JP2000186950A - Karman vortex ultrasonic flowmeter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To downsize a device as a whole, and to reduce assembling construction cost. SOLUTION: This flowmeter device is provided with a Karman vortex ultrasonic flow meter 31, having a prismatic vortex generator inserted into a measuring pipe line and to detect a vortex frequency generated by the vortex generator to measure a flow rate, and a valve 2 provided in a downstream of the flowmeter 31. An upper stream end part 211 of the valve 2 is attached directly to a downstream end part 311 of the flowmeter 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Karman vortex ultrasonic flow meter device in which the entire device can be reduced in size and assembly costs can be reduced.

[0002]

2. Description of the Related Art FIG. 6 is a diagram for explaining the configuration of a Karman vortex flowmeter used in a conventional Karman vortex flowmeter device. For example, Japanese Patent Application Laid-Open No. 3-020618 (Japanese Patent Application No. 1-303256). No.).

In FIG. 1, a conduit 10 is a measuring fluid FL. Is a conduit through which. The nozzle 11 is provided at a right angle to the pipe 10 and has a cylindrical shape. The vortex generator 12 is inserted at a right angle to the pipe 10 while keeping a gap from the nozzle 11, has a trapezoidal cross section, and has a columnar shape.

[0004] One end of the vortex generator 12 is supported on the conduit 10 by a screw 13, and the other end of the vortex generator 12 is a nozzle 11 by a flange portion 14.
Are fixed by screws or welding. The recess 15
The vortex generator 12 is provided on the flange portion 14 side.

In the recess 15, a first common electrode 16, a piezoelectric element 17, an electrode plate 18, an insulating plate 19, an electrode plate 20, and a piezoelectric element 21, which are all made of metal, are sandwiched in this order from the bottom. Arranged, by pressing rod 22 made of all genus,
These are pressed and fixed. Further, a lead wire 23 is provided from the electrode plate 18, a lead wire 24 is provided from the electrode plate 20,
These are drawn out to terminals A and B, respectively.

Each of the piezoelectric elements 17 and 21 is
The left and right sides of the paper 21 are polarized in opposite directions, respectively, and generate opposite-polarity charges on the upper and lower electrodes with respect to the stress in the same direction.

The electric charge generated in the piezoelectric element 17 is applied to the electrode plate 1.
The electric charge generated between the terminal A connected to the electrode plate 8 and the conduit 10 connected via the first common electrode 16 and generated in the piezoelectric element 21 is connected to the terminal B connected to the electrode plate 20, It is obtained between the pressing rod 20 and the connected line 10.

The charges generated on the two electrode plates 18 and 20 are input to charge amplifiers 25 and 26 as shown in FIG. The output of the charge amplifier 25 and the output of the charge amplifier 26 via the poly 27 are added by an adder 28 to obtain a flow signal.

The flow signal is converted into, for example, a current output and transmitted to a load via two wires (not shown).
Next, the operation of the vortex flowmeter configured as described above will be described with reference to FIGS.

When the measuring fluid FLo flows into the pipe 10,
A vibration due to Karman vortex is generated in the vortex generator 12 in the direction indicated by the arrow F. Due to this vibration, a stress distribution as shown in FIG. 8A and a reverse stress distribution are generated repeatedly in the damage generating body 12.

Each of the piezoelectric elements 17 and 21 has a charge of 10 Q and 1 Q corresponding to a signal stress having a vortex circulation number shown in FIG.
Is repeated. In FIG. 8, for convenience of explanation, the electrode plate 18 or 21 is attached to the left stone with respect to the paper surface.
One of the upper and lower electrodes is equivalent to the first common electrode 16 or the pressing rod 22.

On the other hand, the pipe line 10 also generates a pipe line vibration which causes noise. This pipeline vibration has a drag direction in the same direction as the fluid flow, a lift direction perpendicular to the fluid flow,
It is divided into three components in the longitudinal direction of the damage generator.

Among these, the stress distribution with respect to the vibration in the drag direction is as shown in FIG. 8 (b). Positive and negative charges are canceled in one electrode, and no noise charge is generated. Further, as shown in FIG. 8C, the vibration in the longitudinal direction is canceled in the electrode, and no noise charge is generated as in the drag direction.

However, the vibration in the lift direction has the same stress distribution as the signal stress, and generates noise charges. Therefore, the following calculation is executed to eliminate the noise charge.

The electric charges of the piezoelectric elements 17 and 21 are represented by Q ₁ , Q ₂ ,
The signal components are S ₁ and S ₂ , and the noise components in the lift direction are N ₁ and N ₂
When the polarization is reversed by the piezoelectric elements 17 and 21, Q ₁ ,
Q ₂ is represented by the following equation.

Q ₁ = S ₁ + N ₁ -Q ₂ = -S ₂ -N ₂ However, the vector directions of S ₁ and S ₂ and N ₁ and N ₂ are the same.

Here, the relationship between the signal component and the noise component of the piezoelectric elements 17 and 21 is shown in FIG. 9 (this diagram shows the relationship between the noise in the lift direction and the bending moment of the vortex generator with respect to the signal). It has become.

Therefore, as shown in FIG.
When the output of the charge amplifier 25 on the side is added by the adder 28, the output of the piezoelectric element 2 is multiplied by N ₁ / N ₂ together with the poly 27.
When added to the output of the charge amplifier 26 on the first side, Q ₁ −Q ₂ (N ₁ / N ₂ ) = S ₁ −S ₂ (N ₁ / N ₂ ), and the line noise is removed.

Next, the vortex flow meter 1 and the valve 2
As shown in FIG. 10, in the vortex flowmeter device, a straight pipe length L ₁ that is at least 20 times the diameter D of the pipe 10 is provided upstream of the vortex flowmeter 1, and a pipe length is provided downstream thereof. straight pipe L ₂ of more than five times the diameter D of 10 is required.

[0020]

However, in such a device, since the straight pipe lengths L ₁ and L ₂ are required, it is difficult to reduce the size of the device. In addition, installation costs are also high.

An object of the present invention is to solve the above-mentioned problems, and to provide a Karman vortex ultrasonic flow meter device in which the entire device can be reduced in size and assembly cost can be reduced.

[0022]

In order to achieve the above object, according to the present invention, in the first aspect, there is provided a column-shaped vortex generator inserted into a measurement pipe, and the column-shaped vortex generator generates the vortex generator. A Karman vortex ultrasonic flowmeter for measuring a flow rate by detecting a vortex frequency of the Karman vortex ultrasonic flowmeter, and a valve provided downstream of the Karman vortex ultrasonic flowmeter. The upstream end of the valve is directly attached to the downstream end of the sonic flowmeter.

As a result, no disturbance or omission was observed in the measured vortex waveform, and stable data was obtained. Therefore, a Karman vortex ultrasonic flowmeter device that can omit the straight pipe portion downstream of the Karman vortex ultrasonic flowmeter is obtained.

According to a second aspect of the present invention, in the Karman vortex ultrasonic flowmeter according to the first aspect, the Karman vortex ultrasonic flowmeter and the valve are integrally formed from the beginning. .

As a result, the entire device can be further downsized,
A Karman vortex ultrasonic flow meter device that can reduce assembly work costs can be obtained.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is an explanatory diagram of a main part configuration of an embodiment of the present invention.

In FIG. 1, the Karman vortex ultrasonic flow meter 3
1 is connected to the upstream end 211 of the valve 2.
Is directly attached.

Here, the Karman vortex ultrasonic flow meter 3
Reference numeral 1 denotes a Karman vortex flowmeter having a columnar vortex generator inserted into the measurement pipe 10 and detecting a vortex frequency generated by the vortex generator to measure a flow rate. A valve 2, in this case a globe valve, is used.

In the above configuration, for a flow rate range of the flow rate of the measurement fluid FLo from 0.3 m / s to 3.5 m / s,
The output waveform of the measured vortex frequency was measured. Figure 2 shows a flow rate of 0.7
m / s, FIG. 3 shows a flow velocity of 2.4 m / s, and FIG. 4 shows a flow velocity of 3.5 m.
2 shows the measurement results in / s.

FIGS. 2A to 4B show the eddy frequency (A) and its pulsed waveform (B) using an oscilloscope. 2 to 4, the horizontal axis represents time, and the vertical axis represents voltage.

As a result, no disturbance or omission was observed in the measured vortex waveform, and stable data was obtained. Therefore, a Karman vortex ultrasonic flowmeter device that can omit the straight pipe portion downstream of the Karman vortex ultrasonic flowmeter 11 is obtained.

That is, a Karman vortex ultrasonic flow meter device in which the entire device can be reduced in size and the assembly work cost can be reduced is obtained.

FIG. 5 is an explanatory diagram of a main part configuration of another embodiment of the present invention. In the present embodiment, the Karman vortex ultrasonic flowmeter 41 and the valve 42 are integrated into the Karman vortex ultrasonic flowmeter device 40 from the beginning. Further, a Karman vortex ultrasonic flow meter device in which the entire device can be reduced in size and assembly costs can be reduced can be obtained.

The foregoing description has been directed to specific preferred embodiments for the purpose of describing and illustrating the invention. Therefore, the present invention is not limited to the above-described embodiments, and includes many more modifications without departing from the spirit thereof.
This includes deformation.

[0035]

As described above, according to the first aspect of the present invention,
According to the above, the following effects are obtained. Since the upstream end of the valve is directly attached to the downstream end of the Karman vortex ultrasonic flowmeter, a Karman vortex ultrasonic flowmeter device that can omit the downstream straight pipe portion of the Karman vortex ultrasonic flowmeter is provided. can get.

That is, a Karman vortex ultrasonic flow meter device in which the entire device can be reduced in size and assembly cost can be reduced is obtained.

According to the second aspect of the present invention, the following effects can be obtained. Since the Karman vortex ultrasonic flowmeter and the valve are integrally formed from the beginning, a Karman vortex ultrasonic flowmeter device can be obtained in which the entire device can be further reduced in size and the assembly work cost can be reduced.

Therefore, according to the present invention, it is possible to realize a Karman vortex ultrasonic flow meter device in which the entire device can be reduced in size and assembly costs can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a main part configuration of an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of FIG. 1;

FIG. 3 is an operation explanatory diagram of FIG. 1;

FIG. 4 is an operation explanatory diagram of FIG. 1;

FIG. 5 is an explanatory diagram of a main part configuration of another embodiment of the present invention.

FIG. 6 is a diagram illustrating the configuration of a Karman vortex flowmeter used in a Karman vortex flowmeter device that has been generally used conventionally.

FIG. 7 is an electric circuit diagram of FIG. 6;

FIG. 8 is an operation explanatory diagram of FIG. 6;

FIG. 9 is an operation explanatory diagram of FIG. 6;

FIG. 10 is an explanatory diagram of a configuration of a main part of a conventional example generally used in the related art.

[Explanation of symbols]

 2 Valve 211 Upstream end 10 Pipeline 11 Nozzle 12 Vortex generator 13 Screw 14 Flange 15 Depression 17 Piezoelectric element 19 Insulating plate 21 Piezoelectric element 22 Press rod 23 Lead wire 24 Lead wire 25 Charge amplifier 26 Charge amplifier 26 Charger 27 Polium 28 Adder 31 Karman vortex ultrasonic flow meter 311 Downstream end 40 Karman vortex ultrasonic flow meter device 41 Karman vortex ultrasonic flow meter 42 Valve A terminal B terminal FLo Measurement fluid

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shuichi Wakui 2-9-132 Nakamachi, Musashino City, Tokyo Inside Yokogawa Electric Corporation

Claims (2)

[Claims] 1. A Karman vortex ultrasonic flowmeter having a columnar vortex generator inserted into a measurement pipe, detecting a vortex frequency generated by the vortex generator, and measuring a flow rate. A Karman vortex ultrasonic flowmeter device comprising a valve provided downstream of the flowmeter, wherein the upstream end of the valve is directly attached to the downstream end of the Karman vortex ultrasonic flowmeter. Karman vortex ultrasonic flow meter device. 2. The apparatus according to claim 1, wherein the Karman vortex ultrasonic flowmeter and the valve are integrally formed from the beginning.
A Karman vortex ultrasonic flowmeter device as described.