JP5586023B2 - Butterfly valve and seat ring - Google Patents

Description

  The present invention relates to a butterfly valve and a seat ring used therein.

  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 An eccentric butterfly valve having a double eccentric structure that is also eccentric (secondary eccentric) from the center of the flow path is known. In such a double eccentric butterfly valve, when the valve body rotates to the closed position, the seal surface formed by the seat ring interposed between the valve body and the valve box is usually round, The seat ring can be made of an elastic material such as resin or rubber, or a metal material having a configuration having elasticity, so that a good sealing property can be obtained.

  On the other hand, in addition to the double eccentric structure described above, a butterfly valve with a triple eccentric structure in which the centerline of the cone constituting the outer peripheral surface of the valve body is third-order eccentrically inclined with respect to the centerline of the valve box is also known. It has been. Such a triple eccentric butterfly valve has an oval seal surface formed by the seat ring. Further, since the triple eccentric butterfly valve is required to cope with high temperature and high pressure fluid, for example, the triple eccentric butterfly valve disclosed in Patent Document 1 has a seat ring in which metal plates and expanded graphite are alternately laminated. Is used.

JP 2008-256150 A

  When the seat ring is formed of a metal material as in the conventional triple eccentric butterfly valve, the seal surface is configured by contact between rigid metals, so that a large seal surface pressure is required. Therefore, the torque applied to the valve shaft is increased, and it is necessary to make the valve shaft thicker. Also, the actuator that drives the valve shaft is required to have high output, which may increase the cost. In addition, since the sealing surface formed by such a metal seal is elliptical, there is a possibility that the sealing performance may be rapidly deteriorated if the seat ring is slightly deviated from the valve body. The assembly work required skill.

  Then, an object of this invention is to provide the butterfly valve and seat ring which can form an elliptical sealing surface reliably at low cost.

  The object of the present invention is to provide a valve box having a flow path, a valve body disposed in the flow path, a valve shaft that rotatably supports the valve body, and the valve box when the valve body is closed. A seat ring that seals the flow path between the inner periphery of the valve body and the outer periphery of the valve body, the seat ring is a butterfly valve that forms an elliptical sealing surface, the seat ring, A holding ring made of a rigid material having an oval holding surface in plan view and a sealing ring made of an elastic material forming the sealing surface, and the sealing ring elastically deformed along the holding surface This is achieved by a butterfly valve held in the holding ring in a state.

  Further, the object of the present invention is to provide a butterfly valve including 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 that seals the flow path by forming an elliptical sealing surface between the inner peripheral portion of the valve box and the outer peripheral portion of the valve body when the valve body is closed, and has an elliptical shape in plan view A holding ring made of a rigid material having a surface and a sealing ring made of an elastic material forming the sealing surface, and the sealing ring is elastically deformed along the holding surface in the holding ring. This is achieved by the seat ring being held.

  The said seat ring can be set as the structure by which the said sealing ring was hold | maintained along the internal peripheral surface of the said holding ring, and can be provided in the internal peripheral part of the said valve box. Alternatively, the seat ring may be configured such that the sealing ring is held along the outer peripheral surface of the holding ring. In this case, the seat ring can be provided on the outer peripheral portion of the valve body. .

  ADVANTAGE OF THE INVENTION According to this invention, the butterfly valve and seat ring which can form an elliptical sealing surface reliably at low cost can be provided.

It is a cross-sectional view of a 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 a cross-sectional view which shows the modification of the butterfly valve shown in FIG. It is an expanded sectional view of the seat ring of the butterfly valve shown in FIG. It is a cross-sectional view of a butterfly valve according to another embodiment of the present invention. It is an expanded sectional view of the seat ring of the butterfly valve shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a butterfly valve according to an embodiment of the present invention. As shown in FIG. 1, the butterfly valve 1 includes a valve box 10 having a cylindrical flow path 11 formed therein, a plate-shaped valve body 20 disposed in the flow path 11, and a valve body 20. A valve shaft 30 that is movably supported and a seat ring 40 provided on the inner peripheral surface of the valve box 10 are provided.

  In the valve box 10, a step portion 12 is formed on an inner peripheral surface, and a seat ring 40 is disposed between the annular retainer 13 and the step portion 12. The retainer 13 can press the seat ring 40 between the retainer 13 and the step portion 12 by a fastening screw 15 screwed to a fixing ring 14 fixed to the inner peripheral surface of the valve box 10. And can be provided on the inner peripheral portion 10a of the valve box 10.

  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.

  The butterfly valve 1 of the present embodiment has a triple eccentric structure. That is, the center 30a of the valve shaft 30 is eccentric from the seal surface 422a formed by the valve body 20 and the seat ring 40 by a distance E1 along the center line 11L of the flow path 11, and further, the center line of the flow path 11 It is eccentric by a distance E2 in the orthogonal direction from 11L. 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 FIG. 1, the inner peripheral surface 422 of the sealing ring 42 is in contact with the entire outer peripheral surface 22 of the valve body 20 in the closed position, and forms a seal surface 422a composed of this contact portion. The seal surface 422a has an elliptical shape as the outer peripheral surface 22 of the valve body 20 when viewed along the center line 11L of the flow path 11.

  The butterfly valve 1 having the above-described configuration can abut the flange end surfaces of the flange pipes (not shown) on the both ends of the opening of the valve box 10 and fasten the flanges with bolts or the like, Ten flow paths 11 can communicate 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 the present embodiment, the fluid flow 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.

  The seat ring 40 of the present embodiment is configured to hold the sealing ring 42 on the inner peripheral surface 412 of the holding ring 41, thereby forming an elliptical sealing surface formed between the outer peripheral surface 22 of the valve body 20. 422a can be easily formed by the sealing ring 42 made of an elastic material, and a required sealing surface pressure can be reduced as compared with a sealing surface formed by a metal sheet ring. Therefore, while maintaining the effect of the triple eccentric butterfly valve that can suppress the sliding of the seal surface and extend the life, the valve body 20 and the seat ring 40 may be slightly oriented in the elliptical direction during assembly. Even if a deviation occurs, the seal can be surely performed, and the seal can be performed with a low torque using the thin valve shaft 30 and the low output actuator, so that the manufacturing cost can be reduced.

  The configuration of the seat ring 40 is not limited to that of the present embodiment, and an annular groove 423 may be formed on the end surface of the sealing ring 42 as shown in FIG. The seat ring 40 thus configured is disposed in the valve box 10 so that the groove portion 423 faces the retainer 13, and the groove portion provided in the sealing ring 42 as shown in an enlarged sectional view in FIG. By forming the height H1 of the inner diameter portion slightly lower than the height H2 of the holding ring from 423, when fluid pressure acts in the direction of the fluid flow F, the pressure is applied to the inside of the groove portion 423 in the sealing ring 42. Since it acts and deforms the seal surface 422a in the inner diameter direction, 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. . Furthermore, as shown in FIG. 3, a communication hole 131 that communicates with the groove 423 may be formed in the retainer 13. In such a configuration, among the end faces on the retainer 13 side of the sealing ring 42, even when the surface 425 on the inner diameter side of the groove portion 423 is in close contact with the retainer 13, when pressure acts in the direction of the fluid flow F, The fluid pressure can surely act on the groove 423, and the seal surface pressure can be maintained well.

  Further, as shown in FIGS. 3 and 4, an annular lip 424 protruding inward may be provided on the inner peripheral surface 422 of the sealing ring 42, and the lip 424 contacts the outer peripheral surface of the valve body 20. The sealing surface 424a may be formed. 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 seat ring 40 shown in FIGS. 3 and 4 has a groove 423 on the end surface of the sealing ring 42 and a lip 424 on the inner peripheral surface 422, but only one of the groove 423 or the lip 424 is employed. It is also possible to have a configuration as described above.

  In the seat ring 40 of each of the embodiments described above, the holding surface that holds the sealing ring 42 in the holding ring 41 is the inner peripheral surface 412 of the holding ring 41, but as shown in FIGS. 5 and 6, the holding ring 141 is used. The seat ring 140 may be configured by externally fitting the sealing ring 142 to the holding ring 141 such that the outer peripheral surface 1411 thereof becomes the holding surface of the sealing ring 142. In the seat ring 140, the outer peripheral surface 1411 of the holding ring 141 made of a rigid material has an elliptical shape, while the inner peripheral surface 1412 is formed in a perfect circle shape, and a cylindrical projection 123 formed on the valve body 120. It is attached to. In addition, the sealing ring 142 made of an elastic material has both an outer peripheral surface 1421 and an inner peripheral surface 1422 formed in a perfect circle before being held by the holding ring 141, and is attached to the holding ring 141. Thus, the sealing ring 142 is elastically elongated and deformed, and the outer peripheral surface 1421 of the sealing ring 142 has an elliptical shape when viewed along the center line of the flow path 11.

  The seat ring 140 having such a configuration can be sandwiched between the outer peripheral portion of the valve body 120 and the retainer 130 and provided on the outer peripheral portion of the valve body 120 by the mounting screw 115. In the butterfly valve 101 shown in FIG. 5, a valve seat ring 150 is arranged on a step portion 12 formed on the inner peripheral surface of the valve box 10 via an O-ring 151, and is fixed by being screwed to the fixing ring 14. The valve seat ring 150 is fixed to the inner peripheral portion 10 a of the valve box 10 by screws 152. The inner peripheral surface 1501 of the valve seat ring 150 is formed so as to constitute a part of the outer peripheral surface of the inclined virtual cone, like the outer peripheral surface 22 of the valve body 20 shown in FIG. It has an elliptical shape when viewed along the center line. In FIG. 5, the same components as those in FIG. 1 are denoted by the same reference numerals.

  The butterfly valve 101 shown in FIG. 5 also has a triple eccentric structure like the butterfly valve 1 shown in FIG. 1, and the outer peripheral surface 1421 of the sealing ring 142 in the seat ring 140 is the inner peripheral surface of the valve seat ring 150. In contact with 1501, an elliptical sealing surface 1421a is formed. As a result, similar to the butterfly valve 101 of FIG. 1, the elliptical seal surface 1421a can be reliably formed at low cost. In the butterfly valve 101, an annular groove may be formed on the end surface of the sealing ring 142, or a sealing surface 1421a may be formed by an annular lip provided on the outer peripheral surface 1421, as in the configuration shown in FIG. May be.

  The seat ring of the present invention is preferably used for a triple eccentric butterfly valve as described above, but is not necessarily limited to this application. For other butterfly valves in which the seat ring forms an elliptical sealing surface. For example, the present invention can also be used for a butterfly valve having a seal surface with a third eccentricity but not having a first eccentricity or a second eccentricity, or a butterfly valve having an elliptical plate-like valve body.

1 Butterfly valve 10 Valve box 11 Flow path 20 Valve body 30 Valve shaft 40 Seat ring 41 Holding ring 42 Sealing ring 422a Sealing surface 423 Groove 424 Lip

Claims (6)

A valve box provided with a flow path, a valve body disposed in the flow path, a valve shaft that rotatably supports the valve body, an inner peripheral portion of the valve box and the valve when the valve body is closed A seat ring that seals the flow path between the outer periphery of the body, and the seat ring is a butterfly valve that forms an elliptical sealing surface,
The seat ring includes a holding ring made of a rigid material having an elliptical holding surface in plan view, and a sealing ring made of an elastic material forming the sealing surface,
The sealing ring is a butterfly valve that is held by the holding ring in a state of being elastically deformed along the holding surface.   2. The butterfly valve according to claim 1, wherein the sealing ring is held along an inner peripheral surface of the holding ring, and the seat ring is provided at an inner peripheral portion of the valve box.   2. The butterfly valve according to claim 1, wherein the sealing ring is provided along an outer peripheral surface of the holding ring and is provided on an outer peripheral portion of the valve body. A retainer that presses and holds the seat ring on the inner periphery of the valve box or the outer periphery of the valve body;
The butterfly valve according to claim 2 or 3, wherein the sealing ring has an annular groove formed on an end surface thereof.   The butterfly valve according to any one of claims 1 to 4, wherein the sealing surface is formed by an annular lip provided on the sealing ring. For a butterfly valve comprising 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, the valve box is closed when the valve body is closed A seat ring that seals the flow path by forming an elliptical sealing surface between an inner periphery and an outer periphery of the valve body,
A holding ring made of a rigid material having an elliptical holding surface in plan view, and a sealing ring made of an elastic material forming the sealing surface,
The sealing ring is a seat ring that is held by the holding ring in a state of being elastically deformed along the holding surface.

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