JP2009264906A - Flow meter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow meter capable of easily equalizing and symmetrizing flow velocity distribution by devising a sectional shape of a flow passage without arranging a flow straightening means and capable of precisely measuring the flow rate over a wide range from a laminar flow region to a turbulent flow region. <P>SOLUTION: A diversion part 211 is shaped in a curved form at outer and inner circumferential sides continuous to an exit side terminal part of an inlet side connection flow passage 21b directed substantially downward so that the flow of a gas is diverted by 90°. The diversion part 211 includes a reduction part 211a in which an opening height of the flow passage decreases toward a downstream side in the flow direction. An adjustment part 212 is formed so as to be connected to and continuous to the exit side terminal part of the diversion part 211, and arranges the gas flow direction substantially in the horizontal direction. A flow passage height enlargement part 213 includes an increasing part 213a in which the opening height of the flow passage changes and increases in a step shape in the height direction at the outer and inner circumferential sides, continuous to the adjustment part 212, and is connected to a straight intermediate flow passage 21a (ultrasonic measurement section 21a1). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flow meter 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, an ultrasonic wave is oscillated toward the upper side or the lower side of the fluid flow direction on the wall portion (mounting wall surface) of the measurement channel for allowing the fluid to pass, and then the flow direction. A pair of transmission / reception transducers (ultrasonic sensors) that receive ultrasonic waves coming from the upper side or the lower side are attached. In order to asymmetric the flow velocity distribution on the inlet side of the measurement flow path and bias the position where the maximum value of the flow velocity is generated to one side from the center of the measurement flow path, an asymmetry consisting of a bent portion, a stepped portion, an irregularly shaped portion, etc. It is disclosed that a flow promoting means is provided (see Patent Document 1).

Japanese Patent No. 3436247

  According to Patent Document 1, by providing an asymmetric flow promoting means, the difference in the correction coefficient between the laminar flow area and the turbulent flow area is reduced, and even if the viscosity coefficient changes depending on the type of fluid, the change in the correction coefficient is reduced. Is possible. However, in many flowmeters including ultrasonic flowmeters, the transmitter / receiver transducer (measurement unit) usually has a measurement line in the measurement flow path (straight flow path for measurement) because of the arrangement space. It arrange | positions so that it may be located in the center of the up-down direction height (height direction). Therefore, by providing the asymmetric flow promoting means as in Patent Document 1, the flow velocity distribution in the height direction tends to be asymmetric (uneven). Therefore, measures such as arranging a rectifying means for symmetrizing (equalizing) the flow velocity distribution in the height direction, such as a rectifying element, may be required on the front side (the upper side in the flow direction) of the measurement unit.

  The object of the present invention is to devise the cross-sectional shape of the flow path from the introduction-side flow path to the measurement linear flow path, thereby obtaining the flow velocity distribution in the direction perpendicular to the fluid flow direction without arranging a rectifying means. Provides a flow meter that can be easily equalized and symmetrized, and can measure the flow rate over a wide range from laminar flow to turbulent flow even if the viscosity changes with the type of fluid or temperature. There is.

Means for Solving the Problems and Effects of the Invention

In order to solve the above problems, the flow meter 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 A flow meter including a measurement linear flow channel having a long side and a rectangular shape having a short side in the height direction and having a flow channel cross-sectional area smaller than the introduction side flow channel,
Following the outlet side end portion of the introduction-side channel, 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 flow direction 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 section, there is an increasing portion in which 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, and can be connected to the measurement linear flow path. Including a channel height expanding portion,
The direction changing part and the adjustment part constitute a flow path height reducing part in which the opening height of the flow path is smaller than the introduction side flow path,
The flow rate distribution in the direction perpendicular to the fluid flow direction in the linear flow channel for measurement is reduced by the reduction portion and the adjustment portion in the flow passage height reduction portion and the increase portion in the flow passage height enlargement portion. It is characterized by equalization and / or symmetrization.

For example, in order to solve the above-mentioned problem, when using an ultrasonic flow meter for the flow meter according to the present invention,
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 A flowmeter including a measurement linear flow path to which a transmission / reception transducer is attached, which oscillates ultrasonic waves toward the side and / or receives ultrasonic waves coming from the upper side or lower side in the flow direction,
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 section, there is an increasing portion in which 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, and can be connected to the measurement linear flow path. Including a channel height expanding portion,
The direction changing part and the adjustment part constitute a flow path height reducing part in which the opening height of the flow path is smaller than the introduction side flow path,
The flow rate distribution in the direction perpendicular to the fluid flow direction in the linear flow channel for measurement is reduced by the reduction portion and the adjustment portion in the flow passage height reduction portion and the increase portion in the flow passage height enlargement portion. It is characterized by equalization and / or symmetrization.

Specifically, in these flow meters,
In the flow path height reduction part, the flow direction and the maximum flow velocity of the fluid are biased between the outer peripheral side and the inner peripheral side of the reduction part due to the centrifugal force when the fluid flows along the outer peripheral side of the direction changing part. , And aligning the flow direction by the adjustment unit,
In the flow path height enlarged portion, the cross section parallel to the fluid flow direction is suppressed while suppressing an increase in pressure loss (since it is not necessary to arrange a rectifying member such as a rectifying element) by the rectifying action in the increasing portion. Smooth the flow velocity distribution in the height direction of
In the measurement straight flow path (particularly, the flow rate measurement section), the flow velocity distribution in the height direction (flow velocity distribution in the direction orthogonal to the fluid flow direction) in the cross section orthogonal to the fluid flow direction is equalized and / or Symmetrized.

  In such a flow meter, the flow direction is biased while the fluid to be measured (for example, LP gas or city gas) flows 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 channel opening height is orthogonal to the fluid flow direction while passing through the increasing portion (flow channel height expanding portion) where the opening height of the flow channel increases and decreases stepwise in the height direction on the outer peripheral side and the inner peripheral side. The influence of the deviation of the flow velocity distribution in the direction is mitigated, equalized and / or symmetrized. In other words, a drift (a flow in which the direction and position of the maximum flow velocity is biased toward the outer periphery) generated in the direction changing section (decreasing section) is released by the flow path height expanding section (increasing section) via the adjusting section. Accordingly, the flow is corrected to a flow having a peak (maximum flow velocity) of the flow velocity distribution near the center position in the height direction (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) Since the maximum flow velocity can be measured stably, even if the viscosity (kinematic viscosity coefficient) changes with the type of fluid or temperature, fluid always flows 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 over a wide range.

  And in the decreasing part (direction changing part), 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 needs to be arranged in the flow path on the lower side in the flow direction such as the adjusting part. Therefore, the pressure loss is suppressed, and the measurement range at the flow rate measurement unit can be expanded. Moreover, since the rectifying means is not provided, the cost of the flow meter can be reduced.

  As described above, in the ultrasonic flowmeter, the measurement line of the transmission / reception vibrator is arranged at an intermediate position (for example, the central position) of the flow velocity distribution of the measurement linear flow path (flow rate measurement section). Similarly, the present invention can also be applied to a type of flow meter in which the measurement line of the measurement unit is arranged at an intermediate position (for example, the central position) of the flow velocity distribution of the measurement linear flow path. Examples of such a type of flow meter include an electromagnetic flow meter (measurement unit: measurement tube), a Pitot tube type flow meter (measurement unit: Pitot tube), and the like. Moreover, you may use for the vortex-type flow meter (measurement part: the ultrasonic transducer | vibrator provided in the downstream of a vortex generator) of an ultrasonic detection system.

In addition, in order to solve the above problems, a flow meter according to the present invention includes:
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 A flow meter including a measurement linear flow channel having a long side and a rectangular shape having a short side in the height direction and having a flow channel cross-sectional area smaller than the introduction side flow channel,
Following the outlet side end portion 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, and the direction changing unit that changes the flow of the fluid,
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 portion, at least the outer peripheral side has an increasing portion in which the opening height of the channel increases stepwise in the height direction and can be connected to the measurement linear channel. Including an enlarged portion,
In a cross section parallel to the fluid flow direction at the center in the width direction, the flow path of the direction changing portion has a first decreasing portion that decreases as it goes toward the lower side in the flow direction, and is orthogonal to the flow direction. In the cross section, the direction changing portion and the adjusting portion are adjusted by having a second decreasing portion in which the opening height of at least one flow path of the direction changing portion and the adjusting portion decreases toward the end in the width direction. The part constitutes a flow path height reduction part in which the opening height of the flow path is smaller than the introduction side flow path,
The flow direction of the fluid in the linear flow channel for measurement by the first decrease portion, the second decrease portion and the adjustment portion in the flow channel height reduction portion, and the increase portion in the flow channel height enlargement portion The flow velocity distribution in the direction orthogonal to the above is equalized and / or symmetrized.

For example, in order to solve the above-mentioned problem, when using an ultrasonic flow meter for the flow meter according to the present invention,
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 A flowmeter including a measurement linear flow path to which a transmission / reception transducer is attached, which oscillates ultrasonic waves toward the side and / or receives ultrasonic waves coming from the upper side or lower side in the flow direction,
Following the outlet side end portion 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, and the direction changing unit that changes the flow of the fluid,
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 portion, at least the outer peripheral side has an increasing portion in which the opening height of the channel increases stepwise in the height direction and can be connected to the measurement linear channel. Including an enlarged portion,
In a cross section parallel to the mounting wall surface in the center in the width direction, the flow path of the direction changing portion has a first decreasing portion that decreases as it goes toward the lower side in the fluid flow direction, and is orthogonal to the flow direction. In the cross section, the direction changing portion and the adjusting portion are adjusted by having a second decreasing portion in which the opening height of at least one flow path of the direction changing portion and the adjusting portion decreases toward the end in the width direction. The part constitutes a flow path height reduction part in which the opening height of the flow path is smaller than the introduction side flow path,
The flow direction of the fluid in the linear flow channel for measurement by the first decrease portion, the second decrease portion and the adjustment portion in the flow channel height reduction portion, and the increase portion in the flow channel height enlargement portion The flow velocity distribution in the direction orthogonal to the above is equalized and / or symmetrized.

Specifically, in these flow meters,
In the flow path height reducing portion, the flow direction and the maximum flow velocity of the fluid are changed between the outer peripheral side and the inner peripheral side of the first reducing portion by centrifugal force when the fluid flows along the outer peripheral side of the direction changing portion. The second adjusting unit prevents or suppresses the deviation by aligning the flow direction by the adjusting unit and preventing the fluid from diffusing and moving toward the end in the width direction at the first decreasing unit. ,
In the flow path height enlarged portion, the cross section parallel to the fluid flow direction is suppressed while suppressing an increase in pressure loss (since it is not necessary to arrange a rectifying member such as a rectifying element) by the rectifying action in the increasing portion. Smooth the flow velocity distribution in the height direction of
In the measurement straight flow path (especially the flow rate measurement section), the flow velocity distribution in the width direction and the height direction (flow velocity distribution in the direction orthogonal to the fluid flow direction) in the cross section orthogonal to the fluid flow direction is equalized. And / or symmetrized.

  Even in such a flow meter, the flow direction is biased while the fluid to be measured (for example, LP gas or city gas) flows 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 of fluid while passing through an increasing portion (channel height expanding portion) in which 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. The flow velocity distribution in the direction perpendicular to the 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 adjusted to the adjustment section, the second decrease section, and the flow path height expansion section (increase). (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) Since the maximum flow velocity can be measured stably, even if the viscosity (kinematic viscosity coefficient) changes with the type of fluid or temperature, it can be measured over a wide range from laminar flow (small flow) to turbulent flow (large flow). The flow rate can be measured with high accuracy.

  And the 2nd reduction part of the channel height reduction part in the above-mentioned flow meter is the opening of the channel as it goes to the inner circumference side or the outer circumference side from the middle position (for example, center position) of the height direction of the channel. The width may be formed so as to continuously decrease.

  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 shorten the length of the second reduction portion required for equalization (symmetrization) of the flow velocity distribution in the width direction, and hence the section length (length in the flow direction) of the flow path height reduction portion.

  Alternatively, the second decreasing portion of the flow path height reducing portion in the flow meter is configured such that the opening of the flow path increases from the intermediate position (for example, the center position) in the height direction of the flow path toward the inner peripheral side and the outer peripheral side. The width may be formed so as to continuously 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 flow path height reduction portion can be relatively reduced, so that the flow velocity distribution in the width direction is equalized (symmetrized). Therefore, the section length (length in the flow direction) of the second reduction portion and the flow path height reduction portion required for the above can be further shortened. 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 flowmeter described above, the inner and outer flow path wall surfaces of the adjustment unit are arranged in parallel with the wall surface of the long side wall part of the measurement linear flow channel (flow measurement section), and The center in the height direction of the flow path of the passage height expanding portion is arranged so as to be offset (offset; staggered) toward the outer peripheral side or the inner peripheral side with respect to the center of the adjustment portion in the height direction of the flow path. Can do.

  By arranging the central position in the height direction of the flow path height enlargement part on the outer peripheral side or the inner peripheral side rather than the central position in the height direction of the adjustment part, the flow velocity in the height direction at the flow path height enlarged part The maximum flow velocity to be measured in the measurement straight flow path (flow rate measurement section) after smoothing the distribution 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 flow path height enlarged portion required for equalization (symmetrization) of the flow velocity distribution in the height direction can be shortened. Whether the center position in the height direction of the flow path height expanding 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 section depends on whether the adjustment section or the flow path height expanding section is What is necessary is just to determine according to shape (height etc.). 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 is performed. 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 increased portion of the flow channel height enlarged portion has the opening height of the flow channel 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 an extension portion, thereby smoothing the flow velocity distribution in the height direction in a cross section parallel to the fluid flow direction. It is performed quickly with a short section length (length in the flow direction) at the section. 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.

  Thereby, the wall part of the inner peripheral side in the increase part, the wall part of the outer peripheral side, and the extension part are smoothly connected, and the flow of the fluid from the adjustment part to the flow path height enlargement part (increase part) is not obstructed. Therefore, the above-described flow velocity distribution in the height direction 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 part (short side wall part) and the extension part in the increasing part are smoothly connected, and the flow of fluid from the adjusting part to the flow path height expanding part (increasing part) is not obstructed. Therefore, the above-described flow velocity distribution in the height direction can be smoothly smoothed.

  Furthermore, in the flow path height reducing part, one or a plurality of partition parts that divide the opening height of the flow path in the height direction may be arranged along the flow direction.

  By dividing the opening height of the flow path of the flow path height reduction portion in the height direction, disturbance in the flow velocity distribution in the height direction (uneven and / or asymmetric) can be made relatively small. 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).

  The partition portion is arranged across the direction changing portion and the adjustment portion by a single plate material 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 toward the outer peripheral side by the adjusting 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 is likely 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.

  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 flow meter can be formed in a compact box shape. In addition, since the flow velocity distribution equalized (symmetrized) at the flow path height enlarged portion is stably maintained even in the measurement straight flow path (flow rate measurement section), the accuracy of flow rate measurement is improved.

(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 flow meter 100 (flow meter) 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. 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 FIG. 3, the linear intermediate flow path 21a (ultrasonic measurement section 21a1) has a long side L in the width direction of the flow path (the fitting direction to the main body flow cut section 15; the depth direction). Are formed in a rectangular shape having a short side S (see FIG. 2) in the height direction (vertical direction). 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 W in the flow direction, and the wall surface of the short side wall portion that forms 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 an ultrasonic beam passes. 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 transmitters 323a and 323a arranged at a predetermined distance along the flow direction are received by the pair of receivers 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
5 is a perspective view and a front view showing the first embodiment of the flow path configuration of the intermediate flow path in FIG. 2, and FIG. 6 is an enlarged view of the main part of FIG. It is explanatory drawing which shows the flow velocity distribution at the time. In the intermediate flow path 21 shown in FIG. 5, between the inlet-side connection flow path 21b (main flow path 14) and the straight intermediate flow path 21a arranged substantially orthogonally, the flow path height reducing portion 210 and The channel height enlarged portion 213 is connected and formed in this order from the upper side to the lower side in the flow direction. The flow path height reducing part 210 includes a direction changing part 211 and an adjusting part 212 from the upper side in the flow direction, and 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. Furthermore, the flow path height enlarging unit 213 has an increase unit 213a that, following the adjustment unit 212, has an opening 213a in which the flow channel opening height increases and changes stepwise in the height direction on the outer peripheral side and the inner peripheral side. The linear intermediate flow path 21a (ultrasonic measurement section 21a1) is connected. The central position O1 in the height direction of the flow path of the flow path height expanding portion 213 coincides with the central position O2 in the height direction of the flow path of the adjusting portion 212. The center position O1 of the flow path height expanding portion 213 is the center position in the height direction of the ultrasonic measurement section 21a1 (linear intermediate flow path 21a) and the line measurement position of the transmission / reception transducers 123a and 123b of the ultrasonic sensor 23. It also matches the position. 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).

  In the ultrasonic measurement section 21a1 (linear intermediate flow path 21a), the height direction in the ultrasonic measurement section 21a1 (the linear intermediate flow path 21a) is reduced by the decrease part 211a and the adjustment part 212 in the flow path height reduction part 210 and the increase part 213a in the flow path height enlargement part 213. The flow velocity distribution at is equalized and symmetrized.

  Specifically, in the flow path height reducing unit 210, the gas flow direction 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. In addition, the adjustment unit 212 adjusts the flow direction to be substantially horizontal so that the maximum flow velocity is biased. Further, in the flow path height expanding portion 213, the flow velocity distribution in the height direction is smoothed while suppressing an increase in pressure loss by rectifying action in the increasing portion 213a (since it is not necessary to arrange a rectifying member such as a rectifying element). It becomes. As a result, the flow velocity distribution in the height direction is equalized and symmetrized in the ultrasonic measurement section 21a1 (linear intermediate flow path 21a).

  Since the flow path is configured as described above, the gas flow in the flow path is as shown in FIG.

  Since the gas that has flowed into the direction changing section 211 is in the process of turning from the downward (vertical direction) inlet-side connecting flow path 21b to the horizontal (horizontal direction) linear intermediate flow path 21a, the gas is inclined downward (intermediate direction). The speed component of 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. Therefore, as shown in FIG. 6A, the flow velocity distribution at the small flow rate has a pseudo isosceles triangle shape protruding near the central position O1 in the height direction in the adjustment unit 212, but the flow path height is increased. The portion 213 becomes fan-shaped (or arc-shaped or parabolic) equalized and symmetric in the height direction relatively 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. Therefore, as shown in FIG. 6B, the flow velocity distribution at the time of a large flow rate exhibits a pseudo right triangle shape that protrudes below the center position O1 in the height direction in the adjustment unit 212. The enlarged portion 213 has a bathtub shape (or a U-shape) that is slightly delayed and equalized and symmetric in the height direction.

  In this way, while passing through the increasing portion 213a (the channel height expanding portion 213) in which the opening height of the channel increases and decreases stepwise in the height direction on the outer peripheral side and the inner peripheral side, the height direction The effect of the deviation in the flow velocity distribution at the center is alleviated and equalized and symmetrized. That is, the drift generated in the direction changing section 211 (decreasing section 211a) is opened by the flow path height expanding section 213 (increasing section 213a) via the adjusting section 212, so that the vicinity of the center position in the height direction The flow is corrected to a flow having a peak (maximum flow velocity). Therefore, the measurement lines of the pair of transmission / reception vibrators 123a and 123b are arranged at the center position O1 of the flow velocity distribution in the height direction in the flow path height expanding portion 213, and the ultrasonic measurement section 21a1 (linear intermediate flow path 21a) is provided. The maximum flow velocity of the flowing gas can be measured stably. Therefore, even if the viscosity (kinematic viscosity coefficient) changes with the type of gas and temperature, the symmetry of the gas is always secured from the laminar flow region (small flow rate) to the turbulent flow region (large flow rate), and high accuracy over a wide range. Can measure the flow rate.

  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.

(Example 2)
FIG. 7 is a 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. 7, 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 a central position O2 in the height direction of the flow path of the adjustment section 212 (matches a central position O1 in the height direction of the flow path of the flow path height expanding portion 213). The opening width W of the flow path is formed so as to continuously decrease from the center toward the inner peripheral side. And in the 2nd reduction | decrease part 212a shown in FIG. 7, the flow path wall surface is the cross section orthogonal to a flow direction, and 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. The trapezoid shape is reduced.

  In the linear intermediate flow path 21a, the first reduction part 211a, the second reduction part 212a and the adjustment part 212 in the flow path height reduction part 210 and the increase part 213a in the flow path height enlargement part 213 are combined. The flow velocity distribution in the direction orthogonal to the fluid flow direction is equalized and symmetrized.

  Specifically, in the flow path height reducing unit 210, the gas flows between the outer peripheral side and the inner peripheral side of the first reducing unit 211a by centrifugal force when the gas flows along the outer peripheral side of the direction changing unit 211. The direction of flow and the maximum flow velocity are biased so that 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 reduction portion 211a, and the flow velocity distribution in the width direction and the height direction in the cross section orthogonal to the flow direction is constricted at the center (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. 7A). Further, in the flow path height expanding portion 213, the flow velocity distribution in the height direction is smoothed while the pressure loss is suppressed by the increasing portion 213a. As a result, the flow velocity distribution in the height direction is equalized and symmetrized in the ultrasonic measurement section 21a1 (linear intermediate flow path 21a) (see FIG. 6).

  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, while passing through the increasing portion 213a (the channel height expanding portion 213) in which the opening height of the channel increases and changes stepwise in the height direction on the outer peripheral side and the inner peripheral side, The effect of uneven flow velocity distribution is mitigated and equalized and symmetrized. That is, the drift generated in the direction changing portion 211 (first decreasing portion 211a) is released by the channel height expanding portion 213 (increasing portion 213a) via the second decreasing portion 212a and the adjusting portion 212. As a result, the flow is corrected to have a flow velocity distribution peak (maximum flow velocity) near the center in the height direction. Therefore, the measurement lines of the pair of transmission / reception vibrators 123a and 123b are arranged at the center position O1 of the flow velocity distribution in the height direction in the flow path height expanding portion 213, and the ultrasonic measurement section 21a1 (linear intermediate flow path 21a) is provided. The maximum flow velocity of the flowing gas can be measured stably. Therefore, even if the viscosity (kinematic viscosity coefficient) changes with the type of gas and temperature, the symmetry of the gas is always secured from the laminar flow region (small flow rate) to the turbulent flow region (large flow rate), and high accuracy over a wide range. Can measure the flow rate.

  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 flow path height reduction part 210 is shortened.

(Example 3)
FIG. 8 is a 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. 8, the flow path wall surface is a cross section orthogonal to the flow direction, and the flow path opening width W (see FIG. 7) from the central position O2 of the adjustment section 212 toward the inner peripheral side. ) Is formed in an arc shape (or an ellipse shape) that continuously decreases.

Example 4
FIG. 9 is a perspective view and a front view showing a fourth embodiment of the flow path configuration of the intermediate flow path. In the second decreasing portion 212a shown in FIG. 9, the flow passage wall surface is a cross section orthogonal to the flow direction, and the opening width W of the flow passage is increased from the central position O2 of the adjustment portion 212 toward the inner peripheral side (see FIG. 7). ) Is formed in an isosceles triangle shape that continuously decreases.

(Example 5)
FIG. 10 is a perspective view and a main part enlarged view showing a fifth embodiment of the flow path configuration of the intermediate flow path. The second decreasing part 212a shown in FIG. 10 has an opening width W of the flow path from the central position O2 (see FIG. 5) in the height direction of the flow path of the adjustment part 212 toward the inner peripheral side and the outer peripheral side. It is formed so as to continuously decrease. At that time, the second decreasing portion 212a is formed in an asymmetric shape so that the decreasing rate of the opening width from the central position O2 toward the inner peripheral side is larger than the decreasing rate of the opening width toward the outer peripheral side. Yes.

  Specifically, on the inner peripheral side of the second reducing 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 of the adjusting portion 212 toward the inner peripheral side. ) Of the inner peripheral side reduced portion 212a1. On the other hand, on the outer peripheral side of the second reducing portion 212a, the arc-shaped (or elliptical) outer peripheral side decrease in which the opening width W of the flow path continuously decreases from the central position O2 of the adjusting unit 212 toward the outer peripheral side. A portion 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 flow path height reduction unit 210 can be relatively reduced, so that the flow velocity distribution in the width direction can be equalized (symmetrized). It is possible to further shorten the section length (the length in the flow direction) of the required second reduction portion 212a and thus the flow path height reduction portion 210.

(Example 6)
FIG. 11 is a perspective view and a main part enlarged view showing a sixth embodiment of the flow path configuration of the intermediate flow path. 11 is formed in a trapezoidal shape in which the opening width W of the flow path continuously decreases from the central position O2 (see FIG. 5) of the adjustment unit 212 toward the inner peripheral side. . 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 decreases continuously from the central position O2 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. 12 is a perspective view and a main part enlarged view showing a seventh embodiment of the flow path configuration of the intermediate flow path. The inner circumferential side decreasing portion 212a1 shown in FIG. 12 has an arc shape (or an elliptical shape) in which the opening width W of the flow path continuously decreases from the central position O2 (see FIG. 5) of the adjusting portion 212 toward the inner peripheral side. Is formed. On the other hand, the outer peripheral side decreasing portion 212a2 is formed in a trapezoidal shape in which the opening width W of the flow path continuously decreases from the central position O2 of the adjusting portion 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. 13 is a front sectional view showing an eighth embodiment of the flow path configuration of the intermediate flow path. The center position O1 in the channel height direction of the channel height expanding portion 213 shown in FIG. 13 is biased toward the outer peripheral side (offset) than the center position O2 in the channel height direction of the adjustment unit 212; Arranged).

  In this way, by arranging the central position O1 in the height direction of the flow path height expanding portion 213 more biased toward the outer peripheral side than the central position O2 in the height direction of the adjusting section 212, the flow height at the flow path height expanding portion 213 is increased. The maximum flow velocity to be measured in the straight intermediate flow path 21a after smoothing the flow velocity distribution in the height direction is likely to appear on the extension line of the height direction central position O2 of the adjustment unit 212. Therefore, the section length (length in the flow direction) of the flow path height enlarged portion 213 required for equalization (symmetrization) of the flow velocity distribution in the height direction can be shortened. In addition, 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 the extension line of the height direction central position O2 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. 14 is a front sectional view showing a ninth embodiment of the flow path configuration of the intermediate flow path. In the adjusting part 212 shown in FIG. 14, the rear end part 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 part 213a to form an extending part 212b. On the other hand, the increase portion 213a 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 213b.

  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 at the flow path height expanding portion 213. (Length in the flow direction) At the same time, the front end portion on the outer peripheral side of the increasing portion 213a rushes toward the upper side in the flow direction in the adjusting portion 212 to form the plunging portion 213b, so that the above-described centrifugal force tends to cause a gas bias. On the outer peripheral side, the gas can be partially (and temporarily) retained in the intrusion portion 213b formed in the adjustment portion 212 to delay the flow velocity, and the above-described smoothing of the flow velocity distribution in the height direction can be performed more quickly. It can be carried out.

(Example 10)
FIG. 15 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. 15 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 of the increasing portion 213a as it goes to 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 extension portion 212b is smoothly connected to the long side wall portion 21f of the increase portion 213a and does not hinder the gas flow from the adjustment portion 212 to the flow path height enlargement portion 213 (increase portion 213a). The flow velocity distribution in the vertical direction can be smoothly smoothed.

Example 11
FIG. 16 is a perspective view and a front sectional view showing an eleventh embodiment of the flow path configuration of the intermediate flow path. The extension portions 212b shown in FIG. 16 are respectively formed on the inner peripheral side and the outer peripheral side of the adjustment portion 212, and the channel wall surface of each extension portion 212b is on the inner peripheral side in the increasing portion 213a 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 extension portion 212b is smoothly connected to the short side wall portion 21d of the increase portion 213a and does not hinder the gas flow from the adjustment portion 212 to the flow path height enlargement portion 213 (increase portion 213a). The flow velocity distribution in the vertical direction can be smoothly smoothed.

Example 12
FIG. 17 is a perspective sectional view and a front sectional view showing a twelfth embodiment of the flow path configuration of the intermediate flow path. In the flow path height reduction unit 210 shown in FIG. 17, 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 unit 211 and the adjustment unit 212. It is arranged along the flow direction.

  By dividing the opening height of the flow path of the flow path height reduction unit 210 into two equal parts in the height direction, disturbances in the flow velocity distribution in the height direction (uneven and asymmetric) can be relatively reduced. 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. 18 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. 18 has a configuration in which the opening height of the flow path is divided 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 asymmetry) of the flow velocity distribution in the height direction is further reduced on the outer peripheral side where the gas bias is likely to occur due to the centrifugal force. can do.

  Each configuration described in Example 8 (FIG. 13) to Example 13 (FIG. 18) is implemented in combination with each configuration described in Example 2 (FIG. 7) to Example 7 (FIG. 12). be able to.

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 perspective view and front view which show the 1st Example of the flow path structure of the intermediate flow path in FIG. Explanatory drawing which expands the principal part of FIG.5 (b) and shows the flow-velocity distribution at the time of the small flow volume and the large flow volume. The perspective view and front view which show 2nd Example of the flow path structure of an intermediate flow path. The perspective view and front view which show the 3rd Example of the flow path structure of an intermediate flow path. The perspective view and front view which show the 4th Example of the flow path structure of an intermediate flow path. The perspective view and principal part enlarged view which show 5th Example of the flow path structure of an intermediate flow path. The perspective view and principal part enlarged view which show 6th Example of the flow path structure of an intermediate flow path. The perspective view and principal part enlarged view which show 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 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)
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 210 Flow path height reduction part 211 Direction change part 211a First reduction part (reduction part)
212 Adjustment part 212a 2nd reduction part 212a1 Inner peripheral side reduction part 212a2 Outer peripheral side reduction part 212b Extension part 213 Channel height expansion part 213a Increase part 213b Entry part 214 Partition plate (partition part)
23 Ultrasonic sensor 23a, 23b Transceiver transducer (sensor element)
100 Ultrasonic flow meter (flow meter)
L Long side S Short side H Opening height W Opening width O1 Center position in the height direction at the channel height enlarged portion O2 Center position in the height direction at the adjusting portion

Claims (14)

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 A flow meter including a measurement linear flow channel having a long side and a rectangular shape having a short side in the height direction and having a flow channel cross-sectional area smaller than the introduction side flow channel,
Following the outlet side end portion of the introduction-side channel, 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 flow direction 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 section, there is an increasing portion in which 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, and can be connected to the measurement linear flow path. Including a channel height expanding portion,
The direction changing part and the adjustment part constitute a flow path height reducing part in which the opening height of the flow path is smaller than the introduction side flow path,
The flow rate distribution in the direction perpendicular to the fluid flow direction in the linear flow channel for measurement is reduced by the reduction portion and the adjustment portion in the flow passage height reduction portion and the increase portion in the flow passage height enlargement portion. A flow meter characterized by being equalized and / or symmetrized. 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 A flowmeter including a measurement linear flow path to which a transmission / reception transducer is attached, which oscillates ultrasonic waves toward the side and / or receives ultrasonic waves coming from the upper side or lower side in the flow direction,
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 section, there is an increasing portion in which 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, and can be connected to the measurement linear flow path. Including a channel height expanding portion,
The direction changing part and the adjustment part constitute a flow path height reducing part in which the opening height of the flow path is smaller than the introduction side flow path,
The flow rate distribution in the direction perpendicular to the fluid flow direction in the linear flow channel for measurement is reduced by the reduction portion and the adjustment portion in the flow passage height reduction portion and the increase portion in the flow passage height enlargement portion. A flow meter characterized by being equalized and / or symmetrized. 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 A flow meter including a measurement linear flow channel having a long side and a rectangular shape having a short side in the height direction and having a flow channel cross-sectional area smaller than the introduction side flow channel,
Following the outlet side end portion 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, and the direction changing unit that changes the flow of the fluid,
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 portion, at least the outer peripheral side has an increasing portion in which the opening height of the channel increases stepwise in the height direction and can be connected to the measurement linear channel. Including an enlarged portion,
In a cross section parallel to the fluid flow direction at the center in the width direction, the flow path of the direction changing portion has a first decreasing portion that decreases as it goes toward the lower side in the flow direction, and is orthogonal to the flow direction. In the cross section, the direction changing portion and the adjusting portion are adjusted by having a second decreasing portion in which the opening height of at least one flow path of the direction changing portion and the adjusting portion decreases toward the end in the width direction. The part constitutes a flow path height reduction part in which the opening height of the flow path is smaller than the introduction side flow path,
The flow direction of the fluid in the linear flow channel for measurement by the first decrease portion, the second decrease portion and the adjustment portion in the flow channel height reduction portion, and the increase portion in the flow channel height enlargement portion The flow rate distribution in the direction orthogonal to the flowmeter is equalized and / or symmetrized. 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 A flowmeter including a measurement linear flow path to which a transmission / reception transducer is attached, which oscillates ultrasonic waves toward the side and / or receives ultrasonic waves coming from the upper side or lower side in the flow direction,
Following the outlet side end portion 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, and the direction changing unit that changes the flow of the fluid,
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 portion, at least the outer peripheral side has an increasing portion in which the opening height of the channel increases stepwise in the height direction and can be connected to the measurement linear channel. Including an enlarged portion,
In a cross section parallel to the mounting wall surface in the center in the width direction, the flow path of the direction changing portion has a first decreasing portion that decreases as it goes toward the lower side in the fluid flow direction, and is orthogonal to the flow direction. In the cross section, the direction changing portion and the adjusting portion are adjusted by having a second decreasing portion in which the opening height of at least one flow path of the direction changing portion and the adjusting portion decreases toward the end in the width direction. The part constitutes a flow path height reduction part in which the opening height of the flow path is smaller than the introduction side flow path,
The flow direction of the fluid in the linear flow channel for measurement by the first decrease portion, the second decrease portion and the adjustment portion in the flow channel height reduction portion, and the increase portion in the flow channel height enlargement portion The flow rate distribution in the direction orthogonal to the flowmeter is equalized and / or symmetrized.   The second decreasing portion of the flow path height reducing portion is configured so 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 flow meter according to claim 3 or 4, wherein the flow meter is formed.   The second decreasing portion of the flow path height reducing portion is configured so 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. The flow meter according to claim 3 or 4 formed in.   In the second decreasing portion, the decreasing rate of the opening width from the intermediate position in the height direction of the flow path toward the inner peripheral side is larger than the decreasing rate of the opening width toward the outer peripheral side. The flow meter described. 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 flow path height expanding portion is arranged 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 adjustment portion. 8. The flow meter according to any one of 7 above. The increased portion of the flow path height expanding portion is configured such that 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,
9. 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 flow meter according to claim 1.   The flow path wall surface of the extension part is formed in a curved surface shape that gradually contacts the wall surface on the inner peripheral side and / or outer peripheral side in the increasing part as it goes toward the lower side in the flow direction. The flow meter described in 1.   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. Flowmeter.   The one or more partition parts which divide | segment the opening height of a flow path into a height direction are arrange | positioned in the said flow path height reduction part along the flow direction. The flow meter described.   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 13. The flow meter according to Item 12. The introduction side channel and the measurement linear channel are arranged orthogonally,
The flowmeter according to any one of claims 1 to 13, 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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