JPH04151518A - Fluidic flowmeter - Google Patents

Abstract

PURPOSE:To straighten a turbulent flow and also to improve the operability of fitting and assembly of a distributing plate by a method wherein the distributing plate made up of a net-shaped body and support bodies formed in the opposite end parts of the net-shaped body integrally therewith is inserted into two recessed grooves provided inside the main body of a flow channel on the upstream side. CONSTITUTION:In an upstream-side flow channel 28 divided by a partition wall 27, distributing plates 47 and 48 are provided so that they are removable from the main body 23 of the flow channel. Recessed grooves 50 opposed to each other vertically are provided inside the flow channel 28 in the vicinity of an opening end of the partition wall 27 of the main body 23 constituting the flow channel 28. The distributing plate 47 is constructed of a rectangular net-shaped body 51 and support bodies 52 which are formed integrally by inserting the upper and low corner parts in the base end part of the body 51 thereinto. The net-shaped body 51 set vertically is inserted into the flow channel 28 with its fore end side ahead, the fore end part of the net-shaped body 51 is inserted into a slit groove 50a provided in the base part of the main body 23, and the support bodies 52 are inserted into the recessed grooves 50. Thereby the distributing plate 47 is supported in a state of partitioning the flow channel 28. The support bodies 52 are pressed in the direction of the base part of the main body 23 by a cover body closing up an opening of the main body 23 with a packing interposed, and therefore they are fixed to the main body 23.

Description

Detailed Description of the Invention [Purpose of the Invention (Industrial Application Field) This invention detects alternating pressure waves caused by the vibration phenomenon of fluid such as gas ejected from an ejection nozzle into a flow path to determine the flow rate. Regarding fluidic flowmeters that detect

(Prior Art) Fluidic flowmeters installed in general homes and the like to measure the flow rate of gas are known from, for example, Japanese Patent Application Laid-Open No. 63313018 and Japanese Patent Application Laid-open No. 1-250725. In this fluidic flowmeter, a jet nozzle is provided on a partition wall that separates an upstream flow path and a downstream flow path, and fluid is jetted from this jet nozzle to a fluidic element provided in a downstream flow path. Then, the ejected fluid flows, for example, along the right side wall due to the Coanda effect. A part of the fluid that flows to the right side wall becomes a return fluid, and the fluid energy of this return fluid is imparted to the ejected fluid, causing the ejected fluid to flow along the left side wall, which in turn flows to the left side wall. A part of the fluid becomes the return fluid, and the fluid energy of the return fluid is imparted to the ejected fluid, causing the ejected fluid to flow along the right side wall again. That is, alternating pressure waves are generated by the vibration phenomenon of the fluid ejected from the ejection nozzle into the flow path. This alternating pressure wave is detected by a piezoelectric film sensor, and the flow rate is calculated from this frequency to detect the flow rate of the fluid.

(Problem to be Solved by the Invention) By the way, in a fluidic flowmeter, fluid that flows in from an inlet body of a case body is guided to a jet nozzle via an upstream flow path, and the fluid jetted from this jet nozzle is When the fluid that flows into the fluidic element passes through the upstream channel, it passes through a curved channel and turbulence occurs due to the effects of irregularities on the inner wall of the channel.

When turbulence occurs in the upstream channel, the flow rate of the fluid passing through the jet nozzle is disturbed, which also adversely affects the alternating pressure waves in the fluidic element, resulting in the problem that the flow rate cannot be accurately measured.

This invention was made in view of the above-mentioned circumstances, and its purpose is to be able to rectify the turbulent flow of fluid in the upstream flow path of the flow path main body, to perform accurate metering, and to An object of the present invention is to provide a fluidic flowmeter in which a rectifier plate can be easily attached and assembly workability can be improved.

[Structure of the Invention] (Means and Effects for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a partition wall in the flow channel body constituting the flow channel to separate the upstream flow channel and the downstream flow channel. A jet nozzle for jetting the fluid in the upstream flow path to the downstream flow path is provided on this partition wall, a fluidic element is provided in the downstream flow path, and a flow path body forming the upstream flow path is provided. At least two concave grooves are provided on the inner surface of the mesh body in the width direction of the upstream channel, and the grooves are inserted into both ends of the net-like body to form a rectifying plate consisting of an integrally molded support. A body is inserted from one end side of the groove to support a rectifying plate in the channel main body.

The fluid flowing through the upstream channel is rectified when passing through the rectifying plate, and the rectified fluid is ejected from the jet nozzle and heads toward the downstream channel, which has a negative impact on the alternating pressure waves in the fluidic element. The flow rate can be measured accurately.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 8 and FIG. 9 show the entire fluidic flowmeter, and 11 is a case. This case]-1 is composed of a rectangular box-shaped case body 12 and a lid 13 that closes an opening of this case body 12. A gas inlet body 14 and a gas outlet body 15 are provided at the bottom of the case body 12.
are arranged in parallel, and a flow rate display window (not shown) is provided at the top. A fluidic element 17 and a cutoff valve 18, which will be described later, are installed in the lower part of the inside of the case 11.

To explain the fluidic element 17, 23
is the channel body formed by die casting etc.,
A flow path 26 is formed by closing the opening of the flow path main body 23 with a lid 25 via a backing 24. This flow path 26 is divided by a partition wall 27,
The upstream passage 28 communicates with the gas inlet body 14 , and the downstream passage 29 communicates with the gas outlet body 15 .

A valve seat 30 is provided in the middle of the upstream flow path 28, and the valve body 31 of the cutoff valve 18 faces the valve seat 30.

In other words, when a seismic sensor or the like detects an abnormality, the shutoff valve 18
The flow path 26 is configured to be able to be blocked by the flow path 26.

A jet nozzle 32 is provided on the partition wall 27 of the flow path main body 23 . This jet nozzle 32 has a slit shape that opens over the entire depth direction of the channel main body 23, and a protrusion 3 that is used in the upstream channel 28 is provided on both sides of the opening in the elongated direction.
2a and 32b, extending the nozzle passage length.

A first target 3 is provided in the downstream flow path 29 facing the jet nozzle 32 for stabilizing switching of the fluid flow direction.
3 is provided. Side walls 34a and 34b are symmetrically provided on both sides of the first target 33. Further, a second target 35 is provided in the center located downstream of the first target 33, and a return wall 36 extending in the width direction of the downstream channel 29 is provided further downstream. There is. And the side wall 34a
.

Return passages 37a and 37b are formed on the outside of the return wall 34b, and a discharge passage 38a is formed on the outside of both ends of the return wall 36.

38b is provided.

Therefore, when fluid is ejected from the ejection nozzle 32 toward the downstream channel 29, the ejected fluid flows, for example, along the inside of the right side wall 34g due to the Coanda effect. Most of the fluid flowing into the right side wall 34a heads toward the discharge passage 38a, but a portion becomes return fluid and heads toward the return passage 37a. The fluid energy of this return fluid is imparted to the ejected fluid, and the ejected fluid begins to flow along the inside of the left side wall 34b. This time, a part of the fluid that has flowed to the left side wall 34b becomes the return fluid, and this return fluid flows along the inside of the left side wall 34b. The fluid energy of the fluid is imparted to the ejected fluid, causing the ejected fluid to flow again along the inside of the right side wall 34a. In other words,
It is configured so that alternating pressure waves are generated by the vibration phenomenon of the fluid ejected from the ejection nozzle 32 into the downstream flow path 29 .

Furthermore, the flow path main body 2 corresponding to the jet nozzle 32
A flow sensor 40 and a piezoelectric film sensor 41 are installed at the bottom of 3.
is provided. The flow sensor 40 includes a sensor body 4
2 and a sensor chip 43 equipped with a detection part consisting of a heat generating part and a temperature sensing part, the sensor main body 42 is fixed to the bottom of the channel main body 23, and the sensor chip 43 faces the jet nozzle 32. . That is, the flow sensor 40 is
In order to measure a small flow rate region, the flow path is narrowed and installed at a position where the flow velocity is the highest. Further, the piezoelectric film and the sensor 41 are for measuring a large flow rate region,
Consisting of a sensor body 44 and a pressure wave introduction part 45, the sensor body 44 is fixed to the bottom of the channel body 23, and the pressure wave introduction part 45 is located near the outlet of the jet nozzle 32, and absorbs the alternating pressure generated by the vibration phenomenon. It communicates with a pair of pressure wave inlets 46, 46 which open at optimal wave extraction positions.

On the other hand, in the upstream flow path 28, a first baffle plate 4, which will be described later, is provided.
7 and a second rectifying plate 48 are installed, and these are connected to the channel body 2.
3, so that it can be attached and detached.

The first rectifier plate 47 and the second rectifier plate 48 are configured as shown in FIGS. 1 to 7, and are attached to the channel body 23. That is, grooves 50 and 50 that face each other vertically are provided on the inner surfaces of the channel main body 23 and the partition wall 27, which constitute the upstream channel 28, near the opening ends. has a slit groove 50a
is provided. On the other hand, the first rectifying plate 47 is composed of a rectangular mesh body 51 and supports 52 and 52 integrally formed by inserting the upper and lower corners of the base end of the mesh body 51. .

The net-like body 51 is approximately equal in cross-sectional area to the upstream channel 28, and the support body 52 is formed in a size that allows it to be inserted tightly into the groove 50. Then, the net-like body 51 is placed vertically and inserted into the upstream channel 28 from its tip side, and the tip of the net-like body 51 is further inserted into the slit groove 50a, and the support body 52
．． 52 into the grooves 50.50, the first rectifier plate 47 is supported in a state that partitions the upstream channel 28.

Furthermore, the partition wall 27 constituting the upstream flow path 28 has one groove <53.
53 are provided. These grooves 53, 53 are provided over the entire length of the upstream flow path 28 in the width direction, and are located on the base end side,
That is, the first engagement portion 53a formed wide in the portion located near the opening end of the channel body 23 is recessed in the extending direction of the groove 53 at the tip side, that is, the bottom of the channel body 23. A second engaging portion 53b consisting of a recessed portion is provided. On the other hand, the second current plate 48 includes a mesh body 54 bent into a mountain shape, and a support body 55.5 integrally formed by inserting the end edges of both legs of the mesh body 54.
It consists of 5. The net-like body 54 is formed to have a size sufficient to cover the protrusions 32a and 32b protruding into the upstream channel 28. In addition, an engagement protrusion 55a is provided at the base end of the support body 55.55 to be inserted tightly into the tenth engagement portion 53a of the groove 53, and a distal end portion is provided at the second engagement portion 53b. It has a tip portion 55b that can be inserted tightly.

When attaching the second rectifying plate 48, the tip 55b of the support body 55.
b, the engagement convex portion 55a engages with the first engagement portion 53a to prevent the second current plate 48 from floating up, and is supported in a state that partitions the upstream side of the jet nozzle 32. .

Further, the supports 52, 55 of the first and second rectifying plates 47, 48 are arranged so that the openings of the channel main body 23 [-backing 2
Since it is pressed toward the bottom of the channel main body 23 by the lid body 25 that closes through the channel body 25, it is fixed to the channel main body 23 without being fixed with a special fixing member.

Next, the operation of the fluidic flowmeter configured as described above will be explained. The fluid flowing in from the gas inlet body 14 flows through a flow path 28 on the upstream side of the flow path 26 . Even if turbulence occurs in the fluid at this time, it is rectified as it passes through the net-like bodies 51 and 54 of the first rectifier plate 47 and the second rectifier plate 48 and heads toward the jet nozzle 32 . Since the flow path of the jet nozzle 32 is narrowed, the flow velocity of the fluid increases, and the jet nozzle 3
Fluid is ejected from 2 to the downstream flow path 29. When the fluid passes through the jet nozzle 32, the flow rate is measured by the flow sensor 4.
Detected by 0. When fluid is ejected from the ejection nozzle 32 toward the downstream channel 29, the ejected fluid flows, for example, along the inside of the right side wall 34a due to the Coanda effect. Most of the fluid that has flowed to the right side wall 34a heads toward the discharge passage 38a, but a portion becomes return fluid.
Head toward the return passage 37a. The fluid energy of this return fluid is imparted to the ejected fluid, causing the ejected fluid to flow along the inside of the left side wall 34b, and this time, the ejected fluid flows along the inside of the left side wall 34b.
A part of the fluid that has flowed to b becomes a return fluid, and the fluid energy of this return fluid is imparted to the ejected fluid, so that the ejected fluid again flows along the inside of the right side wall 34a. That is, 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 .

This alternating pressure wave, that is, the pressure change caused by the change in the flow direction of the jet from the jet nozzle 32 is caused by the pressure wave inlet 46.
It is detected by the piezoelectric film sensor 41 via 46.

The fluid flow rate is calculated from the frequency of the waveform signals from the flow sensor 40 and the piezoelectric film sensor 41 and displayed on the flow rate display window.

In addition, when assembling the flow sensor 40 and the piezoelectric film sensor 4] to the channel body 23, it is necessary to
Since the flow sensor 40 and the piezoelectric film sensor 41 are mounted on the same side from the same direction, assembly workability can be improved, and workability during maintenance inspection and repair can also be improved.

In addition, in the said one Example, although the 1st and 2nd rectifying plate was provided in the upstream flow path, the number of rectifying plates may be one.

[Effects of the Invention] As explained above, according to the present invention, the fluid flowing in the upstream flow path is rectified when passing through the rectifier plate, and the rectified fluid is ejected from the jet nozzle to flow downstream. Since the flow is directed toward the flow, the alternating pressure waves in the fluidic element are not adversely affected, and the flow rate can be accurately measured. Furthermore, at least two grooves are provided in the width direction of the upstream channel, and these grooves are inserted into both ends of the net-like body to form a rectifying plate made of an integrally colored support. By inserting from one end of the concave groove and supporting a rectifier plate that rectifies fluid from the upstream flow path to the downstream flow path in the flow channel main body, the rectifier plate can be easily installed and the assembly work efficiency is improved. There is an effect that it can be done.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal sectional front view of the flow path body of a fluidic flowmeter showing the structure of the installation of the rectifying plate, and FIG. 3 is a perspective view showing the installation structure of the first rectifying plate, a vertical sectional side view taken along the line The installation is a perspective view showing the structure, and Figure 6 is the second
7 is a front view, FIG. 8 is a partially cutaway front view of the fluidic flowmeter, and FIG. 9 is a partially cutaway side view. 23... Channel main body, 26... Channel, 27... Partition wall, 28... Upstream channel, 29... Downstream channel, 32
...Blowout nozzle, 47...First rectifying plate, 48...
・Second current plate, 50.53...concave, groove, 51.54
...Network, 52.55...Support.

Claims (1)

[Claims] A partition wall is provided in the main body of the flow path to separate an upstream flow path and a downstream flow path, and a jet nozzle is provided on this partition wall to jet the fluid in the upstream flow path to the downstream flow path. In a fluidic flowmeter in which a fluidic element is provided in a side flow path, at least two grooves are provided on the inner surface of a flow path main body constituting the upstream flow path in the width direction of the upstream flow path; This is inserted into both ends of the net-like body to form a rectifying plate consisting of an integrally molded support, and the support is inserted from one end side of the groove to flow from the upstream flow path to the downstream flow path body. A fluidic flowmeter characterized by supporting a rectifier plate that rectifies fluid flowing toward a side flow path.