JP2001074520A - Fluidic element and selecting method of applicable article thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold sufficient measuring accuracy while maintaining a flow measuring range to be wide by setting the clearance from a nozzle injection face up to a target so as to be a specific ratio against a main circular arc radius. SOLUTION: A target 4 and an expanding flow passage forming member 5 are injection-molded out plastic material for example, to be formed so as to integratedly provided them on one plate-like cover body. Since the cover body is fitted to a flow passage forming space 27 so as to bring the upstream side edge end is in contact with a nozzle injection face 3, at this time, the clearance Dt from the nozzle injection face 3 to the target 4 satisfies the relation 0.95<=Dt/R<=1.05. in terms of the radius R of a main circular arc the target 4 is provided upright at a position apart from the upstream side of the cover body. Hereby, measuring error can be received within the statutory critical error (3%).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a nozzle having a nozzle ejection surface orthogonal to the flow path direction, which is disposed in the flow path, and the nozzle is provided on the ejection side of the nozzle with respect to the flow path axis. A flow path enlarged portion formed between the enlarged flow path forming members arranged at positions symmetrical in the width direction of the nozzle is provided, and a straight flow of a jet ejected from the nozzle is provided at a central portion of the flow path in the enlarged flow path portion. A target for preventing the nozzle ejection surface is provided on a main arc having a center at a position separated from the nozzle ejection surface by the main arc radius on the downstream side by the main arc radius and having a radius equal to the main arc radius. A sub-arc portion having a center on a parallel straight line with respect to the nozzle ejection surface separated by the separation distance toward the downstream side and extending along a sub-arc formed with the sub-arc radius as a radius, Formed on the inner surface on the end side, Along the arc and the sub-arc, along a common tangent drawn toward the nozzle side toward the nozzle ejection surface, the enlarged flow path smoothly extends from the sub-arc portion to the nozzle ejection surface side A flat portion is formed on the inner surface on the front end side of the forming member, and further, a throttle channel portion having a channel width narrower than the rear end portion of the channel expansion portion is provided downstream of the channel expansion portion, The present invention relates to a fluidic element constituting the flow path expanding section.

[0002]

2. Description of the Related Art Conventionally, in a fluid vibration type flow meter using a fluidic element, as shown in FIG.
° It is configured to be reversed. That is, the fluid F such as gas and water flows from the apparatus inlet 21 and flows into the storage section 25 through the substantially L-shaped bent path 23 having the pressure fluctuation absorbing mechanism 22. The fluid F flowing into the storage section 25
Flows into the nozzle 2 through the introduction part to the fluidic element 1. The fluid F ejected from the nozzle 2 into the fluidic element 1 oscillates while changing the direction of the jet while vibrating the fluid F. It is configured to flow out of the device outlet 26 through the flow path unit 15. In order to detect the vibration of this jet, on both sides of the nozzle 2,
A pair of fluid vibration detection ends 1 is provided near the nozzle ejection surface 3.
8 is arranged.

As shown in FIG. 15, the fluidic element 1 is provided with a nozzle 2 having a nozzle ejection surface 3 orthogonal to the direction of the flow path in the flow path. The enlarged flow path forming member 5 is disposed symmetrically in the width direction of the nozzle 2 with respect to the flow path axis Z, and the enlarged flow path portion 14 is formed between the two enlarged flow path forming members 5. A target 4 for preventing the jet flow f ejected from the nozzle 2 from traveling straight is provided at the center of the flow channel in the flow channel expanding portion 14, that is, on the flow channel axis Z. A throttle channel portion 15 having a channel width narrower than the rear end portion of the path enlarging portion 14 is provided, and the main jet f1 of the jet from the nozzle 2 passes through the throttle 4 While flowing to the path portion 15, the branched flow f3 branched from the main jet flow f1 flows back along the inner surface 6 of the enlarged flow path forming member 5, and becomes a return flow f2 returning to the nozzle 2 side, and the main jet flow The f1 is configured to oscillate fluid vibration by repeatedly moving from one side on the other side to the other side across the target 4 by the action of the return flow f2. The target 4 was arranged such that the distance (Dt) from the nozzle ejection surface 3 matched a main arc radius (R) set to a predetermined dimensional ratio with respect to the nozzle width (W). .

As shown in FIG. 15, the outer shape of the enlarged channel portion 14 is formed on the inner surface 6 of the enlarged channel forming member 5, and the main arc portion 8 and the flat portion 10 are sequentially arranged from the upstream side.
And the sub-arc portion 9. The main arc portion 8 is provided with the main arc radius (R) from the nozzle ejection surface 3 to the downstream side.
A main arc C1 having a center at a main arc center P1 on the flow path axis Z and having a radius equal to the main arc radius (R), and the sub-arc portion 9 is formed by the main arc C1. Above, the separation distance (D) on the downstream side with respect to the nozzle ejection surface 3
The center is located at the sub-arc center P2 on the parallel straight line S with respect to the nozzle ejection surface 3 that is spaced apart from the nozzle ejection surface 3, and is formed by a sub-arc C2 having a radius of the sub-arc (r). The flat part 10
Are formed along a common tangent between the main arc C1 and the sub-arc C2, drawn toward the nozzle 2 toward the nozzle ejection surface 3. The ratio of the throttle passage width (Pw) of the throttle passage portion 15 to the main arc radius (R) set at a predetermined dimensional ratio with respect to the width (W) of the nozzle from the nozzle ejection surface 3 to the downstream side. As 1.27 to 1.6
0 (usually about 1.3).
The sub-arc portion 9 and the throttle channel portion 15 are formed so as to be smoothly connected by a discharge arc portion 11 formed as a quadrant, and the discharge arc portion 11 has a main arc radius (R). Was formed with a radius about 0.33 times as large as.

As shown in FIG. 5, for example, the target 4 is formed so that its plane cross section is surrounded by a circular arc, and a surface opposing the nozzle ejection surface 3 has a concave radius of curvature having a concave radius of curvature (Rh). It is formed in a curved surface, the back surface is formed as a convex curved surface having a curvature of a convex radius of curvature (Rc), and both ends in the width direction are formed as convex curved surfaces having a curvature of an end local radius of curvature (Rt). Then, the thickness of the target 4 in the channel axis Z direction (T
d) is set to about 0.57 times the width (Tw), and the edge local radius (Rt) is set to about 0.068 times the width (Tw). The concave depth (Dh) of the concave curved surface opposing the ejection surface 3 was set to be about 0.24 times the width (Tw). The concave radius of curvature (R
h) and the convex radius of curvature (Rc) were set so that the entire target 4 was formed with a smooth curved surface in accordance with the above conditions.

[0006]

In the above-mentioned conventional fluidic element, the main object is to extend the flow rate measurement range of the element itself by expanding the lower limit of oscillation of fluid vibration in the fluidic element to a lower flow rate side. The specifications of the element have been determined. In order to expand the lower limit of oscillation to the low flow rate side, as shown in FIG. 16, a predetermined dimensional ratio with respect to the width of the nozzle is provided between the enlarged flow path forming member 5 and the nozzle ejection surface 3. The set escape channel opening 13 is provided,
On the back side of the enlarged flow path forming member 5, a release flow path section 17 communicating the release flow path opening section 13 and the downstream side of the throttle flow path section 15 was formed, but the oscillation lower limit was expanded. However, it may be difficult to ensure the measurement accuracy.
The example shown is the case of a fluidic element used for a No. 6 gas meter for measuring city gas (measured amount 300 to 6000 liters / h). In some cases, the dimensional relationship has not yet been determined in terms of the flow measurement accuracy of the vibratory flow meter.

The oscillation lower limit of the fluid vibration in the fluidic element 1 is extended to the low flow rate side while maintaining the measurement accuracy on the high flow rate side of the fluid vibration type flow meter 20 incorporating the fluidic element 1 described above. Thus, the above-described specifications have been determined with a view to enlarging the flow rate measurement range of the element itself. However, in order to increase the assembly accuracy of the fluidic element 1, the fluid vibration type flow meter is used. A flow path forming space 27 having a peripheral wall portion 28 capable of accommodating the fluidic element 1 is formed in the recess 20 so as to form a lid 29 capable of sealing the flow path forming space 27 as shown in FIG. 4, for example. The fluidic element 1 is formed by erecting the target 4 and the enlarged flow path forming member 5 integrally on a plate-like body and sealing the flow path forming space 27 with the lid 29. Tried to try, target 4 provided upright on the lid 29, it becomes very difficult to re-adjust the target distance (Dt) from the nozzle jetting surface 3. In order to erect and integrally form the target 4 and the enlarged flow path forming member 5 on the lid body 29, injection molding is preferable, and this is also effective from the viewpoint of precision control. However, the target 4 is
There is a possibility that the nozzle 9 may be inclined with respect to 9, and it is necessary to confirm the allowable range of the distance from the nozzle ejection surface 3 to the target 4. Therefore, the fluid vibration type flow meter 20
The allowable range of the target separation distance (Dt) from the nozzle ejection surface 3 of the target 4 that can sufficiently maintain the measurement accuracy of the target 4 was determined. This is extremely important from the viewpoint of securing molding accuracy for maintaining measurement accuracy when the target 4 is to be formed integrally with the lid 29 described above.

An object of the present invention is to provide a fluidic element capable of maintaining sufficient measurement accuracy while maintaining a wide flow rate measurement range.

[0009]

[Means for Solving the Problems]

[Characteristic configuration of the present invention]

A first characteristic configuration of the fluidic element according to the present invention according to claim 1 is that a nozzle having a nozzle ejection surface orthogonal to the flow channel direction is disposed in the flow channel, Along with providing an enlarged flow path portion formed between enlarged flow path forming members disposed at positions symmetrical in the width direction of the nozzle with respect to the flow path axis, at the center of the flow path in the enlarged flow path section, Providing a target for preventing the straight flow of the jet flow ejected from the nozzle, further providing a throttle channel portion having a channel width narrower than the rear end of the channel expansion section on the downstream side of the channel expansion section. Has a center at a position spaced apart from the nozzle ejection surface by the main arc radius on the downstream side, and on a main arc having a radius of the main arc radius on the downstream side with respect to the nozzle ejection surface by the separation distance. Parallel to the nozzle ejection surface A sub-arc portion having a center on the top and extending along a sub-arc formed with the sub-arc radius as a radius is formed on the inner surface on the rear end side of the enlarged flow path forming member, and the nozzle is directed toward the nozzle ejection surface. An inner surface on the front end side of the enlarged flow path forming member that smoothly extends from the sub-arc portion to the nozzle ejection surface side along a common tangent to the main arc and the sub-arc drawn toward the side. In a fluidic element having a flat portion formed therein and constituting the flow channel enlarging portion,
The two main arcs are formed symmetrically with respect to the flow path axis, two around the two points located at specific offset distances from the flow path axis, respectively, and formed with the parallel straight line of each of the two main arcs. Of the intersections, the outermost intersection is defined as the center of the sub-arc, and the plane portions are respectively formed by the common arc of the two main arcs and the sub-arc having a center on the main arc, A relief flow path opening is formed between a flat surface and the nozzle ejection surface, and the relief flow path opening and the downstream side of the throttle flow path communicate with the outside of the enlarged flow path forming member. Forming a relief flow path portion, the flow path width of the throttle flow path section, and the throttle flow path section from the center of an arc forming a discharge arc section for smoothly connecting the sub-arc section to the throttle flow path section; The distance to the discharge end, and the discharge arc radius forming the discharge arc portion, And a ratio of a target separation distance (Dt) from the nozzle ejection surface to the target with respect to the main arc radius (R) is 0.95 ≦ Dt / R. ≦ 1.05 is set.

Further, in the fluidic element of the present invention according to the second aspect, the ratio of the target separation distance (Dt) from the nozzle ejection surface to the target in the first characteristic configuration with respect to the main arc radius (R) is as follows: It is even better if the setting is such that 0.98 ≦ Dt / R ≦ 1.03 (second characteristic configuration).

In the case where a large number of fluidic elements manufactured are selected to conform to the reference shape, the target separation distance from the nozzle ejection surface to the target is determined as described in claim 3. D
t, where the radius of the main arc is R, and in the case of a fluidic element having Dt / R = 1.00 as a reference shape, a fluidic element satisfying 0.95 ≦ Dt / R ≦ 1.05 is within an allowable standard. May be established.

[Function and Effect of Characteristic Configuration]

According to the first characteristic configuration of the fluidic element according to the present invention, it is possible to maintain the measurement accuracy within the legal limit while expanding the measurement range in the fluid vibration type flow meter to the low flow rate side. . That is, by setting the ratio of the target separation distance (Dt) from the nozzle ejection surface to the target to the main arc radius (R) so as to satisfy 0.95 ≦ Dt / R ≦ 1.05, the fluid vibration type Prevents leakage of detection of fluid vibration on the small flow rate side in the flow meter, and
The measurement error can be maintained at 3% or less over the entire measurement range.

Here, by adopting the second characteristic configuration, the measurement accuracy is further improved, and the measurement error is reduced by 2%.
It is possible to maintain:

In the case where a large number of the fluidic elements are manufactured, a fluid vibration type flow meter having a measurement error of 3% or less can be obtained by selecting and setting an allowable criterion as described in claim 3. Can be easily manufactured.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a fluidic device according to the present invention will be described. FIG. 1 is a plan sectional view of a fluidic element according to the present invention, and FIG. 2 is a plan sectional view of an example of a gas meter using the fluidic element.
FIG. 3 is an explanatory view showing a dimensional relationship of the fluidic element, FIG. 4 is a perspective view of a member forming the fluidic element, and FIG. 5 is a plan sectional view showing a shape of the target. 14 to FIG. 1 used in the above-described conventional technique.
6 that are the same as or similar to the elements in FIG. 6 are given the same or related reference numerals as those shown in FIGS. 14 to 16, and a part of the detailed description is omitted.

In the fluidic device described below, as shown in FIG. 1, a nozzle 2 having a nozzle ejection surface 3 perpendicular to the flow path direction is provided in the flow path.
On the ejection side of the nozzle 2, an enlarged flow path forming member 5 having an inner surface 6 and a back surface 7 is disposed at a position symmetrical in the width direction of the nozzle 2 with respect to the flow channel axis Z, A flow channel enlarging portion 14 is formed between the enlarged flow channel forming members 5. Also,
On the downstream side of the enlarged flow path section 14, a throttle flow path section 15 having a narrower flow path width than the rear end of the enlarged flow path section 14 is provided. The enlarged flow path forming member 5 includes:
A flow path narrowing portion 12 is formed to form parallel and linear side walls of the throttle flow path portion 15, and a discharge arc portion 11 is formed to smoothly connect the sub-arc portion 9 to the flow path narrowing portion 12.
Further, the enlarged flow path forming member 5 and the nozzle ejection surface 3
A relief channel opening 13 is formed between the first and second channels, and a relief channel 17 communicating the relief channel opening 13 and the throttle channel 15 is provided on the back surface 7 of the enlarged channel forming member 5. Form. Then, a target 4 for preventing the jet flow f ejected from the nozzle 2 from going straight is provided at the center of the flow channel in the flow channel expansion portion 14 (see FIG. 2).

The above fluidic element 1 is, for example, shown in FIG.
As shown in FIG. That is, the fluid vibration type flow meter 20 constituting the gas meter is configured such that the inflow direction I of the fluid F to be measured is
It is configured to be 0 ° reverse. That is, the fluid F such as gas and water flows from the apparatus inlet 21 and reaches the shutoff valve section 24 via the curved path 23 provided with the pressure fluctuation absorbing mechanism 22. The fluid F passing through the shut-off valve portion 24
Flows into the storage unit 25. The fluid F that has flowed into the storage unit 25 is configured to flow out of the device outlet 26 via the fluidic element 1. As the jet f flowing into the fluidic element 1 and jetting from the nozzle 2, while changing the direction of the jet and vibrating, the flow channel enlarging portion 14 provided downstream of the nozzle jetting surface 3, It flows out toward the device outflow port 26 through the throttle passage section 15. In the fluidic element 1, a pair of fluid vibration detecting ends 18 for detecting the vibration of the jet flow are arranged on both sides of the nozzle 2 and near the nozzle jetting surface 3. The fluid vibration detecting end 18 is an opening formed with a small diameter, and communicates with a fluid vibration detecting section having a pair of pressure introducing sections to detect fluid vibration.

The shape of the fluidic element 1 is determined as follows. In other words, as shown in FIG. 1, at a position separated by a main arc radius (R) on the downstream side from the nozzle ejection surface 3, a specific axis is defined from the flow channel axis Z symmetrically with respect to the flow channel axis Z of the nozzle 2. The two points located at the position of the deviation distance (α) are defined as the main arc center P1, and two main arcs C1 formed around the main arc center P1 and having the main arc radius (R) as the radius are: The sub-arc radii (r) centered on the sub-arc centers P2 located at the outermost intersections with the parallel straight line S separated by the separation distance (D) downstream from the nozzle ejection surface 3 are formed as radii. A sub-arc 9 along the sub-arc C2 is formed on the inner surface 6 on the rear end side of the enlarged flow path forming member 5 (see FIG. 3). The main arc C1 drawn toward the nozzle 2 toward the nozzle ejection surface 3
Along the common tangent (see FIG. 3) to the sub-arc C2 and the sub-arc C2, the inner surface 6 at the front end side of the enlarged flow path forming member 5 extends smoothly from the sub-arc portion 9 to the nozzle ejection surface 3 side.
The flow path expanding portion 14 is formed by forming the flat portion 10 on the upper surface of the substrate.

Further, a discharge arc portion 11 for smoothly connecting the sub-arc portion 9 to the flow path narrowing portion 12 is formed. In addition, a relief channel opening 13 is formed with a predetermined interval between the enlarged channel forming member 5 and the nozzle ejection surface 3, and the relief channel opening 13 is provided outside the enlarged channel forming member 5. A relief channel portion 17 is formed to communicate the flow path 13 with the downstream side of the throttle channel portion 15. The sub-arc radius (r), the separation distance (D) of the parallel straight line S from the nozzle ejection surface 3,
Deviation distance (α) of the main arc center P1 from the channel axis Z,
Relief channel opening width (β) of the relief channel opening 13;
The throttle flow path width (Pw) of the throttle flow path section 15, the width (Tw) of the target 4, the discharge arc radius (Rw) which is the radius of the arc forming the discharge arc section 11, and the discharge arc section 11 From the center P3 of the arc to be formed
And the throttle flow path length (Lr) up to the discharge end 16 with respect to the main arc radius (R), respectively.

[0023]

R / R = 1/2 D / R = 3/2 0.04 ≦ α / R ≦ 0.12 0.57 ≦ β / R ≦ 0.66 1.12 ≦ Pw / R ≦ 1. 25 0.57 ≦ Tw / R ≦ 0.62 0.16 ≦ Rw / R ≦ 0.29 Lr / R ≧ 0.54 In addition, the throttle channel length (L
Although no upper limit is set for r), the fluid vibration type flow meter 20
Is set to be less than or equal to the length limited by the design.

As shown in FIG. 4, the target 4 and the enlarged flow path forming member 5 are formed by injection-molding a plastic material and integrally standing on a single plate-like lid 29, respectively. I do. The length (Lz) of the lid 29 in the flow path axial direction is set so as to satisfy 3.21 ≦ Lz / R ≦ 4.33 as a specific dimensional relationship with respect to the main arc radius (R). . FIG. 2 is a cross-sectional plan view of the fluid vibration type flow meter 20 as viewed toward the lid 29.

As shown in FIG. 5, the target 4 is formed so as to be surrounded by a circular arc.
Is formed as a concave curved surface having a radius of curvature of a concave radius of curvature (Rh), the back surface is formed as a convex curved surface having a radius of curvature of a convex radius of curvature (Rc), and both ends in the width direction are end radii of curvature. (R
The target 4 is formed by a convex curved surface having a curvature t).
Is formed as a smoothly continuous curved surface. Then, the concave depth (D) of the concave curved surface opposing the nozzle ejection surface 3
h) the width (Td) of the target in the thickness direction of the target (Td) and the end radius of curvature (Rt).
The dimensional relationships for w) are:

[0026]

## EQU2 ## It is set so that 0.18 ≦ Dh / Tw ≦ 0.28 0.39 ≦ Td / Tw ≦ 0.78 0.062 ≦ Rt / Tw ≦ 0.083.

The cover 29 has an upstream end in contact with the nozzle ejection surface 3 (see FIG. 2).
Is erected at a position separated from the upstream edge of the lid 29 by a target separation distance (Dt). The lid 29,
The upstream edge is attached to the nozzle ejection surface 3 so as to be in contact therewith. The target separation distance (Dt)
Is set as a feature of the present invention such that the ratio to the main arc radius (R) satisfies the following equation: 0.95 ≦ Dt / R ≦ 1.05.

This corresponds to the target separation distance (Dt).
The measurement error of the fluid vibration type flowmeter 20 was changed to a legal limit error in a gas meter based on the experimental results described below, in which the fluidic element 1 having a different value was incorporated into the fluid vibration type flowmeter 20 shown in FIG. This is a condition found to be within 3%. If the ratio is set so as to satisfy 0.98 ≦ Dt / R ≦ 1.03, the fluid vibration type flow meter 2
The measurement error of 0 can be kept within 2%, which is more preferable.

As shown in FIG. 4, when the target 4 is formed by injection molding as a molded body which is integrally erected on a single plate-like lid 29, when the target 4 is tilted after cooling. 0.95 ≦ Dt / R ≦ 1.05 when the condition of the reference shape is Dt / R = 1.00, where R is the main arc radius and Dt is the target separation distance. If the molded body is within the allowable standard, a fluid vibration type flowmeter may be assembled using a fluidic element incorporating the molded body within the allowable range.

[Another Embodiment] Another embodiment shown in the above embodiment will be described below.

<1> In the above embodiment, the nozzle ejection surface 3 is drawn along the common tangent to the main arc C1 and the sub arc C2 drawn toward the nozzle 2 toward the nozzle ejection surface 3. The example in which the flat portion 10 is formed so as to smoothly extend from the sub-arc portion 9 to the side and form an angle of 60 ° with respect to the nozzle ejection surface 3 has been described.
In order to form 0, the common tangent may be formed at an angle with respect to the common tangent line. A fluid element suitable for the purpose can be formed by the combination.

<2> In the above embodiment, the sub-arc radius (r) is set so as to satisfy the dimensional relationship defined as r / R = 1/2 with respect to the main arc radius (R). Although the above example has been described, it is not necessary that the sub-arc radius (r) is exactly 1/2 times the main arc radius (R), but it is approximately 1/2 times (for example, 1/2). .1 to 1 /
(1.9 times), a fluidic element suitable for the purpose can be formed.

<3> In the above embodiment, the separation distance (D) is set so as to satisfy the dimensional relationship defined as D / R = 3/2 with respect to the main arc radius (R). Although the example has been described, the separation distance (D) does not need to be exactly 1.5 times the main arc radius (R), and is approximately 1.5 times (for example, 1.45 to 1). .65
Double), a fluidic element suitable for the purpose can be formed.

<4> In the above embodiment, the width (Tw) of the target 4 satisfies the relationship of 0.57 ≦ Tw / R ≦ 0.62 with respect to the main arc radius (R). Has been described, but this shows a more preferable range for the width (Tw) of the target 4, and the width (Tw)
Is set outside the above range, a suitable fluidic element can be formed.

<5> In the above embodiment, the deviation distance (α) of the main arc center P1 from the flow path axis Z is defined as 0.04 ≦ α / R ≦ Although an example in which the dimensional relationship of 0.12 is satisfied has been described, this shows a more preferable range of the deviation distance (α), and 0.05 ≦ α / R ≦ 0. .115 is more preferable. Even if the deviation distance (α) is set outside the above range, a fluidic element suitable for the purpose can be formed in combination with the setting relating to other specifications.

<6> In the above embodiment, the escape channel opening width (β) of the escape channel opening 13 is set to be 0.57 ≦ β / R ≦ 0 with respect to the main arc radius (R). 66 has been described, but this shows a more preferable range of the escape channel opening width (β), and the escape channel opening width (β) is Even if it is set outside the above range, a fluidic element suitable for the purpose can be formed.

<7> In the above embodiment, the throttle flow path width (Pw) of the throttle flow path section 15 is set to the main arc radius (R).
In the above, an example in which the relationship of 1.12 ≦ Pw / R ≦ 1.25 is satisfied has been described, but this shows a more preferable range of the throttle flow path width (Pw). Therefore, even if the throttle flow path width (Pw) is set outside the above range, a suitable fluidic element can be formed.

<8> In the above embodiment, the discharge arc radius (Rw) is set so that the ratio to the main arc radius (R) satisfies the relationship of 0.16 ≦ Rw / R ≦ 0.29. However, if the discharge arc radius (Rw) is set such that the ratio to the main arc radius (R) satisfies the relationship of 0.18 ≦ Rw / R ≦ 0.26, The maximum error width (ΔE) can be suppressed to within 2%.

<9> In the above-described embodiment, the throttle passage portion 1 is moved from the center P3 of the arc forming the discharge arc portion 11.
The example in which the restricting flow path length (Lr) to the discharge end 16 of No. 5 is set to be 0.54 times or more of the main arc radius (R) has been described. A preferred range is shown, wherein the throttle flow path length (L
Even if r) is out of the above range, that is, Lr / R <0.54, a suitable fluidic element can be formed.

<10> In the above embodiment, the target 4 and the enlarged flow path forming member 5 are formed by injection-molding a plastic material and integrally standing on a single plate-like lid 29, respectively. However, only the target 4 may be integrally formed upright on the lid 29, or only the enlarged flow path forming member 5 may be formed on the lid 29.
In the former case, the enlarged flow path forming member 5 may be erected on the lid 29 by, for example, bonding, and in the latter case, The target 4 may be erected by bonding or planting the target 4 to the lid 29.

<11> In the above embodiment, the target separation distance from the nozzle ejection surface to the target is Dt, and the main arc radius is R, where Dt / R =
An example has been described in which the selection criteria of a fluidic element having a reference shape of 1.00 are set to be within the allowable criteria when 0.95 ≦ Dt / R ≦ 1.05 is satisfied. It is more preferable that the condition to be within the allowable standard is 0.98 ≦ Dt / R ≦ 1.03, and the measurement accuracy of the fluid vibration type flow meter can be further improved.

[0042]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Regarding the above-described fluidic element,
For a specific example applied to the No. 6 gas meter, the flow rate measurement error of each meter was examined. The specifications of the applied fluidic element are as shown in Table 1. The dimensionless index is obtained by dividing the dimension by the main arc radius (R). The aspect ratio of the nozzle opening is about 9.23
It is.

[0043]

[Table 1]

Table 1 shows that the concave depth of the concave curved surface (D
h), the thickness dimension (Td) and the end radius of curvature (Rt) of the target in the thickness direction are respectively set with respect to the ratio to the target width (Tw) described above in order to obtain the dimensionless index. The value obtained by multiplying the dimensionless index of the target width (Tw) is shown.

In the fluidic element subjected to the test, the distance between the target 4 and the nozzle ejection surface 3, that is, the target separation distance (Dt) was set as follows. Note that the dimensionless index described below is Dt / R as described above. As an example, the target separation distance (Dt)
Were prepared as 12.4, 12.7, 13.0, and 13.6 mm, respectively, and for comparison, a device having the target separation distance (Dt) of 14.0 mm was prepared. In the latter, the target separation distance (Dt) is made larger than that of the conventional size. The target separation distance (Dt) and the dimensionless index of each example are as shown in Table 2.

[0046]

[Table 2]

For each of the No. 6 gas meters incorporating the fluidic elements shown in the above examples, 150 liters /
In the range from h to 7200 liters / h, the measurement error (E) was examined by flowing air instead of city gas. The results are shown in FIGS. FIG. 6 shows the result of the error measurement performed on the first embodiment, FIG. 7 shows the error measurement result on the second embodiment, and FIG. 8 shows the error measurement result on the third embodiment. FIG. 9 shows an error measurement result of Example 4, and FIG. 10 shows an error measurement result of Comparative Example. FIG. 11 shows the results of the first embodiment.
To 4 and Comparative Example 1 The flow rate measurement range (that is, the range of 300 to 6000 l / h) obtained from the error measurement results.
3 shows the maximum error width (ΔE) between the maximum error on the plus side and the maximum error on the minus side.

As is clear from comparison of the figures, when the target separation distance (Dt) is smaller than 12.4 mm (Example 1: the dimensionless index is 0.954), the error is smaller on the small flow rate side. The negative peak of (E) tends to increase in the negative direction, and the target separation distance (Dt)
Is larger than 13.6 mm (Example 4), the error (E) within the flow rate measurement range tends to be biased in the plus direction, and the maximum error width (ΔE) tends to increase. In the above examples, Example 3 (see FIG. 8) shows the best results, and is 300 l / h or more.
6000 liters / h or less range (flow measurement range Rd)
Within, the maximum error width (ΔE) is within 2.0%. In the second embodiment (see FIG. 7) as well, the maximum error width (ΔE) is within 2.5%.
Also in the first embodiment (see FIG. 6) and the fourth embodiment (see FIG. 9), the maximum error width (Δ
E) is within 3.0%. On the other hand, in the comparative example, the maximum error width (ΔE) greatly exceeds 3% (see FIG. 10), and the error (E) on the plus side is largely biased in a range of about 3000 l / h or more. Thus, the error on the large flow rate side tends to diverge. From the above, the dimensionless index (Dt) for the target separation distance (Dt)
It has been found that when (/ R) is in the range of 0.977 to 1.046, it falls within the legal error range without fail. From FIG. 11 shown as a diagram based on the above results, there is no practical problem if the dimensionless index (Dt / R) is in the range of 0.95 to 1.065. By the way, in each of the above figures,
The error limit (3%) of the legal error range is indicated by a dashed line.

In the course of the above experiment, for the purpose of confirmation, the limit flow rate at which the detection leak of the fluid vibration occurred was examined for the fluid vibration type flow meter incorporating the fluidic element according to each of the above-mentioned Examples and Comparative Examples. As shown in FIG. 12, when the target separation distance (Dt) is reduced, leakage of detection of fluid vibration is likely to occur, and the lower detection limit flow rate (Qmin) is such that the dimensionless index (Dt / R) is less than 0.94. Becomes larger as this becomes smaller, and exceeds 150 liters / h. In the fluid vibration type flow meter used for the experiment, the target lower limit flow rate was 150 liter / h.
Therefore, it was found that there was no problem in the flow rate measurement within the range of the target separation distance (Dt) obtained based on the above-mentioned maximum error width (ΔE). Further, as a result of examining the measurement limit on the large flow rate side of the vibratory flow meter, as shown in FIG. 13, in order to satisfy the target maximum flow rate (6000 liter / h), the dimensionless index (Dt / R) is 1.0
It turned out that it was required to be 5 or less. From the above results, the preferred range of the dimensionless index (Dt / R) is:
It was confirmed that the ratio was 0.95 to 1.05.

[Brief description of the drawings]

FIG. 1 is a plan sectional view showing an example of a fluidic element according to the present invention.

FIG. 2 is a cross-sectional plan view showing an example of a gas meter to which the fluidic element shown in FIG. 1 is applied.

FIG. 3 is an explanatory plan view showing a dimensional relationship of the fluidic element shown in FIG. 1;

FIG. 4 is a perspective view showing a main part of the fluidic element shown in FIG. 1;

FIG. 5 is a plan sectional view showing the shape of the target shown in FIG. 1;

FIG. 6 is a characteristic diagram of an example of the gas meter according to the present invention.

FIG. 7 is a characteristic diagram of another example of the gas meter according to the present invention.

FIG. 8 is a characteristic diagram of another example of the gas meter according to the present invention.

FIG. 9 is a characteristic diagram of another example of the gas meter according to the present invention.

FIG. 10 is a characteristic diagram of another example of the gas meter.

FIG. 11 is a diagram showing characteristics of the gas meter according to the present invention.

FIG. 12 is a diagram showing another characteristic of the gas meter according to the present invention.

FIG. 13 is a diagram showing another characteristic of the gas meter according to the present invention.

FIG. 14 is a cross-sectional plan view showing an example of a conventional gas meter.

FIG. 15 is a plan sectional view illustrating a fluidic element provided in the gas meter shown in FIG. 14;

FIG. 16 is a plan sectional view illustrating another example of a conventional fluidic element.

[Explanation of symbols]

 2 Nozzle 3 Nozzle ejection surface 4 Target 5 Enlarged flow path forming member 6 Inner surface of expanded flow path forming member 9 Sub-arc section 10 Planar section 11 Discharge arc section 13 Escape channel opening section 14 Channel expansion section 15 Restricted channel section 16 Discharge end 17 Escape channel part C1 Main arc C2 Sub arc D Separation distance Dt Target separation distance f Jet P3 Center of discharge arc part r Sub arc radius R Main arc radius Rw Discharge arc radius S Parallel straight line Z Channel axis α Main arc Center separation

Claims (3)

[Claims] 1. A nozzle having a nozzle ejection surface orthogonal to a flow channel direction is disposed in the flow channel, and a position on the ejection side of the nozzle symmetrical with respect to the flow channel axis in a width direction of the nozzle. A flow path enlarged portion formed between the enlarged flow path forming members disposed in the flow path is provided, and a target for preventing a straight flow of a jet ejected from the nozzle is provided in a flow path central portion of the flow path enlarged section, A throttle channel portion having a channel width narrower than a rear end portion of the channel expansion portion provided downstream of the channel expansion portion; and a main arc radius (R) from the nozzle ejection surface to the downstream side. A straight line parallel to the nozzle ejection surface, having a center at a position apart from the nozzle ejection surface and having a separation distance (D) downstream from the nozzle ejection surface on the main arc having a radius equal to the main arc radius. With the center on the top and the sub-arc radius (r) as the radius A sub-arc portion along the formed sub-arc is formed on the inner surface on the rear end side of the enlarged flow path forming member, and the main arc and the main arc drawn toward the nozzle toward the nozzle ejection surface are drawn. Along the common tangent to the sub-arc, the nozzle extends smoothly from the sub-arc portion to the nozzle ejection surface side to form a flat portion on the inner surface on the front end side of the enlarged flow path forming member, Wherein the main arc is symmetrical with respect to the flow channel axis, and is centered on two points located at specific offset distances (α) from the flow channel axis, respectively. The two main arcs and a sub-arc having a center on the main arc with the outermost intersection of the intersections of the two main arcs with the parallel straight line as the centers of the sub-arcs, respectively. And the common tangent line to form the flat portions, respectively, and A relief flow path opening is formed between the discharge flow path and the discharge flow path, and a relief flow path communicating with the release flow path opening and the downstream side of the throttle flow path is provided outside the enlarged flow path forming member. Forming a flow path width of the throttle flow path section, and a discharge arc section that smoothly connects the sub-arc section to the throttle flow path section from an arc center to a discharge end of the throttle flow path section. A distance and a discharge arc radius forming the discharge arc portion are formed so as to satisfy a predetermined dimensional relationship with the main arc radius, and a target separation distance (Dt) from the nozzle ejection surface to the target is formed. A fluidic element whose ratio to the main arc radius (R) is set so as to satisfy 0.95 ≦ Dt / R ≦ 1.05. 2. A ratio of a target separation distance (Dt) from the nozzle ejection surface to the target to the main arc radius (R) is set so as to satisfy 0.98 ≦ Dt / R ≦ 1.03. Fluidic element. 3. A nozzle having a nozzle ejection surface orthogonal to the flow path direction is disposed in the flow path, and a position on the ejection side of the nozzle symmetrical with respect to the flow path axis in the width direction of the nozzle. A flow path enlarged portion formed between the enlarged flow path forming members disposed in the flow path is provided, and a target for preventing a straight flow of a jet ejected from the nozzle is provided in a flow path central portion of the flow path enlarged section, A throttle channel portion having a channel width narrower than a rear end portion of the channel expansion portion provided downstream of the channel expansion portion; and a main arc radius (R) from the nozzle ejection surface to the downstream side. A center at a position separated only by a distance, and on a main arc having a radius equal to the main arc radius, separated from the nozzle ejection surface by the separation distance on the downstream side, and centered on a straight line parallel to the nozzle ejection surface. And is formed with the sub-arc radius as the radius A sub-arc along the arc is formed on the inner surface on the rear end side of the enlarged flow path forming member, and the main arc and the sub-arc are drawn toward the nozzle toward the nozzle ejection surface. Along a common tangent line, the flat surface portion is formed on the inner surface on the front end side of the enlarged flow passage forming member by smoothly extending from the sub-arc portion on the nozzle ejection surface side to constitute the flow passage enlarged portion. A method for selecting a conforming product when a certain fluidic element is molded, wherein the main arc is located symmetrically with respect to the channel axis and at a position of a specific deviation distance (α) from the channel axis, respectively. Two of the two main arcs are formed as centers, and among the intersections of the two main arcs with the parallel straight line, the outermost intersection is defined as the center of the sub-arc, and the two main arcs and their main arcs are respectively defined. The plane portions are respectively formed by a common tangent line with a sub-arc having a center at Forming a relief flow passage opening between the flat surface portion and the nozzle ejection surface, outside the enlarged flow passage forming member, the relief flow passage opening portion and the downstream side of the throttle flow passage portion. Forming a relief flow passage communicating with the throttle flow passage; and forming a discharge arc connecting the sub-arc portion to the throttle flow passage smoothly from the center of the arc forming the discharge arc. The distance from the discharge end of the path to the discharge arc and the discharge arc radius forming the discharge arc portion are formed so as to satisfy a predetermined dimensional relationship with respect to the main arc radius, and a target from the nozzle ejection surface to the target is formed. When the separation distance is Dt and the radius of the main arc is R, a fluidic element having Dt / R = 1.00 as a reference shape, wherein a fluid satisfying 0.95 ≦ Dt / R ≦ 1.05 is satisfied. Make sure that the Dick element is Method of screening products conforming to select as Dick element.