JPH02307015A - Vortex flowmeter - Google Patents

Abstract

PURPOSE:To enable stable vortex generation and to obtain an inexpensive, high- accuracy vortex flowmeter by arranging a turbulence generation body on the center axis of a vortex generation column in parallel to it and molding a generation body and an adjustment member in one body. CONSTITUTION:The vortex generation column 3 arranged in a main conduit 1 consists of an upstream-side vortex generation column 31 and a downstream-side vortex generation column 32. A straightener 4 fitted to the opening part of the main conduit 1 on the fluid entrance side and a straightener 7 fitted to the opening part of a subordinate conduit 2 on the fluid entrance side are supported by fixation members 5b and rivets 6. The turbulence generation body 5a is provided on the entrance surface side of the straightener 4 in parallel to the vortex generation column 3 while aligned with the center of the vortex generation column. The adjustment member 5c is provided integrally with the fixation members 5b and turbulence generation body 5a to restrict the passage cross section of the subordinate conduit 2. Thus, the turbulence generation part 5a and adjustment member 5c are molded in one body, so flow rate characteristics are not affected greatly by the size accuracy of the turbulence generation body 5a, thereby obtaining the inexpensive, high-accuracy vortex flowmeter which has small fluctuations even if there is a turbulence in the flow on the upstream side of the vortex generation column 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vortex flow meter used in internal combustion engines such as vehicles, and particularly for measuring fluids whose flow is highly turbulent.

C. Prior art] When a vortex flowmeter is used in an internal combustion engine of a vehicle, etc., it is known as disclosed in, for example, Japanese Patent Application Laid-Open No. 58-21517 and Japanese Patent Publication No. 62-266.
As disclosed in Japanese Patent No. 86, it is always installed downstream of the air cleaner of the engine. In such a configuration, there is a problem that the stability of the fluid flow is low, so that it is not possible to accurately measure the range from low flow rate to high flow rate. For this reason, for example, Japanese Patent Application Laid-Open No. 61-134620 proposes placing a turbulence generator that generates turbulence in a part of the fluid upstream of the vortex generating column in order to improve the stability of vortex generation. ing.

[Spy H that invention tries to solve]

However, in the above method, for example,
As described in Publication No. 67863, turbulence generators have a strong enough influence to correct the vortex frequency, that is, the flow rate characteristics that should be determined by the vortex generation column, so the vortices generated by the turbulence generators When a columnar and periodic so-called Karman vortex is likely to occur, the vortex generator has a large influence on the flow characteristics, so strict requirements have been placed on the shape and placement accuracy of the turbulence generator.

This invention is like the above! ! II! The purpose of this method is to obtain a stable vortex generation, an inexpensive and highly accurate vortex flowmeter.

[Means to solve the problem]

The vortex flow meter according to the present invention has a main pipe and a sub-duct through which a fluid to be measured flows, a vortex generation column that generates a Karman vortex in the main pipe, and a honeycomb-shaped or wire-shaped rectifier on the inlet side of the main pipe. and, in a vortex flow needle equipped with an adjustment member for regulating the passage cross-sectional area on the inlet side of the sub-conduit, the object to be measured is placed on the inlet surface side of the rectifier on and parallel to the central axis of the vortex generating column. The present invention is characterized in that a turbulence generator that obstructs the flow of fluid is disposed, and the turbulence generator and the adjustment member are integrally molded.

[Function] In this invention, by providing the turbulence generating body upstream of the vortex generating column, turbulence is generated in a part of the fluid, thereby stabilizing the Karman vortex generated downstream of the vortex generating column. It is possible to obtain a vortex with little fluctuation.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a cross-sectional plan view of the vortex flowmeter according to the present invention, FIG. 2 is a sectional view taken along the line ■-■ in FIG. The rV-fV line cross-sectional view of Figure 1 is shown.
It consists of. Reference numeral 3 denotes a vortex generating column disposed within the main pipe 1, which is composed of an upstream vortex generating column 31 and a downstream vortex generating column 32.

4 is a honeycomb-shaped rectifier installed at the frontage of the fluid inlet side of the main conduit 1, and 7 is a honeycomb-shaped rectifier installed at the opening of the sub-conduit 2 on the fluid inlet side.These rectifiers 4.7 are fixed. It is supported by member 5b and rivet 6. 5a is a turbulence generator located on the artificial side of the rectifier 4 at a position coinciding with and parallel to the center of the vortex generating column 3; 5c is a turbulence generator provided with the fixing member 5b and the turbulence generator 5a; This adjustment member is integrally provided and regulates the passage cross-sectional area of the sub-conduit 7.

Next, the operation will be explained. In Figure 1, the fluid is F
, ~F, the fluid immediately upstream of the vortex generating column 3 in the main pipe l is f1. f t+.

The flows become as shown by fgt and fx, and a Karman vortex V is generated in the wake of the vortex generating column 3. Here, if there is no turbulence generator 5a, the fluid [, shown by the broken line] will be generated parallel to the fluid r1°f, but if the turbulence generator 5a is present, the fluid F
In y, turbulence occurs immediately after the turbulence generator 5a. And fluid'! The region surrounded by I+ f 1N is a turbulent region.

It is well known that Karman vortices are likely to occur when there is turbulence in the fluid colliding with the vortex generating column 3.

Here, the turbulent state of the above-mentioned turbulent region E will be explained.

The vortices downstream of the turbulent flow generator 5a have a turbulent shape in a cross section perpendicular to the flow. Moreover, the vortex is a so-called Karman vortex. However, since the flow is divided in the perpendicular cross-sectional direction by the rectifier 4 immediately after the turbulent flow generator 5a, the pillar structure is broken as is clear from the flow velocity distribution shown by Vlf shown in FIG. Therefore, within the turbulent region E, turbulence occurs in both directions parallel to and perpendicular to the flow. Therefore, the turbulent flow generated by the turbulence generating body 5a only serves as a triggering factor for the generation of Karman vortices in the vortex generating column 3, and does not greatly affect the Karman vortex generation period of the vortex generating column 3. Even if the width dimension d of the flow generator 5a changes slightly, the Karman vortex generation period determined by the vortex generation column 3 is not disturbed.
There is no need to improve the dimensional accuracy of the turbulent flow generator 5a.

Here, the dimension d of the turbulence generating body 5a and the vortex generating column 3 are shown in FIG.
In this figure, the solid line shows d/D and fluctuation severity according to the present invention, and the broken line shows the fluctuation rate according to the conventional device.

Further, as is clear from FIGS. 2 and 3, the turbulence generator 5a is made integrally with an adjustment member 5C that regulates the passage cross-sectional area of the sub-conduit 2 of the vortex flowmeter.

This adjustment member 5c has a function of shifting the flow rate characteristics of the vortex flowmeter in a substantially parallel manner, and is commonly used.
As shown in FIG. 3, the width is the adjustment dimension. Therefore, if the turbulence generator 5a is integrally molded with the adjustment member 5c, the support member for the turbulence generator 5a is unnecessary, and There is no need to prepare a special member as the turbulence generator 5a. Furthermore, if the turbulence generator 5a and adjustment member 5C are integrally molded with the fixing member 5b that fixes the rectifier 4.7, the number of parts can be greatly reduced. As a result, the manufacturing and assembly of the vortex flowmeter becomes easy.

In this embodiment, the rectifiers 4 and 7 are honeycomb-shaped, but the same effect as described above can be obtained even if the rectifiers are mesh-shaped rectifiers.

〔Effect of the invention〕

As explained above, according to the present invention, the turbulence generator is arranged on the artificial side of the rectifier upstream of the vortex generating column arranged in the main pipe, and the passage cross-sectional area of the turbulence generator and the sub-duct is Since the regulating member and the regulating member are integrally molded, the flow characteristics are not significantly affected by the dimensional accuracy of the turbulence generator.
Moreover, even if there is turbulence in the flow upstream of the vortex generation column, the vortex I
! This results in a highly accurate and inexpensive vortex flowmeter with little lag. Furthermore, by integrally molding the turbulence generator and the adjustment member, the number of parts can be reduced and the labor involved in manufacturing and assembling can be reduced.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional plan view of a vortex flow meter according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is a front view of the vortex flowmeter seen from the inlet side. Figure 4 is IV-I of Figure 1.
FIG. 5, a cross-sectional view taken along the V line, is a characteristic diagram of the fluctuation rate of the vortex. 2... Main pipe, 2... Sub-duct, 3... Vortex generation column,
4゜7... Rectifier, 5a... Turbulence generator, 5C...
・Adjustment member. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Masuo Oiwa C: L! ' Fig. 2 2: Subconduit Fig. 3, etc. 4 Fig. 5, etc. 0, + 0.2 03 04 05 0.6 0.
7 0.8d/D

Claims (1)

[Claims] It has a main pipe and a sub-duct through which the fluid to be measured flows, a vortex generation column that generates a Karman vortex in the main pipe, a honeycomb-shaped or mesh-shaped rectifier on the inlet side of the main pipe, and a rectifier in the form of a wire on the inlet side of the sub-duct. In a vortex flowmeter equipped with an adjustment member that regulates the cross-sectional area of the passage, turbulence is generated on the inlet surface side of the rectifier on the central axis of the vortex generation column and in parallel thereto, obstructing the flow of the fluid to be measured. A vortex flowmeter characterized in that the turbulence generator and the adjustment member are integrally molded.