JPS58127121A - Vortex flowmeter - Google Patents

Abstract

PURPOSE:To enable the measurement of the low speed of a running fluid as well, by providing projections at a joining point of the inner walls of pipelines, and thereby improving the generation of vortexes. CONSTITUTION:A fluid to be measured which is introduced into a pair of introduction pipes 1 and 2 is straightened by straighteners 3 and 4 and then flows into the introduction pipes 1 and 2, and vortexes are generated by the walls of the pipes at the joining point thereof. For the stable and excellent generation of the vortexes, vortex stabilizing plates 7, 8 and 9 are provided. Moreover, the provision of projections 6 and 6' on the right and left sides of a pipe wall 5 improves the generation of the vortexes even in the area wherein the fluid flows at low speed. The frequency of generation of these vortexes is detected by vortex detectors 10 and 10'.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a pair of introduction pipes for introducing measurement fluid, and detects the frequency of occurrence of vortices occurring at a confluence point where the measurement fluid flowing through the introduction pipes joins. This invention relates to an improvement in a vortex flow meter that detects the flow velocity or flow rate of fluid.

An object of the present invention is to realize a vortex flowmeter that can improve the generation of vortices in an ultra-low flow region and can stably measure flow velocity over a wide range.

In the conventional Karman vortex flowmeter, which detects the occurrence frequency of Karman vortices generated by a vortex generation column installed in the measurement conductor, a protrusion is detected on the inner wall of the pipe downstream of the vortex generation column. Japanese Patent Publication No. 54-10505 proposes a method of controlling the conditions for the generation of the Karman vortex by providing a pair of introduction pipes for introducing the measurement fluid, and the measurement fluid flowing through the introduction pipes joins In an eddy current IT meter designed to detect the frequency of occurrence of vortices that occur at a confluence point, a protrusion is provided on the inner wall of the pipe at the confluence point on the upstream side of the vortex generation part, and the size of the protrusion and the vortex stabilizing plate are By making the width l of
Observations by one person have revealed that it is possible to generate stable vortices over a wide range. It has also been found that the upstream side of the protrusion is connected to the inner wall of the conduit by a gently curved surface, which stabilizes the generation of vortices over a wide range. This invention was made based on these findings.

Embodiments of the invention shown in the figures will be described below. FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIG.
It is a sectional view taken along the line BB in the figure. In the figure, (1) and (2) are a pair of introduction pipes for introducing the measurement fluid, and are equipped with rectifiers (3) and (4), respectively. Further, the introduction pipes (1) and (2) have a rectangular cross section with substantially equal passage cross-sectional areas. The above pair of introduction pipes (1) and (2)
) on the pipe wall (5) at the confluence point there are symmetrical protrusions (6),
(6') is provided. On the downstream side of the pipe wall (5), a large number of vortex stabilizing plates (7), (8), and (9) are sequentially placed at desired intervals to improve the generation of vortices generated at the confluence point. It is arranged as follows.

(](J), (10') are vortex detectors for detecting the frequency of occurrence of vortices.

In the above configuration, the measurement fluid introduced into the pair of introduction pipes (1) and (2) is rectified by the rectifiers (3) and (4), respectively, and the fluid is rectified by the respective introduction pipes (1) and (2). flow inside.

The generation of a vortex, which is generated by the pipe wall (5) at the confluence point where the measurement fluids introduced into the introduction pipes (1) and (2) respectively meet, is continuously determined and made good. For this reason, vortex stabilizers (7), (8), and (9) are arranged.
A periodic vortex corresponding to the flow velocity of the measurement fluid is generated downstream of the vortex stabilizing plate (9). The frequency of occurrence of this vortex is detected by the vortex detectors (10) and (10'), and the flow velocity or flow rate of the fluid to be measured is detected in the same way as a conventional Karman vortex flowmeter.

This departure F! A has protrusions (6) on the left and right sides of the tube wall (5),
(6') is provided to improve the generation of the vortex in the low flow velocity region where the vortex generation frequency is low, and to enable stable flow velocity measurement. Fig. 5 shows a comparison of the vortex detection sensitivity between the present invention and the conventional product without the protrusion (6).
It is possible to provide a vortex flow meter that can stably measure flow velocity over a wide range.

FIG. 4 is a block diagram showing another embodiment of the present invention, in which the protrusion (west, upstream part of (a)) is a curved surface.

The above projections (6), (6i) straddle (6°'), (6
The upstream part of the vortex is made into a gently curved surface so that the fluid to be measured flows easily, and by making the width l of the vortex stabilizing plate equal to the dimension of the protrusion, the pressure loss of this flowmeter can be reduced, and the measurement range can be reduced. I got something wide.

As described above, the present invention includes a pair of introduction pipes (1), (2) for introducing the measurement fluid, and the introduction pipes (1), (2).
2) A vortex generation part is formed at the confluence point where the measurement fluid flowing through the vortex generation part joins, and the flow velocity or flow rate of the measurement fluid is detected by detecting the frequency of occurrence of the vortex generated downstream of the vortex generation part. In this case, a protrusion (6) was provided on the inner wall of the pipe at the confluence point, which facilitated the generation of vortices in the low flow velocity region, making it possible to measure the flow velocity at low flow velocity.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIG.
4 is a configuration diagram showing another embodiment of the present invention, and FIG. 5 is a vortex detection sensitivity characteristic diagram of the conventional product and the present invention. ) id pair of inlet tubes, (3), (
4) is a rectifier, (5) is a pipe wall at a confluence point, (6) is a dimpled protrusion, (7), (8), and (9) are vortex stabilizers, (io)
, (Ill') is the vortex detector. Note that the same reference numerals in each figure indicate the same or equivalent parts. Agent Makoto Kuzuno - Figure 1 Figure 4

Claims (3)

[Claims] (1) Completely equipped with a pair of introduction voltages for introducing the measurement fluid;
A vortex generation part is formed at the confluence point where the measurement fluid flowing through the introduction pipe joins, and the frequency of occurrence of the vortex generated downstream of this vortex generation part is detected to detect the flow velocity or fTL amount of the measurement fluid. 2. A vortex flowmeter characterized in that protrusions are provided on the inner wall of the pipe at the confluence point to improve the generation of vortices. (2) The vortex flow rate needle according to claim 1, wherein the upstream side of the protrusion has a gently curved surface so that the measurement fluid can easily flow. (3) Claim 2, characterized in that the device is provided with a fixed vortex plate that improves the generation of vortices generated at the confluence point, and the width l of the vortex stabilizer plate is equal to the size of the protrusion. Vortex flow meter as described.