Butterfly valve

Abstract

To provide a butterfly valve which can reduce metallic sound when a fluid flows.SOLUTION: A butterfly valve 1 includes: a valve shaft 3 perpendicular to a pipe path 2 inside the pipe path 2; a valve body 5 provided inside the pipe path 2 and rotatable around the valve shaft 3 as a rotary shaft; a seat ring 7 fixed on an inner periphery of the pipe path 2 and coming into liquid-tight contact with the valve body 5 when the valve body 5 is at a predefined rotation position: and a first resistance body 6 projecting from an orifice-side end part of the valve body 5 toward a downstream side in a state where the valve body 5 is at the predefined rotation position, and having an outer face of a predefined radius from a rotary axial center of the valve shaft 3. The first resistance body 6 is a comb-shaped projection.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a butterfly valve that closes a pipeline in a closed state and opens the pipeline when rotated from the closed state around a valve stem. [Background technology]

[0002] Conventionally, butterfly valves have been available that switch between the closed and open states of a pipeline by rotating a valve disc around a valve stem. In butterfly valves, a difference in flow rate occurs between the orifice-side flow path and the nozzle-side flow path when the valve disc opens. For this reason, as disclosed in Patent Document 1, for example, some butterfly valves are provided with a resistor protruding downstream from the valve disc on the nozzle side of the valve disc. In this butterfly valve, the resistor suppresses the difference in flow rate between the orifice-side flow path and the nozzle-side flow path, thereby suppressing the occurrence of cavitation. This also reduces the volume of noise generated when fluid flows through the pipeline. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-82932 Summary of the Invention [Problem to be solved by the invention]

[0004] However, even the butterfly valve described in Patent Document 1 does not provide a sufficient effect of reducing noise volume, particularly metallic noise.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide a butterfly valve that reduces metallic noise when fluid flows through it. [Means for solving the problem]

[0006] In order to solve the above problem, the butterfly valve of the present invention comprises a valve stem disposed within a pipeline and perpendicular to the pipeline, a valve element disposed within the pipeline and rotatable around the valve stem as a rotation axis, a seat ring fixed to the inner circumference of the pipeline and in liquid-tight contact with the valve element when the valve element is in a predetermined rotation position, and a first resistor protruding from the orifice side end of the valve element toward the downstream side when the valve element is in the predetermined rotation position and having an outer surface with a predetermined radius from the rotation axis of the valve stem, wherein the first resistor is a comb-like protrusion.

[0007] This configuration can reduce metallic noises that are generated when the fluid flowing through the pipe 2 strikes the inner surface of the casing of the metal butterfly valve 1 when the butterfly valve 1 is open.

[0008] The butterfly valve further includes a second resistor that protrudes from the nozzle end of the valve body toward the upstream side when the valve body is in the predetermined rotational position and has an outer surface with a predetermined radius from the rotation axis of the valve stem, and the second resistor is a comb-like protrusion.

[0009] This configuration can prevent imbalances in the flow rate between the orifice and the nozzle, thereby suppressing the occurrence of cavitation, and as a result, further reducing metallic sounds that occur when liquid flows through the pipeline.

[0010] It is preferable that the first and second resistors have a plurality of recesses formed from one surface of the resistor to the opposing surface, and that a cross section cut parallel to the depth direction of the recesses to include the recesses has a comb-like shape.

[0011] This configuration can further reduce metallic sounds when liquid flows through the pipe.

[0012] It is preferable that the tip surfaces of the first and second resistors are formed in a shape that faces the seat ring with a predetermined gap between them when the valve body rotates, and that the predetermined gap is adjusted according to the resistance of the flow path facing the orifice side end of the valve body.

[0013] This configuration can further reduce metallic sounds when liquid flows through the pipe.

[0014] The valve stem is preferably located downstream of a seal surface, which is an imaginary plane including the seat ring.

[0015] With this configuration, the gap between the valve element and the seat ring opens later on the nozzle side than on the orifice side, or the gap on the orifice side opens wider than on the nozzle side, thereby suppressing imbalances in the flow rates between the orifice side and the nozzle side. [Effects of the Invention]

[0016] In this way, according to the present invention, it is possible to reduce the metallic noise that is generated when liquid flows through a pipe line when the butterfly valve is in an open state. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view showing the configuration of a butterfly valve 1 according to the present invention, showing a state in which a valve element 5 is in a closed position. [Figure 2] 1 is a cross-sectional view showing the configuration of a butterfly valve 1, showing a state in which a valve element 5 is in a 30-degree open position. [Figure 3] 1 is a cross-sectional view showing the configuration of a butterfly valve 1, showing a state in which a valve element 5 is in a 60-degree open position. [Figure 4] 2 is a cross-sectional view of the butterfly valve 1 of FIG. 1 as viewed from the downstream side. [Figure 5] FIG. 3 is a schematic perspective view of the butterfly valve 1 of FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0018] Figures 1, 2, and 3 are cross-sectional views showing the configuration of a butterfly valve (butterfly-type float valve) 1 according to the present invention, with Figure 1 showing the valve element 5 in a closed position, Figure 2 showing the valve element 5 in a 30-degree open position, and Figure 3 showing the valve element 5 in a 60-degree open position.

[0019] As shown in Figure 1, a butterfly valve 1 includes a pipeline 2, a valve stem 3, a valve stem holder 4, a valve disc 5, first and second comb-tooth resistors 6, 6 which are comb-tooth projections, and a seat ring 7. The butterfly valve (butterfly-type float valve) 1 functions as a constant water level valve that controls the constant water level in reservoirs, water tanks, pressure-reducing tanks, farm ponds, etc.

[0020] The pipeline 2 is a cylindrical pipe through which a fluid flows. The butterfly valve 1 is a valve that opens and closes a portion of the pipeline 2 to stop the flow of the liquid or adjust the flow rate.

[0021] The valve stem 3 has a rod shape and extends in a direction perpendicular to the pipeline 2. Both ends of the valve stem 3 are fixed to the inner surface of the pipeline 2.

[0022] The valve stem holding portion 4 holds the valve stem 3 so that it can rotate.

[0023] The valve element 5 has a disk shape, and one surface of the disk shape is fixed to the valve stem holder 4. This allows the valve element 5 to rotate around the valve stem 3 as a central axis. The size of the outer circumference of the circle of the valve element 5 is slightly smaller than the circular shape of the inner surface of the pipeline 2 that is perpendicular to the pipeline 2.

[0024] The valve disc 5 is eccentric to the upstream side of the pipeline 2 with respect to the valve stem 3. Such a butterfly valve 1 is called a single eccentric butterfly valve. A comb-like resistor 6 is attached to the nozzle-side end 5b of the valve disc 5, and protrudes toward the upstream side of the pipeline 2 when the valve disc 5 is in the closed state, as viewed in the cross-sectional direction of the pipeline 2. The comb-like resistor 6 has a predetermined radius from the axis of rotation of the valve stem 3. On the other hand, a comb-like resistor 6 is attached to the orifice-side end 5a of the valve disc 5, and protrudes toward the downstream side of the pipeline 2 when the valve disc 5 is in the closed state, as viewed in the cross-sectional direction of the pipeline 2. The outer surface 6b on the nozzle side (lower side in Figs. 1 to 3) of the comb-like resistor 6 and the outer surface 6a on the orifice side (upper side in Figs. 1 to 3) are shaped along an imaginary arc centered on the rotation axis of the valve stem 3. In addition, in the state shown in Fig. 3, the outer surfaces 6a, 6b also have an arc shape in the direction of the rotation axis of the valve stem 3 so that the gap formed between the outer surface 6a and the inner circumferential surface of the pipeline 2 is constant in the circumferential direction of the pipeline 2. The radius of the outer surfaces 6a, 6b centered on the rotation axis of the valve stem 3 is slightly smaller than the radius of the circumferential edge of the valve disc 5 centered on the rotation axis of the valve stem 3.

[0025] Figure 4 is a cross-sectional view of the butterfly valve 1 of Figure 1 as seen from the downstream side. Figure 5 is a schematic perspective view of the butterfly valve 1 of Figure 2. In Figure 5, the seat ring 7 is omitted to make it easier to understand the structure of the comb-tooth resistor 6. As shown in Figures 4 and 5, the comb-tooth resistor 6 is composed of comb-tooth-shaped protrusions (columnar protrusions), and a plurality of recesses are formed from one surface of the comb-tooth resistor 6 to the opposite surface, and a cross section taken parallel to the depth direction of the recesses to include the recesses is comb-shaped.

[0026] The seat ring 7 has an annular shape and is made of an elastic material such as rubber. The seat ring 7 is located on an imaginary plane (hereinafter referred to as the "seal surface 20") perpendicular to the axial direction of the pipeline 2, and is fixed to the inner surface of the pipeline 2 at a position where it abuts against the circumferential edge of the valve element 5 when the butterfly valve 1 shown in Figure 1 is in the closed position (corresponding to a predetermined rotation position) (hereinafter referred to as the "closed state").

[0027] As shown in Figure 1, when the butterfly valve 1 is in the closed state, the valve element 5 is positioned along and on the seal surface 20. In this state, the circumferential edge of the valve element 5 is in liquid-tight contact with the seat ring 7. As a result, when the butterfly valve 1 is in the closed state, the flow of liquid flowing from the left side to the right side in the pipeline 2 in Figures 1 to 3 is stopped by the butterfly valve 1.

[0028] When the valve element 5 is rotated counterclockwise in FIG. 1 from the position of the valve element 5 shown in FIG. 1, the valve element 5 is placed in an open position (hereinafter referred to as the "open state").

[0029] When the valve disc 5 is closed as shown in Figure 1, no flow path is established and no flow occurs. As the valve disc 5 opens from this state, gaps are created between the arc-shaped outer surfaces 6a, 6b and the seat ring 7 when the arc-shaped outer surfaces 6a, 6b face the seat ring 7, forming flow paths at the orifice end 5a and the nozzle end 5b, as well as through the gaps between the outer surfaces 6a, 6b and the seat ring 7.

[0030] 2 and 3, in the open state of the butterfly valve 1, the liquid flowing through the pipeline 2 flows through flow paths 21 and 22, which are the gaps between the circumferential edge of the valve body 5 and the seat ring 7. In FIG. 3, the flow paths 21 and 22 are larger than in FIG. 2, so more fluid flows through the pipeline 2.

[0031] In this embodiment, the arc-shaped outer surface 6b is integrally formed with the nozzle-side end 5b of the valve element 5. Here, the tip surface of the comb-shaped resistor 6, represented by the arc-shaped outer surface 6b, faces the seat ring 7 with a predetermined gap interposed between them when the valve element 5 rotates. Therefore, when the valve element 5 is in the closed state, no fluid flows, but when the valve element 5 opens and the arc-shaped outer surface 6b faces the seat ring 7, a gap is created at the orifice-side end 5a, forming a flow path. Furthermore, because the gap formed between the arc-shaped outer surface 6b and the seat ring 7 is narrow in the flow path facing the nozzle-side end 5b, the pressure is reduced due to considerable fluid resistance, and the flow rate is either negligible or the flow rate in the nozzle-side flow path is balanced with the flow rate in the orifice-side flow path that is subjected to resistance by the orifice-side end 5a, thereby suppressing cavitation caused by the difference in flow speed between the nozzle-side and orifice-side flow paths. Therefore, it is possible to reduce the metallic sound generated when the fluid flowing in the conduit 2 hits the inner surface of the metal casing of the butterfly valve 1 when the butterfly valve 1 is open. Here, it is desirable that the size of the gap formed between the arc-shaped outer surface 6a and the seat ring 7 be set to a size that balances the flow rate through it and the flow rate in the orifice-side flow path that receives resistance from the orifice-side end 5a. The size of the gap formed between the arc-shaped outer surface 6a and the seat ring 7 is determined by trial and error through prototype manufacturing according to the orifice-side structure, because the flow rate in the flow path at the orifice-side end 5a varies depending on the shape and thickness of the orifice-side end 5a and the structure of the seat ring 7. Note that the angle of the arc-shaped outer surface 6b around the center of valve stem rotation is, for example, 60 degrees.

[0032] When the butterfly valve is in operation, the valve disc 5 rotates counterclockwise from the fully closed position shown in Figure 1, and the flow rate changes according to the opening of the valve disc 5, thereby controlling the flow rate. At this time, the fluid passing through the gaps between the arc-shaped outer surfaces 6a, 6b and the seat ring 7 is transformed into fine jets through the passages formed between the multiple comb-like projections of the comb-like resistors 6 located at the orifice end 5a and the nozzle end 5b, respectively, dispersing any cavitation that may occur downstream of the valve disc 5 and suppressing its growth. Furthermore, by arranging the multiple comb-like projections in multiple arc-shaped rows alternately so as not to overlap each other in the radial direction, the fluid flow passing through these comb-like projections is further subdivided, dispersing energy and effectively suppressing the occurrence of cavitation. This further reduces cavitation caused by the difference in flow velocity between the nozzle and orifice sides of the flow passages, and also reduces the metallic noise that occurs when the fluid flowing through the pipe 2 collides with the inner surface of the metal casing of the butterfly valve 1 when the butterfly valve 1 is open.

[0033] As described above, the butterfly valve 1 comprises the valve stem 3 disposed within the pipeline 2 and perpendicular to the pipeline, the valve element 5 disposed within the pipeline 2 and rotatable around the valve stem 3 as a rotation axis, the seat ring 7 fixed to the inner periphery of the pipeline 2 and in liquid-tight contact with the valve element 5 when the valve element 5 is in a predetermined rotation position, and the first resistor 6 protruding from the orifice side end of the valve element 5 toward the downstream side when the valve element 5 is in the predetermined rotation position and having an outer surface with a predetermined radius from the rotation axis of the valve stem 3, the first resistor 6 being a comb-like protrusion.

[0034] Therefore, compared to a configuration that does not have the first resistor 6, which is a comb-tooth-shaped protrusion, it is possible to reduce the metallic sound generated when the fluid flowing through the pipeline 2 collides with the inner surface of the casing of the metal butterfly valve 1.

[0035] This is thought to be because the fluid is transformed into fine jet streams through the passages formed between the multiple comb-like projections, dispersing cavitation occurring downstream of the valve body 5 and suppressing the growth of cavitation. Furthermore, by arranging the multiple comb-like projections in multiple arc-shaped rows alternately so as not to overlap each other in the radial direction, the fluid flow passing through these comb-like projections is further subdivided, dispersing energy and effectively suppressing the occurrence of cavitation.

[0036] The valve body 5 is provided with a second resistor 6 that protrudes from the nozzle side end of the valve body 5 toward the upstream side when the valve body 5 is in a predetermined rotational position and has an outer surface with a predetermined radius from the rotation axis of the valve stem, and the second resistor 6 is a comb-like protrusion.

[0037] Therefore, it is possible to suppress the imbalance in the flow rate between the orifice side and the nozzle side, and to suppress the occurrence of cavitation, which in turn makes it possible to further reduce the metallic sound that occurs when liquid flows through the conduit 2.

[0038] The first and second resistors 6, 6 have multiple recesses formed from one surface of the resistor 6, 6 to the opposing other surface, and a cross section cut parallel to the depth direction of the multiple recesses to include the multiple recesses has a comb-like shape.

[0039] Therefore, the metallic sound produced when the liquid flows through the pipe 2 can be further reduced.

[0040] This is thought to be because the multiple comb-tooth projections are arranged in multiple arc-shaped rows, alternating so that they do not overlap each other in the radial direction, which further subdivides the fluid flow passing through these comb-tooth projections and diffuses energy, effectively suppressing the occurrence of cavitation.

[0041] The valve stem 3 is located downstream of the sealing surface 20 .

[0042] As a result, the gap between the valve element 5 and the seat ring 7 opens later on the nozzle side than on the orifice side, or the gap on the orifice side opens wider than on the nozzle side, thereby suppressing imbalance in the flow rates between the orifice side and the nozzle side.

[0043] Although one embodiment of the present invention has been described above, the present invention can be embodied in other forms.

[0044] For example, in the above embodiment, the butterfly valve 1 is a single eccentric butterfly valve in which the valve disc 5 is eccentric to the upstream side of the pipeline 2 relative to the valve stem 3, but the butterfly valve 1 may be a butterfly valve in which the valve disc 5 is not eccentric to the valve stem 3, or may be a double eccentric butterfly valve in which the valve disc 5 is eccentric to the valve stem 3 in both the axial and radial directions of the pipeline 2.

[0045] In the above-described embodiment, the pipeline 2 has a cylindrical shape, but it may have a tubular shape other than a cylindrical shape, for example, a tubular shape with a square cross section. In this case, the shape of the valve body 5 may not be a disk shape, but may be a shape that matches the inner peripheral shape of the pipeline 2, such as a square flat plate.

[0046] Furthermore, the first and second comb-tooth resistors 6, 6 and the valve body 5 do not need to be formed integrally, and the first and second comb-tooth resistors 6, 6 may be formed separately from the valve body 5 and fixed to the valve body 5, respectively.

[0047] Furthermore, if the valve element 5 is configured to be rotatable relative to the pipeline 2, the valve element 5 may be fixed to the valve stem 3 and the valve stem 3 may be rotatably held in the pipeline 2, or the valve stem 3 may be fixed to the pipeline 2 and the valve element 5 may be rotatably held on the valve stem 3.

[0048] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as set forth in the claims. [Explanation of symbols]

[0049] 1. Butterfly valve 2 conduit 3 Valve stem 4 Valve stem holding part 5 Valve body 6 Comb resistor 6a Exterior 7 Seat ring 20 sealing surface

Claims

1. a valve stem disposed in the pipeline and perpendicular to the pipeline; a valve body disposed in the pipeline and rotatable about the valve stem; a seat ring fixed to the inner periphery of the conduit and in liquid-tight contact with the valve body when the valve body is in a predetermined rotational position; a first resistor that protrudes from the orifice side end of the valve body toward the downstream side when the valve body is in the predetermined rotation position and has an outer surface with a predetermined radius from the rotation axis of the valve stem, the first resistor is a comb-shaped projection; Butterfly valve.

2. a second resistor protruding from the nozzle-side end of the valve body toward the upstream side when the valve body is in the predetermined rotation position, and having an outer surface with a predetermined radius from the rotation axis of the valve stem; the second resistor is a comb-shaped projection; The butterfly valve of claim 1.

3. 3. The butterfly valve according to claim 2, wherein the first and second resistors have a plurality of recesses formed from one surface of the resistor to the other opposing surface thereof, and a cross section cut parallel to the depth direction of the recesses to include the plurality of recesses has a comb-like shape.

4. a tip end surface of each of the first and second resistors is formed in a shape that faces the seat ring with a predetermined gap therebetween when the valve body rotates; 3. The butterfly valve according to claim 2, wherein the predetermined gap is adjusted in accordance with the resistance of a flow path facing the orifice side end of the valve body.

5. 2. The butterfly valve according to claim 1, wherein the valve stem is located downstream of a seal surface which is an imaginary plane including the seat ring.

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