent region can be further expanded. Further, since no rectifying means is provided, the cost of the ultrasonic flowmeter 100 can be reduced.

  As shown in FIG. 8, the gas flowing into the starting end of the straight intermediate flow path 21a (running section 21a2) has a non-uniform flow velocity distribution in the width direction before flowing into each divided flow path 21a ′ ( Asymmetric). For example, at the time of a small flow rate (low speed; laminar flow area) shown in FIG. 8A, when the flow is divided into the respective divided flow paths 21a ′, the vicinity of the center position in the width direction for each divided flow path 21a ′. A fan-shaped (or arc-shaped or parabolic-shaped) flow velocity distribution in which the maximum flow velocity (peak value) appears is exhibited. In this way, the flow velocity distribution of the straight intermediate flow path 21a (running section 21a2) is divided by the partition wall 40, whereby the flow velocity distribution in the width direction is further equalized and symmetrized (smoothed).

  On the other hand, at the time of a large flow rate (high speed; turbulent flow region) shown in FIG. 8B, when the flow is divided into each divided flow channel 21a ′, the average flow velocity in the width direction is divided for each divided flow channel 21a ′. It exhibits a bathtub-shaped (or U-shaped) flow velocity distribution that substantially matches the maximum flow velocity (peak value). In this way, the flow velocity distribution of the straight intermediate flow path 21a (running section 21a2) is divided by the partition wall 40, whereby the flow velocity distribution in the width direction is further equalized and symmetrized (smoothed).

  As described above, since the ultrasonic beam is not divided by the partition wall 40, the power is not dispersed or attenuated, and the flow rate measurement by the transmission / reception vibrators 123a and 123b can be performed with high efficiency and high accuracy. Moreover, since the linear intermediate flow path 21a is divided in the width direction by the partition wall 40, pressure loss during measurement is suppressed, and the flow velocity distribution in the width direction is equalized and symmetrized (smoothed). A stable flow meter side in a wide measurement range is possible. Note that in the ultrasonic measurement section 21a1, the gas flow between the adjacent divided flow paths 21a ′ via the communication holes 41 is allowed, but the communication holes 41 are provided along the flow direction. The flow velocity distribution in the width direction in the divided flow path 21 a ′ does not change before and after the communication hole 41.

  As a result, even if the viscosity changes according to the type of gas and temperature change, and the kinematic viscosity coefficient fluctuates, the symmetry of the gas is always secured from the laminar flow region (small flow rate) to the turbulent flow region (large flow rate). The flow rate can be measured with high accuracy.

(Modification 1)
FIG. 9 is a plan sectional view and a side sectional view showing a first modified example of the linear intermediate flow path. As shown in FIG. 9, a plurality of (for example, three) plate-like partition walls 40 (partition portions) are arranged in parallel along the flow direction in the linear intermediate channel 21a (measurement linear channel). The opening width W that becomes the long side L of the straight intermediate flow path 21a is divided in the width direction to form a plurality of (for example, four layers) divided flow paths 21a ′ having the same opening width W ′. In each partition wall 40, one communication hole 41 (for example, a circular shape) is formed penetrating in the width direction so as to correspond to the measurement line of the ultrasonic beam. Note that four or more partition walls 40 may be provided.

(Modification 2)
FIG. 10 is a plan sectional view and a side sectional view showing a second modification of the straight intermediate flow path. As shown in FIG. 10, a plurality of (for example, two) plate-like partition walls 40 (partition portions) are arranged in parallel along the flow direction in the linear intermediate channel 21a (measurement linear channel). The opening width W that becomes the long side L of the linear intermediate flow path 21a is divided in the width direction to form a plurality of (for example, three layers) divided flow paths 21a ′. Among them, the opening width W ′ of the divided flow path 21a ′ located in the center in the width direction is formed to be smaller than the opening width W ″ of the divided flow path 21a ′ located in the periphery. Usually, the divided flow path 21a ′. The flow rate of the gas flowing through the wall tends to decrease toward the center of the width direction (short side wall portion 21d side) and decrease (particularly when the flow rate is small). By reducing the opening width W ′ of the divided flow path 21a ′ located in the center of the width W ″, the flow rate in the peripheral portion is increased and the flow velocity distribution in the width direction of the straight intermediate flow path 21a is smoothed. be able to.

(Modification 3)
FIG. 11 is a plan sectional view and a side sectional view showing a third modification of the straight intermediate flow path. As shown in FIG. 11, a plurality of (for example, two) plate-like partition walls 40 (partition portions) are arranged in parallel along the flow direction in the straight intermediate flow path 21a (measurement straight flow path). The opening width W that becomes the long side L of the linear intermediate flow path 21a is divided in the width direction to form a plurality of (for example, three layers) divided flow paths 21a ′ having the same opening width W ′. In each partition wall 40, one communication hole 41 (for example, a circular shape) is formed penetrating in the width direction so as to correspond to the measurement line of the ultrasonic beam, and each communication hole 41 is a thin plate made of a mesh-like material. A sheet-like or sheet-like polymerization network 42 (polymerization part) is superposed.

  The polymerization network 42 is flexible in order to reduce the opening area of the communication hole 41 while allowing the ultrasonic beam to pass through and restricting the gas flow between the adjacent divided flow paths 21a ′. -It is comprised with the mesh fabric M (mesh-like material) made from the polymeric material which has elasticity.

  Specifically, as shown in FIG. 12, a long fiber yarn in which a plurality of (for example, three) single yarns made of a thin (for example, several tens of μm) polymer material (for example, a synthetic resin such as polypropylene (PP)) is bundled. By knitting y (filament) as a weft and warp, a mesh part m (framework) of the mesh fabric M including a large number of apertures h (space) is formed. A hole area ratio represented by a ratio of the total surface area of the hole portions h to the entire surface area of the mesh fabric M is about 30 to 80% (for example, 55%). In this way, by using the mesh fabric M having flexibility and elasticity for the polymerization net 42, components having different phases in the ultrasonic beam are absorbed by the mesh portion m of the mesh fabric M, and transmission / reception vibration on the receiving side. Since the slaves 123a and 123b can easily receive only the beam having the same phase, the S / N ratio is improved. Further, by selecting the opening ratio of the mesh fabric M, the amount of gas flowing (moving) between the adjacent divided flow paths 21a ′ via the communication holes 41 is limited by the polymerization net 42 (limitedly allowed). can do.

  In this way, the linear intermediate flow path 21a is divided and formed into three layers of divided flow paths 21a 'by the two partition walls 40. Thereby, the flow velocity distribution mainly in the width direction in each divided flow path 21a 'is equalized and symmetrized (smoothed). The gas can be circulated between the adjacent divided flow paths 21a ′ via the communication holes 41, but the above-described gas flow can be performed by the polymerization net 42 (mesh fabric M) superimposed on the communication holes 41. Limited to a limited range, the flow velocity distribution in the width direction in each divided flow path 21 a ′ does not change before and after the communication hole 41.

(Example 2)
FIG. 13 is a partially broken perspective view and a front view showing a second embodiment of the flow path configuration of the intermediate flow path. In the intermediate flow path 21 shown in FIG. 13, the direction changing portion 211 has a first decreasing portion 211 a that is formed in a curved shape on the outer peripheral side and decreases as the opening height of the flow path becomes lower in the flow direction. . Moreover, the adjustment part 212 has the 2nd reduction part 212a which decreases as the opening height H of a flow path goes to the width direction edge part side.

  Specifically, the second decreasing portion 212a is located on the inner circumferential side from the center position O2 in the height direction of the flow path of the adjustment section 212 (matches the center position O1 in the height direction of the flow path of the increase section 213). The opening width W of the flow path is formed so as to decrease continuously as it goes to. And in the 2nd reduction | decrease part 212a shown in FIG. 13, the opening width W of a flow path is continuous as it goes to the inner peripheral side from the center position O2 of the adjustment part 212 in the cross section orthogonal to a flow direction. The trapezoid shape is reduced.

  And in the ultrasonic measurement section 21a1 (linear intermediate flow path 21a), the direction change part 211 including the first decrease part 211a, the adjustment part 212 including the second decrease part 212a, and the increase part 213 The flow velocity distribution in the height direction is equalized and symmetrized (smoothed), respectively.

  Specifically, the gas flow direction and the maximum flow velocity are biased between the outer peripheral side and the inner peripheral side of the first reducing portion 211a due to the centrifugal force when the gas flows along the outer peripheral side of the direction changing portion 211. The flow direction is aligned in a substantially horizontal direction by the adjustment unit 212. Then, the gas is diffused and moved toward the end in the width direction at the first decreasing portion 211a, and the flow velocity distribution in the width direction and the height direction is constricted at the center in a cross section orthogonal to the flow direction (for example, a bowl shape). The second ellipse 212a is prevented (suppressed) from attempting to become a shape, and an elliptical shape without any constriction is maintained (see the enlarged sectional view of FIG. 13A). Further, the increase in pressure loss is suppressed by the increasing portion 213, the flow velocity distribution in the height direction is equalized and symmetrized (smoothed), and guided to the ultrasonic measurement section 21a1 (linear intermediate flow path 21a) (FIG. 7).

  Thus, in response to the opening height of the flow path being reduced in the first reducing portion 211a, the gas in the direction changing portion 211 tends to diffuse and move toward the end in the width direction. Since it is blocked (suppressed) by the second reduction portion 212a, the flow velocity distribution in the width direction can be equalized (symmetrized) smoothly. In addition, the influence of the deviation in the flow velocity distribution in the height direction is alleviated while the opening height of the flow path passes through the increasing portion 213 that increases and decreases stepwise in the height direction on the outer peripheral side and the inner peripheral side. , Equalized and symmetrized. That is, the drift generated in the direction changing portion 211 (first decreasing portion 211a) is released by the increasing portion 213 via the adjusting portion 212 including the second decreasing portion 212a, and thereby the center in the height direction. The flow is corrected to have a flow velocity distribution peak (maximum flow velocity) in the vicinity of the position O1. Therefore, the measurement line of the pair of transmission / reception vibrators 123a and 123b is arranged at the center position O1 of the flow velocity distribution in the height direction at the increasing portion 213, and the maximum amount of gas flowing through the ultrasonic measurement section 21a1 (linear intermediate flow path 21a). The flow rate can be measured stably.

  Furthermore, the second reduction portion 212a is formed such that the opening width W of the flow path continuously decreases from the central position O2 in the height direction of the flow path of the adjustment section 212 toward the inner peripheral side. Therefore, the second reduction part 212a required for equalization (symmetrization) of the flow velocity distribution in the width direction, and thus the section length (length in the flow direction) of the direction changing part 211 and the adjustment part 212 are shortened.

(Example 3)
FIG. 14 is a partially broken perspective view and a front view showing a third embodiment of the flow path configuration of the intermediate flow path. In the second reduction portion 212a shown in FIG. 14, the flow path wall surface is a cross section orthogonal to the flow direction, and the flow path opening width W increases from the center position O2 in the height direction of the adjustment section 212 toward the inner peripheral side. (Refer to FIG. 13) is formed in a circular arc shape (or elliptical shape) that continuously decreases.

Example 4
FIG. 15 is a partially broken perspective view and a front view showing a fourth embodiment of the flow path configuration of the intermediate flow path. In the second reduction portion 212a shown in FIG. 15, the flow passage wall surface has a cross section orthogonal to the flow direction, and the opening width W of the flow passage increases from the center position O2 in the height direction of the adjustment portion 212 toward the inner peripheral side. (See FIG. 13) is formed in an isosceles triangle shape that continuously decreases.

(Example 5)
FIG. 16 is a partially broken perspective view and an enlarged view of a main part showing a fifth embodiment of the flow path configuration of the intermediate flow path. In the second reduction portion 212a shown in FIG. 16, the opening width W of the flow path is continuously increased from the central position O2 in the height direction of the adjustment portion 212 (see FIG. 5) toward the inner peripheral side and the outer peripheral side. It is formed to decrease. At that time, the second decreasing portion 212a is formed in an asymmetric shape so that the decreasing rate of the opening width W from the central position O2 toward the inner peripheral side is larger than the decreasing rate of the opening width W toward the outer peripheral side. Has been.

  Specifically, on the inner peripheral side of the second decreasing portion 212a, an arc shape in which the opening width W of the flow path continuously decreases from the central position O2 in the height direction of the adjusting portion 212 toward the inner peripheral side. An (or elliptical) inner peripheral side reduction portion 212a1 is formed. On the other hand, also on the outer peripheral side of the second decreasing portion 212a, an arc shape (or an elliptical shape) in which the opening width W of the flow path continuously decreases from the central position O2 in the height direction of the adjusting portion 212 toward the outer peripheral side. The outer peripheral side reduction part 212a2 is formed. The reduction rate (the reciprocal of the curvature, that is, the radius of curvature) of the opening width W of the inner peripheral side reduction portion 212a1 is larger than the reduction rate of the opening width W of the outer peripheral side reduction portion 212a2.

  In this way, the reduction rate of the opening width W of the outer peripheral side reduction portion 212a2 is made smaller than the reduction rate of the opening width W of the inner peripheral reduction portion 212a1, and the gas is biased by centrifugal force by making it asymmetric inside and outside. On the outer peripheral side that is likely to occur, the diffusion movement capacity of the gas toward the end in the width direction can be secured relatively large. As a result, the disturbance (unevenness and asymmetrical) of the flow velocity distribution in the width direction that occurs in the direction changing section 211 can be relatively reduced, so the second required for equalization (symmetrization) of the flow velocity distribution in the width direction. The section length (length in the flow direction) of the direction change unit 211 and the adjustment unit 212 can be further reduced.

(Example 6)
FIG. 17 is a partially broken perspective view and an enlarged view of an essential part showing a sixth embodiment of the flow path configuration of the intermediate flow path. 17 has a trapezoidal shape in which the opening width W of the flow path continuously decreases from the central position O2 in the height direction of the adjustment unit 212 (see FIG. 5) toward the inner peripheral side. Is formed. On the other hand, the outer peripheral side decreasing portion 212a2 is formed in an arc shape (or an elliptical shape) in which the opening width W of the flow path continuously decreases from the central position O2 in the height direction of the adjusting portion 212 toward the outer peripheral side. . The reduction rate (reciprocal of the gradient) of the opening width W of the inner peripheral side reduction portion 212a1 is larger than the reduction rate (the reciprocal of the curvature, that is, the radius of curvature) of the opening width W of the outer peripheral side reduction portion 212a2.

(Example 7)
FIG. 18 is a partially broken perspective view and an enlarged view of a main part showing a seventh embodiment of the flow path configuration of the intermediate flow path. 18 has an arc shape in which the opening width W of the flow path continuously decreases from the central position O2 in the height direction of the adjustment unit 212 (see FIG. 5) toward the inner peripheral side. (Or elliptical). On the other hand, the outer peripheral side reduction part 212a2 is formed in a trapezoidal shape in which the opening width W of the flow path continuously decreases from the center position O2 in the height direction of the adjustment part 212 toward the outer peripheral side. The reduction rate (the reciprocal of the curvature, that is, the curvature radius) of the opening width W of the inner peripheral side reduction portion 212a1 is larger than the reduction rate (the reciprocal of the gradient) of the opening width W of the outer peripheral side reduction portion 212a2.

(Example 8)
FIG. 19 is a front sectional view showing an eighth embodiment of the flow path configuration of the intermediate flow path. A central position O1 in the height direction of the increasing portion 213 shown in FIG. 19 is arranged to be offset (offset; staggered) toward the outer peripheral side with respect to the central position O2 in the height direction of the adjusting portion 212.

  Thus, by arranging the central position O1 in the height direction of the increasing portion 213 toward the outer peripheral side with respect to the central position O2 in the height direction of the adjusting portion 212, the flow velocity distribution in the height direction at the increasing portion 213 is arranged. The maximum flow velocity to be measured in the straight intermediate flow path 21a after the smoothing is likely to appear on the extension line of the central position O2 in the height direction of the adjustment unit 212. Therefore, the section length (length in the flow direction) of the increasing portion 213 required for equalization (symmetrization) of the flow velocity distribution in the height direction can be shortened. Moreover, the measurement positions of the pair of transmission / reception transducers 123a and 123b in the ultrasonic measurement section 21a1 (linear intermediate flow path 21a) are arranged (matched) on an extension line of the center position O2 in the height direction of the adjustment unit 212. Therefore, the maximum flow velocity of the gas flowing through the ultrasonic measurement section 21a1 can be stably measured.

Example 9
FIG. 20 is a front sectional view showing a ninth embodiment of the flow path configuration of the intermediate flow path. In the adjusting unit 212 shown in FIG. 20, the rear end portion on the inner peripheral side in the height direction of the flow path extends to the lower side in the flow direction at the increasing portion 213 to form an extending portion 212 b. On the other hand, the increase portion 213 has a front end portion on the outer peripheral side in the height direction of the flow path that protrudes toward the upper side in the flow direction at the adjustment portion 212 to form a protrusion portion 213a.

  As described above, the rear end portion on the inner peripheral side of the adjustment portion 212 forms the extension portion 212b, thereby smoothing the flow velocity distribution in the height direction with a short section length (in the flow direction) in the increase portion 213. Length). At the same time, the front end portion on the outer peripheral side of the increasing portion 213 rushes toward the upper side in the flow direction in the adjusting portion 212 to form the plunging portion 213a, so that the above-described centrifugal force tends to cause a gas bias. On the outer peripheral side, gas can be partly (and temporarily) retained in the entry portion 213a formed in the adjustment portion 212 to slow the flow velocity, and the above-described smoothing of the flow velocity distribution in the height direction can be made even faster. It can be carried out.

(Example 10)
FIG. 21 is a front sectional view showing a tenth embodiment of the flow path configuration of the intermediate flow path. The extension portions 212b shown in FIG. 21 are respectively formed on the inner peripheral side and the outer peripheral side of the adjustment portion 212, and the flow path wall surface of each extension portion 212b is on the inner peripheral side in the increasing portion 213 as it goes toward the lower side in the flow direction. It is formed in a curved surface shape that comes into contact with the wall surface of the long-side wall portion 21f on the (or outer peripheral side) after gradually approaching.

  The extending part 212b is smoothly connected to the long side wall part 21f of the increasing part 213 and does not hinder the flow of gas from the adjusting part 212 to the increasing part 213, so that the flow velocity distribution in the height direction described above is smoothed. It can be done smoothly.

(Example 11)
FIG. 22 is a partially broken perspective view and a front sectional view showing an eleventh embodiment of the flow path configuration of the intermediate flow path. 22 are formed on the inner peripheral side and the outer peripheral side of the adjustment unit 212, respectively, and the flow path wall surface of each extension unit 212b is on the inner peripheral side of the increase unit 213 as it goes to the lower side in the flow direction. It is formed in a curved surface shape that comes into contact after gradually approaching the wall surface of the short-side wall portion 21d on the (or outer peripheral side) side.

  The extending part 212b is smoothly connected to the short side wall part 21d of the increasing part 213 and does not hinder the flow of gas from the adjusting part 212 to the increasing part 213, so that the flow velocity distribution in the height direction described above is smoothed. It can be done smoothly.

Example 12
FIG. 23 is a perspective sectional view and a front sectional view showing a twelfth embodiment of the channel configuration of the intermediate channel. In the intermediate flow path 21 shown in FIG. 23, a partition plate 214 (partition section) that divides the opening height of the flow path into two in the height direction across the direction conversion section 211 and the adjustment section 212 in the flow direction. Are arranged along.

  By dividing the opening height of the flow path of the direction changing unit 211 and the adjusting unit 212 into two in the height direction, the disturbance (unevenness and asymmetry) of the flow velocity distribution in the height direction can be relatively reduced. Therefore, the flow rate can be measured with high accuracy over a wide range from the laminar flow region (small flow rate) to the turbulent flow region (large flow rate).

(Example 13)
FIG. 24 is a perspective sectional view and a front sectional view showing a thirteenth embodiment of the channel configuration of the intermediate channel. The partition plate 214 (partition portion) shown in FIG. 24 is configured to divide the opening height of the flow path into two in the height direction across the direction changing portion 211 and the adjustment portion 212 by a single plate material having a smooth surface. Is arranged in. Specifically, the direction conversion unit 211 is positioned near the center (bisected position) in the height direction, while the adjustment unit 212 is disposed (offset; staggered) toward the outer peripheral side.

  Since the partition plate 214 is biased toward the outer peripheral side by the adjusting portion 212, the disturbance (unevenness and asymmetrical) of the flow velocity distribution in the height direction is further reduced on the outer peripheral side where the gas is likely to be biased by the centrifugal force. can do.

  Each configuration described in Example 8 (FIG. 19) to Example 13 (FIG. 24) is implemented in combination with each configuration described in Example 2 (FIG. 13) to Example 7 (FIG. 18). be able to.

  The functions of Example 1 (FIGS. 5 to 8) are the same as those of Example 1 (FIG. 9) to Example 3 (FIGS. 11 and 12) and Example 2 (FIG. 13) to Example 13 (FIG. 24). In some parts, the description is omitted by giving the same reference numerals to the common parts. Moreover, each structure described in each modified example and each Example can be implemented in combination with each other.

1 is an overall perspective view of an embodiment of an ultrasonic flowmeter according to the present invention. FIG. 2 is a front sectional view of FIG. 1. AA sectional drawing of FIG. Explanatory drawing which shows the arrangement | positioning modification of an ultrasonic sensor. The partially broken perspective view and front view which show the 1st Example of the flow path structure of the intermediate flow path in FIG. FIG. 6 is a cross-sectional plan view and a side cross-sectional view of the straight intermediate flow path in FIG. 5. Explanatory drawing which expands the principal part of FIG.5 (b) and shows the flow velocity distribution of the height direction at the time of the small flow volume and the large flow volume. Explanatory drawing which shows the flow velocity distribution of the width direction at the time of the small flow volume and the large flow volume using Fig.6 (a). The plane sectional view and side surface sectional view which show the 1st modification of a linear intermediate | middle flow path. The plane sectional view and side sectional view showing the 2nd modification of a linear middle channel. The plane sectional view and side sectional view showing the 3rd modification of a straight middle channel. Explanatory drawing of the mesh fabric used for a polymerization net. The partially broken perspective view and front view which show 2nd Example of the flow path structure of an intermediate flow path. The partially broken perspective view and front view which show the 3rd Example of the flow path structure of an intermediate flow path. The partially broken perspective view and front view which show the 4th Example of the flow path structure of an intermediate flow path. The partially broken perspective view and principal part enlarged view which show 5th Example of the flow path structure of an intermediate flow path. The partially broken perspective view and principal part enlarged view which show the 6th Example of the flow path structure of an intermediate flow path. The partially broken perspective view and principal part enlarged view which show the 7th Example of the flow path structure of an intermediate flow path. Front sectional drawing which shows the 8th Example of the flow path structure of an intermediate flow path. Front sectional drawing which shows the 9th Example of the flow path structure of an intermediate flow path. Front sectional drawing which shows the 10th Example of the flow path structure of an intermediate flow path. The partially broken perspective view and front sectional drawing which show the 11th Example of the flow path structure of an intermediate flow path. The perspective sectional view and front sectional view showing the 12th example of the channel configuration of the intermediate channel. The perspective sectional view and front sectional view showing the 13th example of the channel configuration of the intermediate channel.

Explanation of symbols

21 Intermediate channel 21a Linear intermediate channel (Straight channel for measurement)
21a1 Ultrasonic measurement section (flow measurement section)
21a2 Run-up section 21b Inlet side connection flow path (introduction side flow path)
21c Outlet side connecting channel (outlet side channel)
21d Short side wall part 21f Long side wall part 211 Direction change part 211a 1st reduction part (decrease part)
212 adjustment part 212a 2nd reduction part 212a1 inner circumference side reduction part 212a2 outer circumference side reduction part 212b extension part 213 increase part 213a rushing part 214 partition plate (partition part)
23 Ultrasonic sensor 40 Partition wall (partition)
41 Communication hole 42 Polymerization network (polymerization part)
100 Ultrasonic flow meter 123a, 123b Transceiver (sensor element)
M mesh fabric (network material)
m Net part h Opening part y Long fiber yarn (filament)
L Long side S Short side H Opening height W Opening width W ', W "Divided flow path opening width O1 Center position in the height direction at the increased portion O2 Center position in the height direction at the adjusting portion

Claims (15)

An introductory side channel having a predetermined channel cross-sectional area for allowing fluid to pass through, and a linear communication crossing the introductory side channel, and the width direction of the channel to measure the fluid flow rate Open in a rectangular shape having a long side and a short side in the height direction, and having a channel cross-sectional area smaller than that of the introduction-side channel, the fluid flow direction upper side or lower side on the mounting wall surface of the short side wall portion An ultrasonic flowmeter including a measurement linear flow channel to which a transmission / reception transducer is attached that oscillates an ultrasonic beam toward the side and / or receives an ultrasonic beam arriving from the upper side or the lower side in the flow direction Because
Following the outlet-side end of the introduction-side flow path, at least the outer peripheral side of the outer peripheral side and the inner peripheral side is formed in a curved shape to change the direction of fluid flow, and parallel to the mounting wall surface at the center in the width direction. In a simple cross-section, the direction changing portion having a decreasing portion that decreases as the opening height of the flow path goes toward the lower side in the flow direction,
An adjustment part that is connected to the outlet side end of the direction changing part and that aligns the flow direction of the fluid;
Following the adjustment part, the increasing part where the opening height of the flow path increases and changes stepwise in the height direction on the outer peripheral side and the inner peripheral side,
The ultrasonic linear beam is arranged along the flow direction in the measurement linear flow path, and a plurality of divided flow paths are formed by dividing an opening width as a long side of the measurement linear flow path in the width direction. One or a plurality of partitioning portions having communication holes formed in the width direction so as to correspond to the line of measurement,
The fluid flowing through the measurement linear flow path in the cross-section orthogonal to the flow direction in the width direction and the height direction by flowing through the direction change part, the adjustment part, and the increase part and divided into the divided flow paths. An ultrasonic flowmeter, wherein flow velocity distributions are equalized and / or symmetrized, respectively. An introductory side channel having a predetermined channel cross-sectional area for allowing fluid to pass through, and a linear communication crossing the introductory side channel, and the width direction of the channel to measure the fluid flow rate Open in a rectangular shape having a long side and a short side in the height direction, and having a channel cross-sectional area smaller than that of the introduction-side channel, the fluid flow direction upper side or lower side on the mounting wall surface of the short side wall portion An ultrasonic flowmeter including a measurement linear flow channel to which a transmission / reception transducer is attached that oscillates an ultrasonic beam toward the side and / or receives an ultrasonic beam arriving from the upper side or the lower side in the flow direction Because
Following the outlet-side end of the introduction-side flow path, at least the outer peripheral side of the outer peripheral side and the inner peripheral side is formed in a curved shape to change the direction of fluid flow, and parallel to the mounting wall surface at the center in the width direction. In a simple cross-section, the direction changing portion having a first reduction portion that decreases as the opening height of the flow path decreases toward the lower side in the flow direction;
It is connected to the outlet side end of the direction changing portion so as to align the flow direction of the fluid, and in the cross section perpendicular to the flow direction, the opening height of the flow path decreases as it goes to the end in the width direction. An adjustment portion having a second reduction portion;
Following the adjustment portion, at least on the outer peripheral side, the opening height of the flow path increases in a stepwise manner in the height direction, and an increasing portion,
The ultrasonic linear beam is arranged along the flow direction in the measurement linear flow path, and a plurality of divided flow paths are formed by dividing an opening width as a long side of the measurement linear flow path in the width direction. One or a plurality of partitioning portions having communication holes formed in the width direction so as to correspond to the line of measurement,
The fluid flowing through the measurement linear flow path in the cross-section orthogonal to the flow direction in the width direction and the height direction by flowing through the direction change part, the adjustment part, and the increase part and divided into the divided flow paths. An ultrasonic flowmeter, wherein flow velocity distributions are equalized and / or symmetrized, respectively.   The second decreasing portion is formed such that the opening width of the flow path continuously decreases from the intermediate position in the height direction of the flow path toward the inner peripheral side or the outer peripheral side. The ultrasonic flowmeter described in 1.   The second decreasing portion is formed such that the opening width of the flow path continuously decreases from the intermediate position in the height direction of the flow path toward the inner peripheral side and the outer peripheral side. 2. The ultrasonic flowmeter according to 2.   5. The reduction rate of the opening width from the intermediate position in the height direction of the flow path toward the inner peripheral side in the second reduction portion is larger than the reduction rate of the opening width toward the outer peripheral side. The described ultrasonic flowmeter. The flow path wall surfaces on the inner peripheral side and the outer peripheral side of the adjustment part are arranged in parallel with the wall surfaces of the long side wall part of the measurement linear flow path, respectively.
The center in the height direction of the flow path of the increasing portion is arranged so as to be biased toward the outer peripheral side or the inner peripheral side with respect to the center in the height direction of the flow path of the adjusting portion. The ultrasonic flowmeter according to item 1. In the increasing portion, the opening height of the flow path increases and changes stepwise in the height direction on the outer peripheral side and the inner peripheral side,
7. The adjustment unit according to claim 1, wherein at least a rear end portion on the inner peripheral side in the height direction of the flow path extends to a lower side in the flow direction in the increase portion to form an extension portion. The ultrasonic flowmeter according to claim 1.   The flow path wall surface of the extension part is formed in a curved surface shape that gradually contacts the inner peripheral side and / or the outer peripheral side wall of the increasing part as it goes toward the lower side in the flow direction. The ultrasonic flowmeter described in 1.   9. The flow path wall surface of the extension part is formed in a curved surface shape that gradually contacts the wall surface on the short side in the increase part as it goes toward the lower side in the flow direction. Ultrasonic flow meter.   The at least one of the direction changing portion and the adjusting portion is provided with one or a plurality of partition portions that divide the opening height of the flow path in the height direction along the flow direction. The ultrasonic flowmeter according to any one of the above.   The partition portion is disposed across the direction changing portion and the adjustment portion by a single plate material having a smooth surface, and is located at least on the outer peripheral side in the height direction of the adjustment portion. Item 11. The ultrasonic flowmeter according to Item 10.   The partition part has a superposition part made of a mesh-like material so as to overlap the communication hole and reduce an opening area of the communication hole while allowing passage of the ultrasonic beam and fluid flow. Item 12. The ultrasonic flowmeter according to any one of Items 1 to 11.   The opening area of the communication hole is equal to or less than a beam projection cross-sectional area in which the ultrasonic beam passing through the communication hole is projected onto a plane parallel to the communication hole. The ultrasonic flowmeter according to item 1.   14. The partition part according to claim 1, wherein a plurality of the partition parts are arranged in parallel to each other in the width direction, and are arranged so that the opening widths of the divided flow paths are equal to each other. Ultrasonic flow meter. The introduction side channel and the measurement linear channel are arranged orthogonally,
The ultrasonic flowmeter according to any one of claims 1 to 14, wherein an opening height and an opening width of the measurement linear flow path are formed constant with respect to a flow direction.

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