JPH10170314A - Fluid vibration-type flowmeter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fluid vibration-type flowmeter in which the shape of target is displayed easily by a size and whose production man-hour and fraction defective can be reduced by a method wherein the shape of the target is simplified. SOLUTION: A target 3 is formed to be cylindrical shape perpendicularly from the reference face of an installation base, a recessed face 3a which reaches the center C2 of the cylindrical shape and whose cross section is arc-shaped is formed. The recessed face 3a is directed to a nozzle flow passage, and the center C2 is situated on a center line C1. In this manner, since the shape of the target is simple, its size can be displayed simply when a height H from the reference face, a diameter ϕ, the radius Rt of the recessed face 3a, the depth (h), the width W of the nozzle flow passage and the radius Re of a protruding curve 3c are set. In addition, the target can be mass-produced by using a plastic or the like. At this time, the setting size of the height H or the like is set to be a size within a prescribed range, and ratios of H/W, ϕ/W and Rt/W are set to be values within prescribed ranges. Thereby, it is possible to obtain a fluid vibration-type flowmeter whose measuring range is wide and whose measuring accuracy is high.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid vibration type flow meter for detecting a flow rate from a fluid vibration generated in a jet ejected from a nozzle of a two-dimensional flow path.

[0002]

2. Description of the Related Art As this type of fluid vibration type flow meter, for example, the one shown in FIG. 3 is known. In the fluid vibration type flowmeter FM shown in FIG. 1, a pair of nozzle members 2 and 2 are provided in a housing 1 closed by a cover 5 so that a nozzle flow path 210 is formed in the housing 1 and the nozzle flow An upstream channel 200 and a downstream channel 220 are formed on the upstream side and the downstream side of the path 210, respectively. The downstream flow path 220 includes the nozzle flow path 2
The target 3 is provided on an extension of 10 (on the center line C). The gas (fluid) ejected through the nozzle flow path 210 collides with the target 3 to generate fluid vibration, and the principle is to detect the flow rate based on the fluid vibration.

The housing 1 is formed by a box-shaped rectangular groove 1a formed in a concave shape. Then, by covering the surface of the groove 1a with the cover 5, a two-dimensional flow path including the upstream flow path 200, the nozzle flow path 210, and the downstream flow path 220 is formed. That is, the upstream flow path 20
0, the nozzle flow path 210 and the downstream flow path 220
The height (dimension in the direction perpendicular to the paper surface of FIG. 3) from the reference surface 10 as the bottom surface is constant, and a left-right symmetric two-dimensional flow path is formed via the center line C.

[0004] Further, the housing 1 is configured to be connectable to another flow path via an inlet 1b and an outlet 1c. Further, the housing 1 has a downstream flow path 220.
The pressure outlet 4 is located near the nozzle flow path 210 in FIG.
One is provided. A pressure sensor is connected to these pressure outlets 4, and the pressure sensor detects the fluid vibration of the jet jetting from the nozzle flow channel 210.

[0005] The target 3 is formed integrally with the mounting table 30. The mounting table 30 is formed in a rectangular plate shape, and is fitted into a rectangular mounting recess 10 a formed on the reference surface 10. The installation recess 10a
The mounting table 30 is placed so that the upper surface 30a of the mounting table 30 is flush with the reference plane 10.

The housing 1 has a screw hole 1e for fixing the cover 5 and a screw hole (not shown) for fixing the nozzle member 2. A bolt 6 for fixing the cover 5 is screwed into the screw hole 1e. The nozzle member 2 has a through hole 2a through which the bolt 6 passes, and a through hole 2b of a bolt 7 for fixing the nozzle member 2 to the housing 1.

The fluid vibration type flow meter FM detects the frequency of the fluid vibration through the pressure sensor because the frequency of the fluid vibration is proportional to the flow rate or flow velocity of the gas (fluid). , Which measures the flow rate. The above-mentioned fluid vibration type flow meter FM is L
This measures the flow rate of the P gas, and measures the fluid vibration of the LP gas. However, in the fluid vibration type flow meter FM having the above structure, other gases other than the LP gas,
It is also possible to measure the flow rate of the liquid.

[0008]

In the fluid vibration type flow meter FM as described above, the measurement range is wide,
And it is important to obtain one with excellent measurement accuracy. Since the measurement range and the measurement accuracy are affected by the shape of the target 3, many targets 3 having various shapes have been developed so far. However, since the shape of the target 3 is complicated, there is a problem that it is difficult to display the shape of the target 3 by dimension. In addition, since the shape is complicated, the number of manufacturing steps of the target 3 is increased, and the occurrence rate of defective products is high.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. By simplifying the shape of a target, the shape of the target can be easily displayed by its dimensions. It is an object of the present invention to provide a fluid vibration type flow meter capable of reducing the rate.

[0010]

In order to achieve the above-mentioned object, the invention according to claim 1 is an invention in which a height from a reference plane is formed to be constant and a bilaterally symmetric shape is formed through a center line. It has an upstream flow path as a dimensional flow path, a nozzle flow path and a downstream flow path, and is configured to detect a flow rate based on fluid vibration of a fluid ejected from the nozzle flow path to the downstream flow path. A fluid vibration type flowmeter, wherein a target is provided at a position of the center line in the downstream flow path, and the target is formed in a columnar shape, and has a cross-sectional circle reaching the center of the column. An arcuate concave surface is formed on the side surface, and the concave surface is directed toward the nozzle flow path side, and the center of the concave surface is made to coincide with the center line so as to be perpendicular to the reference surface, and the nozzle is Set the width of the flow path to W, the reference plane For the height of the target H, the size of the target [Phi, the radius of the concave surface of the target was set to Rt, H / W = 2.483~5.033, Φ / W = 1.8
17 to 3.7, and Rt / W = 0.667 to 1.33.

The invention according to a second aspect is characterized in that an upstream flow path, a nozzle flow path, and a two-dimensional flow path which are formed at a constant height from the reference plane and are formed symmetrically with respect to the center line. A fluid vibration type flow meter having a downstream flow path and configured to detect a flow rate based on a fluid vibration of a fluid ejected from the nozzle flow path to the downstream flow path, wherein the downstream flow path A target is provided at the position of the center line in
This target is formed in a cylindrical shape,
A concave surface having an arcuate cross section reaching the center of the cylinder is formed on the side surface, and this concave surface is directed toward the nozzle flow path side, and the center of the concave surface coincides with the center line, and is perpendicular to the reference surface. The width of the nozzle flow path is W, the height of the target from the reference plane is H, the diameter of the target is Φ, and the radius of the concave surface of the target is R.
t, when the depth of the concave surface of the target is h, H / W =
1.65-5.033, Φ / W = 1.817-3.7,
Rt / W = 0.667 to 1.33, h / W = 0.316
It is characterized by having a relationship of 7 to 0.7.

[0012] The present invention is configured as described above.
In the invention according to the first aspect, the shape of the target is simplified. That is, the target is formed in a columnar shape, and has a concave surface with a circular cross section reaching the center of the column on the side surface, and this concave surface is directed toward the nozzle flow path side, and the center of the concave surface is formed. Is made to be perpendicular to the center plane of the two-dimensional flow path and is set up vertically from the reference plane, so that the shape is simple.

Therefore, the dimensions of the shape of the target can be easily displayed by setting the height H from the reference plane, the diameter Φ, the radius Rt of the concave surface, and the depth h of the concave surface.
Moreover, since the shape is simple, it can be mass-produced by using, for example, injection molding using a polymer material such as plastic, and the occurrence of defective products can be reduced by such molding. Therefore, the number of manufacturing steps and the defect rate can be reduced. Further, since the shape is simple, it can be easily manufactured by machining such as a milling machine. In this case, the number of manufacturing steps and the defective rate can be reduced.

When the width of the nozzle channel is W, the height of the target from the reference plane is H, the diameter of the target is Φ, and the radius of the concave surface of the target is Rt, H / W = 2.483.
５5.033, Φ / W = 1.817-3.7, Rt / W
= 0.667 to 1.33, a target having a wide measurement range and good measurement accuracy can be obtained. Therefore, by using a target having the numerical value of each of the above parameters, a target having a different measurement range can be easily developed.

Further, in the invention according to claim 2, similarly to the invention according to claim 1, the shape of the target is simplified, the width of the nozzle flow path is set to W, and the height of the target from the reference plane is set to W. H, when the diameter of the target is Φ, the radius of the concave surface of the target is Rt, and the depth of the concave surface of the target is h, H / W = 1.65 to 5.033, and Φ / W = 1.81.
7 to 3.7, Rt / W = 0.667 to 1.33, h / W
= 0.3167 to 0.7, a target having a wide measurement range and good measurement accuracy can be obtained. Therefore, by using a target having the numerical value of each of the above parameters, a target having a different measurement range can be easily developed.

Further, since the setting range of the target height H is wide, the setting range of the height of the nozzle flow path as a two-dimensional flow path corresponding to this height H is also widened. Therefore, it is possible to easily develop one having a different measurement range.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. However, the same components as those shown in FIG. 3 are denoted by the same reference numerals, and description thereof is omitted.

First, a first embodiment will be described with reference to the drawings. The fluid vibration type flow meter FM shown in this embodiment includes:
A target 3 as shown in FIGS. 1 and 2 is used. That is, the mounting table 30 is formed to be long in the flow direction of the jet flow ejected from the nozzle flow path 210, the length X in the jet direction is 19.95 to 20.0 mm, and the width Y in the direction orthogonal to the jet flow. Is 14.95 to 15.0 mm,
The thickness Z is 2.95 to 3.0 mm. In addition, installation stand 3
0 is the center line C1 of the two-dimensional flow channel shown in FIG. 3 by fitting into the installation recess 10a shown in FIG.
Is to be matched. And the installation base 30 is
The upper surface 30a is on the same plane as the reference plane 10. For this reason, the target 3 is substantially in a state of standing upright from the reference plane 10.

The target 3 is formed in a columnar shape, and has a concave surface 3a having an arc-shaped cross section reaching the center C2 of the column on the side surface. The concave surface 3a is directed to the nozzle flow path 210. At the same time, the center C2 of the concave surface 3a
Correspond to the center lines C and C1. That is, the target 3 is formed symmetrically with respect to the center line C1,
The center C2 of the cylinder coincides with the center C2 of the concave surface 3a. The outer peripheral surface 3b and the concave surface 3a of the target 3 are continuously connected by a smooth convex curved surface 3c.

The diameter Φ of the outer peripheral surface 3b of the target 3
= 5.55-5.55 mm, height H of target 3 =
7.45 to 7.55 mm, radius Rt of concave surface 3a = 2 m
m, the depth h of the concave surface 3a = 0.95 to 1.05 mm, the radius Re of the convex curved surface 3c = 0.95 to 1.05 mm, and the dimension from the upstream end face of the mounting table 30 to the center C2 of the target 3. Lt = 8 to 10 mm, width W of nozzle passage 210 at nozzle approach distance Ln = 1.5 to 3.0 mm, nozzle distance section Ln = 0 to 30 mm, from the downstream end of nozzle passage 210 to center C2 of target 3 Dimensions Lj = 13 to
The one formed to 15 mm is acceptable as having a wide measurement range and good measurement accuracy. Note that the height of the two-dimensional flow path matches the height H of the target 3.

H / W = 2.483-5.033,
Φ / W = 1.817-3.7, Rt / W = 0.667-
The one set as 1.33 is also acceptable as having a wide measurement range and good measurement accuracy.

When Φ is set to 5.45 to 5.55 mm, the measurement range is wide and the measurement accuracy is improved. When Φ is less than 5.45 mm, the jet colliding with the target 3 is located on the downstream side. After passing through the flow path 220, the outlet 1c
Is more likely to flow out of the system, and Φ is 5.55
If it exceeds mm, it collides with the target 3 and hits the upstream side from the bottom of the downstream channel 220, so that it easily flows out of the system. And preferably, Φ = 5.5
mm.

When H is set to 7.45 to 7.55 mm, the measurement range is wide and the measurement accuracy is improved. When H is less than 7.45 mm, the cover or the reference surface 10 on the surface of the flow path is not used. This is because the flow velocity distribution occurs in the height direction due to the influence of a certain bottom surface, and when H exceeds 7.55 mm,
This is because it becomes difficult to maintain the two-dimensional flow. Then, it is preferable to set H = 7.5 mm.

When Rt is set to 2 mm, the measurement range is wide and the measurement accuracy is improved. When Rt is less than 2 mm, the switching of the fluid vibration becomes unstable.
This is because if t exceeds 2 mm, switching is difficult to occur.

When h is set to 0.95 to 1.05 mm, the measurement range is wide and the measurement accuracy is improved because when h is less than 0.95 mm, the switching of the fluid vibration becomes unstable. , H exceeds 1.05 mm, the switching is difficult to occur. Preferably, h is set to 1.0 mm.

When Re is set to 0.95 to 1.05 mm, the measurement range is wide and the measurement accuracy is high because Re is
Is less than 0.95 mm, the fluid vibration becomes unstable, and when Re exceeds 1.05 mm, it is difficult to generate the fluid vibration. Preferably, Re is set to 1.0 mm.

When W is set to 1.5 to 3.0 mm, the measurement range is wide and the measurement accuracy is improved because W is 1.5 to 3.0 mm.
If W is less than 3.0 mm, the flow velocity becomes too high to form a two-dimensional jet, and if W exceeds 3.0 mm, the cross section of the nozzle flow path 210 becomes close to three-dimensional. Is not formed. Then, it is preferable to set W = 2.0 to 3.0 mm.

When Lj = 13.0 to 15.0 mm is set, the measurement range is wide and the measurement accuracy is improved because of Lj
Is less than 13 mm, the speed at which the jet jet from the nozzle collides with the target becomes too high, and the fluid vibration becomes unstable. When Lj exceeds 15 mm, the speed at which the jet collides with the target becomes This is because the flow rate is too low at a low flow rate. And preferably, Lj = 1
It is good to set to 3 to 15 mm.

On the other hand, when H / W = 2.483 to 5.033, the reason why the measurement range is wide and the measurement accuracy is improved is that when H is less than 2.483, the flow rate in the downstream flow path 220 is reduced. This is because the flow velocity distribution is generated due to the influence of the upper and lower covers and the reference surface 10, and when the H / W exceeds 5.033, the two-dimensional flowing water in the downstream flow path 220 approaches the three-dimensional flow. . Preferably, H / W = 3 mm.

When Φ / W is set to 1.817 to 3.7, the reason why the measurement range is wide and the measurement accuracy is good is that Φ / W
If W is less than 1.817, the jet collides with the target 3 and then easily flows out of the system from the outlet 1c. If Φ / W exceeds 3.7, the downstream flow path 220
This is because it collides with the wall surface on the upstream side from the bottom of the fluid, so that it easily flows out from the outlet 1c, and the fluid vibration becomes unstable. Preferably, Φ / W is set to 2.2.

If Rt / W is set to 0.667 to 1.33, the measurement range is wide and the measurement accuracy is good because
When t / W is less than 0.667, fluid vibration becomes irregular, and when Rt / W exceeds 1.33, fluid vibration becomes difficult to occur. Then, it is preferable to set Rt / W = 0.8.

Further, using W as a denominator, H, Φ, Rt
The reason for choosing a dimensionless number with the numerator as the parameter is as follows.

That is, W is selected because it is the most important dimension for determining the two-dimensionality of the jet jet from the nozzle.

The reason for choosing H is that it is an important factor in determining the two-dimensional flow path and the maximum flow rate.

The reason for choosing Φ is a factor that determines the degree to which the jet colliding with the target 3 flows out of the system after causing fluid vibration.

The reason for choosing Rt is that the jet colliding with the target 3 determines the difficulty or frequency of fluid oscillation.

In the fluid vibration type flow meter FM configured as described above, the shape of the target 3 is simplified, and the size and shape of the target 3 can be determined very easily. That is, the target 3 has a diameter Φ = 5.45-5.
It has a cylindrical outer shape of 55 mm, and a radius Rt =
It has a concave surface 3a of 2 mm, and the depth h of the concave surface is 0.95 to 0.95.
1.05, radius Re = 0.9 of convex curved surface 3c
It has a simple shape that can be easily displayed in dimensions, having a size of 5 to 1.05 mm and a height H of 7.45 to 7.55 mm. Therefore, manufacturing becomes easy, and the incidence of defective products can be reduced.

Further, by molding a high-molecular material such as plastic by, for example, injection molding, it is possible to efficiently produce a large number of products and reduce the incidence of defective products.

Next, a second embodiment of the present invention will be described.
The second embodiment is different from the first embodiment in that the height H of the target 3 is different.

That is, the target 3 has H = 4.95.
To 5.05 mm and H = 7.45 to 7.55 mm. Therefore, H = 4.95 to 7.55
mm, diameter Φ = 5.55-5.55 mm, Rt = 2 mm,
h = 0.95 to 1.05 mm, Re = 0.95 to 1.0
5 mm, Lt = 8 to 10 mm, W = 1.5 to 3.0 m
m and dimensions Lj = 13.0 to 15.0 mm are permissible as having a wide measurement range and good measurement accuracy.

Further, in the range of W = 1.5 to 3.0 mm, H / W = 1.65 to 5.033, and Φ / W = 1.
817-3.7, Rt / W = 0.667-1.33, h
If /W=0.3167 to 0.7, a fluid vibration type flowmeter having a wide measurement range and good measurement accuracy can be obtained.

The target 3 having a height H of 4.95 to 5.05 mm and a two-dimensional flow path having a depth corresponding to the height H of the target 3 have a maximum measured flow rate Qmax = 2. 5 m ³ / h. Also, H =
With a target 3 of 7.45 to 7.55 mm and a two-dimensional flow path having a depth corresponding to the height H of the target 3,
In this embodiment, the maximum measured flow rate Qmax = 4 m ³ /
h. That is, the maximum measured flow rate Qmax is 2.5 m
And ^{3 /} h, good fluid oscillatory flowmeter measurement accuracy at different measurement range of 4m 3 / ^h is obtained.

When H = 7.45 to 7.55 mm, the measurement accuracy is improved by setting Lj = 13.0 to 15.0 mm. H = 4.95 to 5.05 m
In the case of m, the measurement accuracy is improved by setting Lj = 13.5 to 14.0 mm.

When H is set to 4.95 to 5.05 mm, the measurement range is wide and the measurement accuracy is improved.
This is because the flow velocity distribution is generated due to the influence of the upper and lower wall surfaces. If H exceeds 5.05 mm, the flow in the downstream flow path 220 approaches a three-dimensional flow. Then, it is preferable to set H = 5.0 mm.

When H / W = 1.65-5.033, the reason why the measurement range is wide and the measurement accuracy is improved is that when H is less than 1.65, the effect of the upper and lower wall surfaces is two. This is because it becomes impossible to hold the dimensional flow,
If W exceeds 5.033, the flow in the downstream flow path 220 approaches a three-dimensional flow, and the fluid vibration becomes unstable. And, preferably, H / W = 2.0-3.0.
It is good to set to.

When h / W = 0.3167 to 0.7, the reason why the measurement range is wide and the measurement accuracy is good is that h / W
If W is less than 0.3167, the fluid vibration becomes unstable, and the measurement accuracy decreases. If h / W exceeds 0.7, the fluid vibration is hardly generated. Then, it is preferable to set h / W = 0.4.

Here, h is selected because it is an important factor in the phenomenon that the flow of the jet is switched.

In the fluid vibration type flow meter FM configured as described above, since the dimensions of the target 3 and other dimensions are set as described above, the height of the target 3 is adjusted according to the depth of the two-dimensional flow path. By simply changing H, it can be used as a fluid vibration type flow meter with various maximum flow rates. Moreover, since the range of the installation position Lj of the target 3 can be widened, it is possible to cope with a slight error in the position. Further, when the raw material is manufactured by molding such as die casting or plastic, it can cope with a slight change in the position of the target 3 at which good measurement accuracy can be obtained.

[0049]

According to the first aspect of the present invention, the shape of the target is simplified. That is, the target is formed in a columnar shape, and has a concave surface with a circular cross section reaching the center of the column on the side surface, and this concave surface is directed toward the nozzle flow path side, and the center of the concave surface is formed. Is made to be perpendicular to the center plane of the two-dimensional flow path and is set up vertically from the reference plane, so that the shape is simple.

For this reason, the shape of the target can be simply displayed by setting the height H from the reference plane, the diameter Φ, the radius Rt of the concave surface, the depth h of the concave surface, and the radius Re of the convex curved surface 3c. can do. Moreover, since the shape is simple, it can be mass-produced by using, for example, injection molding using a polymer material such as plastic, and the occurrence of defective products can be reduced by such molding.
Therefore, the number of manufacturing steps and the defect rate can be reduced. Further, since the shape is simple, it can be easily manufactured by machining such as a milling machine. In this case, the number of manufacturing steps and the defective rate can be reduced.

When the width of the nozzle flow path is W, the height of the target from the reference plane is H, the diameter of the target is Φ, and the radius of the concave surface of the target is Rt, H / W = 2.483.
５5.033, Φ / W = 1.817-3.7, Rt / W
= 0.667 to 1.33, it is possible to obtain a fluid vibration type flowmeter having a wide measurement range and good measurement accuracy. Therefore, by using a target having the numerical value of each of the above parameters, a target having a different measurement range can be easily developed.

According to the second aspect of the invention, similarly to the first aspect of the invention, the shape of the target is simplified, the width of the nozzle flow path is set to W, and the height of the target from the reference surface is set to W. H, when the diameter of the target is Φ, the radius of the concave surface of the target is Rt, and the depth of the concave surface of the target is h, H / W = 1.65 to 5.033, and Φ / W = 1.81.
7 to 3.7, Rt / W = 0.667 to 1.33, h / W
= 0.3167 to 0.7, it is possible to obtain a fluid vibration type flowmeter having a wide measurement range and good measurement accuracy. Therefore, by using the targets having the numerical values of the respective parameters, it is possible to easily develop a fluid vibration type flow meter having a different measurement range.

Further, since the setting range of the height H of the target is wide, the setting range of the height of the nozzle flow path as a two-dimensional flow path corresponding to this height H is also widened. Therefore, it is possible to easily develop a fluid vibration type flow meter having a different measurement range.

[Brief description of the drawings]

FIG. 1 is a plan view showing a target of a fluid vibration type flow meter shown as a first and a second embodiment of the present invention.

FIG. 2 is a view showing a target of the fluid vibration type flow meter, and is a cross-sectional view taken along line II-II of FIG. 1;

FIG. 3 is a plan view of a fluid vibration type flow meter shown as a conventional example.

[Explanation of symbols]

 2 Nozzle member 3 Target 3a Concave surface 10 Reference surface 200 Upstream flow path 210 Nozzle flow path 220 Downstream flow path C Center line C2 Center FM Fluid vibration type flow meter

Claims (2)

[Claims] An upstream flow path, a nozzle flow path, and a downstream flow path as two-dimensional flow paths formed at a constant height from a reference plane and symmetrically about a center line are provided. A fluid vibration type flowmeter configured to detect a flow rate based on fluid vibration of a fluid ejected from the nozzle flow path to the downstream flow path, wherein the position of the center line in the downstream flow path The target is provided in the shape of a column,
A concave surface having an arcuate cross section reaching the center of the cylinder is formed on the side surface, and this concave surface is directed toward the nozzle flow path side, and the center of the concave surface coincides with the center line, and is perpendicular to the reference surface. When the width of the nozzle flow path is W, the height of the target from the reference surface is H, the diameter of the target is Φ, and the radius of the concave surface of the target is Rt, H / W = 2. 483-5.033 Φ / W = 1.817-3.7 Rt / W = 0.667-1.33 A fluid vibration type flowmeter characterized by the following relationship. 2. An upstream flow path, a nozzle flow path, and a downstream flow path as two-dimensional flow paths which are formed at a constant height from a reference plane and are formed symmetrically with respect to a center line. A fluid vibration type flowmeter configured to detect a flow rate based on fluid vibration of a fluid ejected from the nozzle flow path to the downstream flow path, wherein the position of the center line in the downstream flow path The target is provided in the shape of a column,
A concave surface having an arcuate cross section reaching the center of the cylinder is formed on the side surface, and this concave surface is directed toward the nozzle flow path side, and the center of the concave surface coincides with the center line, and is perpendicular to the reference surface. The width of the nozzle flow path is W, the height of the target from the reference surface is H, the diameter of the target is Φ, the radius of the concave surface of the target is Rt, and the depth of the concave surface of the target is h. H / W = 1.65-5.033 Φ / W = 1.817-3.7 Rt / W = 0.667-1.33 h / W = 0.3167-0.7 A fluid vibration type flow meter, comprising: