JP2576609Y2 - Fluid vibration type flow meter - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a fluid vibration type flow meter.

[0002]

2. Description of the Related Art A fluid vibration type flow meter using a fluidic oscillation element as shown in FIG. 4 has been proposed for measuring gas consumption (see Japanese Patent Application Laid-Open No. 4-62426).

[0003] 1 is a fluidic oscillation element, 2 is a slit-shaped nozzle, 4 is provided on the downstream ejection side of the nozzle 2, and is an inner wall of an enlarged flow passage which is symmetrical with respect to a vertical axis passing through the center of the nozzle 2. An enlarged flow channel portion 4 having 4A is formed,
The enlarged flow path section 4 forms a vibration generation chamber. Reference numeral 3 denotes a target, which is arranged in the enlarged flow path unit 4.

[0004] Reference numeral 5 denotes a throttled outlet provided downstream of the enlarged flow path section 4. In the figure, W indicates the left and right width of the fluidic oscillation element 1.

[0005]

In order to put this kind of flow meter into practical use as a gas meter, it is desired that the unit pulse does not change over a wide flow rate range. To realize this, an oscillation element is formed. It is necessary to select an appropriate value for the dimensional ratio of each part of the flow path.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a fluid vibration type flow meter having an optimal dimensional ratio for reducing a flow measurement error.

[0007]

In order to achieve the above object, a fluid vibration type flowmeter according to the present invention comprises a slit-shaped nozzle and an enlarged flow passage formed symmetrically with respect to the axis of the nozzle on the downstream ejection side of the nozzle. An enlarged flow path portion having a wall surface, a target disposed on the axis of the nozzle and in the enlarged flow path portion, and a narrowed outlet provided downstream of the enlarged flow path portion, wherein the dimensional ratio of each portion is as follows: Is formed so as to satisfy the following condition.

(A) B / A = 1 to 1.5 (B) L / A ≦ 0.625 (C) 0.5A ≦ H ≦ 0.7A (D) 1.5b ≦ D ≦ T (E) R ≦ A / 2 where A is the length of the enlarged flow path in the flow direction, B is the width of the enlarged flow path, b is the width of the nozzle, D is the width of the target, and H is the width of the target from the downstream end of the nozzle. The distance to the upstream end, L is the length of the nozzle in the flow direction, T is the diameter of the outlet, and R is the radius of the corner of the inner wall surface of the enlarged flow path.

Of the conditions (a) to (e), the condition (e) may be replaced with the following condition (f). (F) C ≦ A / 2 where C is the chamfer dimension of the corner of the inner wall surface of the enlarged flow channel.

Further, it is effective if the element for generating the fluid vibration is a fluidic oscillation element and the flow meter is a gas meter.

[0011]

The change of the unit pulse can be reduced over a wide range of the flow rate by adopting the dimensional relation satisfying the above conditions.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment of FIG. 1, reference numeral 1 denotes a fluidic oscillation element for generating fluid vibration, 2 denotes a slit-shaped nozzle having a width b and a length L, 3 denotes a target having a width D and a nozzle 2 The distance from the downstream end of the target to the upstream end of the target is H, and is disposed on the axis Y of the nozzle.

Reference numeral 4 denotes an enlarged flow path section having an enlarged flow path inner wall surface 4A formed symmetrically with respect to the axis Y of the nozzle.
The diameter is T at the constricted outlet provided downstream of. The length of the enlarged flow path portion 4 in the flow direction (vertical direction) is A, and the width in a direction perpendicular to the flow direction is B. Also, the four corners of the enlarged flow path portion 4 are rounded with a radius R.

In the embodiment shown in FIG. 1, when the dimensional relationship of each part is determined so as to satisfy the above-mentioned conditions (a) to (e), the unit pulse when the flow rate of the gas of the fluid to be measured is changed is shown in FIG. As shown in Fig. 2, stable over a wide flow rate range, accurate flow rate measurement was possible.

FIG. 3 shows the results of an experiment excluding the conditions (a) to (e), in which the unit pulse greatly fluctuated and the error as a flow meter became large. In the embodiment of FIG. 1 described above, the corner of the enlarged flow path portion 4 is formed in a round shape. However, the same effect can be obtained by replacing the chamfer of the dimension C as shown in the condition (f).

[0016]

The fluid vibration type flow meter according to the present invention is configured as described above, so that a measurement error can be reduced over a wide flow rate range.

Further, the use of the fluidic oscillation element is effective as a gas meter particularly required to be accurate and compact.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of an embodiment of the present invention.

FIG. 2 is a diagram showing a unit pulse of the embodiment of the present invention.

FIG. 3 is a diagram showing a unit pulse.

FIG. 4 is a perspective view of a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fluidic oscillation element 2 Nozzle 3 Target 4 Expansion channel part 4A Expansion channel inner wall surface 5 Exit

Claims (3)

(57) [Scope of request for utility model registration] 1. An enlarged flow path having a slit-shaped nozzle, an enlarged flow path inner wall surface formed symmetrically with respect to the axis of the nozzle on the downstream ejection side of the nozzle, and disposed on the axis of the nozzle and in the enlarged flow path. A fluid vibration type flow meter comprising a target and a narrowed outlet provided downstream of the enlarged flow path section, wherein a dimensional ratio of each section satisfies the following condition. (B) B / A = 1 to 1.5 (b) L / A ≦ 0.625 (c) 0.5A ≦ H ≦ 0.7A (d) 1.5b ≦ D ≦ T (e) R ≦ A / 2 where A is the length of the enlarged flow path in the flow direction, B is the width of the enlarged flow path, b is the width of the nozzle, D is the width of the target, and H is the distance from the downstream end of the nozzle to the upstream end of the target. , L is the length of the nozzle in the flow direction, T is the diameter of the outlet, and R is the corner radius of the inner wall surface of the enlarged flow path. 2. The fluid vibration type flow meter according to claim 1, wherein the following condition (f) is satisfied instead of the condition (e). (F) C ≦ A / 2 where C is the chamfer dimension of the corner of the inner wall surface of the enlarged flow channel. 3. The fluid vibration type flow meter according to claim 1, wherein the element that generates the fluid vibration is a fluidic oscillation element, and the flow meter is a gas meter.