JP2000241205A - Fluid vibration type flow meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To raise the measuring accuracy of a fluid vibration type flow meter over a side range. SOLUTION: At the upstream of a nozzle 9 of a fluidic element a fluid entrance 1 is provided which has a channel 2 for measuring a low flow rate having a smaller area than the flow cross sectional area of the nozzle 9, the channel 2 has an opening having a rectangular section with the opening with greater than the opening height, the flow cross section of the channel 2 is formed between it and the side wall of the nozzle 9 at one end of the opening height, the opening width of the channel 2 is set less than the opening height of the nozzle 9 and disposed at a passage in the channel 2 to provide a detection end 6a of a flow sensor 6 capable of measuring the fluid flow rate, and a plurality of straightening passages 3 are formed between the channel 2 of the entrance 1 and a wall at the other end of the opening height of the nozzle 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid vibration type flow meter, mainly a gas meter for measuring a fluid flow rate using a fluidic element.

[0002]

2. Description of the Related Art Conventionally, in a fluid vibration type flow meter, a fluid element does not oscillate or oscillates in a small flow rate region, making it difficult to measure a small flow rate. To compensate for this, a device provided with a thermal flow sensor is used. In such a fluid vibration type flow meter, the flow sensor is disposed on one inner wall surface in the height direction in the flow path of the nozzle forming the jet of the fluidic element. And the lower limit flow rate in the micro flow rate area could not be reduced sufficiently. This is because the cross section of the nozzle cut at right angles to the flow direction of the nozzle is a rectangle having a large aspect ratio. For example, the ratio of the length of the long side of the cross section of the nozzle (that is, the opening length of the nozzle) to the length of the short side (that is, the opening width of the nozzle) is about 10. As described above, the distribution of the flow velocity along the inner wall surface of the nozzle, which is the long side of the flow path cross section of the nozzle having a large aspect ratio, and the distribution of the flow velocity along the side walls at both ends in the height direction of the nozzle, which is the short side, are different. Since the maximum flow velocity along the short side is extremely lower than the maximum flow velocity along the side, the problem is that the detection level of the flow velocity that can be detected at the side wall on the short side is extremely low.

As a countermeasure to solve this problem, FIG. 9 shows a cross section of the nozzle forming section 7 orthogonal to the flow direction.
At one end in the height direction of the nozzle 9, the nozzle inner wall surface 9a
It has been proposed to provide an enlarged flow path portion 9c in which a recess is formed in the groove to increase the flow path width (see JP-A-4-326016). As a countermeasure against the fact that the width of the flow rate detecting end 6a of the flow sensor 6 occupies more than half of the opening width of the nozzle 9, the enlarged flow path portion 9c is provided on the side wall surface on the one end side. 6a are arranged facing the flow channel, and arcuate surfaces are formed at the ends of the opposed nozzle inner wall surfaces 9a, respectively, so that the opening width is about twice the nozzle opening width at the one end. is there.

[0004]

In the above-mentioned conventional structure, as shown in FIG. 9, there is a problem in that the nozzle inner wall surface 9a is not flat over the entire height. That is, the oscillation of the fluid vibration may be hindered due to the uneven width of the jet of the fluid ejected from the nozzle ejection surface 9b. As a result, the fluid oscillation becomes unstable, especially in a low flow rate range, causing a problem of increasing the lower limit of the flow rate measurement range.

Accordingly, an object of the present invention is to improve the measurement accuracy of a fluid vibration type flow meter over a wide range.

[0006]

According to a first aspect of the present invention, there is provided a fluid vibration type flow meter according to the first aspect of the present invention, in which a fluid is introduced upstream of a nozzle of a fluidic element. A small flow rate measuring flow path section for measuring a small flow rate having a smaller cross-sectional area than the flow path cross-sectional area of the nozzle section is formed in the fluid introduction section, and the flow rate of the fine flow rate measuring flow path section is reduced. The cross section of the passage is a rectangular cross section in which the opening height direction is narrowed with respect to the opening width direction, and is formed between the nozzle portion and the one end side wall in the opening height direction of the nozzle portion. The opening width is wider than the opening width of the nozzle portion, the opening height of the minute flow rate measurement flow path portion is set smaller than the opening height of the nozzle portion, and the fluid flow rate in the minute flow rate measurement flow path portion is set. The detection end of the flow sensor that can be measured is A channel is provided so as to face the path, and between the micro flow rate measurement flow path section of the fluid introduction section and the wall on the other end side in the opening height direction of the nozzle section, over the opening height direction of the nozzle section. Thus, a plurality of rectifying flow passage portions are formed.

According to a second aspect of the fluid vibration type flowmeter of the present invention, a flow rate measurement flow path portion and an opening of a nozzle portion are formed to form the rectification flow path portion of the first characteristic configuration. Between the wall on the other end side in the height direction, a slit-shaped flow path formed in the opening height direction of the nozzle section is provided, arranged coaxially with the nozzle, and the slit-shaped flow path section The point is that a partition wall portion is formed between the micro flow rate measurement flow path portion and the micro flow rate measurement flow path portion so as to separate them in the opening height direction of the nozzle portion.

According to a third aspect of the fluid vibration type flowmeter of the present invention, the slit-shaped flow path in the second characteristic configuration is formed by opposing the slit-shaped flow path. The surface is a flat portion formed in parallel with a predetermined opening width on the outlet side of the slit-shaped flow channel portion, and the opposed portion in a flat cross section viewed from the height direction, from the upstream end surface of the fluid introduction portion to the flat portion. The point is that the outline of the surface is formed by the introduction curved surface portion formed by a smoothly continuous curve.

According to a fourth aspect of the fluid vibration type flowmeter of the present invention, the length of the flat portion in the flow path direction in the third aspect is set to 1 mm or more and 4 mm or less. It is in.

According to a fifth aspect of the fluid vibration type flow meter according to the present invention, a rectifying flow path in any of the second to fourth aspects is formed by forming a rectifying flow path portion. The point is that a horizontal partition plate part for dividing the slit-shaped flow path part in the opening height direction is provided.

[Function and Effect of Characteristic Configuration] According to the first characteristic configuration of the fluid vibration type flow meter according to the present invention, the measurement range can be expanded while the measurement accuracy of the fluid vibration type flow meter is stabilized. Become like That is, a fluid introduction portion is provided upstream of the nozzle portion of the fluidic element, and the small flow rate measurement flow channel portion for measuring a small flow rate having a smaller cross-sectional area than the flow channel cross-sectional area of the nozzle portion is provided with the fluid introduction portion. Formed in the introduction,
The flow path cross section of the minute flow rate measurement flow path section is a rectangular cross section in which the opening height direction is narrowed with respect to the opening width direction, and is formed between the nozzle section and one side wall in the opening height direction. Setting the opening width of the minute flow rate measurement flow path portion to be wider than the opening width of the nozzle portion, and setting the opening height of the minute flow rate measurement flow path portion to be smaller than the opening height of the nozzle portion; Since the detection end of the flow sensor capable of measuring the fluid flow rate in the flow rate measurement flow path portion is provided facing the flow path in the minute flow rate measurement flow rate flow section, oscillation of fluid vibration in the fluidic element is not caused. While it is possible to accurately measure the fluid flow rate even in the minute flow rate region to be sure, between the minute flow rate measurement flow path portion of the fluid introduction portion and the wall on the other end side in the opening height direction of the nozzle portion, A plurality of nozzles are arranged in the opening height direction of the nozzle portion. By is formed with Nagareryu path portion, it becomes possible to prevent the flow of fluid flowing into the nozzle from the rectifying passage portion is disturbed. Therefore, oscillation of fluid vibration in the fluidic element can be stabilized.
As a result, the measurement accuracy of the fluid vibration type flow meter can be stabilized while improving the sensitivity in the minute flow rate range.

According to the second characteristic configuration of the fluid vibration type flow meter according to the present invention, it is possible to further increase the measurement accuracy of the fluid vibration type flow meter while exhibiting the operation and effect of the first characteristic configuration. Become. That is, a slit-shaped flow path formed in the opening height direction of the nozzle portion is provided between the minute flow rate measurement flow path portion and the wall portion on the other end side in the opening height direction of the nozzle portion, By forming a rectifying flow path portion coaxially with the slit flow path portion, while smoothing the flow unevenness in the direction along the slit flow path portion, between the slit flow path portion and the minute flow rate measurement flow path portion Since the partition walls are formed to separate them in the direction of the opening height of the nozzle, the cross-sectional shape of the micro flow rate measurement flow channel can be made rectangular,
By increasing the flow velocity of the flow in contact with the detection end of the flow sensor disposed there, it becomes possible to increase the sensitivity. Therefore, it becomes possible to improve the flow rate measurement accuracy in the minute flow rate range.

According to the third aspect of the fluid vibration type flowmeter according to the present invention, the measurement accuracy of the fluid oscillation type flowmeter can be maintained at a higher level while the operation and effect of the second aspect are exhibited. Become. In other words, the opposing surface forming the slit-shaped flow channel portion, a flat portion formed in parallel with the outlet side of the slit flow channel portion with a predetermined opening width, from the upstream end face of the fluid introduction portion to the flat portion, Since the outline of the facing surface in the plane cross section viewed from the height direction is formed by the introduction curved surface portion formed by a smoothly continuous curve, the turbulence generated in the flow of the fluid in the slit flow path portion Can be suppressed. Therefore, since the turbulence of the fluid ejected into the fluidic element can be reduced, the fluid vibration in the fluidic element can be stabilized. As a result, the measurement accuracy of the fluid flow rate can be maintained high even in a low flow rate range.

According to the fourth aspect of the fluid vibration type flowmeter according to the present invention, the operation and effect of the third aspect are further ensured. In other words, the length of the plane portion in the channel direction is
By being set to 1 mm or more and 4 mm or less, it is possible to maintain a high rectification effect while reducing the pressure loss in the fluid introduction part. When the length of the flat portion in the flow direction exceeds 4 mm, the pressure loss increases, and the inflow pressure of the fluid at the nozzle inlet of the fluidic element decreases,
There is a possibility that the effect of improving the fluid vibration may be impaired, and when the length of the flat portion in the flow direction is less than 1 mm,
By causing the fluid flowing out of the flat portion to be scattered, there is a possibility that the rectification effect may be easily lost, or the pressure loss due to the scattered flow may be increased.

According to the fifth aspect of the fluid vibration type flowmeter according to the present invention, the measurement of the fluid oscillation type flowmeter can be achieved while the operation and effect of any of the second to fourth aspects are achieved. Accuracy can be maintained even higher. In other words, by providing a rectifying flow channel portion by providing a horizontal partition plate portion that divides the slit-shaped flow channel portion in the opening height direction of the nozzle portion, a plurality of rectifying channels are formed in the height direction of the nozzle portion. Since it is formed and arranged, the flow of the fluid from the slit-shaped flow path portion,
It is possible to level the height of the nozzle portion. Therefore, the fluid vibration in the fluidic element can be stabilized. As a result, the measurement accuracy of the fluid flow rate can be maintained even higher in the low flow rate range.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a fluid vibration type flow meter according to the present invention will be described. FIG. 1 is a plan sectional view showing an example of a gas meter using the fluid vibration type flow meter according to the present invention, FIG. 2 is a plan view sectional view of the fluid vibration type flow meter shown in FIG. 1, and FIG. FIG. 4 is a partially cutaway perspective view of the nozzle forming portion, FIG. 4 is a plan sectional view of the rectifying channel portion, and FIG. 5 is a perspective view of the fluid introducing portion as viewed from the fluid inflow side. 9 that are the same as or similar to the elements in FIG. 9 used in the above-described conventional technique are denoted by the same or related reference numerals as those in FIG. 9 and described in detail. Is partially omitted.

A gas meter which is an example of the above-mentioned fluid vibration type flow meter is a No. 6 meter, and as shown in FIG. 1, a fluid vibration type flow meter according to the present invention which measures a flow rate using a fluidic element 8. 26. The gas meter 20 is configured such that the inflow direction I of the fluid f to be measured is 180 ° opposite to the outflow direction O. That is, the fluid f such as gas and water flows from the apparatus inlet 21 and reaches the shutoff valve section 23 through the bent path 22 provided with the pressure fluctuation absorbing mechanism 25. Then, the fluid f having passed through the shutoff valve portion 23 flows into the storage portion 24. This storage part 2
4 flows into the fluid vibration type flow meter 26
Through the device outlet 27. The fluid f flowing into the fluid vibration type flow meter 26 passes through the fluid introduction section 1 provided in the nozzle forming section 7 forming the nozzle 9 of the fluidic element 8, and the fluid introduction path 7a.
From the nozzle 9. The fluid f ejected from the nozzle 9 into the fluidic element 8 changes its jet direction and vibrates, while its nozzle ejection surface 9 b
The fluid flows out toward the device outlet 27 via the flow channel expanding portion 13 and the throttle flow channel portion 14 provided further downstream. In the fluid vibration type flow meter 26, a pair of fluid vibration detection ends 10 for detecting the vibration of the jet flow are arranged on both sides of the nozzle 9 and near the nozzle ejection surface 9b. The fluid vibration detecting end 10 is an opening formed with a small diameter, and communicates with a fluid vibration detecting sensor having a pair of pressure introducing portions to detect fluid vibration.

As shown in FIG. 2, for example, the shape of the fluidic element 8 is such that the flow channel enlarging portion 13 is formed between the expanded flow channel forming members 12 arranged with the flow channel axis Z as a symmetric axis. A target 11 is provided at the center of the flow path of the flow path enlargement section 13 to prevent the jet flowing from the nozzle 9 from going straight, and the throttle flow path section 1 is provided downstream of the flow path enlargement section 13.
4 are provided. The nozzle 9 is formed such that both inner side surfaces in the nozzle width direction are formed by a nozzle inner wall surface 9a parallel to the flow channel axis Z, and the nozzle ejection surface 9b is orthogonal to the flow channel axis Z. I have. The enlarged flow path forming member 1
2 has a center on a parallel straight line that is spaced a predetermined distance downstream from the nozzle ejection surface 9b and is spaced from the flow channel axis Z by an equal distance. A circular arc portion 12a formed by a pair of circular arcs having an outer surface and contacting the outside of the circular arc, and forming the flow path axis Z on the nozzle ejection surface 9b side.
And a straight line portion 12b formed by a tangent line approaching. At the rear end of the arc portion 12a, a discharge arc portion 12c is formed to smoothly connect the arc portion 12a to the throttle channel portion 14. The target 11 is arranged at a position separated by a predetermined distance from the nozzle ejection surface 9b, and has an effect of stably causing the flow direction of the jet flow to be switched within the flow rate measurement range. By the way, in the flow rate region on the small flow rate side, the fluid f of the return flow tends to accumulate in the vicinity of the nozzle ejection surface 9b in response to the ejection from the nozzle 9 of the fluidic element 8, which hinders the fluid oscillation. In order to avoid this, the enlarged flow path forming member 12 is separated from the nozzle ejection surface 9b,
A relief path 15 is formed on the back side of the enlarged flow path forming member 12, and the return flow is branched near the nozzle ejection surface 9b, and a part of the return flow flows out of the relief path 15 as a branch flow. Let it be done.

In the fluidic element 8, the jet flow jetted from the nozzle jetting surface 9b bypasses the side of the target 11 and flows out of the throttle flow path portion 14 and branches off from the main jet flow. It collides with a downstream portion of the flow channel expanding portion 13 or a reduced cross-sectional portion forming the throttle flow channel portion 14, and returns inside the flow channel to the nozzle 9 along the inner surface of the expanded flow channel forming member 12. When the return flow flows back toward the nozzle ejection surface 9b, the return flow is near the nozzle ejection surface 9b in a direction orthogonal to the straight flow direction of the jet and opposite to the direction in which the jet flows. A directional fluid energy component is imparted, causing the jet to swing in the opposite direction. By repeating this, fluid oscillation occurs, and the oscillation cycle is inversely proportional to the fluid flow rate. Then, since the pressure difference between the pair of fluid vibration detection ends 10 arranged near the nozzle ejection surface 9b is proportional to the square of the flow velocity of the jet, the fluid vibration is measured by the capacitance type pressure vibration sensor. By detecting and measuring the frequency, an attempt is made to measure the flow rate of the fluid f flowing through this flow path.

As shown in FIG. 3 in which the nozzle forming portion 7 is viewed obliquely from the nozzle inner wall surface 9a side, the fluid introducing portion 1 is provided in the fluid introducing passage 7a located on the upstream side of the nozzle forming portion 7.
(In the figure, as shown, a part of the side wall of the nozzle forming portion 7 is cut away.). The fluid introduction unit 1 measures the flow rate of a fluid having a smaller cross-sectional area than the flow path cross-sectional area of the nozzle 9 in a minute flow rate region where the oscillation of the fluid vibration in the fluidic element 8 becomes unstable. Is formed between the minute flow rate measuring flow path 2 and the wall on the other end side in the opening height direction of the nozzle 9 in the direction of the opening height of the nozzle 9. A slit-shaped flow path portion 3A is formed across the slit-shaped flow path portion 3A, and the slit-shaped flow path portion 3A is divided to form a plurality of rectification flow path portions 3. As shown in FIG. 4, a partition wall 5 is formed between the nozzles 9 to separate them in the height direction of the opening of the nozzle 9.

The flow rate sensor 6 capable of measuring the flow rate of the fluid flowing in the minute flow rate measurement flow path section 2 in the minute flow rate range is provided in the minute flow rate measurement flow path section 2. The flow detection end 6a of the flow sensor 6 is arranged on the side wall surface of the minute flow rate measurement flow path unit 2 in the height direction so as to face the flow path. The outlet opening width (Ws) of the micro flow rate measurement flow path section 2 is
The outlet opening width (Wn) of the nozzle 9, which is the opening width of the nozzle 9, is set to be smaller than the opening height of the nozzle 9. The dimensional relationship between the opening width (Ws) of the minute flow rate measurement flow path unit 2 and the outlet opening width (Wn) of the nozzle 9 is set so as to satisfy 2.2 ≦ Ws / Wn ≦ 2.8. I have. Regarding this dimensional relationship, if Ws <Wn × 2.2, the maximum flow velocity near the wall surface where the flow detection end 6a of the flow sensor 6 is arranged may not be sufficiently obtained, and the flow detection sensitivity in a very small flow rate region may be obtained. In some cases, Ws> Wn × 2.8, so that the width of the nozzle forming portion 7 becomes too large and the size of the fluid vibration type flow meter 26 can be reduced. It may not be very desirable from a viewpoint.

The rectifying flow path 3 is formed by arranging a slit flow path 3A formed in the direction of the height of the opening of the nozzle 9 coaxially with the nozzle 9. The opposed surface 4 forming the portion 3A is separated from an outlet flat portion 4a formed in parallel with a predetermined opening width on the outlet side of the slit-shaped flow channel portion 3A, and from the upstream end surface 1a of the fluid introduction portion 1 to the outlet flat surface. The portion 4a is formed by an introduction curved surface portion 4b in which a contour of the facing surface 4 in a flat cross section viewed from the height direction is formed by a smoothly continuous curve. Then, the length of the outlet flat portion 4a in the flow path direction is set to 1 mm or more and 4 m.
m or less. If the length in the direction of the flow path is less than 1 mm, the flow of the fluid flowing out of the outlet flat surface portion 4a is caused to occur, so that the rectifying effect is easily impaired or the pressure loss due to the flow is increased. If it exceeds 4 mm, the pressure loss increases, and if the pressure loss increases, the inflow pressure of the fluid at the nozzle inlet of the fluidic element decreases, which may impair the effect of improving the fluid vibration. It is not preferable. In addition, the rectifying flow path section 3 is configured such that the horizontal partition plate section 3b that divides the slit flow path section 3A in the opening height direction of the nozzle 9 has the same length as the fluid introduction section 1 in the flow direction direction. It is formed to have a length in the flow channel direction (for example, see FIG. 5).

The fluidic element 8 including the nozzle 9 and the fluid introducing section 1 described above are made of synthetic resin. This makes use of the point that the dimensional change due to the use temperature is small, and is selected based on the shape and the number of products manufactured. In particular, the fluid introduction part 1 is precisely machined out by machining. This is because it is difficult and the mold for molding is easier to manufacture.

FIG. 5 is a perspective view of the fluid introducing portion 1. In this example, one vertical partition plate portion 3a and 4
A plurality of horizontal partition plates 3b are provided so that
This is an example of division. In the fluid introduction path 7a in which the fluid introduction unit 1 configured as described above is arranged, the flow velocity distribution of the fluid f at the flow path outlet of the fluid introduction unit 1 is:
For example, the length of the arrow is shown in FIG. That is, the maximum flow velocity in the flow velocity distribution of the fluid f in the direction of the opening width of the nozzle 9 along the wall on one end side in the direction of the opening height of the nozzle 9 in the minute flow rate measurement flow path section 2 becomes the highest. Further, the flow velocity distribution of the fluid f in the opening height direction of the nozzle 9 is substantially the same in each of the flow paths into which the minute flow rate measurement flow path section 2 and the rectification flow path section 3 are divided. As a result, the flow rate distribution of the fluid f is substantially uniform over the entire area in the height direction of the nozzle 9 as a result of being equalized in the fluid introduction path 7 a up to the nozzle 9. Oscillation of the fluid vibration is performed smoothly.

When the city gas 13A is measured by the No. 6 meter, the horizontal partition plate portion 3b
It is most effective when six to six sheets are provided, and among them, five sheets are more preferable. FIG. 3A shows the horizontal partition plate portion 3.
The measurement error of the fluidic element 8 when four b are provided is shown as an instrumental error, and FIG.
(C) shows the instrumental difference when the six horizontal partition plate portions 3b are provided.
Note that the left side of the vertical line at the left end in each figure, that is, the minute flow rate range is measured by the flow sensor 6, and therefore does not need to be within the allowable range of the small flow rate range. The horizontal partition plate portion 3b not only functions as a partition wall in the opening height direction of the slit flow path portion 3A described above, but also connects between the opposing surfaces 4 of the slit flow path portion 3A. It also serves as a reinforcing rib.

[Another Embodiment] <1> In the above embodiment, the fluid vibration type flow meter 2
As an example of No. 6, the gas meter 20 of No. 6 has been described, but the fluid vibration type flow meter according to the present invention is not limited to the above example, and fluidic elements such as gas meters of other sizes, flow meters having different target fluids, and the like. The present invention can be applied to any fluid vibration type flowmeter using the above, and has the above-described effects. The structure of the fluidic element is not limited to the one shown in the drawing, and any fluidic element structure such as one not having the throttle channel portion 14 and one having no escape path 15 can be adopted. <2> In the above embodiment, the plurality of rectification flow path sections 3
Although the example in which the slit-shaped flow path portion 3A is formed and divided has been described, the rectification flow path portion 3 may have another form, for example, an arrangement in which through holes are arranged as shown in FIG. It may be. As shown in FIG. 2A, a plurality of through holes 3B may be arranged in a row in the opening height direction of the nozzle 9 on the other end side with respect to the minute flow rate measurement flow path unit 2. Further, as shown in FIG.
In the direction of the opening height of the nozzle 9,
May be arranged in a plurality of rows on the other end side. In the illustrated example, a square hole (in the illustrated example, a corner is chamfered) or a round hole is shown, but a polygonal through hole may be used, and a curved surface such as an ellipse, an ellipse, or the like may be used. It may be a through hole formed by combining a curved surface and a flat surface. It is more preferable that an introduction curved surface portion is formed on the upstream side of the rectification flow path portion 3. <3> In the above embodiment, the horizontal partition plate 3b is
The example in which the fluid introduction portion 1 is formed to have the same length in the flow direction as the length in the flow direction has been described, but the horizontal partition plate portion 3b has been described.
May be formed to have the same length in the flow direction as the vertical partition plate portion 3a, and may be formed between the length in the flow direction of the fluid introduction portion 1 and the length in the flow direction of the vertical partition plate portion 3a. May be formed in the length in the channel direction. <4> In the above embodiment, the fluid introduction unit 1 is described as being made of a synthetic resin, but this may be made of another material, or may be made of die-cast aluminum. It may be another precision casting, or a metal material formed by casting or forging. In addition, if it does not mind cost, a thing made of fine ceramics is preferred for improvement of accuracy. <5> In the above embodiment, the horizontal partition plate portion 3a is
Although it has been described that it is preferable to provide one to six sheets, more horizontal partition plates 3a may be formed. If the opening height of the slit-shaped flow path portion 3A is sufficient and an appropriate interval can be provided, the number of sheets may be increased.

[Brief description of the drawings]

FIG. 1 is a cross-sectional plan view showing an example of a gas meter according to the present invention.

FIG. 2 is a cross-sectional plan view illustrating a specific configuration of the fluid vibration type flow meter shown in FIG.

FIG. 3 is a partially cutaway perspective view of a nozzle forming portion illustrating an example of a configuration according to the present invention.

FIG. 4 is a cross-sectional plan view for explaining the dimensional relationship of the rectifying flow path according to the present invention.

FIG. 5 is a perspective view of a fluid introduction unit showing an example of a flow regulating channel unit according to the present invention.

FIG. 6 is a perspective view of a fluid introduction unit for explaining the effect of the embodiment of the present invention.

FIG. 7 is a diagram illustrating the effect of the embodiment of the present invention.

FIG. 8 is a perspective view of a fluid introduction part showing another example of the rectifying flow path part according to the present invention.

FIG. 9 is a vertical cross-sectional view of a nozzle for explaining the arrangement of a conventional flow sensor in a front view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fluid introduction part 1a Upstream end face of a fluid introduction part 2 Micro flow rate measurement flow path part 3 Rectification flow path part 3A Slit-shaped flow path part 3b Horizontal partition plate part 4 Opposing surface 4a Exit plane part 4b Introduction curved surface part 5 Partition wall part Reference Signs List 6 Flow sensor 6a Flow detecting end 8 Fluidic element 9 Nozzle Ws Opening width of micro flow rate measuring flow passage Wn Exit opening width of nozzle

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Makoto Okabayashi 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Inside Osaka Gas Co., Ltd. (72) Shuichi Okada 4-chome, Hirano-cho, Chuo-ku, Osaka-shi, Osaka No. 1-2 Inside Osaka Gas Co., Ltd. (72) Inventor Eiji Nakamura 2-10-16 Higashi Kobashi, Higashi-Nari-ku, Osaka-shi, Osaka Inside Kansai Gas Meter Co., Ltd. (72) Inventor Masanobu Namimoto Higashi-Nari-ku, Osaka-shi, Osaka 2-10-16 Kobashi Kansai Gas Meter Co., Ltd. (72) Inventor Kazuichi Tomoda 4-7-131 Nishiiwata, Higashiosaka-shi, Osaka Inside Kinmon Manufacturing Co., Ltd. (72) Inventor Takuya Tadokoro Higashiosaka, Osaka 4-7-31, Nishi-Iwata-shi F-term (reference) in Kinmon Manufacturing Co., Ltd. 2F030 CA05 CA10 CC13 CD13 CE04 CF01 CF05 CF11

Claims (5)

[Claims] 1. A fluid introduction section is provided upstream of a nozzle of a fluidic element, and a small flow rate measurement flow path section for measuring a small flow rate having a smaller sectional area than the flow path sectional area of the nozzle is provided. Formed in the fluid introduction part, the flow path cross section of the micro flow rate measurement flow path part, in a rectangular cross-section where the opening height direction is narrowed with respect to the opening width direction, one end side in the opening height direction of the nozzle part While being formed between the side wall, the opening width of the minute flow rate measurement flow path is wider than the opening width of the nozzle, and the opening height of the minute flow rate measurement flow path is smaller than the opening height of the nozzle. Setting, a detection end of a flow sensor capable of measuring a fluid flow rate in the micro flow rate measurement flow path section is provided facing a flow path in the micro flow rate measurement flow path section, and the micro flow rate measurement of the fluid introduction section is provided. A wall on the other end side in the opening height direction of the flow path portion and the nozzle portion Fluidic oscillator flow meter that is formed with a plurality of rectifying channel portion over, the opening height direction of the nozzle between. 2. The method according to claim 1, further comprising: forming the rectification flow path between the minute flow rate measurement flow path and a wall on the other end of the nozzle in the opening height direction. Providing the formed slit-shaped flow channel portion, and disposed coaxially with the nozzle, separating the slit-shaped flow channel portion and the minute flow rate measurement flow channel portion in the opening height direction of the nozzle 2. The fluid vibration type flow meter according to claim 1, wherein a partition wall portion is formed. 3. A flat surface in which the slit-shaped flow path portion is formed such that an opposite surface forming the slit-shaped flow path portion is formed in parallel with a predetermined opening width to an exit side of the slit-shaped flow path portion. Part, from the upstream end face of the fluid introduction part to the plane part, formed by an introduction curved surface part in which the outline of the facing surface in a flat cross section viewed from the height direction is formed by a smoothly continuous curve. 3. The fluid vibration type flow meter according to claim 2, wherein: 4. The length of the flat portion in the flow path direction is 1 mm.
4. The fluid vibration type flow meter according to claim 3, wherein the flow rate is set to not less than 4 mm. 5. A horizontal partition plate portion for dividing the slit-shaped flow passage portion in a direction of an opening height of the nozzle portion to form the rectification flow passage portion. The fluid vibration type flow meter according to item 6.