JP5696341B2 - Triple eccentric butterfly valve - Google Patents

Description

  The present invention relates to a triple eccentric butterfly valve.

  As a conventional butterfly valve, the center of the valve shaft, which is the rotation shaft of the valve body, is decentered (primary eccentric) from the seal surface formed by the valve body and the seat ring, and in the valve box in which the valve body is accommodated The center of the flow path is also eccentric (secondary eccentricity), and the centerline of the cone constituting the outer peripheral surface of the valve body is inclined with respect to the centerline of the flow path in the valve box (third order eccentricity). An eccentric butterfly valve is known. For example, as disclosed in Patent Document 1, a triple eccentric butterfly valve has a seat ring sandwiched between a seating surface of a mounting groove provided inside a valve box and a retainer, and has an outer peripheral circular shape. The outer peripheral surface of the valve body that is formed in an elliptical shape and includes a part of an eccentric cone is configured to contact the elliptical inner peripheral surface of the seat ring over the entire circumferential direction.

  However, in the triple eccentric butterfly valve disclosed in Patent Document 1, the seat surface of the mounting groove and the inner periphery and outer periphery of the retainer are both formed into a perfect circle, so that the seat ring having an inner peripheral elliptical shape is seated. When placed on the surface, the amount of protrusion of the seat ring from the seat surface and the retainer to the inside becomes uneven in the circumferential direction. For this reason, there is a problem that the seat ring mounting state becomes unstable or a uniform seal surface pressure is difficult to obtain due to the contact of the part with a large amount of protrusion of the seat ring with the valve body.

  In order to make the amount of protrusion of the seat ring uniform in the circumferential direction, the seat surface and the inner periphery of the retainer may be formed in an elliptical shape along the inner periphery of the seat ring. Since it cannot be formed by lathe processing, problems of processing cost and processing time occur. For this reason, in Patent Document 2, an elliptical opening is formed by laser processing or the like by interposing a spacer made of an annular thin plate having an inner peripheral ellipse and an outer peripheral perfect circle between the retainer and the seat ring. A triple eccentric butterfly valve that can be easily formed is disclosed.

  However, the configuration of Patent Document 2 also has the same problem as the configuration of Patent Document 1 because it cannot be solved that the amount of protrusion of the seat ring from the seating surface is not uniform.

JP 2008-256150 A Japanese Patent No. 3740360

  Accordingly, an object of the present invention is to provide a triple eccentric butterfly valve that can maintain good sealing performance while reducing the manufacturing cost.

The object of the present invention includes a valve box having a flow path, a valve body disposed in the flow path, and a valve shaft that rotatably supports the valve body, and an inner peripheral surface of the valve box. A seat ring is sandwiched between an annular seat formed on the annular seat and an annular retainer, and the seat ring seals the flow path with the valve body when the valve body is closed. And the center of the valve shaft is decentered from the seal surface and also from the center of the flow path, and the center line of the cone constituting the outer peripheral surface of the valve body is further centered on the center of the flow path. A triple eccentric butterfly valve configured such that the sealing surface is elliptical by being inclined with respect to a line, and between the seat ring and the seat and between the seat ring and the retainer Between the seat side spacer and the retainer side spacer. With, respectively, said seat-side spacer and the retainer-side spacer are both made of an annular thin plate, and the inner peripheral surface is formed in an elliptical shape, is interposed between the retainer-side spacer and the retainer, the retainer This is achieved by a triple eccentric butterfly valve further comprising a secondary spacer made of an annular thin plate disposed so as to form a gap between the inner peripheral side and the inner peripheral side of the retainer side spacer .

  Moreover, it is preferable that the said seat ring is provided with the sealing ring which consists of an elastic material which forms the said sealing surface.

  ADVANTAGE OF THE INVENTION According to this invention, the triple eccentric butterfly valve which can maintain favorable sealing performance can be provided, aiming at reduction of manufacturing cost.

It is a cross-sectional view of a triple eccentric butterfly valve according to an embodiment of the present invention. It is a top view of the seat ring of the butterfly valve shown in FIG. It is an expanded sectional view of the seat ring shown in FIG. It is a principal part enlarged view of FIG. It is a cross-sectional view of a triple eccentric butterfly valve according to another embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a triple eccentric butterfly valve according to an embodiment of the present invention. As shown in FIG. 1, the triple eccentric butterfly valve 1 includes a valve box 10 in which a cylindrical flow path 11 is formed, a plate-shaped valve body 20 disposed in the flow path 11, and a valve body 20. And a seat ring 40 provided on the inner peripheral surface of the valve box 10.

  The valve box 10 includes a seat portion 12 formed in a step shape on the inner peripheral surface. The seat portion 12 is formed in a planar shape orthogonal to the fluid flow direction F of the flow path 11, and the inner periphery is formed in a perfect circle shape. The seat ring 40 is disposed between the seat portion 12 and the annular retainer 13. The retainer 13 can press the seat ring 40 against the seat 12 with a fastening screw 15 screwed to a fixing ring 14 fixed to the inner peripheral surface of the valve box 10. Hold with. Both the outer peripheral surface and the inner peripheral surface of the retainer 13 are formed in a perfect circle shape, and the outer peripheral surface of the retainer 13 is fitted into the circularly turned portion of the inner peripheral surface of the valve box 10. Has been.

  The valve body 20 is formed in a plate shape, and the outer peripheral surface 22 abuts on the seat ring 40 to block the flow path 11. The valve shaft 30 is inserted into the valve box 10 so that one end side is located in the valve box 10 and the other end side is located outside the valve box 10, and the valve body 20 is fixed to one end side by a taper pin 21. . The other end of the valve shaft 30 is connected to an actuator (not shown), and the valve body 20 rotates in the direction of the arrow together with the valve shaft 30 by driving the actuator, thereby opening and closing the flow path 11.

  In the triple eccentric butterfly valve 1 of the present embodiment, the center 30a of the valve shaft 30 is eccentric by a distance E1 along the center line 11L of the flow path 11 from the seal surface 424a formed by the valve body 20 and the seat ring 40. Furthermore, it is decentered by a distance E2 from the center line 11L of the flow path 11 in the orthogonal direction. Further, the outer peripheral surface 22 of the valve body 20 is formed by a part of an outer peripheral surface 22b of a virtual cone having a center line 22a inclined by an angle E3 from the center line 11L of the flow channel 11. It has an elliptical shape when viewed along 11L.

  The seat ring 40 includes a holding ring 41 made of a rigid material and a sealing ring 42 made of an elastic material, and the sealing ring 42 is held by the holding ring 41.

  FIG. 2 is a plan view of the seat ring 40. As shown in FIG. 1 and FIG. 2, the outer peripheral surface 411 of the holding ring 41 is formed in a perfect circle shape so as to be held in a circularly turned portion on the inner peripheral surface of the valve box 10. On the other hand, the inner peripheral surface 412 of the holding ring 41 is formed in an elliptical shape in plan view having substantially the same flatness as the elliptical outer peripheral surface 22 of the valve body 20. Further, in a state before the sealing ring 42 is held by the holding ring 41, both the outer peripheral surface 421 and the inner peripheral surface 422 are formed in a perfect circle shape, and are slightly longer than the inner peripheral length of the holding ring 41. It has a large outer peripheral length. When the sealing ring 42 is attached to the inner peripheral surface 412 of the holding ring 41, the outer peripheral surface 421 is elastically compressed and deformed along the inner peripheral surface 412 of the holding ring 41, and is securely attached to the holding ring 41. In addition, the inner peripheral surface 422 of the sealing ring 42 is elliptical in plan view. The inner peripheral surface 412 of the holding ring 41 that serves as the holding surface of the sealing ring 42 has a constant cross-sectional shape in the height direction in the present embodiment, but is not necessarily constant.

  The holding ring 41 is formed of a metal material such as stainless steel or aluminum, for example, so that the sealing ring 42 can be securely held while promoting elastic deformation, and the elliptical inner peripheral surface can be easily formed by laser processing or the like. be able to. On the other hand, since both the outer peripheral surface 421 and the inner peripheral surface 422 are round, the sealing ring 42 is made of resin or rubber, for example, like a seat ring used in a conventional double eccentric butterfly valve. Can be used.

  As shown in FIGS. 1 and 2, the seat ring 40 has an annular groove 423 formed on the end surface of the sealing ring 42, and is disposed in the valve box 10 so that the groove 423 faces the retainer 13. Has been. As shown in an enlarged cross-sectional view in FIG. 3, the height H1 of the inner diameter portion of the groove portion 423 provided in the sealing ring 42 is slightly lower than the height H2 of the holding ring, and the fluid flows in the direction F of fluid flow. When fluid pressure acts, pressure acts on the inside of the groove portion 423 in the sealing ring 42 and deforms the seal surface 424a in the inner diameter direction, so that the seal surface pressure can be easily secured. Since the sealing ring 42 is formed in a perfect circle before being attached to the holding ring 41 as described above, an annular groove 423 can be easily formed concentrically with respect to the sealing ring 42. .

  A part or the whole of the inner peripheral surface 422 of the sealing ring 42 comes into contact with the outer peripheral surface 22 of the valve body 20 to form a seal surface 424a. In the present embodiment, an annular lip 424 protruding inward from the inner peripheral surface 422 is provided, and this lip 424 forms a seal surface 424a. According to this configuration, the contact on the seal surface 424a can be easily adjusted, and stable sealing performance can be obtained. The cross-sectional shape of the lip 424 is an arc shape in the present embodiment, but may be a square shape or the like. The seal surface 424a has an elliptical shape, similar to the outer peripheral surface 22 of the valve body 20, when viewed along the center line 11L of the flow path 11.

  4 is an enlarged cross-sectional view showing the vicinity of the seat ring 40 in FIG. As shown in FIGS. 1 and 4, a seat part side spacer 50 is disposed between the seat ring 40 and the seat part 12, and a retainer side spacer 51 is provided between the seat ring 40 and the retainer 13. Is arranged. Further, a secondary spacer 52 is interposed between the retainer 13 and the retainer side spacer 51. The space between the seat 12 and the seat-side spacer 50 is sealed with the gasket 16.

  Each of the seat side spacer 50, the retainer side spacer 51, and the secondary spacer 52 is an annular thin plate made of a metal material or the like, and the outer peripheral surface thereof is a portion of the inner peripheral surface of the valve box 10 that is turned into a circular shape. It is formed in a perfect circle so as to be held. On the other hand, the inner peripheral surfaces of the seat portion side spacer 50, the retainer side spacer 51 and the secondary spacer 52 are formed in an elliptical shape in plan view having substantially the same flatness as the elliptical outer peripheral surface 22 of the valve body 20. The seat ring 40, the seat portion side spacer 50, the retainer side spacer 51, and the secondary spacer 52 are arranged so that the elliptical inner peripheral surface is concentric. In order to facilitate such arrangement, as shown in FIG. 5, positioning holes are formed in the retainer 13, the secondary spacer 52, the retainer side spacer 51, the seat ring 40, the seat side spacer 50, and the seat part 12, respectively. In addition, the positioning holes may be aligned and the pin 60 may be inserted, whereby the assembly workability can be improved. The positioning hole through which the pin 60 is inserted can be formed, for example, on an extension line of the major axis or minor axis of the inner circumference ellipse, and may be formed at one place or at a plurality of places.

  The inner peripheral surfaces of the seat-side spacer 50 and the retainer-side spacer 51 are formed by elliptical openings that are sized to minimize the amount of protrusion of the seat ring 40 interposed therebetween. The protruding amount of the seat ring 40 is substantially uniform. When viewed along the fluid flow direction F, the inner peripheral side of the seat portion side spacer 50 slightly protrudes inward from the inner periphery of the seat portion 12. The inner circumferential surface of the secondary spacer 52 has a larger inner diameter (longer diameter and shorter diameter) than the inner circumferential surface of the retainer side spacer 51, and the inner circumferential side of the retainer 13 and the inner circumference of the retainer side spacer 51. A gap S is formed between the two sides.

  In the triple eccentric butterfly valve 1 having the above-described configuration, the flange end surfaces of the flange pipes (not shown) can be brought into contact with the opening both end surfaces of the valve box 10, respectively, and by fastening the flanges with bolts or the like, The flow path 11 of the valve box 10 can be communicated with the flow path of the flange pipe. However, the connection method between the valve box 10 and the pipe is not limited to such a wafer type, and other methods such as a lug type, a flange type, and a butt weld type may be used. In this embodiment, the fluid flow direction F in the flow path 11 is the downstream side of the valve body 20 where the valve shaft 30 is disposed, but the valve shaft 30 side can also be the upstream side.

  In the triple eccentric butterfly valve 1 of the present embodiment, a seat portion side spacer 50 and a retainer side spacer 51 are disposed between the seat ring 40 and the seat portion 12 and between the seat ring 40 and the retainer 13, respectively. In addition, since the inner peripheral surfaces of the seat portion side spacer 50 and the retainer side spacer 51 are both formed in an elliptical shape, the amount of protrusion of the seat ring 40 in which the inner peripheral surface is also formed in an elliptical shape is set to the entire inner peripheral surface. Can be made substantially uniform. Therefore, when the valve body 20 is closed, there is no possibility that a local force is applied to the seat ring 40, the stable mounting state of the seat ring 40 can be maintained, and the sealing performance can be maintained well. it can. Further, since both the seat side spacer 50 and the retainer side spacer 51 are annular thin plates, an elliptical inner peripheral surface can be easily formed by laser processing or the like, and the seat side spacer 50 and the retainer side Since the inner periphery of the seat 12 holding the spacer 51 and the retainer 13 can be formed into a perfect circle by lathe processing or the like, the above effect can be realized at a low manufacturing cost.

  Further, a secondary spacer 52 is interposed between the retainer 13 and the retainer side spacer 51, and a gap S is formed between the inner peripheral side of the retainer 13 and the inner peripheral side of the retainer side spacer 51, so that FIG. When the pressing force by the valve body 20 closed in the direction indicated by the arrow is transmitted to the retainer side spacer 51 via the seat ring 40, the inner peripheral side of the retainer side spacer 51 is elastically deformed into a leaf spring shape. Can do. Therefore, when the fluid pressure is applied in the direction opposite to the flow direction F due to this elastic force, the seat ring 40 can be prevented from being over-compressed due to the movement or deformation of the valve body, and the sealing performance of the seal surface 424a. Can be stabilized. As a result, it is possible to seal with a low torque using the thin valve shaft 30 and the low output actuator, and the manufacturing cost can be reduced.

  In the seat ring 40, it is preferable to form the sealing ring 42 forming the sealing surface 424a from an elastic material so that the seat ring 40 can be reliably sealed with a low torque. By adopting a configuration in which the sealing ring 42 is held on the peripheral surface 412 in an elastically compressed state, the manufacturing cost can be reduced. However, the holding ring 41 is not indispensable, and the seat ring 40 can be configured by only the sealing ring 42 made of an elastic material. Furthermore, as with the conventional triple eccentric butterfly valve, a sheet ring in which metal plates and expanded graphite are alternately laminated can be used.

  Further, as shown in FIG. 4, the inner peripheral surface 501 of the seat portion side spacer 50 is preferably sealed by contacting the outer peripheral surface 22 over the entire circumference when the valve body 20 is closed. In this configuration, the seat part side spacer 50 is made of a non-combustible material such as metal, so that even if the seat ring 40 is damaged in the event of a fire, the seat part side spacer 50 and the valve body 20 are sealed by contact. The performance can be maintained. When the seat-side spacer 50 is made of a metal material, the outer peripheral surface 22 of the valve body 20 may slide with the seat-side spacer 50 when fully closed to be damaged such as scratches. In the butterfly valve, the sealing surface 22b formed of a part of a cone is formed simultaneously around the entire circumference immediately before full closing by the rotation of the valve shaft 30, and the sealing surface pressure is increased by applying torque to the valve shaft 30. Therefore, this sliding range A1 can be suppressed to a narrow range, and overlapping with the sliding range A2 between the valve body 20 and the seat ring 40 can be avoided. Therefore, there is no possibility that the seal surface 424a is adversely affected by sliding with the seat portion side spacer 50, and the seal performance can be maintained satisfactorily. In particular, when the seal surface 424a is formed by the annular lip 424 as in the present embodiment, it is easy to form the seal surface 424a at a position separated from the sliding range A1, and the above-mentioned problem is reliably ensured. Can be resolved.

DESCRIPTION OF SYMBOLS 1 Triple eccentric butterfly valve 10 Valve box 11 Flow path 12 Seat part 13 Retainer 20 Valve body 30 Valve shaft 40 Seat ring 41 Holding ring 42 Sealing ring 424 Lip 424a Sealing surface 50 Seat part side spacer 51 Retainer side spacer 52 Secondary spacer

Claims (5)

A valve box including a flow path, a valve body disposed in the flow path, and a valve shaft that rotatably supports the valve body,
A seat ring is sandwiched between an annular seat formed on the inner peripheral surface of the valve box and an annular retainer,
The seat ring forms a sealing surface that seals the flow path with the valve body when the valve body is closed,
The center of the valve shaft is decentered from the seal surface and also decentered from the center of the flow path. Further, the center line of the cone constituting the outer peripheral surface of the valve body is set with respect to the center line of the flow path. A triple eccentric butterfly valve configured such that the sealing surface becomes elliptical by being inclined,
Between the seat ring and the seat portion, and between the seat ring and the retainer, each includes a seat portion side spacer and a retainer side spacer,
The seat side spacer and the retainer side spacer are both made of an annular thin plate, and the inner peripheral surface is formed in an elliptical shape,
A secondary spacer comprising an annular thin plate interposed between the retainer and the retainer side spacer and disposed so as to form a gap between the inner peripheral side of the retainer and the inner peripheral side of the retainer side spacer. A triple eccentric butterfly valve further comprising: 2. The triple eccentric butterfly valve according to claim 1, wherein the inner circumferential side of the retainer side spacer is elastically deformed into a leaf spring shape in the gap when the valve body is closed. 3.   The triple eccentric butterfly valve according to claim 1, wherein the seat ring includes a sealing ring made of an elastic material forming the sealing surface.   The triple eccentric butterfly valve according to any one of claims 1 to 3, wherein the seat side spacer contacts the outer peripheral surface of the valve body over the entire circumferential direction when the valve body is closed.   The triple eccentric butterfly valve according to any one of claims 1 to 4, wherein the seat ring includes an annular lip that forms the sealing surface.

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