JPH0593636A - Fluid flow meter - Google Patents

Abstract

PURPOSE:To obtain a flowmeter which can suppress adverse effects on the performance of a fluidic element can improve the measuring sensitivity of a flow-speed sensor and can perform accurate measurement in a region. CONSTITUTION:A plurality of partition plates 29 are arranged in a jetting nozzle 28 with a specified interval being provided. Of these partition plates 29, the interval between the uppermost partition plate 29U and the upper surface of the jetting nozzle 28 and the interval between the lowermost partition plate 29L and the lower surface of the jetting nozzle 28 are made larger than the interval between the partition plates 29. Furthermore, at the rear-edge parts of the partition plates 29 located at the input side of the jetting nozzle 28 and at the leading-edge parts of the partition plates 29 located at the output side of the jetting nozzle 28, tapered parts 30a, 30b, 30c, 31a, 31b and 31c are formed. The thickness each tapered part becomes gradually thin toward the edge part. The fluid passing the jetting nozzle 28 is dispersed in the upper and lower directions through the partition plates 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidic flow meter which detects an alternating pressure wave generated by an oscillating phenomenon of a fluid such as a gas ejected from an ejection nozzle into a flow passage to detect a flow rate.

[0002]

2. Description of the Related Art A fluidic flow meter for measuring the flow rate of gas, which is installed in a general household or the like, is disclosed in, for example, Japanese Patent Laid-Open No.
It is known from JP-A-313018 and JP-A-1-250725.

In this fluidic flow meter, a jet nozzle is provided on a partition wall that divides the flow passage into an upstream flow passage and a downstream flow passage, and a fluidic element provided in the downstream flow passage from the jet nozzle. When the fluid is ejected, the ejected fluid flows along the side wall on the right side, for example, due to the Coanda effect.

A part of the fluid flowing to the right side wall becomes a return fluid, the fluid energy of the return fluid is applied to the jet fluid, and the jet fluid comes to flow along the left side wall. A part of the fluid flowing on the side wall becomes a return fluid, the fluid energy of the return fluid is applied to the jet fluid, and the jet fluid again flows along the right side wall.

That is, an alternating pressure wave is generated by the vibration phenomenon of the fluid ejected from the ejection nozzle into the flow path. This alternating pressure wave is detected by the piezoelectric film sensor, the flow rate is calculated from this frequency, and the flow rate of the fluid is detected.

[0006]

By the way, in the fluidic flow meter, the fluid flowing from the inlet of the case body is guided to the ejection nozzle via the upstream side flow passage, and the fluid ejected from the ejection nozzle is Although it flows into the fluidic element, the sensitivity of the flow velocity sensor is poor in the minute flow rate range,
Highly accurate measurement is not possible.

Therefore, a plurality of partition plates are provided at equal intervals inside the ejection nozzle to prevent the fluid flowing from the upstream flow passage to the downstream flow passage from concentrating in the central portion of the ejection nozzle. Dividing is performed by a plate.

When the partition plate is provided on the jet nozzle as described above, the sensitivity of the flow velocity sensor can be increased to some extent, but since the end of the partition plate is at right angles to the flow direction of the fluid, the fluid flows through the partition plate. A vortex is generated at the end, causing turbulence. Therefore, there is a problem that the performance of the fluidic element deteriorates and accurate measurement cannot be performed.

The present invention has been made in view of the above circumstances, and an object thereof is to suppress an adverse effect on the performance of the fluidic element, improve the measurement sensitivity of the flow velocity sensor, and reduce the flow rate range. It is to provide a fluidic flow meter that can perform accurate measurement even in.

[0010]

In order to achieve the above-mentioned object, the present invention provides a flow passage main body which constitutes a flow passage with a partition wall to form an upstream flow passage and a downstream flow passage. The partition wall is provided with jet nozzles for jetting the fluid of the upstream flow passage to the downstream flow passage, and a plurality of partition plates are provided inside the jet nozzle in parallel with the bottom surface of the flow passage body and at predetermined intervals. Among these partition plates, the distance between the uppermost partition plate and the upper surface of the ejection nozzle and the distance between the lowermost partition plate and the lower surface of the ejection nozzle are set between the partition plates. It is characterized in that it is larger than the interval.

According to a second aspect of the present invention, one end portion of the partition plate located on the inlet side of the jet nozzle and the other end portion of the partition plate located on the outlet side of the jet nozzle are provided with tapered portions gradually thinned toward the end portions. It is characterized by being formed.

According to a third aspect of the present invention, the taper portion at the distal end of the partition plate is a taper that is gradually inclined toward the end toward the central portion of the ejection nozzle, and the fluid passing through the ejection nozzle is dispersed above and below the ejection nozzle. The taper portion at the other end of the partition plate is a taper that is gradually inclined toward the upper and lower parts of the ejection nozzle toward the end, and vertically distributes the fluid ejected from the ejection nozzle. According to a fourth aspect of the present invention, the tapered portion of the partition plate is a straight or curved taper formed by chamfering.

[0013]

The fluid flowing from the upstream flow passage to the downstream flow passage through the ejection nozzle is diverted by the partition plate provided inside the ejection nozzle, and the fluid flows to the lower portion of the ejection nozzle having the flow velocity sensor. Is concentrated and circulates toward the fluidic element, and the sensitivity of the flow velocity sensor increases, and accurate measurement can be performed even with a minute flow rate.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

3 and 4 show the entire fluidic flow meter, and 11 is a case. This case 1
Reference numeral 1 denotes a rectangular box-shaped case body 12 and the case body 12
And a lid 13 that closes the opening.

A gas inlet body 1 is provided on the upper portion of the case body 12.
4 is provided, and the gas outlet body 15 is provided in the lower part. A fluidic element 17, which will be described later, is installed in the lower part inside the case 11, and a shutoff valve 18 is installed in the upper part.

The fluidic element 17 will be described. Reference numeral 19 is a flow path body formed by die casting or the like. The opening of the flow path body 19 is packed 2
The flow path 22 is formed by closing the cover body 21 through 0. The channel 22 is partitioned by a partition wall 23, the upstream channel 24 communicates with the gas inlet body 14, and the downstream channel 25 communicates with the gas outlet body 15.

A valve seat 26 is provided in the middle of the upstream flow path 24, and the valve body 27 of the shutoff valve 18 faces the valve seat 26. That is, the flow passage 22 can be shut off by the shut-off valve 18 when the seismic sensor or the like senses an abnormality.

A jet nozzle 28 is provided on the partition wall 23 of the flow path body 19. The jet nozzle 28 has a slit shape that opens over the entire depth direction of the flow path body 19, and has projections 28a and 28b projecting toward the upstream flow path 24 on both side edges of the opening in the longitudinal direction, and the nozzle passage The length is extended.

Inside the jet nozzle 28, as shown in FIGS. 1 and 2, a plurality of partition plates 29 are provided. These partition plates 29 are parallel to the bottom surface of the flow path body 19, and the partition plates 29 are arranged at equal intervals. That is, the bottom surface of the flow path body 19 is a lower part, and the lid body 2 is
With 1 as the upper part, the plurality of partition plates 29 are arranged at equal intervals in the vertical direction.

Further, among these partition plates 29, the distance a between the uppermost partition plate 29U and the upper surface of the jet nozzle 28 is a.
The interval c between the lowermost partition plate 29L and the lower surface of the jet nozzle 28 is formed to be larger than the interval b between the partition plates 29, and is set to satisfy a> b and c> b. Then, the lower surface of the ejection nozzle 28, that is, the partition plate 2
A flow velocity sensor 40, which will be described later, is provided in a passage having a wider distance from 9L.
Is provided.

The partition plate 29 is formed so that the inlet side of the jet nozzle 28 is wide and the outlet side thereof is narrow along the inner surface shape of the jet nozzle 28. Then, of the plurality of partition plates 29, an end portion of the central partition plate 29 located on the inlet side of the ejection nozzle 28 is formed with a tapered portion 30a that is gradually thinned toward the end portion by double-sided chamfering. Has been done.

The end portion of the partition plate 29, which is disposed above the central partition plate 29 and located on the inlet side of the ejection nozzle 28, is chamfered on one side to gradually reduce the thickness toward the end portion. A tapered portion 30b is formed, and the end portion of the partition plate 29 disposed on the lower side located on the inlet side of the ejection nozzle 28 has a taper that gradually becomes thinner toward the end portion by chamfering one side of the lower surface side. The portion 30c is formed.

Further, the end portion of the central partition plate 29 located on the outlet side of the jet nozzle 28 is tapered by double-sided chamfering, and the taper portion 3 is gradually thinned toward the end portion.
1a is formed.

The end portion of the partition plate 29 disposed on the upper portion of the central partition plate 29, which is located on the outlet side of the ejection nozzle 28, is gradually thinned toward the end portion by chamfering one side of the lower surface side. The taper portion 31b is formed, and the end portion of the partition plate 29 disposed on the lower side, which is located on the outlet side of the ejection nozzle 28, has a taper portion 31c which is gradually thinned toward the end portion by chamfering one side of the upper surface side. Are formed.
Moreover, the uppermost and lowermost partition plates 29U and 29L extend to the outlet side of the jet nozzle 28, and the other partition plates 2
The length is longer than 9.

A first target 33 for stabilizing the flow direction switching of the fluid is provided in the downstream flow passage 25 facing the outlet side of the jet nozzle 28. Side walls 34a, 3 are provided on both sides of the first target 33.
4b are provided symmetrically.

Further, a second target 35 is provided in the central portion located on the downstream side of the first target 33, and a return wall 36 extending in the width direction of the downstream side flow passage 25 is further provided on the downstream side. It is provided. Return passages 37a and 37b are formed outside the side walls 34a and 34b, and discharge passages 38a and 37a are formed outside both ends of the return wall 36.
38b is provided.

Therefore, the fluid ejected into the downstream flow path 25 is, for example, due to the Coanda effect, the right side wall 34a.
Flows along the inside of. Most of the fluid that has flowed to the right side wall 34a goes to the discharge passage 38a, but part of the fluid becomes return fluid and goes to the return passage 37a.

The fluid energy of the return fluid is applied to the jetted fluid so that the jetted fluid flows along the inside of the left side wall 34b, and a part of the fluid that has flowed to the left side wall 34b becomes the return fluid this time. , The fluid energy of this return fluid is applied to the jetted fluid, and the jetted fluid is again fed to the right side wall 3
It comes to flow along the inside of 4a. In other words, the alternating pressure wave is generated by the vibration phenomenon of the fluid ejected from the ejection nozzle 28 into the downstream flow passage 25.

Further, a flow velocity sensor 40 and a piezoelectric film sensor 41 are provided at the bottom of the flow path body 19 corresponding to the jet nozzle 28. The flow velocity sensor 40 includes a sensor body 42 and a detection unit 43.
Is fixed to the bottom of the flow path body 19, and the detection unit 43 is exposed to the ejection nozzle 28.

That is, the flow velocity sensor 40 is installed at a position where the flow velocity in the width direction is narrowed and the flow velocity is maximized in order to measure the minute flow rate region. Further, the piezoelectric film sensor 41 is for measuring a large flow rate region, and is composed of a sensor body 44 and a pressure wave introducing section 45. The sensor body 44 is fixed to the bottom of the flow path body 19, The wave introducing portion 45 is in communication with a pair of pressure wave introducing ports 46, 46 which are open at the position where an alternating pressure wave is generated by the vibration phenomenon on the outlet side of the jet nozzle 28.

Therefore, the alternating pressure wave generated by the vibration phenomenon of the fluid ejected from the ejection nozzle 28 into the downstream flow passage 25, that is, the pressure change due to the change of the flow direction of the jet from the ejection nozzle 28 is the pressure wave inlet. It is detected by the piezoelectric film sensor 41 via 46, 46. The waveform signals from the flow velocity sensor 40 and the piezoelectric film sensor 41 calculate the fluid flow rate from the frequency and are displayed in the flow rate display window.

In the above embodiment, among the plurality of partition plates 29, the space between the uppermost partition plate 29U and the upper surface of the jet nozzle 28 and the lowermost partition plate 29L.
And the lower surface of the jet nozzle 28, the partition plate 29
The flow velocity sensor 40 is formed to be larger than the mutual distance.
Bottom surface of the jet nozzle 28 having the
Even if the space between the partition plates 29 is larger than the space between the partition plates 29, the sensitivity of the flow velocity sensor 40 can be increased, and the same effect can be obtained.

Further, among the plurality of partition plates, the shapes of the central partition plate and the upper and lower partition plates are changed to distribute the fluid, but all the partition plates have the same tapered parts. Alternatively, the shape of the taper portion may be a taper having the same vertical inclination. Furthermore, although the tapered portion is formed by linear chamfering in the above-described embodiment, it may be curved chamfering.

[0035]

As described above, according to claim 1 of the present invention, a plurality of partition plates are arranged inside the jet nozzle at a predetermined interval, and at least one of these partition plates is provided. It is characterized in that the distance between the lowermost partition plate and the lower surface of the ejection nozzle is made larger than the distance between the partition plates. Therefore, there is an effect that the measurement sensitivity of the flow velocity sensor can be improved and accurate measurement can be performed even in a minute flow rate range.

According to the second and third aspects, one end of the partition plate located on the inlet side of the jet nozzle and the other end of the partition plate located on the outlet side of the jet nozzle are gradually thinned toward the end. And the taper portion at one end of the partition plate is a taper inclined toward the center of the ejection nozzle, and the taper portion at the other end of the partition plate is inclined toward the top and bottom of the ejection nozzle. It is characterized in that it is tapered. Therefore, the fluid flows along the taper and is stabilized, and the performance can be further improved.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a jet nozzle of a fluidic flow meter showing an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional side view of the ejection nozzle according to the embodiment.

FIG. 3 is a front view showing the internal structure of the fluidic flow meter of the embodiment.

FIG. 4 is a partially cutaway side view of the fluidic flow meter of the embodiment.

[Explanation of symbols]

17 ... Fluidic element, 19 ... Flow path main body, 22 ... Flow path, 23 ... Partition wall, 24 ... Upstream flow path, 25 ... Downstream flow path, 28 ... Jet nozzle, 29 ... Partition plate, 30a-30
c ... tapered portion, 31a to 31c ... tapered portion.

Front page continuation (72) Inventor Toshiaki Aoki 1-32 Shimura, Itabashi-ku, Tokyo Inside Kinmon Co., Ltd. (72) Inventor Naoshi Isshiki 1-3-2 Shimura, Itabashi-ku, Tokyo Kinmon, Inc. Inside the factory

Claims (4)

[Claims] 1. A jet which jets a fluid of the upstream channel to the downstream channel by partitioning the upstream channel and the downstream channel by providing a partition on the channel body that constitutes the channel. With a nozzle,
In a fluidic flowmeter provided with a fluidic element on the lower surface of the jet nozzle and a fluidic element in the downstream flow passage, a plurality of partition plates inside the jet nozzle are parallel to the bottom surface of the flow passage body, In addition, it is characterized in that the partition plates are arranged at a predetermined interval, and at least the partition plate at the bottom of these partition plates and the lower surface of the ejection nozzle are made larger than the interval between the partition plates. Fluidic flow meter. 2. A taper portion is formed at one end of the partition plate located on the inlet side of the jet nozzle and at the other end of the partition plate located on the outlet side of the jet nozzle, the taper portion gradually thinning toward the end. The fluidic flowmeter according to claim 1, wherein 3. A taper portion at one end of the partition plate is a taper that is concentrated and inclined toward a central portion of the jet nozzle toward the end, and a fluid passing through the jet nozzle is dispersed above and below the jet nozzle to form a partition plate. 3. The flue according to claim 1 or 2, wherein a taper portion at the other end portion of the sluice is a taper that is distributed and inclined toward upper and lower portions of the ejection nozzle toward the end portion, and vertically disperses the fluid ejected from the ejection nozzle. Dick flow meter. 4. The fluidic flow meter according to claim 1, wherein the tapered portion of the partition plate is a straight or curved taper formed by chamfering.