JPS6143205Y2 - - Google Patents

Description

[Detailed description of the invention] This invention provides a columnar vortex generator in the middle of the pipe through which the fluid to be measured flows, and measures the flow velocity or flow rate by detecting the vortex generated from the vortex generator. This relates to flow velocity/flow measuring devices.

Conventionally, a triangular prism, a T-shaped prism, etc. has been used as a vortex generator, and the vortex generator has a first part facing upstream in a fluid flow.
a second surface whose lateral cross section decreases downstream from the first surface; the first surface is provided with a first pressure guiding hole for guiding high pressure; A vortex flow rate is provided by providing second and third pressure guiding holes communicating with the first pressure guiding hole at an intermediate position on the front surface, and providing a vortex detecting element such as a thermistor in the middle of a flow path that communicates these holes. The meter is known.

However, in such a vortex flowmeter, since the first surface facing the upstream side of the vortex generator is a flat surface, the region in which the Strouhal number is stable is narrow, making it unsuitable for wide-range measurement as a flowmeter. . Also,
The corner angle of the intersection of the first surface and the second surface is 60° when the vortex generator is an equilateral triangular prism, and for other shapes, the corner angle is 60° or more, and the fluid does not flow sufficiently at the corner. There was a drawback that separation did not occur and a strong Karman vortex could not be obtained. For this reason, the pressure change between the second and third pressure guiding holes provided on the second surface is small, resulting in a drawback that a high-level signal cannot be obtained.

The present invention is an improvement on the drawbacks of the conventional flow rate/flow measuring device, and will be described below with reference to embodiments shown in the drawings.

In the drawings, reference numeral 1 denotes a columnar vortex generator provided in the middle of the pipe, and the vortex generator 1 is provided through the diameter portion of the main body 2 of the flow rate/flow meter that serves as the pipe, and includes a sealing member 3, 3, it is air-liquid-tightly sealed. Furthermore, a preamplifier 4 is provided at the upper part of the main body 2 to be connected to an eddy detection element to be described later.

Next, as shown in FIG. 2, the vortex generator has a first surface 11 facing the flow, and second surfaces 12 and 13 at the top and bottom of the figure whose lateral cross section decreases as they move downstream of the flow. and has. The first surface 11 is formed as a concave surface 11A having a predetermined radius of curvature,
The second surfaces 12 and 13 are respectively parallel to the fluid flow and include upstream second surfaces 12A and 13A;
A downstream second surface 12B, 1 which is continuous with the surfaces 12A, 13A and whose lateral cross section decreases as it goes downstream.
It consists of 3B. The intersections of the first surface 11 and the upstream second surfaces 12A, 13A become corner portions 14, 14 having sharp angles, and the separation of the fluid is ensured at each corner portion 14, and strong Karman It is configured to generate vortices.

The vortex generator 1 also has a concave surface 11 on the first surface 11.
A first pressure guiding hole 15 is opened at the innermost part of A, and second and third pressure guiding holes 1 are also opened on the second surfaces 12 and 13, respectively.
6 and 17 are open. And the first to third
The pressure guiding holes 15, 16, 17 are connected to the communication pipe 1, respectively.
It communicates with a cylindrical portion 21 bored at the axial center of the vortex generating body 1 via 8, 19, and 20. Here, the second and third pressure guiding holes 16 and 17 open on the upstream second surfaces 12A and 12B, respectively, and the opening positions of the respective pressure guiding holes 16 and 17 are located at the first and second surfaces in the fluid flow. It opens at a distance δ upstream of the opening position of the pressure guiding hole 15 . By configuring like this,
The first pressure hole 15 and the second and third pressure holes 16,1
7 can be made larger, and a high level signal can be detected.

Further, 22 indicates an inner cylinder that is inserted into the cylindrical part 21 of the vortex generator 1, and the inner cylinder 22 is shown in FIGS. 4 and 5.
As shown in the figure, three annular grooves 23 are carved in the upper portion thereof, and two vertical grooves 24 and 25 extending downward in the figure from the annular grooves 23 are carved.
Here, the annular groove 23 is located at a position corresponding to the opening on the cylindrical portion 21 side of the communication pipe 18, and the annular groove 23
3 is covered with a strainer 26 to prevent dust from entering (see Fig. 4). Further, the vertical grooves 24 and 25 hang down to positions corresponding to the openings on the cylindrical portion 21 side of the communication pipes 19 and 20 (see FIG. 3), and a thermistor, for example, , piezoelectric elements, strain gauges, and other vortex detection elements 27 and 28 are provided, respectively. 29 is a lead wire for inputting the signals from the eddy detection elements 27 and 28 to the preamplifier 4.

In the flow velocity/flow measuring device configured in this way, when the fluid flows in the direction indicated by the arrow in FIG. The static pressure on the side where no vortex is generated is lower. As a result, the fluid entering the annular groove 23 from the first pressure guiding hole 15A via the communication path 18 and the strainer 26 flows alternately into the vertical grooves 24 and 25, and flows through the communicating paths 19 and 20 into the annular groove 23. hole 16,
17 alternately flow out. At this time, the vertical groove 24,
The vortex detection elements 27 and 28 provided in the middle of the vertical grooves 25 differentially detect the flow velocity, temperature, pressure, etc. of the fluid flowing in the vertical grooves 24 and 25, and send this detection signal to a preamplifier via a lead wire 29. 4 and measure it as flow velocity or flow rate.

However, since the first surface 11 of the vortex generating body 1 facing the flow is formed as a concave surface 11A, the corner portion 14 becomes a very acute angle, and the separation point of the fluid can be fixed, and the fluid that hits the concave surface 11A can be fixed. The separation becomes more reliable and strong, and the strength of the Karman vortex can be increased. Further, since the first pressure guiding hole 15 is opened at the innermost part of the concave surface 11A, the fluid flow from upstream to downstream is sucked in from the pressure guiding hole 15 as it is, and a good pressure guiding effect can be achieved. At the same time, by opening the second and third pressure guiding holes 16 and 17 directly below the corner portions 14 of the upstream second surfaces 12A and 13A, the pressure is discharged to the point where the pressure is at its minimum state at the moment of separation. can be done,
The pressure change between the first pressure guiding hole 15 and the first pressure guiding hole 15 can be maximized.

In addition, as a result of the experiment, compared to the first pressure guiding hole 15,
By locating the second and third pressure-pulling holes 16 and 17 upstream by a distance δ in the fluid flow, the pressure flows from the first pressure-pulling hole 15 and flows into the second and third pressure-pulling holes 16 and 17.
We were able to obtain a flowmeter in which the flow flowing out from the flowmeter changes regularly and alternately, the Strouhal number has a large stable region, and the instrumental error characteristics are improved down to the low flow rate region.

In the embodiment of the present invention, the second surfaces 12 and 13 of the vortex generator 1 are the upstream second surfaces 12A and 1
3A and the downstream second surfaces 12B and 13B, but the shape is not limited to this, and the upstream second surface parallel to the fluid flow is
It is also possible to use a triangular vortex generator with the surfaces 12A and 13A omitted. In this case, the corner portions 14 can be formed to have even more acute angles than those of this embodiment. In addition, due to manufacturing problems, the inner cylinder 22 has an annular groove 23. Although it has been described that the vertical grooves 24 and 25 are formed and the vortex detection elements 27 and 28 are provided in each of the vertical grooves 24, the point is that the first pressure guiding hole 1
5 and the second and third pressure guiding holes 16 and 17 through a flow path, respectively, and vortex detection elements 27 and 28 are provided in the middle of each flow path.

The flow rate/flow rate detection device of the present invention is as described in detail above, and has the following effects.

Since the first surface facing the upstream side is formed into a concave surface, the corner portion becomes an acute angle, and the separation point of the fluid can be fixed, and separation is ensured.
The strength of the vortex can be increased.

Since the first pressure-conducting hole is opened at the innermost part of the concave surface of the first surface, and the second and third pressure-conducting holes are opened at the second surface, especially directly under the corner of the second surface, the first It is possible to increase the pressure change between the pressure guiding hole and the second and third pressure guiding holes, and it is possible to obtain a high level vortex signal.

If the opening positions of the second and third pressure holes are on the upstream side compared to the opening position of the first pressure hole,
The effects of each of the above items are even greater.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway overall view of the flow rate/flow measuring device according to the present invention, Fig. 2 is a cross-sectional view in the direction of the − arrow in Fig. 1, and Fig. 3 is a perspective view of the appearance of the vortex generator. 4 is an external perspective view of the inner cylinder provided in the vortex generator, and FIG. 5 is a perspective view showing a state in which the strainer is removed from FIG. 4. 1... Vortex generator, 2... Main body, 11... First surface, 11A... Concave surface, 12, 13... Second surface,
12A, 13A... Upstream second surface, 12B, 1
3B...Downstream second surface, 14...Corner part, 1
5, 16, 17... 1st to 3rd pressure guiding holes, 18, 1
9, 20...Communication path, 21...Cylindrical portion, 22...
Inner cylinder, 23... annular groove, 24, 25... vertical groove,
26... Strainer, 27, 28... Vortex detection section.

Claims (1)

[Claims for Utility Model Registration] (1) A columnar vortex generator is provided in the middle of the pipe through which the fluid to be measured flows, and the vortex generator has a first surface facing upstream in the fluid flow, In a flow velocity/flow rate measuring device having a second surface whose lateral cross section decreases downstream from the first surface, the first surface has a concave surface facing the flow, and the first surface has a concave surface facing the flow, and the first surface has a concave surface facing the flow, and the first surface has a concave surface facing the flow. A first pressure guiding hole is opened in the innermost part, and second and third pressure guiding holes are opened in the second surface, and the first pressure guiding hole and the second and third pressure guiding holes are connected to each other. 1. A flow rate/flow rate measuring device, characterized in that the pressure holes are connected to each other by a flow path, and a vortex detection element is provided in the middle of each flow path. (2) The flow rate/flow rate according to claim (1) of the utility model registration claim, in which the second and third pressure holes are opened on the upstream side in the fluid flow compared to the first pressure hole. Measuring device. (3) The second surface is formed from an upstream second surface that is parallel to the fluid flow, and a downstream second surface that is continuous with the upstream second surface and whose lateral cross section decreases downstream. and the intersection of the first surface and the upstream second surface is a corner part, and the second and third pressure guiding holes are opened in the upstream second surface. Flow rate/flow measuring device described in scope (1).