JPS61223376A - Butterfly valve - Google Patents

Abstract

PURPOSE:To facilitate manufacture of the seal part of a valve body, by a method wherein a pair of about semicircular main discs, being different in radius, are welded to both sides of a valve axis on each surface of a valve body for coupling. CONSTITUTION:An opening part S of a valve body has both sides of a valve axis X-X on each surface of the valve body closed with a pair of about semicircular main discs 25 and 26, being different in radius. A pair of the main discs are disposed linearly symmetrically to each other about the valve axis X-X, and are welded together for coupling. A sealing part 27 is formed to the outer peripheral edge part of the one main disc 25 having radius being a size of deltalarger than that of the other disc 26. This constitution eliminates finish process of the surface of a seal part after assembly of a valve, and enables sharp reduction of a manufacturing time and a cost of a valve body.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a butterfly valve, which is particularly used to control a large flow rate in relatively low-pressure flowing water, and is used in highly corrosive flowing water such as seawater. Among other things, it relates to improvements in butterfly valves that can be used.

[Technical background of the invention and its problems]

In general, a butterfly valve has a valve body that is symmetrical about the spindle, and due to its structure, it is usually used to control relatively low-pressure fluid.

By the way, butterfly valves, which are used for electric power projects such as water horns, thermal power plants, and nuclear power plants, have a low pressure but a large flow.
Therefore, compared to a general butterfly valve, the diameter itself is very large, and the associated pressure-receiving area is increased, so the operating torque is also large, and the spindle, main plate, etc. The strength of the valve body is also required to be □.

Conventionally, the β strategy for manufacturing a large-diameter valve body for this scale was as follows:
Two methods have been proposed: a manufacturing method using an Il structure and a manufacturing method using a welded structure. When constructing a valve body with a welded structure, the main plate has a curved plate structure and reinforcing ribs are provided inside the main plate due to the above-mentioned strength problem.

14 and 15 show a valve body of a conventional large-diameter butterfly valve with a single-contact structure. , a lower spindle boss 5, and reinforcing ribs 6.7, which are integrated by welding.

In the conventional welded structure butterfly valve having the above configuration, the diameters of the upper and lower spindles (not shown) attached to both spindle bosses 4 and 5 are not made too small due to opening/closing torque and receiving pressure. Therefore, both spindle bosses 4 and 5 also have a large diameter and protrude from the outer surface of the main plate 2.

For this reason, it is necessary to provide a notch in the main plate 2 at a portion corresponding to each spindle boss 4, 5.

Conventionally, this method involves making a notch in the main plate 2 by gas cutting, etc., and shaping the rear notch with a grinder, or after welding the main plate 2 around the entire circumference, the spindle boss 4 is formed with a drill press or the like. A method of providing a notch to match the shape of .5 has been adopted, but both methods have the drawback of requiring a lot of time and cost to manufacture.

Further, the water drop acting on the butterfly valve when the valve is closed is received by the upper and lower spindle portions, and therefore, a bending moment in the direction of water flow is applied to the valve body 1 using both spindle portions as fulcrums.

For this reason, the strength of the valve body 1 in the spindle axial direction becomes an issue, and in conventional welded structure butterfly valves, one main plate 2 and the reinforcing rib 6 can be fillet welded on both sides due to its structure, but the other main plate 2 and reinforcing ribs 6 must be plug welded from the outer surface of the main plate 2. For this reason, there is a drawback that the strength of this plug welded portion is weak, and since the main plate 2 is flat in the spindle bosses 4 and 5, the strength of this portion is also weak.

Conventionally, a reinforcing rib is added at an angle of 45 degrees between the two reinforcing ribs 6 and 7, but this is not preferable because it increases the number of parts and man-hours as well as the weight. . - Also, the conventional welded structure butterfly valve has both spindle bosses 4.5. protrudes from the outer surface of the main plate 2, as shown in Fig. 16, a trailing vortex is generated on the downstream side of both spindle bosses 4.5 when the valve is opened, resulting in agitation loss of the flowing water and the characteristics of the flowing water. There is a problem in that the noise is worsened and that noise is also generated in this trailing vortex.

In particular, for butterfly valves used in piping systems that use seawater as working water in thermal power plants, nuclear power plants, etc., the wake vortex generation area becomes a stagnation area of seawater and the flow decreases. As shown in the figure, marine creatures 8 such as Fujibbo tend to adhere, and once this adheres, multiple layers of marine organisms 8 adhere to the core, which spreads to the seal ring 3, and when the valve is closed, This is a problem because it may destroy the water sealing function between the valve body 1 and the valve body (not shown).

On the other hand, conventional butterfly valves, in which the valve body is produced by casting, require a wooden mold or mold, and are prone to casting defects such as cavities, so it is necessary to increase the wall thickness. However, it has the drawbacks of increased weight and cost.

In addition, in conventional cast butterfly valves, the spindle boss protrudes from the outer surface of the main plate, similar to the welded butterfly valve described above, which causes similar problems such as generation of wake vortices and destruction of water sealing function due to adhesion of marine organisms. be.・ ・□ Therefore, in order to solve the above problems, the applicant first provided a butterfly valve that has a simple structure, can be manufactured at low cost, and has improved water flow characteristics. (See the text and drawings of JP-A-159-227354).

However, the butterfly valve disclosed in the prior art has a structure in which the seal part is integrally formed in the center part of the valve body in the width direction, so that after welding and assembling the valve body, the seal part is inside the valve body. It was necessary to separately finish the surface of the sealing part so that it could be in close contact with the surrounding surface.

In addition, since the seal ring that makes up the valve body is made of a thin semi-circular ring member, it is easily deformed by welding heat, and the seal ring and main plate do not align well, causing problems in welding work. child .

[Purpose of the invention]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a butterfly valve that solves the problems of the above-mentioned prior art and facilitates the manufacture of a seal portion of a valve body.

(Summary of the Invention) In order to achieve the above object, the present invention provides a structure in which upper and lower spindle bosses are disposed on the valve axis line at a predetermined distance and are connected by a reinforcing rib on both sides, which are symmetrical with respect to the valve axis line. In the butterfly valve, a semicircular arc-shaped circumferential frame member whose width becomes narrower as it moves away from the spindle boss is joined together, and the inner opening of the circumferential frame member is closed with a main plate. A pair of approximately semicircular main plates having different radii are symmetrically welded to each side of the valve axis on each side, and the main plate having the larger radius is arranged point-symmetrically with respect to the valve axis, Further, a sealing portion is formed at the outer peripheral edge of the main plate with the larger radius.

[Embodiments of the invention]

Embodiments of the butterfly valve according to the present invention will be described below with reference to FIGS. 1 to 13.

FIG. 1 is an exploded perspective view of a butterfly valve, and reference numeral 11 indicates a valve body, and this valve body 11 has an upper spindle boss 12 and a lower spindle boss 13 arranged at intervals along the valve axis aX-X. The two are welded together by reinforcing ribs 14. At the center of each spindle boss 12 and 13, receiving holes 12a and 13a are bored into which a valve shaft is inserted. Also, a part of the circumferential surface of each □ spindle boss 12, J: and 13 is notched in parallel, and in the center of this notch surface there is a protruding strip 15°16 of the same size as the plate thickness of the reinforcing rib 1/I.
is formed, and shelf portions 17 are formed on both sides of the protruding strips 15 and 16.
．． 18 are formed.

On both sides of the outer ends of the upper and lower spindle bosses 12 and 13 are quarter-arc shaped circumferential frame members 19°20.21.2.
2 are welded together at one end as shown in FIG. 1, and the entire structure is ring-shaped.

The circumferential frame members 19.20, 21.22 are formed so that their widths become narrower as they move away from the spindle bosses 12, 13.
, 13 and reinforcing ribs 14 define a semicircular opening S. Furthermore, as shown in FIGS. 2 and 3, the edge of the circumferential frame member 19°20.21.22(7) located symmetrically with respect to the valve shaft ax-x has an angular cross section. Shelf portions 19a, 20a, 21a, . . . 22a are formed. Note that the circumferential frame member may be formed of a semicircular arc.

Furthermore, reinforcing ribs 23 and 24 perpendicular to the valve axis line xx are welded to both sides of the reinforcing rib 14 at the central portion thereof in the longitudinal direction. The reinforcing ribs 23, 24 are formed so that their width becomes narrower as they move away from the welded joint, and their tips end at the circumferential trunk members 19, 20, 24.
．． 22 to the free end thereof.

Further, the opening S of the valve body is closed by a pair of substantially semicircular main plates 25 and 26 having different radii on both sides of the valve shaft aX-X on each surface of the valve body. There is. The pair of main plates 26 and 2d are arranged symmetrically with respect to the valve axis x-X, and are welded together.

As shown in FIGS. 4 and 5, one main plate 25 is formed slightly larger than the opening S and has a radius larger than the other main plate 26 by δ, and has an i-sealing portion 27 at its outer peripheral edge.
is formed. This sealing portion 27 protrudes outward from the circumferential frame member, and constitutes a sealing portion that comes into close contact with the inner circumferential surface of the valve body on which the valve body 11 is disposed, and its cross section has a mountainous shape. formed into a shape. Further, the inner peripheral edge of the main plate 25 is placed on the shelf portions 17, 18 of the upper and lower spindle bosses, and there is an inner court θ (for example, 45°) between the protruding strips 15.16 of the upper and lower spindle bosses and the reinforcing ribs 14. A V-shaped groove 28 is formed.

The other main plate 26 is formed in a size that just closes the opening S, as shown in FIGS. 6 and 7.
Its outer peripheral edge forms a V-shaped groove 29 with an angle θ (for example, 45°) between the circumferential frame members, and its inner peripheral edge forms a /-shaped groove 28 similar to the main plate 25.

Next, the procedure for assembling the butterfly valve will be explained. FIG. 8 shows a front half-sectional view of the assembled valve body 11, and FIG. 9 shows a side half-sectional view of the valve body.

First, the upper spindle boss 12 and the lower spindle boss 13
are arranged at intervals along the valve axis line X-x, and both are welded and connected by reinforcing ribs 14. Next, one ends of quarter-arc-shaped circumferential frame members 19, 20, 21, and 22 are welded to both outer end surfaces of the spindle bosses 12 and 13, respectively, to form a ring shape as a whole. Also, the reinforcing rib 23
24 are welded to the reinforcing rib 14 in a cross shape.

After producing the framework of the valve body in this way, a semicircular opening S defined by the spindle bosses 12, 13, the reinforcing i-knob 14 and the circumferential frame members 19.20, 21.22 is formed. A pair of semicircular main plates 25 and 26 are welded together so as to close the main plates 25 and 26, respectively.

As shown in FIG. 10, the inner peripheral edges of the pair of main plates 25 with large radii are placed on the shelves 17. A welded portion 30 is formed. Further, as shown in FIGS. 11 and 12, the outer peripheral edge of the main plate 25 that protrudes outward from the circumferential frame members 19, 20, 21, and 22 and forms the sealing portion 27 is placed on the circumferential frame member. A fillet weld 31 is formed between the circumferential frame members. Further, fillet welds 32 are formed between the main plate 25 and the reinforcing ribs 23 and 24, as shown in FIG. 24 and the circumferential frame member 19, 20, 21, and 22 along the entire line.

Furthermore, as shown in FIG. 10, the pair of main plates 26 having a small radius are welded to form a section 30 along a groove 28 formed in a part of the inner peripheral edge -11, similarly to the main plate 25 described above. At the same time, as shown in FIGS. 11 and 12, a welded portion 33 is formed along the groove 29 formed on the outer peripheral edge. As shown in FIG. 13, intermittent plug welds 34 are formed roughly between the reinforcing ribs 23 and 24, whereby the main plate 26 is also welded together in the same manner as the main plate 25. Note that the reinforcing ribs 23 and 24 are welded to the main plate 26 by plug welding, but the reinforcing ribs 23 and 24 are used to prevent deformation of the valve body 11, and the bending moment due to water pressure is not applied intermittently. Even a simple plug welded portion 34 is sufficient in terms of strength.

As described above, according to the present invention, the outer surface of the main plate of the valve body can meet the butterfly valve flush with the spindle boss, and since there is no protrusion on the surface of the valve body, 1. It is possible to effectively prevent stirring loss and vibration caused by vortices and improve water flow characteristics. Furthermore, the sealing part 27, which is an important part of the valve body, is formed on the outer peripheral edge of the main plate 25 and can be preformed when the main plate 25 is manufactured, so that the structure becomes simple. Furthermore, since the sealing part 27 is integrally molded with the main plate 25, it is less deformed by welding heat than conventional seal rings, and there is no need to finish the surface of the sealing part after welding and assembly. Body production time and cost can be significantly reduced.

Further, since the circumferential frame members 19, 20, 21° 22 having a quarter-arc shape are used, deformation of the circumferential frame members due to welding heat is small. Therefore, the compatibility between the main plate and the framework of the valve body, which is manufactured by mounting on the circumferential frame member, etc., is good, and welding work becomes easier.

〔Effect of the invention〕

As can be seen from the above description, according to the present invention, a pair of substantially semicircular main plates having different radii are welded to both sides of the valve axis line on each face of the valve body, and the main plates having the larger radius are welded together. The main plate is arranged point symmetrically with respect to the axis of the valve body,
Furthermore, since a sealing part is formed on the outer peripheral edge of the main plate with a larger radius, there is no need to finish the surface of the sealing part after the valve body is assembled (this significantly reduces the manufacturing time and cost of the valve body. In addition, each component of the valve body can be welded with good consistency without being affected by welding heat, and most parts are welded all around, making welding work easier and reducing the risk of damage to the valve body. It can be improved.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of a butterfly valve according to the present invention;
The figure is a front view of the circumferential frame member used for the valve body, Fig. 3 is a side view of the circumferential frame member, Fig. 4 is a front view of the main plate with a large radius, and Fig. 5 is v-v of Fig. 4. 6 is a front view of the main plate with a small radius, FIG. 7 is a sectional view taken along the line Vl-Vl of FIG. 6, and FIG. 8 is a front sectional view of the valve body according to the present invention. is a side half-sectional view of the valve body taken along the line ■-TX in FIG. 8, FIG. 10 is a cross-sectional view taken along the line X--X in FIG. 8, and FIG. , Figure 12 is the same as Figure 8)
13 is a sectional view taken along the xm-xm line in FIG. 8, FIG. 14 is a front half sectional view of a conventional butterfly valve,
FIG. 15 is a side half-sectional view of the butterfly valve, FIG. 16 is a diagram showing the water flow characteristics of the butterfly valve, and FIG. 17 is a diagram showing the state of adhesion of marine organisms to the butterfly valve. 11... Valve body, 12... Upper spindle boss, 13
...lower spindle boss, 1/1.23.24...
Reinforcement rib, 15.16... Projection strip, 17.18.19
a. 20a, 21a, 22a...shelf, 19.20°21
．． 22... Circumferential frame member, 25... Main plate with large radius, 26... Main plate with small radius, 27... Sealing portion, 2
8.29...Bevel, 30.31, 32.33°34.
··welded part,. Applicant's agent Hiroshi Inomata 1 Figure 25. 2 to Figure 2, Figure 3''2:e!0 Figure 1O Figure 11 b ¥12I!1 Figure 13 Figure 14 Figure 15 Figure 16 Country Figure 17

Claims (1)

[Claims] 1. On both sides of the upper and lower spindle bosses, which are arranged at a predetermined distance on the valve axis line and connected by reinforcing ribs, are symmetrical with respect to the valve axis line and narrow as they move away from the spindle boss. In a butterfly valve formed by joining semicircular arc-shaped circumferential frame members with the same width and closing the inner opening of the circumferential frame members with a main plate, both sides of the valve axis line on each surface of the valve body A pair of approximately semicircular main plates with different radii are welded together, and the main plate with the larger radius is arranged symmetrically with respect to the valve axis, and the main plate with the larger radius is arranged symmetrically with respect to the valve axis. A butterfly valve characterized by having a sealing part formed on the outer periphery. 2. The butterfly valve according to claim 1, wherein the sealing portion has a mountain-shaped cross section.