JP2000337935A - Straightening device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the low-cost straightening device which has a small pressure loss and is neither stopped up in a hole nor carried away downstream. SOLUTION: The internal wall surface 3c of a straightening passage 3a is so shaped as to become narrower in the outline shape of a 1/4 ellipse along the flow direction of fluid (front half shape 3c1) and wider in the outline shape of a 1/4 ellipse from the narrowest position along the flow direction of the fluid (rear half shape 3c2). The fluid having a disordered streamline shape is supplied into the straightening passage 3a and its flow is straightened to remove a drift and a vortex, thereby obtaining the same straightening effect with passage of a long straight tube distance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rectifying device for rectifying a flow of a fluid flowing in a pipe.

[0002]

2. Description of the Related Art A fluid flowing in a pipe flows through a curved pipe or an on-off valve and then becomes a drift or a vortex. The drift or eddy current thus generated does not easily return to a normal flow, but returns to a normal flow only after flowing through a long straight pipe. For example, if a flow meter is inserted immediately after a curved pipe, a drift or a vortex is generated there, and a flow meter that is particularly susceptible to the drift, such as the Karman vortex flow meter, cannot perform accurate measurement. In this case, it is conceivable to measure the flow rate after flowing the fluid through the straight pipe until the drift is stabilized.However, the straight pipe portion for that becomes a considerable length, the space factor is poor, and it is very uneconomical. Become. In such a case, if the rectifying device is installed immediately after the curved pipe, the drift and the eddy current can be corrected, and the rectification can be performed as if the fluid flows after flowing through a long straight pipe distance.

[0003]

Conventionally, as a rectifying device, a rectifying device such as a bundled tube, a rectifying device using a perforated plate in which a number of small holes are formed in a honeycomb shape, and changing the diameter and arrangement of the holes. Forcibly rectifying was generally used. However, since such a rectifying device is provided inside the pipe, the pressure loss is large and the hole is clogged. In addition, if the rectifier is made of a weak material and the fixation is poor, the rectifier itself may be swept away by the force of the fluid, and as a result, an unexpected situation may occur downstream. Further, the processing is difficult and the cost is high.

The present invention has been made to solve such a problem, and has as its object to reduce pressure loss, to prevent clogging of holes, and to prevent downstream flow. It is to provide a low-cost rectifier.

[0005]

In order to achieve the above object, the present invention provides a throat-like rectifying passage, and the inner wall surface of the rectifying passage is formed to have a shape substantially along the flow direction of the fluid. The shape is narrowed by a contour shape of a / 4 ellipse, and gradually expanded from the narrowed final position along the flow direction of the fluid. Thus, according to the present invention, the fluid flows along the inner wall surface of the rectification passage formed substantially in the same shape as the streamline of the jet when the water falls naturally, and the drift and the vortex are removed.

[0006] For example, water flowing from a tap of a water tap flows out from a wide mouth in a quiet state and becomes a thin flow.
If the flow is turbulent, the thin flow will be biased to the corners or swirling. The present invention is based on the idea that utilizing this phenomenon in reverse, the turbulence can be rectified if the shape of the pipe wall is fixed with the flow shape in a quiet state. And the shape of the flow at that time (the shape of the streamline of the jet) is 1/4.
Paying attention to approximation to the contour shape of an ellipse, the rectifying effect is obtained by narrowing the inner wall surface of the rectifying passage along the flow direction of the fluid with a contour shape of approximately 1/4 ellipse. In addition, if it spreads suddenly after squeezing, there is a possibility that a new drift or eddy current may occur. Therefore, by gradually expanding the shape, such as expanding with the same 1/4 elliptical contour shape, the effect of rectification is not disturbed. To

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments. FIG. 1 is a side sectional view of a pipeline showing a state where a rectifying device according to the present invention is mounted. In the figure, 1 is an upstream pipeline, 2 is a downstream pipeline, and 3 is a rectifier mounted between the upstream pipeline 1 and the downstream pipeline 2.

The rectifying device 3 has a throat-shaped rectifying passage 3a.
And a flange 3b. The flange 3b is sandwiched between the flange 1a of the upstream pipe 1 and the flange 2a of the downstream pipe 2, and is tightened with a bolt (not shown) so as to be positioned on the upstream side. It is fixed between the pipeline 1 and the downstream pipeline 2.

The shape of the inner wall surface 3c of the rectifying passage 3a narrows along the flow direction of the fluid in the shape of a 1/4 ellipse (first half shape 3c1), and also from the narrowest position along the flow direction of the fluid. It has a shape that is widened by a contour shape of a quarter ellipse (second half shape 3c2). This rectification passage 3
When a fluid having a disturbed streamline is caused to flow in a, and the flow is shaped, the drift and the vortex are removed, and a rectification effect equivalent to a state where the fluid has passed through a long straight pipe distance is obtained.

Hereinafter, the principle of the rectifying passage 3a having a rectifying effect will be described. When water falls naturally, the shape of the streamline of the jet approximates the shape of a 1/4 ellipse contour. This seems to apply to gases as well. FIG. 2 shows that the shape of the streamline of the water jet approximates to the shape of a 1/4 elliptical contour.
This will be described with reference to FIG.

When water spouts from the tip of the circular tube, in a quiet state without any disturbance, the streamline becomes as shown in FIG. 2 (a). In FIG. 2A, reference numeral 4 denotes a circular pipe, 5 denotes water jetted from the tip of the circular pipe 4, and 5a denotes a streamline of the water 5 jetted. The shape of the streamline 5a can be calculated as follows.

The falling speed v of the water after a lapse of time t
Gives g the gravitational acceleration (9.8 m / s ^Two)
It is expressed by equation (1). v = g · t (1) The time required to fall by the distance h is expressed by the following equation (2).
Is done. ∫vdt = h (2) The following equation (3) is obtained from the above equations (1) and (2).
It is.

[0013]

(Equation 1)

The falling speed v of the water at that position is:
It is expressed by the following equation (4) by the equation (1).

[0015]

(Equation 2)

Similarly, if the cross-sectional area a at that position is continuous at the flow rate q, then a = q / v (5), and the total volume ΔV of the water column is expressed by the formula (4) and (5) ) Is expressed by the following expression (6).

[0017]

(Equation 3)

The shape of the stream line 5a can be calculated as follows. First, the jet velocity can be calculated by equation (4).
Since there are initial velocity V ₀ when leaving the, by the following equation (7).

[0019]

(Equation 4)

The initial speed V ₀ can be calculated by the following equation (8). _{V 0 = q / a 0 =} q / (d 0 2 π / 4) ···· (8) where, a _0: the inner area of the circular tube _{^{4 (m 2), d 0}} : the circular tube 4 inside diameter ( m). The sectional area a of the jet is given by the following equations (9) and (10) based on the above equations (5) and (7).

[0021]

(Equation 5)

The diameter d of the jet is given by the following equation (11) based on the equations (9) and (10).

[0023]

(Equation 6)

When d is plotted with h in equation (11) as a variable, the shape of the streamline 5a is approximately a 1/4 ellipse contour. FIG. 2B shows a state in which an elliptical contour is superimposed on the shape of the streamline 5a. From this figure, it can be seen that the shape of the streamline 5a matches well with the contour shape of the 1/4 ellipse.

Although not present as a natural phenomenon, when gravity reverses, the jet spreads in a 輪 郭 elliptical contour shape. What is important here is that the naturally falling jet is 1/4
In order to narrow the shape with an elliptical outline, there is no flow or eddy current as a flow condition. When a drift or eddy current is included in the flow,
The spontaneously falling jet is not narrowed by a 1/4 elliptical contour. The jet will bend or bulge.

Therefore, the rectifying device 3 according to the present embodiment is used.
When the fluid is forced to flow through the rectifying passage 3 having the inner wall surface 3c (first half shape 3c1) narrowing along the flow direction of the fluid in the shape of a 1/4 ellipse, and the flow is shaped, a drift or eddy current is generated. It is removed and a rectification effect equivalent to a state where a straight line has been passed is obtained.

It should be noted that if the squeezing is performed immediately after the squeezing, a new drift or eddy current may be generated. Therefore, in the present embodiment, the rear half shape 3c2 of the inner wall surface 3c is formed to have a shape of a 1/4 elliptical contour along the flow direction of the fluid so as not to disturb the rectification effect. The latter half shape 3c2 of the inner wall surface 3c does not necessarily have to be a shape that spreads in a contour shape of a quarter ellipse, but may be a shape that gradually expands, and a shape that expands linearly as shown in FIG. Is also good.

Further, in the present embodiment, the narrowest position of the inner wall surface 3c of the rectifying passage 3a between the former half shape 3c1 and the latter half shape 3c2 when narrowed by a １ ／ elliptical contour shape. However, it may be set to be a little before that. In this case, the division is 1/4
A final position narrowed by an elliptical contour shape is formed, and a gradually expanding shape in the latter half is started from this final position.

In this embodiment, the flange 3b is provided, and the flange 3b is mounted between the upstream pipeline 1 and the downstream pipeline 2 with the flange 3b being sandwiched between the flanges 1a and 2a. However, as shown in FIG. 4, a rectifying device 6 having flanges 6b1 and 6b2 provided at an inlet and an outlet of a fluid,
The flanges 6b1 and 6b2 are connected to the flanges 1a and 1b.
In addition, it may be attached between the upstream pipeline 1 and the downstream pipeline 2. In FIG. 4, reference numeral 6a denotes a rectifying passage, 6c denotes an inner wall surface, and the shape of the inner wall surface 6c is the same as the inner wall surface 3c of the rectifying device 3 shown in FIG.

As described above, the rectifier 3 of the present embodiment
According to (6), the inner wall surface 3c (6c) of the throat-shaped rectifying passage 3a (6a) is formed into a special shape, thereby preventing flow from the center of the pipe (a large number of fine holes, tubes, and the like). And the pressure loss can be reduced, and the holes are not clogged. Further, the pressure applied to the rectifying device itself is small, and there is no fear that the rectifying device will break down and flow downstream. Further, the contour shape of the ellipse can be easily produced by the NC machine, can be mass-produced inexpensively, and can be provided at low cost. This structure is particularly effective for a multi-phase fluid that tends to cause clogging or a low-pressure fluid that dislikes pressure loss, and can be easily made of a corrosion-resistant synthetic resin for a strongly corrosive fluid.

[0031]

As is apparent from the above description, according to the present invention, a throat-shaped rectifying passage is provided, and the shape of the inner wall surface of the rectifying passage is changed by about 1 along the flow direction of the fluid.
The shape is narrowed by the contour shape of the 輪 郭 ellipse, and it gradually expands from the narrowed final position along the flow direction of the fluid, so it is formed almost in the same shape as the streamline of the jet when water falls naturally. The fluid flows along the inner wall surface of the rectifying passage, and the drift and the vortex are removed. Thus, there is no obstruction to the flow from the center of the pipe, so that the pressure loss can be reduced, and the hole does not become clogged, and there is no fear that the pipe is flowed downstream. Also,
Processing is simple and low cost.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a pipeline showing a state where a rectifier according to the present invention is mounted.

FIG. 2 is a diagram for explaining that the shape of a streamline of a water jet approximates a contour shape of a １ ／ ellipse.

FIG. 3 is a side sectional view of a pipeline showing a state in which a rectifying device according to the present invention in which the rear half of the inner wall surface of the rectifying passage is linearly spread is attached.

FIG. 4 is a perspective view showing another embodiment of the rectifier according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Upstream piping, 2 ... Downstream piping, 3 ... Rectifier, 3a
... Rectifier passage, 3b ... Flange, 3c ... Inner wall surface, 3c1 ... First half shape, 3c2 ... Second half shape, 6 ... Rectifier device, 6a ... Rectifier passage, 6b1, 6b2 ... Flange portion, 6c ... Inner wall surface, 6c
1: first half shape, 6c2: second half shape.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Nobutaka Chimura 2-12-19 Shibuya, Shibuya-ku, Tokyo Co., Ltd. Takeuchi Shayama (72) Inventor Tatsuya Ichihara 32-1-1, Shinurashima-cho, Kanagawa-ku, Yokohama-shi, Kanagawa 32 F-term in Yamatake Sangyo System Co., Ltd. (reference) 2F030 CF01

Claims (2)

[Claims] 1. A rectification device provided with a throat-like rectification passage that is attached to a pipe through which a fluid flows and rectifies the flow of the fluid, wherein the rectification passage is approximately ゞ along a flow direction of the fluid. A rectifying device characterized in that it has an inner wall surface that is narrowed in an elliptical contour shape and that gradually widens from the narrowed final position in the fluid flow direction. 2. A rectifying device attached to a pipe through which a fluid flows and comprising a rectifying passage for rectifying the flow of the fluid, wherein the rectifying passage has a substantially quarter-elliptical contour along a flow direction of the fluid. A rectifying device characterized in that it has an inner wall surface that is narrowed in a linear shape and that extends from the narrowed final position in the same flow direction as the fluid in a substantially quarter elliptical contour shape.