Butterfly valve, valve body for butterfly valve, and method for straightening fluid flow using the butterfly valve.

Abstract

The present invention provides a butterfly valve that can reliably rectify the turbulence generated by the fluid passing around the valve body when the valve body opening exceeds 30 degrees. [Solution] The butterfly valve 10 comprises a valve body 11 that forms a fluid passage 19 for tap water, and a valve body 16 that opens and closes the passage 19. The valve body 16 has an upstream side 20b located on the upstream side in the flow direction F of the tap water when in the fully closed position, a downstream side 20c located on the downstream side in the flow direction F when in the fully closed position, and on the valve body nozzle side 27a that moves in the flow direction F of the tap water when the passage 19 is opened, comb teeth 21 formed on the edge of the downstream side 20c, comb teeth 22 formed between the comb teeth 21 and the center DC of the downstream side 20c, and on the valve body orifice side 27b that moves in the direction opposite to the flow direction F of the tap water when the passage 19 is opened, comb teeth 23 formed on the edge of the upstream side 20b, and comb teeth 24 formed between the comb teeth 23 and the center UC of the upstream side 20b.

Description

Technical Field

[0001] The present invention relates to a butterfly valve used for controlling a fluid, a valve body for the butterfly valve, and a method for rectifying a fluid by the butterfly valve.

Background Art

[0002] Conventionally, a butterfly valve connected to a pipeline through which a fluid such as water supply and drainage or gas flows is known (for example, see Patent Document 1). The butterfly valve of Patent Document 1 includes four comb teeth each composed of a plurality of protrusions, and each comb tooth is formed along the edge of the valve body of the butterfly valve. FIG. 6 is a diagram used to explain the flow of a fluid inside a pipeline 68 to which a conventional butterfly valve 60 is connected.

[0003] In FIG. 6, a butterfly valve 60 and a pipeline 68 are connected, and the butterfly valve 60 includes a valve box 67 and a valve body 65. The valve box 67 forms a fluid flow path by being connected to the pipeline 68. The valve body 65 rotates between a fully open position along the flow direction F of the fluid flowing from upstream to downstream and a fully closed position along a direction orthogonal to the flow direction F, and opens and closes the fluid flow path formed by the valve box 67.

[0004] The valve body 65 in the fully closed position has an upstream side surface 66a located on the upstream side in the flow direction F and a downstream side surface 66b located on the downstream side in the flow direction F. When stopping the fluid flow, the fluid pressure is applied to the upstream side surface 66a. When the valve body 65 in the fully closed position is opened, the valve body 65 is divided into two regions: a valve body nozzle side that moves in the same direction as the flow direction F and a valve body orifice side that moves in a direction opposite to the flow direction F. A narrow flow path C1 is formed between the edge of the valve body 65 on the valve body nozzle side and the valve box 67, and a narrow flow path C2 is formed between the edge of the valve body 65 on the valve body orifice side and the valve box 67.

[0005] When the fluid, which was previously held back by the upstream side 66a, passes through the narrow channels C1 and C2 when the valve body 65, which is in the fully closed position, opens, it collides with the upstream side 66a and the inner wall of the valve body 67, causing turbulence, which is an irregular fluctuation of the fluid. When turbulence occurs, cavitation occurs, in which bubbles are repeatedly formed and collapsed. When cavitation occurs, bubbles impact the inside of the pipe 68, damaging the pipe 68.

[0006] In response to this, the valve body 65 is equipped with comb teeth 61 to 64. Comb teeth 61 straighten the fluid before it passes through the narrow channel C1, comb teeth 62 straighten the fluid after it passes through the narrow channel C2, comb teeth 63 straighten the fluid after it passes through the narrow channel C1, and comb teeth 64 straighten the fluid before it passes through the narrow channel C2. As a result, turbulence is less likely to occur before and after the fluid passes through the narrow channels C1 and C2, thereby suppressing the occurrence of cavitation and preventing damage to the pipeline 68. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2015-129551 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, when the valve body 65 is set to 0 degrees in the fully closed position and 90 degrees in the fully open position, the comb teeth 61-64 straighten the fluid before and after it passes through the narrow passages C1 and C2 when the valve body 65 is set to 30 degrees or less. However, when the valve body 65 is set to 30 degrees or more, the flow rate of the fluid passing through the narrow passage C1 increases, and the upstream side surface 66a on the valve body orifice side moves in the opposite direction to the fluid flow direction F. As a result, the flow rate at which the fluid strongly collides with the upstream side surface 66a on the valve body orifice side increases. Consequently, the comb teeth 61-64 are unable to straighten the turbulence generated when the fluid passes through the narrow passage C1 and the turbulence generated when the fluid collides with the upstream side surface 66a on the valve body orifice side, resulting in cavitation based on this turbulence. In other words, there was a problem in that the turbulence generated by the fluid passing around the valve body 65 when the valve body opening degree exceeded 30 degrees could not be reliably straightened.

[0009] The object of the present invention is to provide a butterfly valve, a valve body for a butterfly valve, and a method for rectifying fluid flow using the butterfly valve, which can reliably rectify turbulence generated by the fluid passing around the valve body when the valve body opening exceeds 30 degrees. [Means for solving the problem]

[0010] To achieve the above objective, the butterfly valve according to claim 1 comprises a valve body connected to a pipeline through which a fluid flows and forming a fluid passage, and a valve element for opening and closing the passage formed in the valve body, wherein the valve element has: a first movable part that moves in the same direction as the fluid flow direction from upstream to downstream in the passage when the passage is opened; a second movable part that moves in the opposite direction to the flow direction when the passage is opened; an upstream side surface located on the upstream side in the flow direction when the passage is closed; a downstream side surface located on the downstream side in the flow direction when the passage is closed; a first straightening part formed along the edge of the downstream side surface of the first movable part; a second straightening part formed between the center of the first straightening part and the center of the downstream side surface and along the first straightening part; a third straightening part formed along the edge of the upstream side surface of the second movable part; and a fourth straightening part formed between the center of the third straightening part and the center of the upstream side surface and along the third straightening part.

[0011] To achieve the above objective, the valve body for a butterfly valve according to claim 7 is used in a butterfly valve that is connected to a pipeline through which a fluid flows and has a valve body that forms a flow path for the fluid, and is a valve body for a butterfly valve that opens and closes a flow path formed in the valve body, and is characterized by having: a first movable part that moves in the same direction as the flow direction of the fluid flowing from upstream to downstream in the flow path when the flow path is opened; a second movable part that moves in the opposite direction to the flow direction when the flow path is opened; an upstream side surface located on the upstream side in the flow direction when the flow path is closed; a downstream side surface located on the downstream side in the flow direction when the flow path is closed; a first straightening part formed along the edge of the downstream side surface of the first movable part; a second straightening part formed between the center of the first straightening part and the center of the downstream side surface and along the first straightening part; a third straightening part formed along the edge of the upstream side surface of the second movable part; and a fourth straightening part formed between the center of the third straightening part and the center of the upstream side surface and along the third straightening part.

[0012] To achieve the above objective, the method for straightening fluid flow using a butterfly valve according to claim 8 comprises a valve body connected to a pipeline through which fluid flows and forming a fluid passage, and a valve element for opening and closing the passage formed in the valve body, wherein the valve element has a first movable part that moves in the same direction as the fluid flow direction from upstream to downstream in the passage when the passage is opened, a second movable part that moves in the opposite direction to the flow direction when the passage is opened, an upstream side located on the upstream side in the flow direction when the passage is closed, a downstream side located on the downstream side in the flow direction when the passage is closed, a first straightening part formed along the edge of the downstream side of the first movable part, and the first straightening part and the downstream side A method for straightening fluid using a butterfly valve, the butterfly valve having a second straightening portion formed between the centers of its surfaces and along the first straightening portion, a third straightening portion formed along the edge of the upstream side surface of the second movable portion, and a fourth straightening portion formed between the center of the third straightening portion and the center of the upstream side surface and along the third straightening portion, characterized in that it comprises a first straightening step in which the first straightening portion or the second straightening portion straightens the fluid that has passed through a narrow passage formed between the valve body and the first movable portion, and a second straightening step in which the third straightening portion or the fourth straightening portion straightens the fluid before it passes through another narrow passage formed between the valve body and the first movable portion. [Effects of the Invention]

[0013] According to the present invention, turbulence generated by the fluid passing around the valve body when the valve body opening exceeds 30 degrees can be reliably straightened. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic front view showing a butterfly valve according to an embodiment of the present invention. [Figure 2]These diagrams are used to explain the valve body in the butterfly valve shown in Figure 1. Figure 2(a) is a perspective view of the valve body in Figure 1, Figure 2(b) is a front view of the valve body in Figure 1 viewed from the upstream side in the flow direction when the valve body is in the fully closed position, Figure 2(c) is a front view of the valve body in Figure 1 viewed from the downstream side in the flow direction when the valve body is in the fully closed position, and Figure 2(d) is a cross-sectional view along line AA in Figure 2(a). [Figure 3] Figure 1 is a flowchart showing the procedure for a flow straightening method in which the turbulent flow of tap water is straightened by the butterfly valve. Figure 3(a) is a flowchart showing the procedure for a first flow straightening method in which the tap water is straightened before and after passing through the narrow channel formed on the valve nozzle side in Figure 2. Figure 3(b) is a flowchart showing the procedure for a second flow straightening method in which the tap water is straightened before and after passing through the narrow channel formed on the valve orifice side in Figure 2. [Figure 4] Figure 1 is used to illustrate the internal structure of the valve body when the butterfly valve shown is connected to a pipeline and the valve body opening is 30 degrees. [Figure 5] These figures are used to illustrate modified valve bodies in Figure 2. Figure 5(a) is a perspective view of a modified valve body from Figure 2. Figure 5(b) is a front view of the valve body from the upstream side in the flow direction when the valve body from Figure 5(a) is used in the butterfly valve in Figure 1 and is in the fully closed position. Figure 5(c) is a front view of the valve body from the downstream side in the flow direction when the valve body from Figure 5(a) is used in the butterfly valve in Figure 1 and is in the fully closed position. Figure 5(d) is a cross-sectional view along the BB line in Figure 5(a). [Figure 6] This diagram is used to illustrate the fluid flow inside a pipeline to which a conventional butterfly valve is connected. [Modes for carrying out the invention]

[0015] Embodiments of the present invention will be described in detail below with reference to the drawings.

[0016] FIG. 1 is a front view schematically showing a butterfly valve 10 according to an embodiment of the present invention.

[0017] The butterfly valve 10 in FIG. 1 includes a valve box 11, a speed reducer 12, a connection base 13, an operating machine 14, a valve rod 15, a valve body 16 (valve body for butterfly valve), and a bearing portion 17. The valve rod 15 penetrates the valve body 16, and the valve rod 15 and the valve body 16 are fixed by bolts 18 and nuts (not shown). The valve box 11 is connected to a pipeline (not shown) through which fluid flows and forms a fluid flow path 19. Hereinafter, in the present embodiment, it will be described on the premise that the fluid flowing through the valve box 11 is the service water used for beverages or the like.

[0018] The speed reducer 12 is fixed to the connection base 13 by bolts (not shown). One ends of the operating machine 14 and the valve rod 15 are connected to the speed reducer 12, and the other end of the valve rod 15 is held by the bearing portion 17. When the operating machine 14 is operated, a predetermined torque is input to the speed reducer 12. The speed reducer 12 increases and outputs the input torque. The valve body 16 and the valve rod 15 rotate based on the torque output from the speed reducer 12. Thereby, the valve body 16 rotates between a fully open position along the flow direction F of the service water flowing from the upstream to the downstream and a fully closed position along a direction orthogonal to the flow direction F, and opens and closes the service water flow path 19 formed by the valve box 11.

[0019] FIG. 2 is a view used to explain the valve body 16 in the butterfly valve 10 of FIG. 1. FIG. 2(a) is a perspective view of the valve body 16 in FIG. 1, FIG. 2(b) is a front view of the valve body 16 viewed from the upstream side in the flow direction F when the valve body 16 in FIG. 1 is in the fully closed position, FIG. 2(c) is a front view of the valve body 16 viewed from the downstream side in the flow direction F when the valve body 16 in FIG. 1 is in the fully closed position, and FIG. 2(d) is a cross-sectional view taken along the line A-A in FIG. 2(a).

[0020] In Figures 2(a) to 2(d), the valve body 16 is disc-shaped and includes an insertion portion 20a, an upstream side 20b, a downstream side 20c, a valve seat 20d, and comb teeth 21-26. When the valve body 16 rotates between the fully open and fully closed positions, it has two regions: a valve nozzle side 27a (first movable part) that moves in the same direction as the flow direction F when opening the flow path 19, and a valve orifice side 27b (second movable part) that moves in the opposite direction to the flow direction F when opening the flow path 19. A valve stem 15 that penetrates the valve body 16 is inserted into the insertion portion 20a. The upstream side 20b is located upstream of the flow direction F of the tap water flowing from upstream to downstream in the fully closed position of the valve body 16, and is a water-stopping surface that stops the tap water flowing from upstream. The downstream side 20c is located downstream of the flow direction F in the fully closed position of the valve body 16, and is a facing surface opposite to the upstream side 20b. The upstream side surface 20b and the downstream side surface 20c are integrated. The valve seat 20d is formed on the edges of the integrated upstream side surface 20b and downstream side surface 20c and is in close contact with the valve body 11 when the valve body 16 is in the fully closed position. There is a virtual boundary surface L at the boundary between the upstream side surface 20b and the downstream side surface 20c (Figure 2(d)), and in this embodiment, the valve seat 20d is formed on the virtual boundary surface L.

[0021] The comb teeth 23 (the third rectifying portion) has a plurality of protrusions and is formed along the edge of the upstream side surface 20b on the valve body orifice side 27b. Further, the comb teeth 24 (the fourth rectifying portion) also has a plurality of protrusions and is formed between the comb teeth 23 and the center UC of the upstream side surface 20b on the valve body orifice side 27b of the upstream side surface 20b. In FIGS. 2(a) to 2(d), the comb teeth 23 and 24 have a certain interval. Specifically, the difference between the distance from the center UC of the upstream side surface 20b to the comb teeth 23 in the radial direction and the distance from the center UC of the upstream side surface 20b to the comb teeth 24 in the radial direction is constant. However, in the present embodiment, the comb teeth 24 may be formed between the comb teeth 23 and the center UC of the upstream side surface 20b, and the distance D4 from the center UC of the upstream side surface 20b to the comb teeth 24 in the radial direction with respect to the distance D3 from the center UC of the upstream side surface 20b to the comb teeth 23 in the radial direction is preferably 0.2 to 0.8. Further, the comb teeth 25 (the fifth rectifying portion) also has a plurality of protrusions and is formed along the edge of the upstream side surface 20b on the valve body nozzle side 27a. The comb teeth 23, 24, and 25 protrude from the upstream side surface 20b in the direction opposite to the flow direction F at the fully closed position of the valve body 16. Further, each protrusion constituting the comb teeth 23, 24, and 25 has a tip portion 29 located at the most upstream side thereof at the fully closed position of the valve body 16.

[0022] The comb teeth 21 (first flow straightening section) have multiple protrusions and are formed along the edge of the downstream side surface 20c on the valve nozzle side 27a. The comb teeth 22 (second flow straightening section) also have multiple protrusions and are formed between the comb teeth 21 and the center DC of the downstream side surface 20c on the valve nozzle side 27a of the downstream side surface 20c. In Figures 2(a) to 2(d), the comb teeth 21 and 22 are spaced at a constant interval. Specifically, the difference between the distance from the center DC of the downstream side surface 20c to the comb teeth 21 in the radial direction and the distance from the center DC of the downstream side surface 20c to the comb teeth 22 in the same radial direction is constant. However, in this embodiment, the comb teeth 22 only need to be formed between the comb teeth 21 and the center DC of the downstream side surface 20c, and the distance D2 from the center DC of the downstream side surface 20c to the comb teeth 22 in the radial direction relative to the distance D1 from the center DC of the downstream side surface 20c to the comb teeth 21 in the radial direction is preferably 0.2 to 0.8. Furthermore, the comb teeth 26 (the seventh flow straightening section) also have multiple protrusions and are formed along the edge of the downstream side surface 20c on the valve body orifice side 27b. The comb teeth 21, 22, and 26 protrude from the downstream side surface 20c toward the flow direction F when the valve body 16 is in the fully closed position. In addition, each protrusion constituting the comb teeth 21, 22, and 26 has a tip portion 29 located at the most downstream side when the valve body 16 is in the fully closed position.

[0023] The height of each projection constituting the comb teeth 21-26 is the length of the perpendicular from the tip 29 of each projection to the virtual interface L. Furthermore, each comb tooth 21-26 has the highest projection among its projections, 21a-26a. The height of each projection in each comb tooth 21-26 should be 0.5 cm or more. Also, the height M2 (maximum length) of projection 22a relative to the height M1 (maximum length) of projection 21a is preferably 0.3-1.5, and even better 1.0-1.5. Similarly, the height M4 of projection 24a relative to the height M3 of projection 23a is preferably 0.3-1.5, and even better 1.0-1.5.

[0024] Figure 3 is a flowchart showing the procedure for a flow straightening method in which the turbulent flow of tap water is straightened by the butterfly valve 10 in Figure 1. Figure 3(a) is a flowchart showing the procedure for a first flow straightening method in which the tap water is straightened before and after passing through the narrow channel C1 formed on the valve nozzle side 27a in Figure 2. Figure 3(b) is a flowchart showing the procedure for a second flow straightening method in which the tap water is straightened before and after passing through the narrow channel C2 formed on the valve orifice side 27b in Figure 2.

[0025] In Figure 3(a), first, the valve body 16 rotates in the fully closed position (S1). When the valve body opening exceeds 30 degrees, the tap water either collides with the upstream side surface 20b on the valve body nozzle side 27a and passes through the comb teeth 25, or flows directly into the narrow channel C1 (Figure 4) without colliding with the upstream side surface 20b (S2). The tap water that flows into the narrow channel C1 passes through the narrow channel C1 while colliding with the valve body 11 and the valve body 16. At this time, turbulence is generated in the tap water passing through the narrow channel C1, and this turbulence increases as it passes through the narrow channel C1. The turbulent tap water that has passed through the narrow channel C1 is straightened by passing through at least one of the comb teeth 21 and 22 (S3, first straightening step). Furthermore, the turbulent flow of the water that has passed through the narrow channel C1 initially forms vortices around the downstream side surface 20c even without passing through the comb teeth 21 and 22. These vortices soon pass through the comb teeth 21 and 22 and are straightened (S4, first straightening step), and the first straightening process is completed.

[0026] In Figure 3(b), when the valve body 16 rotates in the fully closed position (S5) and the valve body opening exceeds 30 degrees, the tap water collides with the upstream side surface 20b on the valve body orifice side 27b and passes through at least one of the comb teeth 23, 24, or flows directly into the narrow channel C2 (Figure 4) without colliding with the upstream side surface 20b (S6, second rectification step). The tap water that flows into the narrow channel C2 passes through the narrow channel C2 while colliding with the valve body 11 and the valve body 16. At this time, turbulence is generated in the tap water passing through the narrow channel C2, and this turbulence increases as it passes through the narrow channel C2. The turbulent tap water that has passed through the narrow channel C2 is rectified by passing through the comb teeth 26 (S7). Furthermore, the turbulent flow of the water that has passed through the narrow channel C2 initially forms a vortex around the downstream side surface 20c even without passing through the comb teeth 26. This vortex soon passes through the comb teeth 26 and is straightened (S8), thus completing the second straightening process.

[0027] In the butterfly valve 10 of this embodiment, the valve body 16 has, on the valve body nozzle side 27a, comb teeth 21 formed along the edge of the downstream side 20c, and comb teeth 22 formed between the center DC of the comb teeth 21 and the downstream side 20c and along the comb teeth 21, and on the valve body orifice side 27b, comb teeth 23 formed along the edge of the upstream side 20b, and comb teeth 24 formed between the center UC of the comb teeth 23 and the upstream side 20b and along the comb teeth 23.

[0028] When the valve body 16 is set to 0 degrees in the fully closed position and 90 degrees in the fully open position, if the valve body 16's opening exceeds 30 degrees and the amount of tap water passing through the narrow channel C1 formed between the valve seat 20d and the valve body 11 on the valve nozzle side 27a increases, the turbulence generated as the water passes through the narrow channel C1 increases and is straightened by the comb teeth 21, while any turbulence not straightened by the comb teeth 21 is straightened by the comb teeth 22. Furthermore, any turbulence that is not initially straightened by either the comb teeth 21 or 22 flows as a vortex around the downstream side surface 20c and is then straightened by the comb teeth 21 and 22. Furthermore, while the valve body nozzle side 27a moves in the same direction as the water flow direction F, the valve body orifice side 27b moves in the opposite direction to the water flow direction F. Therefore, the impact force when the water collides with the upstream side surface 20b of the valve body orifice side 27b is greater than the impact force when the water collides with the upstream side surface 20b of the valve body nozzle side 27a, making it easier for turbulence to occur around the upstream side surface 20b of the valve body orifice side 27b.

[0029] When the valve body opening of the valve body 16 exceeds 30 degrees and the amount of tap water impacting the upstream side surface 20b on the valve body orifice side 27b increases, the turbulence generated around the upstream side surface 20b on the valve body orifice side 27b increases. However, it is straightened by at least one of the comb teeth 23 and 24 before passing through the narrow channel C2 formed between the valve body seat 20d and the valve casing 11 on the valve body orifice side 27b. Therefore, the turbulence generated when passing through the narrow channel C1 is straightened by the comb teeth 21 and 22, and the turbulence generated around the upstream side surface 20b on the valve body orifice side 27b is straightened by the comb teeth 23 and 24 before passing through the narrow channel C2. As a result, negative pressure due to turbulence or vibration based on such negative pressure is reduced, and the turbulence generated by the tap water passing through the valve body 16 when the valve body opening exceeds 30 degrees can be reliably straightened.

[0030] Furthermore, in this embodiment, the distance D2 from the center DC of the downstream side surface 20c to the comb teeth 22 in the radial direction, relative to the distance D1 from the center DC of the downstream side surface 20c to the comb teeth 21 in the radial direction, is preferably 0.2 to 0.8. This ensures that the comb teeth 22 are positioned where turbulent flow that was not rectified by the comb teeth 21 passes before reaching the vicinity of the center DC of the downstream side surface 20c and returning to the comb teeth 21. Thus, the turbulent flow that was not rectified by the comb teeth 21 can be rectified without generating shocks.

[0031] Furthermore, in this embodiment, the distance D4 from the center UC of the upstream side surface 20b to the comb teeth 24 in the radial direction, relative to the distance D3 from the center UC of the upstream side surface 20b to the comb teeth 23 in the radial direction, is preferably 0.2 to 0.8. As a result, the comb teeth 23 and 24 are positioned so that the turbulence generated when the water strikes the upstream side surface 20b on the valve body orifice side 27b passes through the comb teeth 24 and 23 sequentially, or through the comb teeth 23. Therefore, the negative pressure caused by the turbulence or vibrations based on that negative pressure when it strikes the upstream side surface 20b on the valve body orifice side 27b is reduced, and the turbulence generated before passing through the narrow channel C2 can be reliably straightened.

[0032] Furthermore, in this embodiment, the height M2 of projection 22a relative to the height M1 of projection 21a is preferably 0.3 to 1.5. This allows turbulent flow that was not rectified by the comb teeth 21 to pass through the comb teeth 22 regardless of whether it increases in magnitude before reaching the vicinity of the center DC of the downstream side surface 20c and returning to the comb teeth 21. Note that if the height M2 of projection 22a relative to the height M1 of projection 21a is 1.0 to 1.5, turbulent flow that was not rectified by the comb teeth 21 can more reliably pass through the comb teeth 22.

[0033] Furthermore, the height M4 of projection 24a relative to the height M3 of projection 23a is preferably 0.3 to 1.5. This allows the water that strikes the upstream side surface 20b on the valve body orifice side 27b, specifically the water that strikes the area between the center UC of the upstream side surface 20b and the comb teeth 24, to pass through the comb teeth 24, thereby reducing the load on the comb teeth 23 to straighten the turbulent flow. If the height M4 of projection 24a relative to the height M3 of projection 23a is 1.0 to 1.5, the amount of water that passes through the comb teeth 24 increases, further reducing the load on the comb teeth 23 to straighten the turbulent flow.

[0034] The valve body 16 further includes comb teeth 25 formed along the edge of the upstream side surface 20b on the valve body nozzle side 27a, and comb teeth 26 formed along the edge of the downstream side surface 20c on the valve body orifice side 27b. The comb teeth 25 straighten the water flow before it passes through the narrow channel C1, thereby reducing the risk of turbulence occurring in the water flow after it has passed through the narrow channel C1, and the comb teeth 26 straighten the turbulence generated when the water passes through the narrow channel C2, thereby reliably eliminating the effects of turbulence generated when the water passes through the narrow channel C2.

[0035] Figure 5 is a diagram used to illustrate a modified version of the valve body 16 in Figure 2. Figure 5(a) is a perspective view of valve body 50, which is a modified version of valve body 16 in Figure 2. Figure 5(b) is a front view of valve body 50 viewed from the upstream side in the flow direction F when valve body 50 of Figure 5(a) is used in the butterfly valve 10 in Figure 1 and is in the fully closed position. Figure 5(c) is a front view of valve body 50 viewed from the downstream side in the flow direction F when valve body 50 of Figure 5(a) is used in the butterfly valve 10 in Figure 1 and is in the fully closed position. Figure 5(d) is a cross-sectional view along the line BB in Figure 5(a). The valve body 50 in Figure 5 has basically the same configuration and operation as valve body 16 described above, but differs from valve body 16 in that it has comb teeth 56 (sixth flow straightening section) on the upstream side surface 20b and comb teeth 58 (eighth flow straightening section) on the downstream side surface 20c. In the following, explanations of overlapping components and functions will be omitted, and explanations of different components and functions will be provided.

[0036] In Figures 5(a) to (d), the valve body 50 further comprises a comb tooth 56 formed between the comb tooth 25 and the center UC of the upstream side and formed along the comb tooth 25, and a comb tooth 58 formed between the comb tooth 26 and the center DC of the downstream side and formed along the comb tooth 26.

[0037] The comb teeth 56 straighten the water that collides with the upstream side, specifically the water that collides between the center UC of the upstream side and the comb teeth 56. As a result, the water straightened by the comb teeth 56 passes sequentially through the comb teeth 25 and then through the narrow channel C1, reducing the load on the comb teeth 25 to straighten the water. This further reduces the risk of turbulence occurring in the water after passing through the narrow channel C1, and the risk of the turbulence increasing in magnitude. The comb teeth 58 straighten the turbulence that was not straightened by the comb teeth 26 and reaches the vicinity of the center DC of the downstream side before returning to the comb teeth 26. This allows for a more reliable elimination of the effects of turbulence generated when passing through the narrow channel C2.

[0038] Although the present invention has been described above using the embodiments described above, the present invention is not limited to the embodiments described above. For example, at least one of the comb teeth 21-26 in the valve body 16 in Figure 2 or the comb teeth 21-26, 56, 58 in the valve body 50 in Figure 5 may be replaced with other flow straightening means, such as a perforated plate having multiple through holes with a diameter of 1 mm to 20 mm in a plate-like member. Specifically, replacing the comb teeth 22, 24 in the valve body 16 with a perforated plate, replacing the comb teeth 21-26 in the valve body 50 with a perforated plate, or replacing all of the comb teeth 21-26, 56, 58 in the valve body 50 with a perforated plate will produce the same effects as the valve bodies 16 and 50. [Explanation of symbols]

[0039] 10 Butterfly valve 16,50 valve body 11 Valve box 27a Valve body nozzle side 27b Valve body orifice side 20b Upstream side 20c downstream side 21, 22, 23, 24 Comb teeth

Claims

1. A butterfly valve comprising a valve body connected to a pipeline through which a fluid flows and forming a fluid passage, and a valve element for opening and closing the passage formed in the valve body, The valve body is, A first moving part that moves in the same direction as the fluid flow direction of the fluid flowing from upstream to downstream when the flow path is opened, A second movable part that moves in the direction opposite to the flow direction when the flow path is opened, When the flow path is closed, the upstream side located on the upstream side in the flow direction, When the flow path is closed, the downstream side located on the downstream side in the flow direction, In the first moving part, a first flow straightening part is formed along the edge of the downstream side surface, A second flow straightening section is formed between the first flow straightening section and the center of the downstream side surface, and is formed along the first flow straightening section, In the second moving section, a third flow straightening section is formed along the edge of the upstream side surface, A butterfly valve characterized by having a fourth flow-straightening portion formed between the third flow-straightening portion and the center of the upstream side surface, and formed along the third flow-straightening portion.

2. The butterfly valve according to claim 1, characterized in that the distance from the center of the downstream side to the second straightening section is 0.2 to 0.8 as a ratio to the distance from the center of the downstream side to the first straightening section, and the distance from the center of the upstream side to the fourth straightening section is 0.2 to 0.8 as a ratio to the distance from the center of the upstream side to the third straightening section.

3. The butterfly valve according to claim 1, characterized in that the maximum length of the second flow straightening portion protruding from the downstream side surface is 0.3 to 1.5, relative to the maximum length of the first flow straightening portion protruding from the downstream side surface, and the maximum length of the fourth flow straightening portion protruding from the upstream side surface is 0.3 to 1.5, relative to the maximum length of the third flow straightening portion protruding from the upstream side surface.

4. The butterfly valve according to claim 1, characterized in that the first, second, third, or fourth flow straightening section is a plate-shaped member having a plurality of holes through which the fluid passes.

5. In the first moving section, a fifth flow straightening section is formed along the edge of the upstream side surface, The butterfly valve according to claim 1, further comprising a sixth flow straightening portion formed between the fifth flow straightening portion and the center of the upstream side surface, and formed along the fifth flow straightening portion.

6. In the second moving section, a seventh flow straightening section is formed along the edge of the downstream side surface, The butterfly valve according to claim 5, further comprising: an eighth flow straightening portion formed between the seventh flow straightening portion and the center of the downstream side surface, and formed along the seventh flow straightening portion.

7. A butterfly valve valve is used in a butterfly valve that is connected to a pipeline through which a fluid flows and has a valve body that forms a flow path for the fluid, and the valve body for the butterfly valve opens and closes the flow path formed in the valve body, A first moving part that moves in the same direction as the fluid flow direction of the fluid flowing from upstream to downstream when the flow path is opened, A second movable part that moves in the direction opposite to the flow direction when the flow path is opened, When the flow path is closed, the upstream side located on the upstream side in the flow direction, When the flow path is closed, the downstream side located on the downstream side in the flow direction, In the first moving part, a first flow straightening part is formed along the edge of the downstream side surface, A second flow straightening section is formed between the first flow straightening section and the center of the downstream side surface, and is formed along the first flow straightening section, In the second moving section, a third flow straightening section is formed along the edge of the upstream side surface, A valve body for a butterfly valve, characterized by having a fourth flow-rectifying portion formed between the third flow-rectifying portion and the center of the upstream side surface, and formed along the third flow-rectifying portion.

8. A method for straightening fluid using a butterfly valve, comprising: a valve body connected to a pipeline through which a fluid flows and forming a fluid passage; a valve element for opening and closing the passage formed in the valve body, wherein the valve element has: a first movable part that moves in the same direction as the fluid flowing from upstream to downstream in the passage when the passage is opened; a second movable part that moves in the opposite direction to the flow when the passage is opened; an upstream side located on the upstream side in the flow direction when the passage is closed; a downstream side located on the downstream side in the flow direction when the passage is closed; a first straightening portion formed along the edge of the downstream side of the first movable part; a second straightening portion formed between the center of the first straightening portion and the center of the downstream side and along the first straightening portion; a third straightening portion formed along the edge of the upstream side of the second movable part; and a fourth straightening portion formed between the center of the third straightening portion and the center of the upstream side and along the third straightening portion, A first straightening step in which the first straightening section or the second straightening section straightens the fluid that has passed through the narrow passage formed between the valve body and the first movable section, A method for straightening fluid using a butterfly valve, characterized by comprising: a second straightening step of straightening the fluid before the third straightening section or the fourth straightening section straightens the fluid before it passes through another narrow passage formed between the valve body and the first movable section.

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