JP6232293B2 - Butterfly valve - Google Patents

Description

  The present invention relates to a butterfly valve, and more particularly, to a butterfly valve that adjusts a flow rate by rotating a valve element disposed so as to cross the inside of a valve box with a valve rod.

  The butterfly valve includes a cylindrical valve box that is a part of a flow path, a valve rod that is disposed in a direction orthogonal to the axis of the valve box, and a disc-shaped valve that rotates about the valve rod as a rotation center. When the valve is closed, the valve body crosses the inside of the valve box. As the valve body in the conventional butterfly valve, a so-called lens-type valve body or a flat-plate-type valve body having a plurality of reinforcing ribs is often used, and cavitation is suppressed in the downstream part of the orifice side or the upstream part of the nozzle side. For example, Patent Documents 1 and 2 were used.

JP-A-57-157866 Japanese Utility Model Publication No. 4-13872

  Therefore, the conventional butterfly valve has a structure that determines the upstream side and the downstream side of the valve body. Therefore, when using it for connecting pipes such as a pipe network or for filling pipes such as a parent-child butterfly valve, The performance varies greatly depending on the flow direction of the valve, and the valve installation direction is often restricted.

  Accordingly, an object of the present invention is to provide a butterfly valve that can perform pressure reduction control and flow rate control without being affected by the fluid flow direction, and has excellent cavitation resistance.

  In order to achieve the above object, a butterfly valve according to the present invention includes a cylindrical valve box that is a part of a flow path, a valve rod that is disposed in a direction perpendicular to the axis of the valve box, and a valve rod that rotates the valve rod. A butterfly valve provided with a disc-like valve body that is pivotally provided from a fully closed state that shuts off the flow path in the valve box as a moving center to a fully open state that is parallel to the flow path, A valve body main body formed in a flat plate shape with a thickness smaller than the outer diameter of the valve stem, and a valve stem insertion tubular portion provided in the diameter direction of the center of the valve body main body, The valve body outer surface extending from the outer surface of the valve rod insertion tubular portion to the outer surface of the valve body main body is formed as a hyperboloid, and at a position along the outer periphery of the valve body main body toward the valve body closing direction. A closed-side rectifying portion protruding toward the valve body opening direction, and the closed-side rectifying portion is A large number of through-holes are provided in the rectifying plate projecting in an arc shape, and the opening-side rectifying portion is formed in a comb-teeth shape in which a plurality of protrusions are projected at a predetermined interval. Yes.

  According to the butterfly valve of the present invention, the main part of the outer surface of the valve body is formed by a hyperboloid, so that the maximum principal stress can be concentrated on the centroid of the half-moon part of the valve body, and the stress distribution of the valve body is It can be made uniform. Thereby, the thickness of the valve body can be reduced, and the weight can be reduced and the manufacturing cost can be reduced. Furthermore, by providing the opening side rectification part and the closing side rectification part on the outer peripheral part of the valve body main body part, the flow of the fluid can be smoothly dispersed between the nozzle side and the orifice side. In addition, by distributing the flow by the rectification effect of the closed side rectification unit provided on the downstream side of the valve body on the orifice side, it is possible to suppress the generation of negative pressure on the downstream side of the valve body and to pass through the closed side rectification unit By generating a rotational force along the valve body of the fluid vortex against the flow path by the vortex generated in the fluid and the hyperboloid of the outer surface of the valve body, the generation of negative pressure downstream of the valve body can be more reliably suppressed At the same time, the growth of cavitation can be reliably suppressed.

It is a front view which shows one example of the butterfly valve of this invention. It is a perspective view of a valve body similarly. It is a cross-sectional top view of the butterfly valve made into the fully closed state similarly. It is the cross-sectional top view of the butterfly valve made into the half open state similarly.

  1 to 4 show one embodiment of the butterfly valve of the present invention. The butterfly valve shown in the present embodiment includes a cylindrical valve box 11 that is a part of a flow path, a valve rod 12 that is disposed in a direction perpendicular to the axis of the valve box 11, and the valve rod 12 that rotates. A disc-shaped valve body 13 that rotates about the center is provided, and the lower end of the valve rod 12 penetrates the lower portion of the valve box 11 so as to be rotatable and is held by a fastening member 14. The upper end of the valve 11 is pivoted through the upper part of the valve box 11 and extends upward, and is connected to the switch 15. Further, flanges 16 for connecting to the front and rear pipes are respectively provided on the outer periphery of both ends of the valve box 11, and a cylindrical metal sheet 17 is attached to the inner periphery of the valve box 11.

  The valve body 13 includes a valve body main body 21 formed in a flat plate shape having a thickness smaller than the outer diameter of the valve stem 12, and a valve stem provided in the diameter direction of the central portion of the valve body main body 21. The valve rod 12 inserted into the valve rod insertion cylindrical portion 22 and the valve body 13 are fixed to the upper and lower end portions of the valve rod insertion cylindrical portion 22. A reamer bolt attaching portion 23 for attaching a reamer bolt for the purpose is provided. The outer surface of the valve rod insertion tubular portion 22 protrudes from the outer surface of the valve body main body portion 21, and from the protruded outer surface portion of the valve rod insertion tubular portion 22 excluding the vicinity of the reamer bolt mounting portion 23. The outer surface of the valve body that reaches the planar outer surface of the valve body main body 21 is formed by a hyperboloid 24 having a concave outer surface in the cross section perpendicular to the valve stem 12, and both ends of the hyperboloid 24 are smoothly tangentially. It continues to the outer surface of the cylindrical part 22 for valve-rod insertion and the planar part outer surface of the valve body main-body part 21 so that it may connect.

  The valve element 13 is rotated in the direction indicated by the arrow O in FIGS. 3 and 4 by opening the valve rod 12 in the clockwise direction in FIG. 3 from the fully closed state shown in FIG. In the half-open state shown in FIG. 4, the valve stem 12 is rotated counterclockwise in FIG. 4 to rotate in the valve closing direction indicated by the arrow C in FIG.

At the position along the outer peripheral portion of the valve body main body 21 in the valve body 13, the closed side rectifying portion 31 protruding in the valve body closing direction (arrow C direction) and the valve body opening direction (arrow O direction). And an open-side rectifying unit 32 protruding in the direction. The closed-side rectifying unit 31 is provided with a large number of through holes 34 in a rectifying plate 33 projecting in an arc shape along the outer periphery of the valve body main body 21, and the outer surface of the rectifying plate 33 is small. It is formed in a shape close to a spherical surface in a state along the inner peripheral surface of the valve box 11 at the time of opening, and the center portion is formed higher than the height of the portion close to the valve rod insertion tubular portion 22. Further, a plurality of groove portions 35 are provided at the leading edge 33 a of the rectifying plate 33.
The opening-side rectifying unit 32 is formed in a comb-like shape in which a plurality of protrusions 36 are protruded at a predetermined interval, and slit-like channels 37 are formed between the protrusions 36. The height of 36 is formed lower than the height of the current plate 33.

  The fluid passing through the butterfly valve in a small opening state until the valve body 13 is changed from the fully closed state to the half-open state is on the downstream side of the valve body (2) on the orifice side where it protrudes upstream (primary side). Since the fluid flowing toward the low pressure portion generated on the secondary side is rectified by the respective through holes 34 of the closed side rectification unit 31 located on the downstream side of the valve body and dispersed on the downstream side of the valve body, The generation of the negative pressure is suppressed, and the vortex generated in the fluid that has passed through the closed-side rectifying unit 31 and the hyperboloid 24 on the outer surface of the valve body generate a rotating vortex of the fluid with respect to the flow path, thereby The generation of negative pressure on the downstream side can be more reliably suppressed, and the growth of cavitation can also be reliably suppressed.

  Further, the fluid passing through the slit-like flow path 37 of the comb-like protrusion 38 that protrudes toward the upstream side of the valve body on the orifice side is formed on the upstream side of the valve body in a state where a fine vortex is formed at the rear part of the protrusion 36. The fluid flows along the hyperboloid 24, and the fluid smoothly flows toward the nozzle side in combination with the suppression of the flow resistance by the fine vortex.

  In the closed-side rectification unit 31 located on the upstream side of the nozzle part that protrudes to the valve body upstream side surface, the fluid flowing from the upstream side and the fluid flowing along the valve body upstream side surface merge, The air smoothly flows toward the downstream side through the through hole 34 while being radially guided between the peripheral edge of the valve body 13 and the inner peripheral surface of the valve box 11. Furthermore, the fluid that has passed through the periphery of the valve body 13 is in a state of sucking in the fluid that has flowed from the orifice side to the downstream side surface of the valve body, but the fluid that flows along the hyperboloid 24 on the downstream side surface of the valve body Since the air is sucked through the slit-like flow path 37 of the open-side rectification unit 32 that protrudes to the side, it is possible to suppress the occurrence of a large turbulence in the fluid flow.

  As described above, the rectification effect by the rectification units 31 and 32 and the effect of the hyperboloid 24 can effectively suppress the occurrence of cavitation in the fluid passing through the butterfly valve 11. Further, by forming the hyperboloid 24 on the outer surface of the valve body 13, the maximum principal stress can be concentrated on the centroid of the half-moon part of the valve body 13, and the stress distribution can be made uniform. It is possible to reduce the weight by reducing the thickness. Furthermore, since the valve body 13 is symmetrical, the control performance is not affected by the fluid flow direction, and the valve installation direction is not restricted.

  The shape of each rectification unit can be appropriately selected according to various conditions such as the state of the fluid pipe line where the butterfly valve is installed, that is, the diameter of the butterfly valve, the fluid pressure, the flow rate adjustment range of the fluid, Cavitation growth can be effectively suppressed by setting the number and size of through-holes, the direction of the axis, the height of protrusions, the number and width of slit-shaped channels, and the flow direction to the optimum state. Cost reduction can be achieved.

DESCRIPTION OF SYMBOLS 11 ... Valve box, 12 ... Valve rod, 13 ... Valve body, 14 ... Fastening member, 15 ... Switch, 16 ... Flange, 17 ... Metal sheet, 21 ... Valve body main-body part, 22 ... Tubular shape for valve-rod insertion , Reamer bolt mounting part, 24 ... hyperboloid, 31 ... closed side rectifying part, 32 ... open side rectifying part, 33 ... rectifying plate, 33a ... tip edge, 34 ... through hole, 35 ... groove part, 36 ... projection part 37 ... slit-shaped flow path

Claims (2)

  A cylindrical valve box that is a part of the flow path, a valve stem that is arranged in a direction perpendicular to the axis of the valve box, and a valve block that shuts off the flow path in the valve box with the valve stem as a center of rotation. A butterfly valve provided with a disc-like valve body rotatably provided from a closed state to a fully open state parallel to the flow path, the valve body being a flat plate having a thickness smaller than the outer diameter of the valve stem A valve body main body portion formed in the shape of a valve body, and a valve rod insertion tubular portion provided in the diameter direction of the central portion of the valve body main body portion, and the valve body from the outer surface of the valve rod insertion tubular portion A valve body outer surface reaching the outer surface of the main body is formed as a hyperboloid, and at the position along the outer peripheral portion of the valve body main body, a closing side rectifying portion protruding toward the valve body closing direction, and a valve body opening direction An opening-side rectifying portion protruding toward the closed-side rectifying portion, and a plurality of through holes are provided in a rectifying plate protruding in an arc shape, To open side rectifier unit, a butterfly valve, characterized in that it is formed in a plurality of protrusions the preset comb shape that is protruded at intervals. The butterfly valve according to claim 1, wherein a height of the plurality of protrusions is lower than a height of the rectifying plate .

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