JP3368684B2 - 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 high-sensitivity flow meter for detecting such a minute flow rate, a hot-wire type fluid flow meter as shown in FIG. 4 is well known.

That is, a recess 2 is provided on the surface of a substrate 1 made of semiconductor or the like by a fine processing technique such as etching, an electrically insulating thin film 3 is formed on the recess 2 in a bridge shape, and a plurality of thin insulating films 3 are further formed on the recess. Providing resistance temperature detectors 4 and 5 with excellent temperature characteristics
Electrical insulation so that each is thermally insulated
Slits 6 are formed on the thin film 3 and the resistance temperature detectors 4,
A fluid temperature detecting element 7 made of a resistance temperature detector for detecting the temperature of the fluid is arranged on the electrically insulating thin film 3 in the vicinity of 5.
Met.

The fluid indicated by the arrow is made to flow, and at the same time
Flow, constant current to the resistance thermometers 4 and 5 placed downstream
When a constant current from the source is applied to heat and raise the temperature, the fluid flow
Due to the cooling effect depending on the speed,
Causes a temperature difference, that is, a resistance difference.
It was detected (Japanese Patent Publication No. 6-25684).

[0005]

However, in the above structure, the accuracy is poor in the low flow rate region due to the influence of thermal convection, and the sensitivity is lowered in the high and low flow rate regions. , Problems such as large error
The flow rate detection range was narrow.

The present invention solves the above-mentioned conventional problems, and covers a wide detection range from a low flow rate range to a high flow rate range.
It is possible to detect with high precision and high accuracy.
It is intended to provide a flow-free fluid flow meter .

[0007]

In order to solve the above-mentioned problems, a fluid flow meter of the present invention has a fluid introduction hole for introducing a fluid.
And move according to the flow rate of fluid from this fluid introduction hole.
Fluid shield plate and this fluid shield plate as the end face of the fluid introduction hole
If you support it so that it can be displaced while maintaining the parallel relationship
Together, they are urged to close the end face of the fluid introduction hole.
Detects the position of the flat gimbal spring and the fluid shield plate
And a position detecting means for

A fluid shield plate is used as the position detecting means.
It is made of a conductive material and is attached to the end face of the fluid introduction hole.
A capacitor is formed by providing a ring-shaped electrode,
The displacement of the fluid shield is detected by the capacitance of this capacitor.
It was to so.

A fluid introducing hole for introducing a fluid, and the above-mentioned flow
Displacement moves according to the fluid flow rate from the body introduction part
, The flow is energized so as to close the end face of the fluid introduction hole.
The body shield plate and the center rod and the center rod provided on the downstream side of the fluid shield plate.
And a differential transformer composed of the center rod guide.
When one of the above guides is closed and the center rod is displaced,
I tried to exert the air damper function of.

[0010]

[Function] The fluid shield plate is adapted to the fluid flow rate from the body introduction part.
To move. That is, when the fluid flow rate decreases
The pressure of the fluid it receives and the urging force in the closing direction
Displace in the direction of the end face of the fluid introduction hole until balanced,
Is displaced in the direction away from the end face direction of the fluid introduction hole.

Therefore, the displacement amount of the fluid shield plate
The position detection means detects the
The flow rate can be detected in a wide range up to the flow rate range.

In addition, the fluid shield plate is supported and the fluid introduction hole is provided.
The spring that closes the
Change the fluid shield plate while maintaining the parallel relationship with the end face of the introduction hole.
Since the fluid shield plate moves to the nearest
The followability is extremely good, and therefore flow rate detection is also more accurate.
It will be done accurately.

Moreover, the fluid shield plate has both a shield function and a shield function.
As a result, fluid backflow occurs in any case.
There is nothing to do.

Further , the fluid shield plate is formed of a conductive material.
At the same time, by providing an electrode on the end face of the fluid introduction hole,
Capacitor to configure the displacement movement of the fluid shield plate.
Since it is detected by the change in the amount, it has excellent detection accuracy.
You get a degree. In addition, the center rod of the fluid shield plate and
Air damper machine with differential transformer composed of mandrel guide
Since it is designed to exert its ability, the fluid flow
Even if it fluctuates, the fluid shield plate does not vibrate and is stable.
The flow rate can be detected.

[0015]

Embodiments will be described below with reference to the accompanying drawings.
It

In FIG . 1, the fluid 8 indicated by the arrow is cylindrical.
So that the fluid is introduced from the fluid introduction part 9 to the frame 10.
It

A circular shape is provided opposite to the end surface of the fluid introducing portion 9.
The fluid shield plate 11 includes a circular and flat gimbal spring 14.
It is movably supported via the. This gimbalba
Reference numeral 14 is a connecting portion 15 in which a plurality of ring portions are alternately orthogonal to each other.
The innermost ring part is connected to the
The outermost ring portion of the shielding plate 11 is attached to the frame body 10, respectively.
Are connected.

Therefore, the displacement movement of the fluid shield plate 11 is
It is always performed in parallel with the end surface of the fluid introduction hole 9.
It is something. Further, the gimbal spring 14 is the fluid shield plate 11.
Also has a function of urging the fluid in the direction of the end surface of the fluid introduction hole 9.
It is a thing.

The displacement amount of the fluid shield plate 11
Is a non-contact type position detecting means 13 such as a laser type displacement meter.
It is detected by.

In the above structure, no fluid is flowing.
In this state, the fluid shield plate 11 is moved by the urging force of the gimbal spring 14.
The end face of the fluid introduction hole 9 is pressed against the end face to close it,
Therefore, the fluid flows backward from the frame body 10 toward the fluid introduction hole 9
Even if it tries, it is cut off by the fluid blocking plate 11.

Next, if there is a regular fluid flow, that flow
To the position where the force of the body and the force of the gimbal spring 14 are balanced.
Thus, the fluid shield plate 11 is displaced. The fluid shield plate 11
Displacement amount of movement is one that substantially proportional to the flow rate of the fluid,
When the flow rate is small, the displacement movement is small.
The amount of movement is large.

Therefore, the fluid shielding plate 11
The flow rate can be measured by detecting the position with the position detection means 13.
It can be done.

As described above, the gimbal spring 14
If the constant is set to a predetermined value, the fluid shield plate 11
Easy for wide range of flow rate
In addition, it can be accurately detected.

In addition, the support material for the fluid shield plate 11 is a gimbal.
Displacement depending on the flow rate of the fluid
Movement is performed while maintaining parallel to the end surface of the fluid introduction hole 9.
It does not cause tilting. As a result, as the fluid flow rate fluctuates,
As a displacement meter, it is possible to reliably detect displacement movements when lying
The accuracy of can be further improved.

FIG . 2 shows that the end face of the fluid introducing hole 9 has a ring shape.
The electrode 16 is provided, and the fluid shield plate 11 is made of a conductive material.
This is an example in which a capacitor is formed by using a material.
If such a capacitor is adopted, the fluid shield plate 11
Displacement movement amount can be accurately measured by capacitance in micron order.
I can know.

Also, a ring-shaped electrode that serves as a substantial fluid passage.
The facing portion between the pole 16 and the fluid shielding plate 11 is set wide.
Therefore, the viscosity can be increased, resulting in a minute flow rate.
It is possible to reliably detect the range.

In FIG . 3, the fluid shield plate 11 is a coiled spring.
Is urged toward the end surface of the fluid introduction hole 9 via 12
The center rod 19 protruding toward the flow side can be slid with the guide 20.
The differential transformer 21 is configured to be held at
Is. The bottom of the guide 20 is a sealing plate 22.
It is sealed with and is set in a concave shape.

According to this structure, the central rod 19 and the concave guide
The damper function will be added by the driver 20,
Therefore, the fluid shield plate 11 is provided even for rapid changes in the flow rate.
Will not vibrate and more stable flow detection
It is possible.

[0029]

As described above, the fluid flow meter of the present invention is
Fluid introduction hole for introducing body and fluid from this fluid introduction hole
A fluid shield plate that displaces and moves according to the flow rate, and this fluid shield
Supports the plate and closes the end face of the fluid introduction hole
Flat gimbal spring that urges like
And a position detecting means for detecting the position of the plate.
Therefore, reliable flow rate detection is possible over a wide flow rate range.
Of. In particular, the gimbal supports the fluid shield plate.
Since it is a spring, the displacement movement of the fluid shield plate always flows.
It was done while maintaining a parallel relationship with the end face of the body introduction part,
As a result, the flow rate changes will be reliably followed, and
It is possible to realize high accuracy of the laminar flow rate detection.

Moreover, the fluid shielding plate is simply the end of the fluid introducing portion.
Rather than adjusting the distance to the surface, it also has a valve function
Since it is a thing, it prevents abnormalities such as backflow in advance.
Is.

If the fluid shield plate is made of a conductive material,
Also, provide a ring-shaped electrode on the end face of the fluid introduction hole.
The capacitor is constructed by the
If the capacitance of the capacitor is used for detection, fluid blocking
Displacement and movement of the cover plate can be performed without contact, which improves detection accuracy.
It is possible to increase the number of steps and the ring-shaped electrode
The effective fluid passage area is increased, and
Intellectual property is significantly improved.

Further, a center provided on the downstream side of the fluid shield plate
With a differential transformer composed of rod and concentric rod guides
And one of the guides is closed and the center rod is displaced.
Since the air damper function at the time of
Even if the amount of change is sudden, the fluid shield plate may vibrate.
Without rubbing, it can further improve the detection performance.
It In addition, the displacement movement of the fluid shield plate will not affect the dust.
You can expect the effect of not receiving it.

[Brief description of drawings]

FIG. 1A is 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 sectional view of a fluid flow meter showing another embodiment of the present invention.

FIG. 3 shows a fluid flow meter showing still another embodiment of the present invention .
Cross section

FIG. 4 is a perspective view of a detection unit of a conventional fluid flow meter.

[Explanation of symbols]

9 Fluid introduction hole 11 Fluid blocking plate 13 Position detection means 14 Gimbal spring 16 electrodes 19 center rod 20 guides 21 differential transformer

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Fujieda 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP 61-130818 (JP, A) Actual development Sho 59- 162620 (JP, U) Actually open 3-57762 (JP, U) Actually open 61-122521 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01F 1/00-9 / 02

Claims (2)

(57) [Claims] 1. A fluid introduction hole for introducing a fluid, a fluid shield plate that is displaced and moved from the fluid introduction hole according to a fluid flow rate, and the fluid shield plate is displaced while maintaining a parallel relationship with an end face of the fluid introduction hole. And a fluid-shielding plate conductive gimbal spring that urges the fluid introduction hole to close so as to close the end face of the fluid introduction hole.
Made of a conductive material and has a ring on the end face of the fluid introduction hole.
Forming a circular electrode, forming a capacitor, and the above-mentioned fluid shield plate
A fluid flow meter that detects the displacement of the capacitor by the capacitance of the capacitor . 2. A fluid introducing hole for introducing a fluid, and the fluid.
In addition to moving according to the flow rate of fluid from the inlet,
The fluid shield is urged to close the end face of this fluid introduction hole.
A shield plate, a center rod provided on the downstream side of the fluid shield plate, and
Equipped with a differential transformer composed of the same center rod guide,
Air when one of the guides is closed and the center rod is displaced
A flow meter designed to exert its damper function .