JPH10318808A - Vortex flowmeter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vortex flowmeter with improved linearity. SOLUTION: This vortex flowmeter to detect a Karman vortex generating in a vortex generating body and measure flow velocity and flow rate thereof is provided with a columnar vortex generating body 3, which is formed vertically inside a measuring conduit 1 and plugs 12 provided with plane parts 12 which are formed symmetrically on the inner wall of the conduit 1 with the body 1 in between and are parallel to the axis of pipe in the conduit 1, and the quantity of projection of the plane part 12 from the inner wall of the conduit 11 is adjusted, thereby realizing a means 4 for improving linearity to improve the linearity of a vortex flowmeter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vortex flowmeter having improved linearity characteristics.

[0002]

2. Description of the Related Art FIG. 6 is an explanatory view of the configuration of a conventional example generally used in the prior art. For example, Japanese Patent Laid-Open No. 7-71987.
No. Title of Invention; Ultrasonic Fluid Vibration Flowmeter (Japanese Patent Application No. Hei 6-4)
No. 240). FIG. 7 is a side view of FIG.

In FIG. 1, reference numeral 1 denotes a conduit through which a measurement fluid 2 flows. Reference numeral 3 denotes a vortex generator inserted into the pipeline 1.
Reference numerals 4 and 5 denote ultrasonic transmitters and receivers provided on the outer peripheral portion of the pipeline 1 so as to face each other with the pipeline 1 interposed therebetween.

In the above configuration, the measurement fluid 2 is connected to the pipe 1.
Is caused to flow, Karman vortices are generated by the vortex generator 3,
The ultrasonic wave S emitted from the transmitter 4 due to the Karman vortex is modulated by the Karman vortex in the measurement fluid 2 and received by the receiver 5.

[0005]

However, in such an apparatus, the linearity characteristic is limited, and it is difficult to improve the linearity characteristic to ± 0.5% or more.

The present invention solves this problem. It is an object of the present invention to provide a vortex flowmeter with improved linearity characteristics.

[0007]

In order to achieve this object, the present invention relates to (1) a vortex flowmeter for detecting a Karman vortex generated by a vortex generator and measuring a flow velocity flow rate; A column-shaped vortex generator provided vertically, and a plug provided on a pipe wall of the measurement pipe symmetrically with the vortex generator interposed therebetween and having a flat portion parallel to a pipe axis of the measurement pipe; A vortex flowmeter comprising a linear characteristic improving means for improving the linearity characteristic of the vortex flowmeter by adjusting the amount of projection of the flat portion from the pipe wall of the measurement conduit. (2) The vortex flowmeter according to claim 1, wherein the plug is used as an electrode of an ultrasonic vortex flowmeter.

[0008]

In the above configuration, when the measurement fluid is caused to flow through the conduit, Karman vortices are generated by the vortex generator, and the ultrasonic waves emitted from the transmitter are modulated by the Karman vortices of the measurement fluid. And received by the receiver. Then, the plug is moved to adjust the amount of protrusion of the flat portion of the plug from the tube wall of the measurement conduit, so that the linearity characteristic of the vortex flowmeter is improved. Hereinafter, a detailed description will be given based on embodiments.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of a main part of an embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA of FIG. In the figure, the configuration of the same symbol as FIG. 6 represents the same function. Hereinafter, only differences from FIG. 6 will be described.

Reference numeral 11 denotes a linear characteristic improving means. The straight line characteristic improving means 11 has a plug 13 provided symmetrically with respect to the vortex generator 3 on the pipe wall of the measurement pipe 1 and provided with a flat portion 12 parallel to the pipe axis of the measurement pipe 1. The plug 13 adjusts the amount of projection of the flat portion 12 from the pipe wall of the measurement pipe 1 so that the linearity characteristics of the vortex flowmeter can be improved.
It is slidably mounted on the pipe wall of the measurement pipe 1.

In the above-described configuration, the measurement fluid 2 is
Is caused to flow, Karman vortices are generated by the vortex generator 3,
The ultrasonic wave emitted from the transmitter 4 by the Karman vortex is modulated by the Karman vortex of the measurement fluid 2 and received by the receiver 5.

Thus, by moving the plug 13 and adjusting the amount of protrusion of the flat portion 12 of the plug from the tube wall of the measurement conduit 1, adjustment is made so that the linearity characteristic of the vortex flowmeter is improved. .

FIG. 3 shows the measuring line 1 of the flat part 12 of the plug.
2 shows the relationship between the amount of protrusion from the tube wall and the Reynolds number Re and Strohar number St. In FIG. 3, graph 1 shows the case where the flat portion 12 of the plug does not protrude from the tube wall of the measurement conduit 1.

Graph 2 shows the case where the flat portion 12 of the plug projects from the tube wall of the measuring pipe 1 by 0.1 mm.
Graph 3 shows a case in which the flat portion 12 of the plug protrudes from the tube wall of the measurement pipe 1 by 1.1 mm.

Graph 4 shows a case where the flat portion 12 of the plug projects from the wall of the measuring pipe 1 by 1.7 mm.
Graph 5 shows the case where the flat portion 12 of the plug projects 2.3 mm from the tube wall of the measurement pipeline 1.

Here, as shown in FIG. 4, the protruding amount is obtained by (diameter D ₁ of measuring pipe line 1−distance D ₂ between plane portions 12) / 2.

FIG. 5 shows the measuring line 1 of the flat part 12 of the plug.
Of the vortex flowmeter in which the amount of protrusion from the pipe wall is adjusted to the optimum amount of protrusion (Graph 6) and the vortex flowmeter in which the flat portion 12 of the plug does not protrude from the pipe wall of the measurement pipe 1 (Graph 7) ,
It shows the relationship between Reynolds number Re and Strohar number St.

A plane portion 12 which is provided symmetrically with respect to the vortex generator 3 on the pipe wall of the measuring pipe 1 and is parallel to the pipe axis of the measuring pipe 1.
By adjusting the amount of projection of the flat portion 12 from the pipe wall of the measurement pipe 1, the linearity characteristics of the vortex flowmeter can be improved.

As a result, a vortex flowmeter having improved linearity characteristics can be obtained. Specifically, a vortex flowmeter that easily achieves linearity within ± 0.5% is obtained. In the ultrasonic vortex flowmeter, if the protruding plug 13 is used as an electrode of the ultrasonic vortex flowmeter, an ultrasonic vortex flowmeter with good ultrasonic transmission / reception efficiency can be obtained.

[0020]

As described above in detail, according to the first aspect of the present invention, the vortex generator is provided symmetrically on the pipe wall of the measurement pipe and is parallel to the pipe axis of the measurement pipe. The vortex flowmeter can be improved in linearity by adjusting the amount of projection of the flat portion from the pipe wall of the measurement pipe by adjusting the amount of protrusion of the flat portion from the pipe wall. As a result, a vortex flowmeter with improved linearity characteristics is obtained.

According to the second aspect of the present invention, in the ultrasonic vortex flowmeter, if the protruding plug is used for an electrode of the ultrasonic vortex flowmeter, the ultrasonic transmission / reception efficiency is good. A vortex flow meter is obtained.

Therefore, according to the present invention, a vortex flowmeter with improved linearity characteristics can be realized.

[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 a sectional view taken along line AA of FIG.

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

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

FIG. 5 is an operation explanatory diagram of FIG. 1;

FIG. 6 is an explanatory diagram of a configuration of a conventional example generally used in the related art.

FIG. 7 is a side view of FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pipeline 2 Measurement fluid 3 Vortex generator 4 Transmitter 5 Receiver 11 Linearity improving means 12 Flat part 13 Plug

Claims (2)

[Claims] 1. A vortex flowmeter for measuring a flow velocity by detecting Karman vortices generated by a vortex generator, comprising: a columnar vortex generator provided vertically to a measurement pipe; A plug provided symmetrically on the pipe wall of the measurement pipe and having a flat section parallel to the pipe axis of the measurement pipe, by adjusting an amount of protrusion of the flat section from the pipe wall of the measurement pipe; A vortex flowmeter comprising a linear characteristic improving means capable of improving the linearity characteristic of the vortex flowmeter. 2. The vortex flowmeter according to claim 1, wherein said plug is used as an electrode of an ultrasonic vortex flowmeter.