JPH081455Y2 - Vortex flowmeter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a vortex flowmeter, and more particularly to a vortex flowmeter having excellent measurement sensitivity.

[Prior Art] Conventionally, there is a vortex flowmeter as a flowmeter for measuring a flow rate.

This vortex flowmeter generates a so-called Karman vortex street on the downstream side of the vortex generating column provided in the pipeline, and measures the flow rate of the fluid flowing in the pipeline based on the vortex generation cycle. .

A vortex flowmeter of this type is disclosed in, for example, Japanese Patent Laid-Open No. 54-6.
As disclosed in Japanese Patent Laid-Open No. 62-62, there is a method in which the stress generated in the vortex generating column itself due to the generation of the Karman vortex train is detected by a piezoelectric element and the flow rate is measured based on the detection result.

[Problems to be Solved by the Invention] By the way, the piezoelectric element is susceptible to external influences such as vibrations generated in the conduit, and accurately measures the stress generated in the vortex generating column due to the Karman vortex street. There were things I couldn't do.

Also, when the diameter of the pipe is increased, the stress generated in the vortex generating column becomes unbalanced, and it becomes difficult to detect the stress by the piezoelectric element.Therefore, a vortex flowmeter using this type of piezoelectric element has a small size. It could only be adapted to caliber conduits.

The present invention has been made in view of the above circumstances, and provides a vortex flowmeter that is not easily affected by external vibrations and that can perform good measurement even in a large-diameter pipe line. Is intended.

[Means for Solving the Problems] The vortex flowmeter of the present invention is a vortex flowmeter in which a vortex generating column is provided in a pipe line and the flow rate is measured based on a Karman vortex train generated by the vortex generating column, A transmitter for transmitting a surface acoustic wave to the vortex generating column is provided at one end of the vortex generating column, and a receiver for receiving the surface acoustic wave is provided at the other end of the vortex generating column. .

[Operation] According to the vortex flowmeter of the present invention, when the surface acoustic wave is transmitted from the transmitter provided at one end of the vortex generating column, this surface acoustic wave causes the other end of the surface of the vortex generating column to oscillate. Propagates to the side and is received by the receiver provided at the other end.

Here, when a vortex is generated from the vortex generating column, stress is generated in the vortex generating column, so that the propagation characteristics (amplitude, phase, frequency, etc.) of the surface acoustic wave propagating in the vortex generating column are changed.

Then, the surface acoustic wave having the changed propagation characteristic is received by the receiver, and the change in the propagation characteristic of the surface acoustic wave is detected, whereby the vortex generation period is detected and the flow rate of the fluid is measured.

[Embodiment] An embodiment of the vortex flowmeter of the present invention will be described below with reference to FIGS. 1 to 3.

In the figure, reference numeral 1 is a conduit. In this pipeline 1,
The vortex generation column 4 is supported by the support members 3, 3 at a position substantially orthogonal to the flow direction of the fluid (the direction of arrow a in FIG. 3).

At one end 4a of the vortex generating column 4, surface acoustic waves W, W are transmitted to both side faces 5, 5 facing the inner peripheral surface 1a of the conduit 1, respectively, and both side faces 5, 5 of the vortex generating column 4 are generated. Transmitter 6,6 to propagate on the surface of 5
Is provided.

On the other hand, the other end 4b of the vortex generating column 4 is provided with receivers 7, 7 for receiving the surface acoustic waves W, W on the both side surfaces 5, 5 side.

A signal source 8 for generating a predetermined surface acoustic wave W, W from each of the transmitters 6, 6 is connected to each of the transmitters 6, 6, and each of the receivers 7, 7 has this receiver 7. A detector 9 for detecting the surface acoustic waves W, W received by 7, 7 and calculating the flow rate of the fluid flowing in the conduit 1 is connected.

Here, the surface acoustic waves W, W are elastic waves in which energy is concentrated near the surface of the vortex generating column 4 (medium),
The propagation velocity is as slow as about 1 / 100,000 of the electromagnetic wave and the wavelength is short, and the propagation characteristics are extremely sensitively changed by the stress generated in the vortex generating column 4 and the vortex generating column 4
It is not easily affected by the movement of the mass such as the vibration of.

According to the vortex flowmeter configured as described above, the fluid flows in the pipe line 1, and the inner peripheral surface 1a of the pipe line 1 and both side faces of the vortex generating column 4
When it flows into between the vortex generating column 5 and the vortex generating column 5, the fluid is alternately separated on both side surfaces 5 and 5 of the vortex generating column 4, and vortices are alternately generated on the downstream side of the vortex generating column 4 so-called Karman vortex. It becomes a line.

Here, when a vortex is generated from the vortex generation column 4, stress is generated in the vortex generation column 4 due to the generation of this vortex.

Then, when stress is generated in the vortex generating column 4, the propagation characteristics (amplitude, phase, frequency, etc.) of the surface acoustic waves W, W propagating on the surfaces of both side surfaces 5, 5 of the vortex generating column 4 change.

Then, the surface acoustic waves W, W whose propagation characteristics have changed are
It is received by the receivers 7, 7 and detected by the detector 9,
From the change in the propagation characteristics of the surface acoustic waves W, W, the vortex generation period is calculated, and the flow rate of the fluid flowing in the conduit 1 is measured.

As described above, according to the vortex flowmeter of the above-described embodiment, the surface acoustic waves W, W, which are hardly affected by the external vibration, are propagated to the both side surfaces 5, 5 of the vortex generating column 4 and propagated. Using the fact that the propagation characteristics (amplitude, phase, frequency, etc.) of surface acoustic waves W, W are changed by the stress generated in the vortex generating column 4, the vortex generation period is detected and the flow rate of the fluid is measured. Therefore, the vortex generation period can be measured with certainty, and the flow rate of the fluid can be measured extremely accurately. Further, even if the conduit 1 has a large diameter, it is possible to reliably detect the change in the propagation characteristics of the surface acoustic waves W, W as compared with the case where the stress is directly detected as shown in the conventional example. Therefore, the flow rate can be measured.

The flow direction of the fluid (the direction of arrow A in FIG. 3) and the cross-sectional shape of the vortex generating column 4 are not limited to those in the above embodiment.

Further, the specific structure of the vortex flowmeter of the above embodiment is not limited to the embodiment.

[Advantages of Device] As described above, according to the vortex flowmeter of the present invention, the following effects can be obtained.

A surface acoustic wave that is not easily affected by external vibration is propagated to the vortex generating column, and the propagation characteristics (amplitude, phase, frequency, etc.) of this propagated surface acoustic wave are changed by the stress generated in the vortex generating column. By utilizing this, the vortex generation period is detected and the flow rate of the fluid is measured.Therefore, the vortex generation period can be measured reliably, and the fluid flow rate can be measured extremely accurately. It can be carried out.

In addition, even if the pipe has a large diameter, as shown in the conventional example, the flow rate is measured by reliably detecting the change in the propagation characteristic of the surface acoustic wave, as compared with the method of directly detecting the stress. be able to.

[Brief description of drawings]

1 to 3 are views for explaining an embodiment of the present invention. FIG. 1 is a transverse sectional view of a vortex flowmeter, FIG. 2 is a sectional view taken along line AA of the vortex flowmeter, and FIG. FIG. 4 is a side sectional view of the vortex flowmeter. 1 ... Pipe line, 4 ... Vortex generating column, 4a ... One end, 4b ... Other end, 6 ... Transmitter, 7 ... Receiver, W ... Surface acoustic wave.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 62-198716 (JP, A) JP 61-253423 (JP, A) Actual development JP 55-130221 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A vortex flowmeter in which a vortex generating column is provided in a pipe line and a flow rate is measured based on a Karman vortex train generated by the vortex generating column, in which a surface acoustic wave is transmitted to the vortex generating column. A vortex flowmeter, wherein a vessel is provided at one end of the vortex generating column, and a receiver for receiving the surface acoustic wave is provided at the other end of the vortex generating column.