JP3181139B2 - Fluidic flow meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid flow meter for detecting a flow rate by detecting an alternating pressure wave generated by a vibration phenomenon of a fluid such as gas ejected from an ejection nozzle into a flow path.

[0002]

2. Description of the Related Art A fluidic flow meter installed in a general household or the like for measuring a gas flow rate is disclosed in, for example,
It is known from JP-A-313018 and JP-A-1-250725.

In a fluidic flow meter, an ejection nozzle is provided on the inlet side of a flow path. When a fluid is ejected from the ejection nozzle into the flow path, the ejected fluid flows, for example, along the right side wall due to the Coanda effect. A part of the fluid flowing to the right side wall becomes return fluid, and the fluid energy of this return fluid is applied to the ejected fluid, and the ejected fluid flows along the left side wall, and then flows to the left side wall. A part of the returned fluid becomes a return fluid, and the fluid energy of the return fluid is applied to the jet fluid, and the jet fluid flows again 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. The alternating pressure wave is detected by the piezoelectric film sensor, and the flow rate is calculated from the frequency to detect the flow rate of the fluid.

[0005] The conventional fluidic flow meter is configured as shown in FIGS. 2 and 3. That is, 11 is a case. The case 11 includes a rectangular box-shaped case body 12 and a lid 13 that closes an opening of the case body 12.

The gas inlet 1 is located at the lower part of the case body 12.
4 and a gas outlet 15 are arranged side by side, and a fluidic element 17 and a shutoff valve 18 described later are installed inside the case 11.

The fluidic element 17 will be described. Reference numeral 23 denotes a flow passage main body formed by die casting or the like.
The flow path 26 is configured by being closed by the lid 25 through the cover 4.

The flow passage 26 is vertically divided by a partition wall 27, the upstream flow passage 28 communicates with the gas inlet 14, and the downstream flow passage 29 communicates with the gas outlet 15. A partition wall 22 integral with or separate from the flow path main body 23 is provided in the middle of the upstream flow path 28.
Partition on the way.

A valve seat 30 is provided on the partition wall 22, and a valve body 31 of the shut-off valve 18 fixed to the flow path main body 23 is opposed to the valve seat 30. That is, when a pressure switch, a seismic sensor, or the like (not shown) detects an abnormality, a shut-off signal is input to the shut-off valve 18, the shut-off valve 18 is operated, and the valve body 31 is pressed against the valve seat 30, so that the upstream side The configuration is such that the flow path 28 can be shut off.

The ejection nozzle 3 is provided on the partition wall 27 of the flow path main body 23.
2 are provided. The jet nozzle 32 is connected to the flow path main body 2.
3 has a protruding portion 32a, 32b protruding into the upstream flow path 28 on both side edges in the longitudinal direction, and extends the length of the nozzle passage.

A first target 33 for stabilizing the switching of the flow direction of the fluid is provided in the downstream flow path 29 facing the ejection nozzle 32. Side walls 34a and 34b are provided symmetrically on both sides of the first target 33.

Further, a second target 35 is provided at a central portion located downstream of the first target 33, and a return wall 36 extending in the width direction of the downstream flow path 29 is further provided downstream. Is provided. Return passages 37a, 37b are formed outside the side walls 34a, 34b, and discharge passages 38a,
38b are provided.

Therefore, when the fluid is ejected from the ejection nozzle 32 toward the downstream flow path 29, the ejected fluid flows, for example, along the inside of the right side wall 34a by the Coanda effect.

Most of the fluid flowing to the right side wall 34a goes to the discharge passage 38a, but a part of it becomes return fluid and goes to the return passage 37a. The fluid energy of the return fluid is applied to the ejected fluid, and the ejected fluid is supplied to the left side wall 34.
b, and a part of the fluid that has flowed to the left side wall 34b becomes a return fluid, and the fluid energy of this return fluid is applied to the ejected fluid, and the ejected fluid is again returned to the right side wall 34a. Will flow along the inside of the. That is, the configuration is such that an alternating pressure wave is generated by the vibration phenomenon of the fluid ejected from the ejection nozzle 32 into the downstream flow path 29.

Further, a flow sensor 40 and a piezoelectric film sensor 41 are provided on the side surface of the flow path main body 23 corresponding to the jet nozzle 32. The flow sensor 40
The sensor body 42 includes a sensor main body 42 and a sensor chip 43 having a detection unit including a heating unit and a temperature sensing unit.
Is fixed to the side surface of the flow path main body 23, and the sensor chip 43
Face the ejection nozzle 32.

That is, the flow sensor 40 is installed at a position where the flow path is narrowed and the flow velocity becomes the fastest in order to measure a minute flow rate region. The piezoelectric film sensor 41 is for measuring a large flow rate region, and includes a sensor main body 44 and a pressure wave introducing section 45.
Is fixed to the side surface of the flow path main body 23, and the pressure wave introducing portion 45
Is installed near the outlet of the ejection nozzle 32 at a position where an alternating pressure wave generated by the vibration phenomenon occurs.

By the way, there are a plurality of fluidic flowmeters from a large-capacity flowmeter to a small-capacity flowmeter so that a fluidic flowmeter configured as described above can be used in accordance with a gas demand. The basic configuration is the same regardless of whether the flowmeter is a large-capacity flowmeter or a small-capacity flowmeter.

However, in a small-capacity flow meter, the flow path width is naturally narrower than that in a large-capacity flow meter. Therefore, the diameter of the valve seat 30 provided on the partition wall 22 is also reduced, and the small shutoff valve 18 is incorporated. However, if dedicated shut-off valves 18 differing in size according to the capacity of the flow meter are incorporated, it is necessary to prepare a plurality of types of shut-off valves 18, and the number of produced shut-off valves 18 for each model decreases, resulting in an increase in cost and This is also disadvantageous in terms of management of a plurality of types of shut-off valves 18. Therefore, it has been practiced to unify the shut-off valve 18 for a large-capacity flow meter and to incorporate the shut-off valve 18 for a large-capacity flow meter even in a small-capacity flow meter.

FIG. 4 and FIG. 5 are cross-sectional lines (AB) of FIG.
FIG. 4 is a cross-sectional plan view of the flow path main body 23 taken along a line CD-D). FIG. 4 is a large-capacity flow meter, and FIG. 5 is a small-capacity flow meter. In the large-capacity flow meter, the flow path width of the flow path 26 is wide, and the valve seat 3
The cover plate 46, which has the same width from the partition wall 22 having a zero to the downstream side of the fluid and closes one side of the flow path 26, is also a single flat plate.

However, in the small-capacity flow meter, the flow path width of the flow path 26 is extremely narrow with respect to the width of the partition wall 22 having the valve seat 30, and a step 47 is formed in the flow path 26. Therefore, the gas inlet port 14 side of the partition wall 22 is covered with the cover plate 48.
a, and the flow channel 26 side is closed by a cover plate 48b. Further, the flow passage 30 surrounded by the valve seat 30
The outlet side of a is formed to have a small diameter in accordance with the width of the flow path 26.

[0021]

However, as described above, in the case of a small-capacity flowmeter, the partition wall 22 is provided with a cover plate 48.
a, the width of the flow path 26 becomes extremely narrow with respect to the partition wall 22 having the valve seat 30, even if the flow path 26 side is closed by the cover plate 48b. There is a problem that the part 47 is formed, which adversely affects the instrumental performance of the flow meter.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a large-capacity flow meter, a large-capacity flow meter, and a small-capacity flow meter. Fluidic flow rate, which can mass-produce shut-off valves of the same model without unaffected performance even if they are integrated for use in a single unit, and achieves unification of assembly work and drastic cost reduction. To provide a total.

[0023]

According to the present invention, in order to achieve the above object, a partition is provided in a flow path main body constituting a flow path to divide the flow path into an upstream flow path and a downstream flow path. In a large-capacity flow meter, the partition is formed in a wide width, and in a small-capacity flow meter, the partition is formed in a narrow width. One side in the width direction of the flow path is closed by the flow path main body, and the other side is closed by a cover plate. And a valve seat provided on a partition wall of the upstream flow passage, and a valve body that opens and closes the upstream flow passage so as to be able to freely contact and separate from the valve seat. A fluid shutoff valve, wherein the partition wall is provided with an ejection nozzle for ejecting a fluid in an upstream channel to a downstream channel, and a fluidic flow meter provided with a fluidic element in the downstream channel. To the shut-off valve for large-capacity flowmeters. The serial cover plate, in that formed in an arc shape so as to gradually narrow the passage width toward the partition wall having a valve seat on the downstream side of the flow path.

Therefore, the fluid flowing from the gas inlet into the flow passage body passes through the flow passage surrounded by the valve seat and smoothly moves from the partition wall side to the downstream side along the arcuate curved surface of the cover plate. Flows to

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a small-capacity flow meter, and is a cross-sectional plan view of a flow path main body 23 taken along a cross-sectional line (AB-CD) of FIG. It is formed integrally with the flow path main body 23. The partition wall 27 formed integrally with the flow path main body 23 is formed to have a narrow width. One side in the width direction of the flow path 26 is closed by the flow path main body 23, and the other side is closed by one cover plate 50. ing.

The cover plate 50 is formed by deep drawing of a steel plate or by aluminum die casting. The gas inlet port 14 is formed by a partition wall 22 having a valve seat 30 at one end.
A flat portion 50a is formed in the middle portion, and a curved surface portion 50b is formed in the middle portion so as to gradually narrow the flow path width from the partition wall 22 toward the downstream side of the flow path 26 (toward the ejection nozzle 32).
However, a bent portion 50c which is bent at a right angle along the edge of the flow path main body 23 is provided at the other end.

The cover plate 50 is fixed to the flow path main body 23 by a plurality of mounting screws 51, and a cover plate is provided between an outer surface of an intermediate portion of the cover plate 50 and an inner surface of the case body 12. Curved surface 50b formed by bending 50 toward the flow path 26
The space 52 is formed by this.

Therefore, even if the flow path width of the flow path 26 becomes extremely narrow with respect to the width of the partition wall 22, no step is formed in the flow path 26, and the flow path width can be smoothly changed. In addition, it is possible to eliminate the adverse effect on the instrumental performance caused by the step.

According to the fluidic flow meter constructed as described above, the diameter of the valve seat 30 provided on the partition wall 22 and the flow passage 30a surrounded by the valve seat 30 are formed to be the same as those of the large capacity flow meter. The shut-off valve 18 for opening and closing the flow passage 30a can be incorporated with a shut-off valve for a large-capacity flow meter as it is. be able to.

[0030]

As described above, according to the present invention, in the small-capacity flowmeter, the flow path width is gradually reduced from the partition wall side having the valve seat toward the downstream side of the flow path. By forming the flow path wall by the arc-shaped cover plate, there is an effect that the performance can be improved without affecting the instrumental performance.

Further, the shut-off valve can be integrated for a large-capacity flowmeter regardless of whether it is a large-capacity flowmeter or a small-capacity flowmeter. Therefore, the same type of shut-off valve can be mass-produced, the assembly work can be unified, and the cost can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional plan view showing a main part of a fluidic flow meter according to an embodiment of the present invention.

FIG. 2 is a partially cutaway front view of a conventional fluidic flow meter.

FIG. 3 is a partially cutaway side view of a conventional fluidic flow meter.

FIG. 4 is a cross-sectional plan view of a conventional large-capacity fluidic flow meter.

FIG. 5 is a cross-sectional plan view of a conventional small-capacity fluidic flow meter.

[Explanation of symbols]

17 ... fluidic element, 18 ... shut-off valve, 22 ... partition wall, 23 ... flow path main body, 26 ... flow path, 27 ... partition wall, 28
... upstream flow path, 29 ... downstream flow path, 30 ... valve seat, 31 ...
Valve element, 32: ejection nozzle, 50: cover plate.

Continuation of front page (72) Inventor Hideyuki Oike 1-3-2 Shimura, Itabashi-ku, Tokyo Inside Kinmon Manufacturing Co., Ltd. (56) References JP-A-6-265380 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01F 1/20 G01F 3/22 G01F 7/00

Claims (1)

(57) [Claims] 1. A partition is provided in a flow path main body constituting a flow path and divided into an upstream flow path and a downstream flow path. In a large-capacity flowmeter, the partition is wide, and in a small-capacity flowmeter, The partition wall is formed to have a narrow width, one side in the width direction of the flow path is closed by the flow path main body, and the other side is closed by a cover plate to have a flow path width according to the capacity, and the upstream side flow is A shut-off valve comprising a valve seat provided on a partition wall of the passage and a valve body which can freely contact and separate from the valve seat and open and close the upstream flow path, and the fluid of the upstream flow path is supplied to the partition wall on the downstream side. In the fluidic flow meter provided with the ejection nozzle for ejecting the fluid in the flow path and the fluidic element provided in the downstream flow path, the shut-off valve is unified with the shut-off valve for the large-capacity flow meter, and in the small-capacity flow meter, The cover plate is moved from the partition wall side having the valve seat toward the downstream side of the flow path. A fluidic flowmeter, characterized in that the formation of the channel width in an arc shape so as to narrow gradually.