JP3167490B2 - Rectifier structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow meter for various fluids (gas, liquid) such as a gas meter, and more particularly, to a method for transferring a fluid from a wide channel to a pair of narrow channel forming walls. The present invention relates to a structure of a rectifying unit that rectifies and supplies a two-dimensional flow having a uniform flow velocity distribution in a thickness direction of the flow channel to a formed narrow flow channel.

[0002]

2. Description of the Related Art Conventionally, a rectifying section of this type has a wire mesh, a punching metal, a honeycomb, or the like as a rectifier disposed near an inlet of a narrow flow path, and a plurality of fluids arranged in parallel to such members. Rectification is performed by passing through the straight flow path.

[0003]

However, in the above-mentioned prior art, rectification is forcibly performed while utilizing the parallel solid walls forming the respective flow paths. In addition to being largely governed by the turbulence of the fluid flowing into the rectifier, it was necessary to increase the width of the rectifier in the flow direction in order to increase the rectification effect. Therefore,
It was impossible to make the equipment compact, and it was difficult to obtain a structure of a rectifying section having a high rectifying action. Under such circumstances, a semicircular arc-shaped shielding member 10 as shown in FIG.
It has been proposed to perform rectification by providing 0 at the entrance of a narrow channel (Japanese Patent Laid-Open No. 4-160209). However, when such a shielding member 100 is used, there is a problem that the positioning of the shielding member 100 needs to be performed quite accurately. Further, since at least two members, the flow path forming wall 101 and the shielding member 100, are required in the rectifying portion, there is a disadvantage that the manufacturing process is complicated and the cost is increased.

[0004] It is an object of the present invention to provide a two-dimensional flow that is compact and capable of good rectification, and that is sufficiently controlled only by a pair of walls constituting a flow path upstream of a narrow flow path. Is to obtain a structure of a rectifying unit capable of obtaining the following.

[0005]

The feature of the structure of the rectifying section according to the present invention for achieving this object is that the main flow of the fluid which is smoothly connected to one of the narrow flow path forming walls and flows into the narrow flow path. And a curved inner peripheral wall connected to the other narrow flow path forming wall surface and forming a rectifying space together with the curved outer peripheral wall. The flow from the wide flow path to the rectifying space is a curved outer peripheral wall. And a guide restricting portion for narrowing the flow path between the wide flow path and the rectifying space is provided, and a vortex generating space for forming a stationary vortex is provided in the rectifying space on the curved inner peripheral wall side. The operation and effect are as follows.

[0006]

In other words, the fluid flowing from the wide flow passage through the straightening section is guided to the straightening space via the guide throttle section, is straightened in this space, and is supplied to the narrow flow passage. Here, in the rectification space, the flow flows along the curved outer peripheral wall, and is composed of the main flow smoothly flowing into the narrow channel and the stationary vortex formed in the vortex generating space on the curved inner wall side. By the way, in the flow of this configuration, the flow velocity component of the main flow in the thickness direction of the flow path is adjusted to be uniform by the stationary vortex on the inner side. And it is supplied to a narrow channel as a favorable two-dimensional flow.

[0007]

Accordingly, in this configuration, a rectifying section such as a wire mesh is not provided in the flow path, so that a relatively compact rectifying section can be obtained. Furthermore, compared with the case where an arc-shaped shielding member is provided at the entrance portion of the narrow flow path and rectification is performed, there can be obtained one that is comparable in terms of rectification performance and friction loss. FIGS. 3 and 5 show the flow rate-instrument difference characteristics of the fluid vibration type flow meter adopting the rectifying section structure of the present invention.
FIG. 6 and FIG. 10 show the results of the above, and the results of the friction loss of the two. As a result, a rectifying section having a simple configuration and capable of obtaining a two-dimensional flow sufficiently controlled by the shape of the pair of wall surfaces constituting the flow path upstream of the narrow flow path was obtained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A flow measuring device 1 incorporating a fluid vibration type flow meter according to the present invention will be described with reference to FIGS. FIG. 1 is a plan view of the flow rate measuring device 1, and FIG. 2 shows details of main parts of a fluid vibration type flow meter 2 and a rectifying unit 7 incorporated in the flow rate measuring device 1.

First, a schematic configuration of the flow measuring device 1 will be described. The apparatus 1 is configured such that the inflow direction A of the fluid f to be measured is 180 degrees opposite to the outflow direction B. That is, the fluid flowing from the device inflow port 3 flows into the storage section 6 via the shutoff valve section 5. Then, after being subjected to a rectifying action by a rectifying section 7 provided to be connected to the storage section 6, it flows into the nozzle 8. The jet flowing out from the jetting surface 11 of the nozzle becomes an oscillating flow in the flow path expanding section 12 of the fluid vibration type flow meter 2 and flows out of a throttle flow path section 13 provided on the downstream side thereof.

Hereinafter, the configuration and operation of each operation section will be described in more detail. First, the flow up to the nozzle 8 will be described. Fluid f such as gas and water flowing from the apparatus inlet 3 passes through the substantially L-shaped first bent path 4 and the shutoff valve section 5.
Sent to After passing through the shut-off valve section 5, it flows into the storage section 6. The storage section 6 is connected to the rectifying section 7 via a guide throttle section 7d, and is connected to the nozzle 8 on the downstream side. That is, the two-dimensional flow having a uniform flow velocity distribution in the thickness direction of the flow path from the storage section 6 which is a wide flow path to the nozzle 8 which is a narrow flow path formed between the pair of narrow flow path forming wall surfaces 8w. The rectifying unit 7 fulfills the role of rectifying and supplying the fluid. The rectifying section 7 forms a rectifying space S sandwiched between a curved outer peripheral wall 7a formed in a semicircular arc shape and a curved inner peripheral wall 7c provided with a vortex generating wall 7b perpendicular to the flow direction of the nozzle 8. It is provided with. As shown, the curved outer peripheral wall 7a is smoothly connected to one wall surface 8w of the nozzle 8, and the main flow L1 of the flow flowing through the rectification space S
Flows along the curved outer peripheral wall 7a. On the other hand, within the aforementioned rectification space S, the curved inner peripheral wall 7c
The stationary vortex V is formed in contact with the vortex generation wall surface portion 7b on the side (a space in which the vortex is formed is referred to as a vortex generation space Sv). This stationary vortex V is in contact with the above-mentioned main flow L1, and when the main flow L1 is disturbed in the flow velocity in the thickness direction of the flow path,
It works to make this uniform. Now, as described above, the storage section 6 and the flow straightening section 7 are connected by the guide throttle section 7d, and this section 7d is formed to be relatively narrow in cross-sectional area in the cross flow direction (that is, the flow is once throttled). After being separated, it is separated into the main flow L1 and the stationary vortex V) and the main flow L1 of the flow
Is oriented along the above-mentioned curved outer peripheral wall 7a. On this side, the direction of the flow from the storage section 6 which is a wide flow path to the nozzle 8 which is a narrow flow path is curved by 90 ° or more. The main relational dimensions of these portions are shown as follows: width of throttle portion / nozzle width b / wo = 2.0-4.
0 Radius of curved outer peripheral wall / nozzle width Rf / wo = 2.5-
4.5.

Next, the configuration of the nozzle 8 will be described. The nozzle 8 has a width wi of the suction part and a width wo of the ejection part, and between the edge portions thereof is constituted by a pair of linear inner walls 8w as a pair of narrow flow path forming walls.
It is configured to have a constant rectification length Nl. And
In order to obtain this rectification length Nl, as described above, the storage section 6
A protruding portion 9 is formed so as to protrude. The protruding portion 9 is formed of a rectangular member having a protruding portion width NW and a protruding portion length (which is substantially equal to the aforementioned rectification length) Nl. The suction side end 9R of the nozzle 8 in the protruding portion 9 has an arc shape, and the radius of the arc is the nozzle entrance arc diameter rn. The actual numerical relationship is as follows: wi / wo = 0.9 to 1.2 (in the case shown in FIG.
0) rn / wo = 0.25 to 0.62 (in the case shown in FIG. 3,
0.31) Nl / wo = 5.00 to 6.88 (in the case shown in FIG. 3,
6.25) NW / wo = 2.30 to 2.94 (in the case shown in FIG. 3,
2.63).

Next, the configuration of the fluid vibration type flow meter 2 will be described with reference to FIG. The fluid vibration type flow meter 2 includes a nozzle 8, a flow path expanding section 12, and a flow path expanding section 1.
2 is provided with a throttle flow path portion 13 that is smoothly connected to the second flow path 2. In this nozzle 8, the nozzle ejection surface 11
Is perpendicular to the flow path direction. Next, the flow channel enlarging portion 12 will be described. The flow channel enlarging portion 12 includes an enlarged flow channel inner wall surface 15 symmetrical with respect to the axis of the flow channel that coincides with the flow channel direction. It comprises a main arc portion 16 in contact with the nozzle ejection surface 11, a linear enlarged wall portion 17 connected thereto, and a sub-arc portion 18 connected to the linear enlarged wall portion 17. The rear end of the sub-arc portion 18 is connected to the above-described throttle channel portion 13 by an arc-shaped discharge arc portion 19 in the same manner. Further, the flow path expanding portion 12
In the center of the flow path, there is provided a target 20 for preventing the jet flowing from the jetting surface from going straight. Detailed dimensions are shown in the drawings.

It is shown that the detailed structure of this target will be explained. As shown in the figure, this target is formed symmetrically with respect to the axis of the flow path, and has left and right upstream arc portions 2.
In addition to the upstream recess 20b between 0a, the projection 20c further protrudes downstream and is formed as a single arc that is formed as a single arc that makes the side of the target along the flow path direction. That is, the projecting portion 20c has a center on the axis of the flow meter, and has a shape formed by the same circle from the downstream end to both sides (position corresponding to the center) in the flow direction. This target 20 has the effect of stably switching the flow direction of the jet in the minute flow rate region, and forms the overhang portion 20c with a single arc portion,
Since the bulge is extended in the lower part of the flow path and in the cross direction of the flow path as compared with the conventionally used target, the flow control between the target side wall part and the throttle flow path part is ensured, and the measurement is performed. It will further contribute to the expansion of the range.

Here, the first radius of the main arc portion 16 is R, the distance of the center of the sub arc portion 18 from the ejection surface in the flow path direction is L, and the flow of the center of the sub arc portion 18 in the cross flow direction is L. Assuming that the distance from the axis of the path is x1, the second radius of the sub-arc portion 18 is r, the horizontal width of the target 20 is Tw, the vertical width of the target is TL, and the width of the throttle channel portion 13 is P,
When o, R, L, x1, r, Tw, TL, and P are R / wo = 3.0 to 4.7 (in FIG. 3, 10 /
3) L / R = 1.5, x1 / R = (√3) / 2 r / R = 0.5 Tw / wo = 1.56 to 2.00 (in the case shown in FIG. 3,
5/3) TL / wo = 1.0 to 1.5 P / R = 1.24 to 1.62 (in the case shown in FIG.
36). Therefore, the center position of the nozzle ejection surface 11 and the center of the pair of sub-arc portions 18 form an equilateral triangle.

The radius r1 of the discharge arc portion 19 is equal to R / 3, and the maximum transverse dimension of the enlarged flow channel portion 12 is (1).
+ $ 3) Set to R. Further, the distance between the tip end position of the target 20 in the flow path direction from the nozzle ejection surface is Tl, the target 20 and the discharge arc portion 19 described above.
Is formed to be the same as the first radius R which is the radius of the main arcuate portion 16. Further, the distance Z from the nozzle ejection surface 11 to the rear end of the fluid vibration type flow meter 2 is:
Z = 2.59-3.14R.

Hereinafter, measurement results of the fluid vibration type flowmeter 2 having the structure of the rectifying section will be described. First, a description will be given of a measurement permissible error allowed for the fluid vibration type flow meter. In the case of a gas meter, the permissible measurement error (error between the actual flow rate and the value detected by the measuring instrument as a detection value) allowed by the meter is 0.15 to 0.1.
± 2.5% in a range of 6 m ³ / h, and a flow rate of 0.6 to 3
± 1.5% in the range of m ³ / h (FIGS. 3, 5, 7, 9).
Is indicated by the outer frame. ). Further, in the following examples and experimental examples, when testing the flow rate-instrument difference characteristic of the flow meter, the test is performed on air up to a flow rate range of 5 m ³ / h. The reason for this is that the upper limit flow rate value of 3 m ³
This is because a change in Reynolds number when measuring another kind of gas such as methane with respect to / h is taken into consideration.

FIG. 3 shows the flow rate-instrument difference characteristic of the flow rate measuring apparatus provided with the rectifying section shown in FIG. The results are within the standard from the low flow rate range to the large flow rate range, and good results are obtained.
Further, the state of the pressure loss of the flow rate measuring device is shown by a circle in FIG. Compared with the result of the flow measurement device having the configuration of FIG. 8 shown in FIG. 10, good results comparable to those are obtained. FIG. 9 shows the flow rate-instrument difference characteristics of the flow rate measuring device having the configuration shown in FIG.

[Another Embodiment] FIG. 4 shows another embodiment of a flow rate measuring device having a rectifying section obtained based on the same technical idea. In this example, the shape of the curved outer peripheral wall and the shape of the curved inner peripheral wall are substantially the same as those described above, but the guide throttle portion is substantially lower in the drawing opposite to the direction of fluid advection in the nozzle. It is formed as a relatively wide linear flow path from the area to the upper area. Also in the case of this example, the main flow in the rectification space is a swirling flow flowing along the arcuate curved outer peripheral wall, in which a stationary vortex is formed at a position along the curved inner peripheral wall, and the flow flowing into the nozzle is Rectification in the thickness direction is performed well. FIG. 5 shows the flow rate-instrument difference characteristics of this embodiment, and ● in FIG. 6 shows the friction loss of the flow rate measuring device. Although the friction loss is increased as compared with the above-described embodiment, the flow rate-instrument difference characteristic gives a good result, and it can be seen that a good rectification result is obtained.

[Comparative Experimental Example] In the above-described embodiments, the case where a stationary vortex is formed inside the main flow of the swirling flow flowing into the nozzle (giving good results) has been described. A description will be given of the result when the portion is formed only by an arc-shaped flow path formed between substantially parallel wall surfaces and without a vortex generating space. FIG. 7 shows the flow path shape and the flow rate-instrument difference characteristic in this case. Other shapes and dimensions are the same as those shown in FIG. As a result, although the flow rate-instrument difference characteristic falls within the standard, the tendency of the runout in the low flow rate region and the error increase on the large flow rate side is remarkable as compared with the results of FIGS. Therefore, it turns out that this structure is not preferable.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a flow measurement device provided with a rectification unit of the present application.

FIG. 2 is a view showing details of a rectifying unit and a fluid vibration type flow meter.

FIG. 3 is a diagram showing a flow rate-instrument difference characteristic of a flow rate measuring device.

FIG. 4 is a diagram showing a configuration of a flow measurement device according to another embodiment.

FIG. 5 is a diagram showing a flow rate-instrument difference characteristic of another embodiment.

FIG. 6 is a view showing a friction loss state of the flow rate measuring device.

FIG. 7 is a diagram showing a flow rate-instrument difference characteristic when no stationary vortex is formed.

FIG. 8 is a diagram showing a configuration of a proposed rectifying unit structure.

9 is a diagram showing a flow rate-instrument difference characteristic of the flow rate measuring device shown in FIG.

FIG. 10 is a view showing a friction loss state of the flow measuring device shown in FIG. 8;

[Explanation of symbols]

 Reference Signs List 6 Wide flow path 7 Rectifying part 7a Curved outer peripheral wall 7b Vortex generating wall part 7c Curved inner peripheral wall 7d Guide restrictor part 8 Narrow flow path 8w Narrow flow path forming wall surface L1 Main flow S Rectifying space Sv Vortex generating space V Stationary vortex

Continued on the front page (72) Inventor Makoto Okabayashi 4-1-2, Hirano-cho, Chuo-ku, Osaka City, Osaka Prefecture Inside Osaka Gas Co., Ltd. (72) Inventor Tetsuro Naganuma 1-5-2, Kaigan 1-chome, Minato-ku, Tokyo (72) Inventor Yukio Kimura 19-18 Sakurada-cho, Atsuta-ku, Nagoya-shi, Aichi Examiner, Toho Gas Co., Ltd.Masaguchi Moriguchi (56) Reference JP-A-5-40054 (JP, A) JP JP-A-5-67283 (JP, A) JP-A-5-107096 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01F 1/20

Claims (3)

(57) [Claims] A narrow flow path (8) formed between a wide flow path (6) and a pair of narrow flow path forming walls (8w) has a uniform flow velocity distribution in a thickness direction of the flow path. A rectifying section configured to rectify and supply the two-dimensional flow, wherein the main flow (L) of a fluid that is smoothly connected to one of the narrow flow path forming wall surfaces (8w) and flows into the narrow flow path (8);
1) is connected to the curved outer peripheral wall (7a) flowing therethrough and the other narrow flow path forming wall surface (8w), and forms a rectification space (S) together with the curved outer peripheral wall (7a) ( 7c), the flow from the wide channel (6) to the rectification space (S) is along the curved outer peripheral wall (7a), and the wide channel (6) and the rectification space (S) are provided. And a vortex generation space (Sv) that forms a stationary vortex (V) in the rectification space (S) on the curved inner peripheral wall (7c) side. The structure of the rectification unit provided with. 2. The curved outer peripheral wall (7a) is formed in a semicircular arc shape, and the curved inner peripheral wall (7c) has a vortex generating wall surface perpendicular to the flow direction of the narrow flow path (8). 2. The rectifying unit structure according to claim 1, wherein the rectifying unit is configured to include a portion (7 b), and a flow direction from the wide channel (6) to the narrow channel (8) is formed to be curved at least 90 °. . 3. The rectifying unit according to claim 1, wherein the narrow flow path is a nozzle of a fluid vibration type flow meter.