JPH112337A - Valve element of butterfly valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a cavitation loss particularly in an orifice flow part side of a valve element of a butterfly valve. SOLUTION: In two almost semicircular parts of a valve unit 11 journalled by a valve rod 3 orthogonal in the center part of a cylindrical main unit 2, from almost a half circumferential part of the upstream valve unit in one nozzle flow part, relating to a valve plate 12, comb teeth 13 extended at a right angle are provided, by action of the comb teeth 13, cavitation is suppressed by a fine jet flow, in almost the semicircular part of the downstream valve unit in the other orifice flow part, comb teeth 14 extended at a right angle in a valve shaft part toward a circumferential part are provided, by the comb teeth 14, a flow passing through this part is formed in a fine jet flow of small turbulence, cavitation can be more effectively suppressed.

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 having reduced loss such as adverse effects and adverse effects due to cavitation.

[0002]

2. Description of the Related Art Conventionally, various 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.

FIG. 6 is a view showing an essential part of a conventionally known butterfly valve showing an example of such a butterfly valve, which is described in Japanese Patent Application Laid-Open No. 57-157866. FIG.
(A) is a vertical sectional view of a valve body of a butterfly valve pivotally supported inside a main body (valve main body), and (b) is a front view of the valve body viewed from below in FIG. .

In the drawing, reference numeral 1 denotes a valve body 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 a) 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
Is formed so as to be substantially parallel to the inner surface 2a of the main body 2 when fully closed, and the end 1c is formed to be located in a plane perpendicular to the inner surface 2a of the main body 2. In the drawing, b indicates the direction in which the valve element 1 in the fully closed state opens from the illustrated position.

When the valve body 1 rotates in the direction of arrow b from the fully closed state shown in FIG. 6A during the operation of the valve, as shown in FIG.
The fluid flows in the direction of the arrow in the main body 2, and the flow rate changes according to the opening degree of the valve body 1 so that the flow rate is controlled.

When the above-mentioned conventional butterfly valve having comb teeth is operated, the valve body 1 is rotated about the valve rod 3 in the main body 2 as shown in FIG. When the passing flow rate is reduced, the inner surface 2a of the main body 2 and the peripheral portion of the valve body 1 located downstream from the valve rod 3 are formed similarly to the valve body of the conventional standard butterfly valve having no comb teeth. The orifice flow portion of the opening formed by the inner surface 2a of the main body 2 and the peripheral portion of the valve element 1 located upstream of the valve rod 3 as compared with the flow rate of the nozzle flow portion B of the opening formed by The passing flow rate of A is smaller.

[0007] This phenomenon is more oblique toward the flow direction a as compared with the fluid flowing through the nozzle flow portion B formed by the valve body end portion inclined obliquely downward along the flow direction a and the main body inner surface 2a. This is because the fluid flowing through the orifice flow portion A formed by the valve body end protruding upward and the main body inner surface 2a tends to be contracted. In the conventional standard type butterfly valve body having no comb teeth, the flow passing through the nozzle flow portion B and the orifice flow portion A is provided behind the valve body with a jet region and a vortex region generated from the jet region. And a partial pressure drop occurs downstream of the valve body 1,
When this pressure value falls below the saturated vapor pressure of the liquid at that temperature, bubbles (vapor) precipitate in the liquid, develop and become cavities, and cavitation occurs when the cavities disappear rapidly with increasing pressure. This causes impact noise, vibration, vibration of structures, noise mixed with resonance, and erosion of the material surface, resulting in damage to equipment and shortened service life. Was causing the outbreak.

The valve body of the butterfly valve provided with the teeth as shown in FIGS. 5 and 6 is provided to reduce the adverse effects of the cavitation described above, and includes an orifice flow portion A and a nozzle flow portion B. The fluid passing through the turbulence is converted into small individual jet flows by the rectifying action of the comb teeth 1c existing in the portion, thereby reducing bubbles due to cavitation and reducing adverse effects.

[0009]

As described above, the valve body of a conventional butterfly valve having comb teeth (FIGS. 5 and 6) is as follows.
By making the fluid into a jet stream by the comb teeth, the bubbles due to cavitation are fined and lost (damage)
Actually, the jet flow is reduced by the valve body at the nozzle flow portion B side of the valve body and at the orifice flow portion A side, the comb tooth 1c has almost the effect. Without causing cavitation. This has been confirmed in an actual flow test by an experiment using a visualization tube.

On the other hand, the one disclosed in Japanese Patent Publication No. 5-78713 discloses a vent hole which is provided with a gap from the surface on the downstream side (back side) of the valve body and penetrates further rearward from the surface on the downstream side of the valve body. A straightening plate having a valve body is provided on the valve body, whereby a part of the fluid passing through the orifice flow portion passes through the gap between the downstream surface of the valve body and the straightening plate from the ejection hole to the downstream side of the valve body and the nozzle. In order to prevent the occurrence of cavitation, a discontinuous surface between the orifice flow portion and the jet flow region behind the nozzle flow portion is eliminated so as to prevent the occurrence of cavitation. There is a problem that cavitation may be generated on the flow side, and that a large number of parts are required.

An object of the present invention is to suppress cavitation loss in a valve body of a butterfly valve, particularly on an orifice flow portion side.

[0012]

In order to solve the above-mentioned problems, the means adopted by the present invention is to provide two substantially half of a valve body which is axially supported by a valve stem perpendicular to the center of a cylindrical body. In the valve body of the butterfly valve provided with the comb teeth on one upstream side and the other downstream side of the circular portion, respectively, the valve is formed from a substantially semicircular portion of the upstream side valve body located downstream of the one valve stem. A comb tooth extending perpendicular to the plate is provided, and a comb tooth extending perpendicular to the valve stem toward the circumferential portion is provided in a substantially semicircular portion of the downstream valve body located upstream of the other valve stem. It is characterized by that.

[0013] Further, in the substantially semicircular portion of the downstream side valve body, the mutual interval of the comb teeth extending toward the circumferential portion at right angles to the valve shaft portion is provided.
It is characterized in that it is gradually increased from the center of the valve body to both ends. The spacing between the combs can be equal or different.

Also, the cross-sectional shape of a comb tooth extending toward the circumferential portion at right angles to the valve shaft portion is formed in a substantially semicircular portion of the downstream side valve body so that the upstream side is made thinner and the downstream side is made thicker. And

When the valve is closed, the end of the comb tooth extending toward the circumferential portion at right angles to the valve shaft is positioned in a substantially semicircular portion of the downstream valve body in a plane perpendicular to the inner surface of the main body when the valve is closed. It is characterized by that. When the valve is closed, the end of the comb tooth can be located in a plane changed within ± 20 ° with respect to a plane perpendicular to the inner surface of the main body.

[0016] Further, a comb-shaped tooth extending toward the circumferential portion at right angles to the valve shaft portion is formed in a lattice shape in a substantially semicircular portion of the downstream side valve body.

Also, one or all of the comb teeth extending toward the circumferential portion at right angles to the valve shaft portion are connected to the substantially semicircular portion of the downstream valve body by a columnar body from the valve plate surface. It is characterized by.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the embodiments shown in the drawings. 1A and 1B are drawings showing a valve body of a butterfly valve showing one embodiment of the present invention, wherein FIG. 1A is a plan view of an inflow side, FIG.
(C) is a plan view of the outflow side as viewed from below in FIG. (B), (d) is a side view of FIG. 3 (c), in which the same reference numerals as those shown in FIG. 6 denote the same or similar parts. Shall be shown.

In FIG. 1B, reference numeral 11 denotes a valve body of the present invention showing a fully closed state in which the center of the main body 2 is pivotally supported by a valve stem 3 orthogonal to the center. A nozzle flow portion which is an opening formed by the peripheral portion of the valve element 11 located downstream of the valve stem 3 and the inner surface 2a of the main body 2 of the valve plate 12 having the (boss portion) fixedly supported by the valve stem 3. When the valve is closed (the state shown in FIG. 3B), a comb tooth 13 extending substantially parallel to the inner surface 2a of the cylindrical body 2 is provided on a substantially semicircular portion of the upstream valve body. The (surface) 13a is located in a plane perpendicular to the inner surface 2a of the main body at the valve closed position, and a peripheral portion of the valve body 11 of the valve plate 12 located upstream of the valve rod 3. And a substantially semicircular portion on the downstream side of the orifice flow portion, which is an opening formed by the main body inner surface 2a,
When the valve is closed, as shown in the right half of FIG. 1C, a plurality of comb teeth 14 extending toward the circumferential portion at right angles to the valve stem are provided at intervals A to D from each other.

The distances A to D between the comb teeth 14
Is generally provided gradually from the center to both ends as A <B <C <D. However, A = B = C =
D may be provided at equal intervals, and A {B {C}
D can be provided at unequal intervals.

The cross-sectional shape of these comb teeth 14 is
As shown in FIG. 1D, the upstream side is formed to be thinner and the downstream side is made thicker with respect to the flow direction a, and the downstream end surfaces 14a of the respective comb teeth 14 are closed. At the position (FIG. 1B), the semicircular valve body provided with the comb teeth 13 is positioned in a plane such that an angle c between the semicircular valve body and the downstream back surface 12a is usually 180 °. However, the angle c is
The angle may be changed within a range of 160 ° to 200 °. The above angle c =
In the case of 160 °, the end face 14a of the comb tooth 14 is
(B) is located on 12b of 20 °, and c
In the case of = 200 °, the end face 14a of the comb tooth 14 is positioned on the straight line 12c having the angle θ ′ of −20 °.

Next, the operation will be described. When the valve body 11 rotates counterclockwise from the fully closed state shown in FIG. 1B during valve operation, fluid flows through the main body 2 as shown in FIG. Although the fluid flows in the direction of the arrow, in the conventional example shown in FIG. 5, the effect of dispersing the fluid by the comb teeth 1c is small, especially at the orifice flow portion side A, and cavitation is likely to occur. In the present invention shown in FIG. 1, the peripheral portion of the valve body 11 located on the upstream side of the valve rod 3 and the inner surface 2a of the main body 2 as shown in FIG. In the orifice flow portion A of the opening formed by the comb teeth 14, the comb teeth 14 are located downstream from the valve plate 12 and the comb teeth 14
As shown in FIG. 1 (c), the orifice is formed in a substantially semicircular portion of the circumference of the valve body so as to extend at right angles to the valve stem toward the circumference. Fluid
A straight stream extending straight from the shaft portion of the comb tooth 14 to the circumferential portion at a right angle to the circumferential portion has a turbulent jet stream downstream with less turbulence. As described in Japanese Patent Publication No. 5-98713, a swirl region is rarely formed in the downstream region following the jet region after passing through the orifice flow portion, and thus cavitation can be more effectively suppressed. .

Similarly, in the nozzle flow portion B of the opening formed by the peripheral portion of the valve element 11 located downstream of the valve stem 3 and the inner surface 2a of the main body, the nozzle flow portion B is formed by the comb teeth 13. The flow that has passed becomes a fine jet flow due to the action of the comb teeth, and cavitation can be suppressed by this jet flow.

At this time, as shown in FIG. 1D, the cross-sectional shape of the comb tooth 14 is formed to be thinner on the upstream side and thicker on the downstream side with respect to the flow direction a. 1
4 can be smoothly passed between the respective comb teeth with a reduced resistance of the flow passing therethrough, and a jet stream having less turbulence toward the downstream can be obtained.

Further, by gradually increasing the distance A to D between the respective comb teeth 14 from the center of the valve plate to both ends thereof as A <B <C <D, the flow of the fluid flowing in the main body 2 is increased. The portion of the fast flow that flows near the center is passed through the center AB of the narrow comb teeth,
It is usually configured so that a fluid having a low flow velocity flowing around the main body passage passes through both ends of the comb teeth having a wide interval so as to have a flow with little turbulence.
D may be equally formed as A = B = C = D,
Alternatively, unequal intervals such as A ≠ B ≠ C で き る D can be used.

FIG. 2 shows another embodiment of the present invention.
FIG. In this embodiment, as shown in FIGS. 2 (c) and (d), the comb teeth 24 provided on the orifice flow portion side include a comb tooth 24a extending toward the circumferential surface at right angles to the shaft portion and the comb teeth 24a. It is formed in a lattice shape by a connecting member 25 that connects the respective comb teeth 24a at right angles to the teeth 24a.

According to this embodiment, as compared with the embodiment shown in FIG. 1, since the comb teeth 24 are formed in a lattice shape, each of the comb teeth 24a extending at a right angle from the shafts arranged side by side. Are connected by the orthogonal connecting members 25, so that the entire comb teeth 24 are reinforced so as not to be affected by the flow of the fluid.

FIG. 3 is a view similar to FIG. 2 showing still another embodiment of the present invention. In this embodiment, FIG.
As shown in (c) and (d), the comb teeth 34 provided on the orifice flow portion side have comb teeth 34a extending toward the circumferential surface at right angles to the shaft portion, as shown in FIG. It is formed in a lattice shape by a connecting member 35 connected to each of the comb teeth 34a at right angles to the comb teeth 34a, and one or all of the comb teeth 34a are separated from the surface of the valve plate 32 by the columnar body 36. It is formed as follows.

According to this embodiment, one or all of the comb teeth 34 are formed like a rod 36 directly connected to the surface of the valve body 32 as compared with the embodiment shown in FIG. Therefore, since the comb teeth formed like the columnar bodies 36 are directly connected to the valve plate, they are hardly deformed by the flow of fluid passing between the comb teeth, and are directly connected to the valve plate 32. By combining the columnar body 36 with the other comb teeth 34a, 35 formed in a lattice shape, the strength of the valve plate 32 is reinforced, and the entire comb teeth 34 are effectively prevented from being deformed by the fluid flow. Can be protected.

[0030]

As described above, according to the present invention,
In a valve body of a butterfly valve provided with comb teeth on one upstream side and the other downstream side of two substantially semicircular portions of a valve body which is axially supported by a valve stem orthogonal to a center portion of a cylindrical body. A comb that extends perpendicular to the valve plate from a substantially semicircular portion of the upstream valve body located downstream of the one valve stem, and a downstream valve body located upstream of the other valve stem. An opening formed by a valve body peripheral edge located downstream of the valve stem and the inner surface of the main body by providing a comb tooth extending substantially perpendicularly to the valve stem toward the circumferential portion in a substantially semicircular portion of the valve shaft. Not only can the jet flow on the nozzle flow portion side be made into a fine jet flow by the action of the comb teeth, but especially the valve located upstream of the valve rod, which could not be expected to have the effect of the comb teeth in the conventional example. Flow on the orifice flow side of the opening formed by the body periphery and the inner surface of the body And it can be less jet stream turbulence, not the nozzle flow side only, it is possible to suppress the occurrence of cavitation in the orifice flow section to more effectively.

In the substantially semicircular portion of the downstream valve body, the interval between the comb teeth extending toward the circumferential portion at right angles to the valve shaft portion is set.
By gradually increasing from the center of the valve body to both ends,
The part of the fast flow that flows near the center of the body passes through the center of the narrow comb teeth, and the slow flow of fluid that flows around the body passage passes through the ends of the wide teeth. The flow can be made to have less turbulence by passing through the section. However, each interval of the above-mentioned comb teeth is formed equally,
Alternatively, the intervals may be irregular.

Further, the cross-sectional shape of the comb tooth extending toward the circumferential portion at right angles to the valve shaft portion in the substantially semicircular portion of the downstream valve body is formed thinner on the upstream side and thicker on the downstream side. A jet that can smoothly pass through each of the comb teeth and has less turbulence toward the downstream by reducing the flow resistance passing through the comb teeth that are formed thinner on the upstream side and thicker on the downstream side with respect to the direction of the flow. It can be flow.

When the valve is closed, the end of a comb tooth extending toward the circumferential portion at right angles to the valve stem is positioned in a substantially semicircular portion of the downstream valve body in a plane perpendicular to the inner surface of the main body when the valve is closed. As a result, the end portions of the comb teeth on the side of the nozzle flow portion are parallel to each other, thereby facilitating the manufacture.

When the valve is closed, the end of the comb tooth can be positioned within a plane which is changed within ± 20 ° with respect to a plane perpendicular to the inner surface of the main body, thereby providing a flow state, particularly when used. The fluid passing through the orifice flow portion according to the flow rate (flow velocity) can be a jet stream with little turbulence.

Also, by forming comb teeth extending in a lattice shape substantially perpendicularly to the valve stem toward the circumferential portion in the substantially semicircular portion of the downstream valve body, the comb teeth are arranged at right angles to the shafts arranged side by side. Are connected by the orthogonal connecting members, so that the entire comb teeth are reinforced so as not to be affected by the flow of the fluid.

Also, one or all of the comb teeth extending toward the circumferential portion at right angles to the valve shaft portion are connected to the substantially semicircular portion of the downstream valve body by a columnar body from the valve plate surface. Thus, since the comb teeth formed like the columnar bodies are directly connected to the valve plate, deformation of the fluid flowing between the comb teeth is prevented, and cavitation is performed as a jet stream with little turbulence. This is effective in suppressing the occurrence of the blemishes.

[Brief description of the drawings]

FIG. 1 is a drawing showing a valve body of a butterfly valve showing one embodiment (example) of the present invention, wherein (a) is a plan view of an inflow side,
(B) is a vertical sectional view, (c) is a plan view of the outflow side as viewed from below in FIG. (B), and (d) is a side view of FIG.

FIG. 2 is a drawing similar to FIG. 1 showing a valve body of a butterfly valve showing another embodiment (example) of the present invention, wherein (a) is a plan view on the inflow side, (b) is a vertical sectional view, (c) is a plan view on the outflow side, and (d) is a side view.

FIG. 3 is a view similar to FIG. 1 showing a valve body of a butterfly valve showing still another embodiment (example) of the present invention, wherein (a) is a plan view on the inflow side, (b) is a vertical sectional view, (C) is a plan view on the outflow side, and (d) is a side view.

FIG. 4 is a comparative explanatory diagram showing a flow state of a butterfly valve (valve opening degree: 40 °) of the present invention.

FIG. 5 is a comparative explanatory diagram showing a flow state of a butterfly valve (valve opening degree of 40 °) showing a conventional example.

FIG. 6 is a drawing of a conventional butterfly valve having comb teeth;
(A) is a vertical sectional view, and (b) is an inflow side plan view as seen from below in FIG. (A).

[Explanation of symbols]

 2 Body 2a Inner body surface 3 Valve stem 11, 21, 31 Butterfly valve body 12, 22, 32 Valve plate 13, 23, 33 Comb teeth on the inflow side on the nozzle flow side 14, 24, 34 Comb on the outflow side on the orifice flow part side Teeth 24a, 34a Comb teeth extending at right angles from the valve shaft part 25, 35 Combined body that forms a grid perpendicular to the comb teeth 36 Columnar body projecting from the valve plate surface

Claims (9)

[Claims] 1. A butterfly provided with comb teeth on one upstream side and the other downstream side of two substantially semicircular portions of a valve body which is axially supported by a valve stem orthogonal to a central portion of a cylindrical main body. In the valve body of the valve, a comb tooth extending perpendicular to the valve plate is provided from a substantially semicircular portion of the upstream valve body located downstream of the one valve stem, and is located upstream of the other valve stem. A butterfly valve body characterized in that comb teeth extending toward a circumferential portion at right angles to a valve shaft portion are provided in a substantially semicircular portion of the downstream valve body. 2. In a substantially semicircular portion of the downstream valve body, the interval between the comb teeth extending toward the circumferential portion at right angles to the valve shaft portion is gradually increased from the center portion of the valve body to both end portions. The valve body of a butterfly valve according to claim 1, wherein 3. The butterfly according to claim 1, wherein the intervals between the comb teeth extending toward the circumferential portion at right angles to the valve stem are substantially equal to the semicircular portion of the downstream valve body. Valve body of the valve. 4. The device according to claim 1, wherein the substantially half circle portion of the downstream side valve body has a different interval between the comb teeth extending toward the circumferential portion at right angles to the valve stem. Butterfly valve. 5. A cross-sectional shape of a comb tooth extending toward a circumferential portion at right angles to a valve shaft portion in a substantially semicircular portion of the downstream-side valve body, wherein the cross-sectional shape is formed thin on the upstream side and thick on the downstream side. The valve body of a butterfly valve according to any one of claims 1 to 4, wherein 6. An end portion of a comb tooth extending toward a circumferential portion at right angles to a valve shaft portion at a substantially semicircular portion of the downstream valve body, when the valve is closed.
The valve body of a butterfly valve according to any one of claims 1 to 5, wherein the valve body is located in a plane perpendicular to the inner surface of the main body. 7. An end portion of a comb tooth extending toward a circumferential portion at right angles to a valve shaft portion at a substantially semicircular portion of the downstream valve body, and when the valve is closed,
The butterfly valve body according to any one of claims 1 to 5, wherein the valve body is positioned within a plane which is changed within ± 20 ° with respect to a plane perpendicular to the body surface. 8. The comb according to claim 1, wherein comb teeth extending toward the circumferential portion at right angles to the valve stem are formed in a lattice shape in a substantially semicircular portion of the downstream side valve body. The valve body of the butterfly valve according to claim 1. 9. A method according to claim 1, wherein one or all of the comb teeth extending at right angles to the valve stem toward the circumferential portion are connected to the substantially semicircular portion of the downstream valve body by a columnar body from the valve plate surface. The valve body of a butterfly valve according to any one of claims 1 to 8, characterized in that: