JP3110002B2 - Butterfly valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butterfly valve, and more particularly to a butterfly valve body and a valve body for a control valve.

[0002]

2. Description of the Related Art Conventionally, various types of valve bodies have been devised for the purpose of reducing adverse effects such as noise and vibration and loss due to cavitation of a butterfly valve, and FIG. 5 shows an example of a conventional butterfly valve. A drawing showing a main part of a valve, which is similar, is described in JP-A-57-157866. 5A is a front view of the valve body when fully closed, FIG. 5B is a cross-sectional view taken along line YY of FIG. 5A, and FIG. 5C is a cross-sectional view taken along line XX of FIG.

[0003] In the drawings, reference numeral 1 denotes a valve element which is fully closed and supported by a valve stem 3 orthogonal to the center of a main body (valve body) 2. A valve plate 1a fixedly supported by a rod 3 and an inflow side comb protruding in a fluid inflow direction (indicated by a thick arrow f) over a semicircle of the valve plate 1a during use. A tooth 1b and an outflow-side comb tooth 1c similarly protruding from the valve plate 1a in the fluid outflow direction on the opposite side to the comb tooth 1b over the other semicircle. And these two comb teeth 1b, 1c
Are formed so as to be substantially parallel to the inner surface 2a of the main body 2 when fully closed, and the ends of these comb teeth are formed on the inner surface 2a of the main body 2.
It is formed so as to be located in a plane perpendicular to a.

During valve operation, when the valve element 1 rotates counterclockwise from the fully closed state shown in FIG. 5 (c), the flow rate changes according to the degree of opening of the valve element 1 so that the flow rate is controlled. It has become. At this time, the nozzle flow portion, which is an opening formed by the inner surface 2a of the main body 2 and the peripheral portion of the valve element 1 located downstream of the valve stem 3, and similarly, the inner surface 2a of the main body 2 and the valve stem Fluid passing through the orifice flow portion, which is an opening formed by the peripheral portion of the valve element 1 located on the upstream side with respect to 3, becomes a fine jet flow due to the action of the comb teeth 1b and 1c present in the portion. The aim is to reduce the noise to the pipes by reducing bubbles caused by cavitation and prevent damage.

[0005]

When the valve body (FIG. 5) of the above-mentioned conventional comb-shaped control valve is fully closed, the peripheral surface of the valve body and the inner surface of the main body are in close contact with each other, and the hatched portion in FIG. The valve body 1 is fixedly supported in the valve stem direction, while being sealed by a sealing surface b shown by. However, when the valve element is in the open state (intermediate opening degree), the valve element peripheral surface and the main body inner surface separate from each other, and at the same time, as shown in FIG. 5B, the valve element (valve plate 1a).
Is completely cut off at the valve stem hole, and becomes partially flat, so that when the valve is opened at the valve stem hole, a gap c is formed between the inner surface of the main body and the peripheral surface of the valve body. Due to the presence of c,
The valve element moves up and down. Therefore, in order to eliminate this movement, conventionally, the valve stem 3 fixed integrally with the valve body 1 is fixed to the outside of the main body 2 by bolts and bearing means for preventing vertical movement. I have.

Further, a gap c above and below the valve stem hole is provided.
As a result, leakage of the liquid occurs on the outflow side and the valve stem side. 5 (b) shows the width of the peripheral portion of the valve plate 1a in FIG. 5 (c), and the gap a in FIG. A gap (in the figure (a), for the sake of illustration, the gap is displayed larger than it actually is).

There is leakage of liquid from the gap a between the valve element 1 and the valve rod 3, and the amount of leakage particularly in the fully closed state is increased. This phenomenon cannot be avoided with the conventional shape of the center type butterfly valve in which the sealing surface on the peripheral surface of the valve element crosses the center of the valve stem.

As described above, in the valve body shape of the center type butterfly valve as shown in FIG. 5 (c), since the sealing surface has an appropriate angle with the main body when fully closed, it has a certain angle in advance. The opening from the fully closed position is smooth, and control (control) is possible from fully closed to near full open.
Good control performance. However, there were the following two problems.

(I) When the valve opening degree is other than the fully closed state, the valve body is in a state of floating from the main body as described above, so that it is necessary to position the valve rod up and down, which complicates the structure. (Ii) Further, since leakage at the time of fully closing occurs from the gap a between the valve rod and the valve element, the leakage amount is large as a normal control valve.

On the other hand, as an example, Japanese Patent Application Laid-Open No. Hei 7-260016
In the known valve eccentric butterfly valve in which the sealing surface of the valve body is shifted from the center of the valve stem, that is, the center of rotation of the valve body, as described in Japanese Patent Application Laid-Open No. H10-205, the center type butterfly valve described above (FIG. ), The sealing effect on the peripheral surface of the valve body crosses the valve stem, so that no leaking action occurs especially in the fully closed state. On the other hand, when the pressure is applied from the valve stem side by the flow in the opposite direction. However, there is a problem that the opening torque increases due to the structure, the unbalance torque at the intermediate opening degree is large, and the operability and control performance deteriorate.

An object of the present invention is to provide a butterfly valve which eliminates a gap (floating) between a valve body and an inner surface of a main body at an intermediate opening degree and reduces an amount of leakage when fully closed. And

[0012]

In order to solve the above-mentioned problems, a means adopted in the present invention is as follows. A peripheral surface of a valve body which is axially supported by a valve stem perpendicular to the center of the main body and an inner surface of the main body come into contact with each other. An eccentric butterfly valve having a structure in which the sealing surface of the valve element does not pass through the valve stem hole of the valve element, wherein both the sealing surface of the valve element and the inner surface of the main body, which is substantially half downstream of the center of the main body, are formed by spherical surfaces. In the butterfly valve, the inner surface of the other half of the main body on the upstream side from the center of the main body is formed by a cylindrical surface, the surface provided with the comb-shaped protrusion of the valve body has a V-shaped cross section in a direction perpendicular to the valve stem. The comb-shaped protrusion is provided so as to be substantially parallel to the inner surface of the main body on the upstream side and to be inclined with respect to the inner surface of the main body on the downstream side when the valve is closed. Further, a comb-shaped projection for rectifying action is provided integrally on the substantially semicircular portion on the upstream side of the valve body and the other semicircular portion on the downstream side. Also,
The inner body surface is formed in three stages of a cylindrical shape, a spherical shape, and a cylindrical shape sequentially from the entrance side.

[0013]

[0014]

[0015]

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the embodiments shown in the drawings. FIG. 1 is a cross-sectional side view of a main part of a main body and a valve body according to an embodiment of the present invention in a fully closed state. FIG. 2 is a downstream front view of FIG.
(A) is a front view of the valve body, (b) is a cross-sectional view taken along the line YY of FIG. (A), and (c) is a cross-sectional view taken along the line XX of FIG.

In FIG. 1, reference numeral 11 denotes a valve body of the present invention showing a fully closed state in which a center portion of a main body 12 is pivotally supported by a valve stem 3 orthogonal to the valve body. And body 1
The sealing surface of the valve element which is in close contact with the inner surface of the valve element 2 belongs to a valve element of a so-called eccentric butterfly valve which cannot pass through a valve stem hole, and a cross section perpendicular to the valve stem 3 is formed in a V shape.
The sealing surface (corresponding to the hatched portion A in FIG. 3 (c)) with the inner surface of the main body 12 of the cross-shaped valve body 11 is formed by a spherical surface, and further, the cross-shaped valve plate 11a. In the substantially semicircular portion on the upstream side with respect to the flow direction of the large arrow f, a comb-shaped projection 13 for rectification is integrally provided so as to be substantially parallel to the cylindrical inner surface 12a of the main body 12. A comb tooth-shaped protrusion 14, which also has a rectifying action, is provided integrally with the other semicircular portion on the downstream side so as to be inclined with respect to the inner surface of the main body 12.

On the other hand, the body 12 has a cylindrical inner surface 12a on the upstream side (entrance side) of the center portion, and a half of the inner surface 1a on the downstream side (outlet side) from the center portion.
2b is formed by a spherical surface, and furthermore, an inner surface 12c in contact with the spherical inner surface 12b and reaching the downstream (outlet) end surface.
Are formed by cylindrical surfaces.

Next, the operation will be described. As shown in FIG. 1 and FIG. 3 (c), when the valve body 11 is fully closed in the main body 12, the sealing surface of the valve body 11 formed by a spherical surface is formed. A (FIG. 3 (c)) is in close contact with the inner surface of the main body 12, and at this time, the contact state of both (the valve body 11 and the inner surface of the main body 12) is shown in FIG. 4 (a) and FIG. FIG. 3C is an enlarged view of a main part of the part. That is, in the fully closed state, the inner surface of the main body 12 is bisected by a center portion passing through the center of the valve stem 3, the inflow (inlet) side half 12a is formed by a cylindrical surface, and the outflow (outlet) side substantially half 12b. Is formed by a spherical surface, and the inner surface 12c which is in contact with the spherical surface portion 12b and reaches the outflow (outlet) side end is formed by a cylindrical surface. Therefore, when fully closed, the contact seal between the valve element peripheral surface and the main body inner surface is formed. The surface is indicated by the cross-hatched line B in FIG.
The B portion is formed by a spherical surface on both contacting surfaces, and the contact portion between the peripheral portion of one (inflow side) of the V-shaped valve element 11 and the inner surface of the main body is also a main portion. As shown in the enlarged view (c), approximately half of the cross section of the valve plate 11a (lower half portion c in the figure) contacts with a spherical surface, and the upper half portion d in FIG. The non-contact state is shown by the main body cylindrical portion 12a. As described above, in the fully closed state, the peripheral surface of the valve body and the inner surface of the main body are in contact with each other by the spherical surface over the entire circumference. Since no gap c is formed, no liquid leaks to the outflow side through the gap c, and the sealed state is maintained.

Next, in FIG. 4A, when the valve body 11 is rotated counterclockwise as shown by an arrow and is in an open state as shown in FIG. Spherical part and body 12
Is always in contact with the spherical inner surface 12b by the portion C which is in contact with each other by the spherical portions. Therefore, in the conventional example (FIG. 5), the gap between the valve body and the inner surface of the main body in the valve stem hole when the valve is opened. c does not occur, and the valve body 11 does not move in the vertical direction, so that the valve rod fixed integrally with the valve body is prevented from moving in the vertical direction by bolts and bearings outside the main body as in the conventional example. This has the advantage that no special measures need to be taken.

On the other hand, during valve operation, when the valve body 11 rotates counterclockwise from the fully closed state shown in FIG. 4A and the valve body 11 opens as shown in FIG. Flows in the direction indicated by the arrow f in the body 12, and a comb-shaped protruding portion 13 is formed on the valve plate 11 a of the valve element 11 over a substantially semicircle on the upstream side, and on a substantially semicircle on the downstream side. The comb-shaped protrusions 14 are provided integrally with each other, and the comb-shaped protrusions 13 on the upstream side of the valve body are located on the inner surface of the main body and on the downstream side of the valve rod 3 when the valve is opened. The comb-shaped projection 14 on the downstream side of the valve body is located on the inner surface of the main body and on the upstream side of the valve rod 3 when the valve is opened. Valve body 11
The fluid passing through the orifice flow portion and the nozzle flow portion is finely jetted by the rectifying action of the comb-shaped protrusions 14 and 13 existing in the orifice flow portion and the nozzle flow portion formed by the orifice flow portion. It is flowing, and the bubbles due to cavitation are made finer, and a low noise effect is exhibited.

In a conventional valve body having such a comb-shaped protrusion (FIG. 5), the effect of the comb-shaped protrusion on the orifice flow portion side is inferior to that on the nozzle flow portion side. However, in the present invention, in particular, in the present invention, the comb-shaped protrusion 14 on the downstream side of the valve element located on the orifice flow portion side is inclined toward the inner surface of the main body 12. 4, the comb-shaped protrusion 14 is located at a position downstream from the peripheral edge of the valve plate 11a as shown in FIG. 4 (a). In the flow direction f, the flow passing through the peripheral portion of the valve plate 11a bent in a V-shape in the cross section tends to be disturbed on the back surface (back side) of the peripheral portion of the valve plate 11a. Side of the comb-shaped protrusion 14 located away from the side As a result, the jet stream becomes less turbulent toward the downstream while being rectified. Accordingly, as in the conventional example (FIG. 5), a vortex area is formed in the wake area following the jet area after passing through the orifice flow section. Therefore, cavitation can be more effectively suppressed.

4 is connected to a spherical inner surface 12b formed downstream of the center of the inner surface of the main body 12.
As shown in (a), when fully closed, the cylindrical surface portion 12c is located between the downstream (outlet) side end portion except for the portion in contact with the valve body peripheral surface portion.
When the valve is opened counterclockwise from the fully closed state in FIG. 4A, the peripheral portion of the valve element (valve plate 11a)
It has a unique effect that it can be separated from the spherical main body inner surface portion 12b more rapidly and can flow the fluid at a minute opening, thereby enabling fluid control at the minute opening.

[0024]

As described above, according to the present invention,
An eccentric butterfly valve having a structure in which a sealing surface of a valve body in which a peripheral surface of a valve body which is axially supported by a valve stem orthogonal to a center portion of the main body and an inner surface of the main body do not pass through a valve stem hole of the valve body, In the butterfly valve, the sealing surface of the valve element and the inner surface of the main body on the downstream side from the center of the main body are both formed by spherical surfaces, and the inner surface of the other half of the main body on the upstream side from the center of the main body is formed by a cylindrical surface. The surface provided with the comb-shaped protrusions of the valve body is provided so that the cross section in the direction perpendicular to the valve stem has a U-shape, and the comb-shaped protrusions are formed on the inner surface of the main body on the upstream side when the valve is closed. The eccentric butterfly valve is provided in such a manner that the surface of the valve body provided with the comb-shaped protrusion is formed in a V-shape in cross-section by being provided substantially parallel and inclined with respect to the inner surface of the main body on the downstream side. Even when the valve is fully closed, at least one Can maintain a contact state with the spherical portion of the inner surface of the main body over the entire peripheral surface, the hermetically sealed state including the valve stem hole is maintained, and leakage to the outflow side can be reduced as compared with the conventional example. In addition, on the orifice flow side of the peripheral edge of the valve body where cavitation is likely to occur, the comb-shaped projection on the downstream side of the valve body provided so as to be inclined with respect to the inner surface of the main body is separated from the peripheral edge of the valve body downstream. Since it is located, the flow passing through the portion is rectified and becomes a jet flow with little turbulence toward the downstream while being rectified, so that noise, vibration and the like due to cavitation can be suppressed.

[0025]

In addition, a comb-shaped projection for rectifying action is provided integrally on the substantially semicircular portion on the upstream side of the valve body and the other semicircular portion on the downstream side, so that the valve is opened when the valve is opened. By the rectifying action of the comb-shaped projections provided integrally on the respective semicircular portions on the upstream side and the downstream side of the valve body, the valve body peripheral edge provided with these comb-shaped projections and the inner surface of the main body are formed. The flow passing through the space becomes a fine jet flow, and the bubbles due to cavitation are made finer, thereby exhibiting a low noise effect.

[0027]

[0028]

Further, the inner surface of the main body is formed in three stages of a cylindrical shape, a spherical shape, and a cylindrical shape in order from the inlet side. Since the fluid can be quickly separated from the portion and can flow at a minute opening, fluid control at the minute opening becomes possible.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view perpendicular to a valve body and a valve stem of a main body of a butterfly valve in a fully closed state according to an embodiment (example) of the present invention.

FIG. 2 is a front view of the downstream side of FIG. 1;

FIG. 3A is an embodiment (example) of a valve body of the present invention.
(B) is a cross-sectional view taken along line YY in FIG.
(C) is a sectional view taken along line XX of (a).

FIGS. 4A and 4B show the operating state of FIG. 1, wherein FIG. 4A is an explanatory view showing a contact state between a valve body peripheral surface in a fully closed state and an inner surface of a main body, and FIG. FIG. 3C is an explanatory view showing a state of contact with FIG.

FIGS. 5A and 5B show a conventional butterfly valve having a comb-like convexity, wherein FIG. 5A is a front view of a valve body, and FIG. 5B is YY of FIG.
FIG. 3C is a cross-sectional view taken along line XX of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 Valve stem 11 Butterfly valve body 11a Valve plate 12 Main body 12a Cylindrical main body inner surface part 12b Spherical main body inner surface part 12c Cylindrical main body inner surface part 13, 14 Comb-shaped protrusion

Continuation of the front page (56) References JP-A-61-252971 (JP, A) JP-A-57-157866 (JP, A) JP-A-48-79331 (JP, A) Jpn. , U) Fully open 4-18733 (JP, U) Fully open sho 60-93074 (JP, U) Fully open 1983 58-89654 (JP, U) Fully open 1979-133020 (JP, U) Really open 55-2812 (JP, U) JP 1-55708 (JP, B2) JP 59-47183 (JP, B2) JP 1-38378 (JP, Y2) JP 2-35089 (JP, B2) Y2) Jiko 3-5724 (JP, Y2) Jiko 46-1754 (JP, Y1) Jiko 45-11169 (JP, Y1) (58) Fields surveyed (Int. Cl. ⁷ , DB name) ) F16K 1/16-1/226 F16K 47/02

Claims (3)

(57) [Claims] 1. An eccentric type having a structure in which a sealing surface of a valve body, in which a peripheral surface of a valve body which is axially supported by a valve stem orthogonal to a center portion of the main body and an inner surface of the main body does not pass through a valve stem hole of the valve body. A butterfly valve, in which a sealing surface of a valve body and a substantially half body inner surface downstream from the center of the body are both formed by spherical surfaces, and the other half body inner surface upstream from the body center is defined by a cylindrical surface. In the formed butterfly valve, the surface provided with the comb-shaped protrusion of the valve body is provided so that the cross section in the direction perpendicular to the valve stem has a V-shape, and the comb-shaped protrusion is provided upstream when the valve is closed. The butterfly valve is provided so as to be substantially parallel to the inner surface of the main body on the side and inclined with respect to the inner surface of the main body on the downstream side. 2. A comb-shaped projection for rectifying action is integrally provided on the substantially semicircular portion on the upstream side of the valve body and the other semicircular portion on the downstream side. Item 7. The butterfly valve according to item 1, wherein 3. An inner surface of a main body is sequentially formed in a cylindrical shape from an inlet side.
3. The butterfly valve according to claim 1, wherein the butterfly valve is formed in three stages of a spherical shape and a cylindrical shape.