JP3339209B2 - Fluid 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 of a fluid, and more particularly to a fluid flow meter capable of detecting a minute flow rate and having a wide flow rate detection range.

[0002]

2. Description of the Related Art As a conventional liquid flow meter of this type, a differential pressure type fluid flow meter as shown in FIG. 5 is well known.
That is, the orifice 2 is provided in conduit 1 of fluid flow, the pressure difference generated between the upstream and downstream of the <br/> orifice 2 is detected by the differential pressure gauge 3, through a conduit 1 from the differential pressure The fluid flow rate was detected.

[0003] Reference numerals 4 and 5 denote pressure introduction pipes provided upstream and downstream of the orifice 2, respectively, and reference numeral 6 denotes a direction in which a fluid flows (Japanese Patent Application Laid-Open No. 5-118890).

[0004]

However, in the above configuration, although the flow rate can be measured using the principle of being proportional to the square root of the differential pressure, there is a problem that a wide flow rate range cannot be accurately detected. there were.

In the low flow rate range, there are problems such as low sensitivity and a large error , and in some cases, there is a problem that the fluid flows backward. The present invention solves the above-mentioned conventional problems, and accurately performs detection over a wide detection range from a low flow rate range to a high flow rate range, and performs detection with high sensitivity .
It is another object of the present invention to provide a fluid flow meter without fluid backflow .

[0006]

In order to solve the above-mentioned problems, a fluid flow meter according to the present invention is provided with a fluid introduction portion for introducing a fluid, and is displaced and moved according to a fluid flow rate from the fluid introduction portion.
Fluid shield plate, and the fluid shield plate
If you support it so that it moves while maintaining the parallel relationship
Both urge to close the end face of the fluid introduction part
A flat gimbal spring, upstream and below the fluid shielding plate
Provided with differential pressure detecting means for detecting a differential pressure with the flow side
It is.

Further, the fluid shielding plate is formed of a conductive material.
In addition, by providing electrodes on the end face of the fluid introduction section,
To form the electrical contacts.

Furthermore, a fluid introducing unit for introducing a fluid, upper
The displacement movement according to the fluid flow rate from the fluid inlet
It was urged to close the end face of this fluid introduction part.
Fluid shielding plate and the difference between the upstream and downstream sides of the fluid shielding plate
Pressure difference detecting means for detecting pressure, wherein the fluid shielding plate
The center rod provided on the downstream side is displaced by a concave guide.
It is movably supported.

[0009]

[Function] The fluid shielding plate is adapted to the fluid flow from the body introduction part.
To move. That is, the smaller the fluid flow rate,
The pressure of the fluid it receives and the biasing force in the closing direction
Displace toward the end face of the fluid introduction section until the balance
Fluid channel narrows, and conversely, from the end face of the fluid introduction section
Displaced away, widening the substantial fluid flow path. did
Therefore, the fluid is blocked in a wide area from low flow rate to high flow rate.
A certain differential pressure appears between the upper and lower sides of the shield plate,
Accurate flow detection in a wide range from low flow to high flow
Can be done.

[0010] Moreover, the fluid shielding plate has a substantially variable flow path.
Does it not only have a shielding function
Should not cause fluid backflow in any case.
No. In addition, the fluid shielding plate may be formed of a conductive material.
In addition, by providing electrodes on the end face of the fluid introduction section,
By configuring the contact point, the state where no fluid is flowing can be detected.
This means that the differential pressure at zero flow can be calibrated.
You.

Further, a fluid shielding plate is provided downstream of the fluid shielding plate.
Center rod is supported by a concave guide so that it can be displaced and moved.
, The damper function will be added,
Fluid shielding plate vibrates even if the fluid flow fluctuates rapidly
And the differential pressure can be detected stably.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
You.

In FIG . 1, a fluid 8 indicated by an arrow is cylindrical.
Flow from the fluid inlet 9 to the frame 10.
You.

A circular shape opposed to the end face of the fluid introduction portion 9
The fluid shielding plate 11 includes a circular and flat gimbal spring 16.
It is supported so that it can be displaced and moved. This gimbalba
Ne is a connecting portion 17 which alternately intersects a plurality of ring portions at right angles.
And the innermost ring is fluid-tight.
The ring part on the outermost peripheral side is attached to the frame 10
Connected.

Therefore, the displacement movement of the fluid shielding plate 11 is
The operation is always performed while maintaining the parallel relation with the end face of the fluid introduction section 9.
Things. The gimbal spring 16 is connected to the fluid shielding plate 11.
Has the function of urging the fluid in the direction of the end face of the fluid introduction portion 9.
Things.

The differential pressure gauge 13 as the differential pressure detecting means is
The pressure of the fluid inlet 9 upstream of the fluid shielding plate 11
The difference from the pressure of the frame 10 on the flow side is detected.

One of the differential pressure gauges 13 has a pressure introducing pipe 1.
4 through the fluid introducing portion 9, that is, the fluid shielding plate 11.
The pressure on the upstream side, on the other hand,
10, that is, the pressure downstream of the fluid shielding plate 11
Each is set to be introduced.

In the above configuration, no fluid flows.
In the state, the fluid shielding plate 11 is moved by the urging force of the gimbal spring 16.
It was pressed against the end face of the fluid introduction part 9 and was closed.
Therefore, the fluid flows backward from the frame 10 toward the fluid introduction portion 9.
In this case, the fluid is blocked by the fluid shielding plate 11.

Next, when there is a normal fluid flow, the flow
Move to a position where the body force and the gimbal spring 16 balance.
, The fluid shielding plate 11 is displaced and moved. The fluid shielding plate 11
Is substantially proportional to the flow rate of the fluid,
When the flow rate is small, the displacement amount is small and the end face of the fluid introduction section 9 is small.
Gap is small, and conversely, the displacement is large when the flow rate is large.
The gap with the end face of the fluid introduction part 9 is wide and automatically
Adjusted.

As described above, when the flow rate is small, the fluid shielding plate 11
The amount of displacement and movement is small and the gap between the
The differential pressure between upstream and downstream is clear to
DOO-than, differential pressure gauge 13 which fluid flow a small amount by der
That is to accurately detect that

In a large flow rate state, the gap is widened.
Therefore, pressure loss of fluid can be suppressed as much as possible.
is there. Of course, the differential pressure detection characteristics of the upstream and downstream
I will not do it.

As described above, the gimbal spring 16
If the constant is set to a predetermined value, the fluid shielding plate 11
From the differential pressure generated between the upstream and downstream sides,
Easy and accurate detection over a wide area
It can be.

FIG . 2 shows the spring constant of the gimbal spring 16.
Is set to 1 g / mm, and the inner diameter of the fluid introduction part 9 is set to 20 mm.
Flow (mL / min) and differential pressure (mmAq)
The relationship is shown below.

According to this, a very small flow rate of several mL / min
0 to 6 mmA from the area to the large flow rate area of several tens of L / min
This indicates that detection can be performed with a differential pressure in the range of q.

Therefore, the differential pressure gauge 13 measures 0 to 6 mmAq
If a pressure in the range of is detected, a small flow rate of several mL / min
Can detect the flow rate from the area to the large flow rate area of several tens of L / min
The Rukoto.

The supporting material of the fluid shielding plate 11 is a gimbal.
Since the spring 16 is used, the displacement is changed according to the flow rate of the fluid.
The movement is performed while maintaining parallel to the end face of the fluid introduction part 9,
There is no inclination. As a result, the
The differential pressure at any time can be reliably taken, and the accuracy as a flow meter is further improved
And can be improved.

FIG . 3 shows a ring-shaped end face of the fluid introduction section 9.
An electrode 18 is provided, and the fluid shielding plate 11 is made of a conductive material.
This is an example in which an electric contact is formed with these materials.

By adopting such an electrical contact configuration, the flow
When there is no body flow, the electrode 18 and the fluid shielding plate 11
The flow rate is zero because the electrical contacts are closed by contact.
Be able to detect and calibrate the differential pressure gauge 13
To detect abnormalities in the differential pressure gauge 13 itself
Can be.

FIG . 4 shows a state in which the fluid shielding plate 11 is a coiled spring.
12 urges in the direction of the end face of the fluid introduction part 9 and
The center rod 20 protruding to the flow side can be slid freely by the guide 21
It is held in. And this guide 21 is at the bottom
The portion is closed by a sealing plate 22 and is set in a concave shape.

According to this configuration, the center rod 20 and the concave guide
The damper function will be added by the
Therefore, the fluid shielding plate 11 can be used for a rapid change in the flow rate.
No longer vibrates, and more stable flow detection
It is possible.

[0031]

As described above, the fluid flow meter of the present invention has a
Fluid introduction part for introducing the body and fluid from this fluid introduction part
A fluid shield plate that moves in accordance with the flow rate, and this fluid shield
The plate is displaced while maintaining the parallel relationship with the end face of the fluid inlet.
And the end face of the fluid introduction section.
A flat gimbal spring that urges the
Differential pressure detection that detects the differential pressure between the upstream and downstream sides of the fluid shielding plate
Since it is equipped with a
Reliable flow rate detection and small pressure loss
It can be cheap.

In particular, a gimba supporting the fluid shielding plate is provided.
The displacement of the fluid shielding plate is always
This is performed while maintaining the parallel relationship with the end face of the fluid introduction section.
Therefore, the differential pressure will surely follow the flow rate change.
The flow rate detection can be more accurate.
You.

Moreover, the fluid shielding plate is simply located at the end of the fluid introduction section.
Rather than adjusting the distance from the surface, it also has a valve function
Because it is something that prevents abnormalities such as backflow
It is.

Further , the fluid shielding plate is formed of a conductive material.
In addition, by providing electrodes on the end face of the fluid introduction section,
If the electrical contacts are configured as
Both can easily detect zero flow and calibrate the differential pressure gauge
Becomes

Further, the center provided on the downstream side of the fluid shielding plate
The rod is supported so that it can be displaced and moved by a concave guide.
In this case, these center rods and concave guides provide a damper function
Even if the flow rate changes suddenly, the fluid
What can raise the detection performance further without causing elephants
It is. In addition, the displacement movement of the fluid shield plate
You can also expect the effect of not being affected.

[Brief description of the drawings]

FIG. 1 (a) Cross section of a fluid flow meter showing an embodiment of the present invention
Figure (b) Plan view of the main part

FIG. 2 is a characteristic diagram of the flow meter.

FIG. 3 is a sectional view of a fluid flow meter showing another embodiment of the present invention.

FIG. 4 shows a fluid flow meter according to still another embodiment of the present invention .
Sectional view

FIG. 5 is a sectional view of a conventional fluid flow meter.

[Explanation of symbols]

 Reference Signs List 9 fluid introduction part 11 fluid blocking plate 12 coiled spring 13 differential pressure detecting means (differential pressure gauge) 16 gimbal spring 18 electrode 20 center rod 21 guide

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroshi Fujieda 1006 Kazuma Kadoma, Kadoma City, Osaka Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-3-28717 (JP, A) 162620 (JP, U) JP-A 3-57762 (JP, U) JP-A 61-122521 (JP, U) (58) Fields studied (Int. Cl. ⁷ , DB name) G01F 1/00-9 / 02

Claims (3)

(57) [Claims] 1. A fluid introducing portion for introducing a fluid, the fluid
Fluid shielding plate that moves in accordance with the flow rate of fluid from the inlet
And maintain the fluid shield parallel to the end face of the fluid introduction section.
While supporting it so that it can move while holding it,
A flat gin that urges the end of the fluid inlet to close
Differential pressure between the valve spring and the upstream and downstream sides of the fluid shielding plate
And a differential pressure detecting means for detecting pressure . 2. The method according to claim 1, wherein the fluid shielding plate is formed of a conductive material.
In addition, by providing electrodes on the end face of the fluid introduction section,
2. The fluid flow meter according to claim 1, wherein the fluid flow meter comprises an air contact . 3. A fluid introduction part for introducing a fluid, and the fluid
While displacing and moving according to the fluid flow rate from the introduction section,
A fluid shield urged to close the end face of the fluid introduction section
The differential pressure between the shielding plate and the upstream and downstream sides of the fluid shielding plate is detected.
And a differential pressure detecting means for detecting the pressure difference.
The center rod provided on the downstream side is displaceable and movable with a concave guide
Fluid flow meter supported on .