JPH06241851A - Fluidic flowmeter - Google Patents

Abstract

PURPOSE:To provide a fluidic flowmeter which can eliminate an irregularity in the performance of an instrumental error. CONSTITUTION:A partition which divides a flow passage 22 into an upstream- side flow passage and a downstream-side flow passage is installed in a flow- passage body 19 which is provided with a side-face-opening 19a on one side face, which blocks the side-face opening 19a via a sealing material 20 by a lid body 21 and which constitutes the flow passage 22. A jet nozzle is installed in the partition. A cover plate 43 which blocks the side-face opening 19a is installed in the flow-passage body 19. The sealing material 20 is bonded to the outside of the cover plate 43. Thereby, it is possible to prevent the packing 20 from being bent to the inside of the flow passage 22 and from encroaching on the jet nozzle due to a change with the passage of time or due to an irregularity in the clamping force of a clamp screw 44.

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. 63-63.
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 from this jet nozzle to a fluidic element provided in the downstream flow passage. When a fluid is jetted, the jetted fluid flows along the right sidewall, 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.

That is, the fluidic flowmeter is shown in FIG.
It is configured as shown in FIG. 11 is a case. The case 11 is composed of a rectangular box-shaped case body 12 and a lid 13 that closes an opening of the case body 12.

A gas inlet body 1 is provided on 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.

Reference numeral 19 denotes a flow path body formed by die casting or the like. A side surface opening 19a is provided on one side surface of the flow path body 19, and the side surface opening 19a is covered via a packing 20 as a sealing material. The flow path 22 is configured by being closed by the body 21. This channel 22 is a partition wall 2
3, the upstream flow path 24 communicates with the gas inlet body 14, and the downstream flow path 25 has the gas flow outlet body 1.
It communicates with 5.

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 integrally provided on the partition wall 23 of the flow path body 19. The jet nozzle 28 has a slit-like shape that opens over the entire depth direction of the flow path body 19, and has projections 28a and 28b that project toward the upstream flow path 24 on both side edges of the opening in the longitudinal direction. The passage length is extended. Further, a side surface opening 29 that opens in the same direction as the side surface opening 19 a of the flow path body 19 is provided on one side surface of the ejection nozzle 28.

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.

Thus, the side surface opening 19a of the flow path body 19 is formed.
And the side opening 29 of the jet nozzle 28 is packed 20
The lid body 21 is closed by means of a through hole, and the lid body 21 is fastened and fixed to the flow path body 19 by a plurality of fastening screws 30.

[0014]

By the way, the flow path body 1
The side surface opening 19a of
In the structure in which it is closed and sealed by means of the tightening screw 30, it cannot be surely sealed unless it is strongly tightened.

However, in the flow passage body 19, the flow passage 22 is surrounded by the peripheral wall 19b, and the jet nozzle 28, the first target 33, the side wall 34a,
34b, the second target 35, the return wall 36, and the like are provided so as to project, and the return flow paths 37a and 37b and the discharge passage 38 are provided.
a and 38b are formed.

Therefore, the side surface opening 19 of the flow path body 19 is
a is an uneven surface, and this uneven surface is packed 20
Is blocked by. Therefore, the packing 20, which is formed of an elastic material such as rubber, bends with time and swells into the recess forming the flow path 22.

Further, if the tightening force of the plurality of tightening screws 30 varies, the inner surface of the packing 20 becomes wavy, and in particular, the part of the packing 20 facing the side opening 29 of the jet nozzle 28 swells and the jet nozzle 20 is expanded. However, there is a problem in that the opening cross-sectional area of the ejection nozzle 28 becomes small, the pressure loss is affected, and the instrumental error performance varies.

The present invention has been made in view of the above circumstances, and an object thereof is to suppress variations in instrumental error performance without impairing sealing performance and to stabilize characteristics for a long period of time. An object is to provide a fluidic flowmeter that can be designed.

[0019]

In order to achieve the above object, the present invention has a side surface opening on one side surface, and the side surface opening is closed by a lid member via a sealing material to form a flow path. A flow channel main body, a partition wall provided in the flow channel main body for partitioning the flow channel into an upstream flow channel and a downstream flow channel, and a side surface opening closed by a lid via the sealing material in the partition wall. In a fluidic flowmeter comprising a jet nozzle having and a fluidic element provided in the downstream side flow passage, a step portion lower than an end surface outer peripheral edge is provided at an inner peripheral edge of an end surface of a peripheral wall of the flow passage main body, and the step portion Fit a cover plate with rigidity that closes the entire side opening of the flow path body to
The lid is provided outside the cover plate via the sealing material.

[0020]

Since the uneven surface of the side surface opening of the flow path main body is closed by the cover plate having rigidity, the packing does not bend inside the flow path or bite into the ejection nozzle, and the openings of the flow path and the ejection nozzle are prevented. The cross-sectional area can be maintained constant and variations in instrumental error can be eliminated.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

1 to 3 show the entire fluidic flowmeter, the flow passage 22 inside the flow passage body 19 is surrounded by a peripheral wall 41, and the inner peripheral edge of the peripheral wall 41 has an outer peripheral edge 41a. A lower step portion 41b is provided.

Further, the partition wall 23 protruding from the bottom surface of the channel 22 of the channel body 19, the ejection nozzle 28, the first target 33, the side walls 34a and 34b, the second target 35 and the return wall 36 are the peripheral wall 41. It is formed at the same height as the step portion 41b.

Further, a plurality of screw holes 42 are provided on the outer peripheral edge 41a of the end face of the peripheral wall 41, and the outer peripheral edge of the cover plate 43 for closing the side surface opening 19a of the flow path body 19 is joined to the step portion 41b.

The cover plate 43 is made of a material having rigidity such as a metal plate, and the thickness thereof is the same as the depth of the step portion 41b, and the cover plate 43 is designed to be flush with the outer peripheral edge 41a of the end face. ing.

The packing 20 is joined to the outside of the cover plate 43, and the lid 21 is joined to the outside of the covering plate 43. The lid 21 is screwed into a screw hole 42 by a tightening screw 44.
The side surface opening 19a of the flow path body 19 is triple-closed by the cover plate 43, the packing 20 and the lid body 21, and the flow path body 19 and the lid body 21 are sealed by the packing 20.

Therefore, the side surface opening 19 of the flow path body 19 is
Even if there is an uneven portion in the flow path, the cover plate 43 closes it flatly, and the cover plate 43 does not bite the packing 20 into the flow path 22 or the ejection nozzle 28.
2 and the opening cross-sectional area of the jet nozzle 28 can be maintained constant to eliminate variations in instrumental error.

In the embodiment described above, the fluidic flowmeter having the inflow port body 14 in the upper part of the flow path body 19 and the outflow port body 15 in the lower part has been described. It can also be applied to a fluidic flowmeter in which the inlet body 14 and the outlet body 15 are arranged in parallel.

[0029]

As described above, according to the present invention, since the uneven surface of the side surface opening of the flow path body is closed by the cover plate having rigidity, packing is performed due to a change with time and a variation in the tightening force of the tightening screw. Does not bend inside the flow path or bite into the ejection nozzle, the opening cross-sectional areas of the flow path and ejection nozzle can be maintained constant, and variations in instrumental error can be eliminated, and long-term stability of performance can be achieved. The effect is that you can do it.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view of a fluidic flow meter showing a first embodiment of the present invention.

FIG. 2 is a front view showing the internal structure of the fluidic flow meter of the embodiment.

FIG. 3 is a vertical cross-sectional side view showing an enlarged part A of FIG.

FIG. 4 is a side view in which a conventional fluidic flow meter is partially cut away.

FIG. 5 is a front view showing the internal structure of the fluidic flow meter.

FIG. 6 is a vertical cross-sectional side view showing a portion B of FIG. 4 in an enlarged manner.

[Explanation of symbols]

17 ... Fluidic element, 19 ... Flow path main body, 20 ... Packing, 21 ... Lid, 22 ... Flow path, 23 ... Partition wall, 24
... upstream side channel, 25 ... downstream side channel, 28 ... jet nozzle,
Reference numeral 19a ... Side opening, 41 ... Peripheral wall, 41a ... End surface outer peripheral edge, 41b ... Step portion, 43 ... Cover plate.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Naoshi Isshiki 1-3-2 Shimura, Itabashi-ku, Tokyo Inside Kinmon Manufacturing Co., Ltd.

Claims (1)

[Claims] 1. A flow path main body having a side surface opening on one side surface, the side surface opening being closed by a lid via a sealing material to form a flow path, and the flow path provided in the flow path main body. A partition wall that divides the upstream flow path and the downstream flow path, a jet nozzle having a side surface opening that is closed by a lid through the sealing material in the partition wall, and a fluidic nozzle provided in the downstream flow path. In a fluidic flowmeter comprising an element, a step portion lower than the end surface outer peripheral edge is provided on the inner peripheral edge of the end surface of the peripheral wall of the flow channel main body, and the step portion has a rigidity that closes the entire side surface opening of the flow channel main body. A fluidic flowmeter characterized in that a plate is fitted and the lid is provided outside the cover plate via the sealing material.