JPS6326468A - Butterfly valve - Google Patents

Abstract

PURPOSE:To restrict cavity, by providing guides on a circumferential edge side of a valve body in a direction along a rotary shaft core of the valve body. CONSTITUTION:A plurality of pleat-shaped guides 4 are disposed in parallel on a half surface portion on a side near to a downstream side when a rotary valve body 2 is opened in its upperstream side, the guides 4 guiding fluid striking against the surface portion in a direction along a rotary shaft core P to a circumferential edge portion of the valve body 2 and dispersing the same. Then, the fluid liable to gather in a portion A1 having a larger width in a space A defined between the valve body 2 and an inner circumferential wall of a pipe is dispersingly guided into a portion A2 having a smaller width by the action of the pleat-shaped guide 4. As a result, a concentrated flow of the fluid discharged to a downstream side is eased, whereby occurrence of cavitation is restricted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a butterfly valve, and more particularly to a structure for suppressing cavitation.

[Conventional technology]

Conventionally, to suppress cavitation, rectifiers of various shapes were installed in the pipeline downstream of the valve body (
For example, Japanese Utility Model Publication No. 44-2616, Japanese Unexamined Patent Publication No. 60-4
(See Publication No. 4673).

[Problem that the invention seeks to solve]

However, the conventional structure still cannot sufficiently suppress cavitation, and there is room for improvement.

[Means for solving problems]

The characteristic structure of the butterfly valve according to the present invention is that a guide is provided on the upstream side of the rotary valve body to guide and disperse fluid toward the peripheral edge of the valve body in a direction substantially along the rotation axis of the valve body. , its actions and effects are as follows.

[For production]

In other words, in a butterfly valve, fluid flowing downstream from the gap formed between the rotary valve body and the inner circumferential wall of the pipeline concentrates, and cavitation occurs because the concentrated fluid is discharged downstream in the form of a jet. be.

Therefore, the guide provided on the upstream side of the rotary valve body directs the fluid to the peripheral side of the valve body in a direction substantially along the rotation axis of the valve body.
(that is, to the side of the narrow part of the gap formed between the rotary valve body and the inner circumferential wall of the pipe line) and disperse the gap between the valve body and the inner circumferential wall of the pipe line. It can fundamentally alleviate the cause of cavitation, which is the concentration of fluid in the wide part near the center of the valve body, and is more effective at reducing cavitation than the conventional structure, which only rectifies the flow downstream of the valve body. can be suppressed.

〔Effect of the invention〕

As a result, noise generation due to cavitation and damage to valves and pipelines can be greatly reduced, allowing for good fluid transport over a long period of time.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

As shown in Figs. 1 and 2, a disc-shaped rotary valve body (2) is installed inside a cylindrical valve box (1), and the valve body (2) is extended between a valve opening position and a valve closing position. Rotating valve stem (3
) is supported in the valve box (1) in a penetrating manner, thereby forming a butterfly valve.

As shown in FIGS. 1 to 8, in the valve open position of the upstream side surface of the rotary valve body (2), the half surface of the rotary valve body (2) that approaches the downstream side is designed to prevent fluid that collides with the half surface of the valve body (2). A plurality of pleat-like guides (4) are arranged in parallel to guide and disperse the valve body (2) toward the peripheral edge of the valve body (2) in a direction substantially along the rotation axis (P) of the valve body (2). ) and the inner circumferential wall of the pipeline (inner circumferential wall of the valve box).
By dispersing and guiding the fluid that tends to concentrate in the AI) to the narrow gap part (A2) by the action of the pleated guide (4), the concentrated jet flow is prevented from being discharged downstream and cavitation occurs. The purpose is to suppress this.

The pleat-like guide (4) has a curved shape with a ridge line shaped like a "he" when viewed from the surface of the valve body, and extends approximately in the direction of the valve body rotation axis (P), and is aligned with the valve body rotation axis (P) in a cross-sectional shape. The (P) side is shaped like a hanging wall, and the side opposite to the rotating (P) side of the valve body is shaped like an inclined wall, and the height of the pleats increases from the center of the valve body toward the periphery of the valve body. It is.

On the periphery of the half of the upstream side surface of the rotary valve body (2) that is closer to the upstream side in the valve open position, there is a guide for suppressing the vortex generated near the downstream side of the valve body periphery as fluid passes. Grooves (5) are arranged in parallel, and this guide I (5)
It is formed in a V-shaped valley shape in which the groove width and groove depth are larger on the peripheral edge side of the valve body.

On the other hand, the half of the downstream side of the rotary valve body (2) that approaches the upstream side in the valve closed position has a downstream side that acts to guide the passing fluid so as to disperse it in the direction of the valve body rotation axis (P). A plurality of pleated guides (6) are arranged in parallel, and the upstream pleated guide (4) and the downstream pleated guide (6) cooperate to suppress the vortex flow in the guide groove (5). This action effectively suppresses cavitation, which causes vibration and damage to valves and pipes.

The downstream pleated guide (6) is arranged so that the ridgeline extends radially from the center of the valve body toward the periphery when viewed from the valve body plate, and also extends from the center of the valve body to the periphery of the valve body. The farther you go, the higher the folds become.

[Another example]

Next, another embodiment of the present invention will be described.

The fluid colliding with the upstream side of the valve body (2) is transferred to the valve body rotating ring core (
A guide (4) for guiding toward the peripheral edge of the valve body (2) in a direction substantially along P) may be formed on the entire surface of the upstream side surface of the valve body.

Also, the specific shape of the guide (4) and the valve body (2)
) can be modified in various ways.

The passing fluid guide structure attached to the downstream side surface of the rotary valve body (2) may be of any type, or may be omitted.

[Brief explanation of drawings]

1 to 8 show embodiments of the present invention, FIG. 1 is a longitudinal sectional view, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is an upstream side view of the valve body. Figure 4 shows the IV in Figure 3.
-IV line arrow view, Figure 5 is a V-V line arrow view in Figure 3, Figure 6 is a vr-vr line arrow view in Figure 3, Figure 7
The figure is a sectional view taken along the line ■--■ in FIG. 3, and FIG. 8 is a downstream side view of the valve body. (2)... Valve body, (4)... Guide,
(P)・・・Rotating wheel core.

Claims (1)

[Claims] A guide (4) is provided on the upstream side of the rotary valve body (2) to guide and disperse the fluid toward the peripheral edge of the valve body (2) in a direction substantially along the rotation axis (P) of the valve body (2). Butterfly valve installed.