JP3089221B2 - Shaft sealing device for butterfly valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft sealing device for a center type butterfly valve, and more particularly to a shaft sealing device for improving the sealing performance between a seat ring and a valve stem.

[0002]

2. Description of the Related Art Conventionally, a seat ring made of an elastic sealing material is fixed in a valve body having a hollow cylindrical flow path extending in a flow direction of a fluid, and an outer peripheral edge of the seat ring comes into contact with or separates from the seat ring. The center type butterfly valve which rotatably supports the valve body with a valve stem and rotates the valve stem from outside the valve body to rotate the valve body to open and close the valve is known. The valve stem of such a butterfly valve penetrates the valve body and the seat ring and is fixed to the valve body, and the stem portion of the valve stem leaks fluid from the stem portion due to the close contact between the valve body and the seat ring. To prevent it. However, the shaft hole may be deformed due to the elastic deformation of the seat ring, the fluid pressure, and the like, and the sealing performance between the valve body and the seat ring at the valve shaft portion may be reduced.

[0003] Therefore, an annular groove is formed in the outer peripheral surface of the seat ring near the shaft hole, that is, the contact surface side with the valve body, and a rigid ring is attached to the groove to prevent deformation of the shaft hole. Such a configuration is disclosed in Japanese Utility Model Laid-Open No. 55-144255, Japanese Utility Model Publication No. 1-281616, and the like.
However, in such a structure, since the rotation of the valve stem causes the rotation of the rigid ring through the seat ring shaft hole,
The shaft hole may be deformed and the sealing performance of the valve shaft may be impaired. Also, the claws of the rigid ring are difficult to settle into the groove of the valve body, and the rigid ring falls off from the seat ring or rotates when the seat ring is assembled to the valve body, making assembly difficult and increasing the number of work steps. Was. As shown in FIGS.
The rigid ring (1) is inserted into the groove of the seat ring (2), and the primary pressure is applied as a surface pressure to the total area of the valve body (3) when the valve is closed. Along with the valve stem (4), it is slightly deviated to the secondary side (by a difference in dimension between the upper and lower valve body shaft holes). And may cause fluid leakage.

In Japanese Utility Model Publication No. 52-3699, an annular seat ring is mounted on the inner peripheral surface of an annular valve body made of a rigid material, and a portion of the valve shaft passing through the seat ring has a U-shaped cross section made of the rigid material. There is disclosed a structure in which a ring-shaped annular holder is embedded, and an O-ring is arranged in the holder. The holder is molded into the seat ring by integral vulcanization. However, if the position of the holder is not constant due to the vulcanization pressure during vulcanization and is biased inward, the elastic force with the valve body (sealability) On the other hand, if it is deviated outward, the molding surface with the seat ring is changed from three U-shaped surfaces to two surfaces.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems encountered in the conventional butterfly valve, and the shaft hole does not move relative to the valve stem due to an external force or a fluid pressure on the seat ring. And to prevent the rigid ring from falling off or moving during assembly to the valve body. In addition, the holder to be integrally vulcanized is held at a predetermined position so as not to move. Further, it is intended to prevent the fluid from leaking from the outer peripheral portion of the holder to the back side of the seat ring, and to prevent the seat ring from expanding in the inner diameter direction. Further, the rotation of the valve stem improves lubrication of the shaft portion, particularly, smooth rotation of the valve stem and the durability of the O-ring, thereby prolonging the life of the valve.

[0006]

In order to solve the above-mentioned problems, the present invention adopts a method in which a seat ring made of an elastic sealing material is fixed to the inner peripheral surface of a valve body having a hollow cylindrical fluid passage. A disc-shaped valve body whose outer peripheral surface comes into contact with and separates from the seat ring is rotatably supported in the valve body, and an O-ring case made of a rigid material is integrally vulcanized in a valve shaft hole of the seat ring. It is mounted by molding, and O
In a shaft sealing device for a butterfly valve with a ring attached ,
An annular groove is formed on the entire inner peripheral surface of the main body, and the inner peripheral surface of the valve main body is formed.
The inner peripheral surface of the valve body covers the entire outer peripheral surface of the seat ring
A convex portion extending toward the ring is formed in an annular shape, and the convex portion is
The O-ring case is inserted into the concave
Of is extending out to a height to diameter direction outwardly, characterized in that fitted into the groove of the valve body inner peripheral surface.

The width and height of the O-ring case extending outward are matched with the width and height of the convex portion formed on the outer peripheral surface of the seat ring.

Further, the O-ring case is formed of a non-metallic material.

Further, an oil groove is formed on the inner peripheral surface of the O-ring case.

Further, a portion of the O-ring case extending outward in the diameter direction is formed to be smaller in diameter than the O-ring insertion portion.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below. Referring to the drawings, reference numeral (10) denotes a valve body of a butterfly valve, which is made of a synthetic material such as a metal and a synthetic resin, and has a hollow cylindrical flow path provided therethrough. Valve body (1
A seat ring (11) made of an elastic sealing material such as rubber or synthetic resin is fixed to the inner peripheral surface of (0). (12) is the valve body (10)
A disc-shaped valve body rotatably supported by valve rods (13) and (14) inside, and the outer peripheral surface comes into contact with and separates from the inner peripheral surface of the seat ring (11) to open and close the valve. . The drive-side valve rod (13) has an inner end connected to the valve body (12) so as not to rotate, and a desired actuator can be freely connected to the outer end. Idling side valve stem (14)
Is rotatably inserted in the valve body (12), and the outer end is a gasket.
It is fixed with the bottom lid (16) via (15).

An O-ring case (17) is integrally vulcanized and attached to the seat ring (11) at a valve stem insertion portion of the seat ring (11). An O-ring (18) adapted to the diameter is mounted. Seat ring (1
The primary seal portion (19) of the shaft portion is constituted by the pressure contact between 1) and the valve body (12), and the O-ring (18) constitutes the secondary seal portion. Basically, the fluid pressure is reliably shut off at the primary seal (19). If fluid leaks from the primary seal portion (19) due to the opening / closing frequency of the valve, fluid conditions, etc., the fluid is reliably shut off by the secondary seal portion of the O-ring (18). As described above, the O-ring case (17) is integrally vulcanized with the seat ring (11), and there is no leakage of fluid from the outer peripheral portion of the O-ring case (17). The O-ring case (17) may be formed with a mountain-shaped groove or the like on the outer peripheral surface to increase the surface area, so that the vulcanization molding of the O-ring case (17) and the seat ring (11) may be more reliably performed. . The O-ring case (17) is preferably made of stainless steel, but the cost can be reduced by using a steel material or a hard resin.

The O-ring case (17) is provided with a seat ring (1).
A concave groove (22) extending from the outer peripheral surface of ( 1) toward the inner peripheral surface of the valve body in the diametrically outward direction along the valve stem, and formed annularly along the inner peripheral surface of the valve body (10). ) And engages directly with the valve body.
I agree. Insert the O-ring case (17) into the groove (22),
By matching the width (W1) of the O-ring case (17) with the concave groove of the valve body, the movement of the seat ring in the flow path direction can be more reliably prevented. On the entire inner peripheral surface of the valve body
The O-ring case (1 ) of the concave groove (22)
In the part where 7) is not fitted, as shown in FIG.
Of the seat ring (11) except the part where the ring case exists
An annular convex portion (11a) is fitted along the entire outer peripheral surface .

2 and 3, the width (W1) of the O-ring case (17) is equal to the width (W2) of the projection (11a) of the seat ring (11) at a position perpendicular to the valve stem (13) in FIG. ), And the height (H1) of the O-ring case (17) extending outward in the diameter direction is also formed to be the same as the height (H2) of the convex portion (11a). Thus, the seat ring (11) has a convex portion (11a).
Accordingly, it is possible to prevent the seat ring (11) from moving in the direction of the flow path, increase the thickness of the seat ring (11) when the valve is closed, increase the elasticity, and improve the sealing performance. By making the outer end of the O-ring case (17) the same as the seat ring convex portion (11a), the outer end of the O-ring case abuts on the outer periphery of the vulcanizing mold during vulcanization molding of the seat ring, The thickness (T) of the shaft hole of the seat ring can be made uniform.
As a result, regardless of the opening and closing of the valve element, the compression is always performed at a constant compression ratio. As a result, the sealing performance of the primary seal portion is improved, and the effect of preventing fluid leakage is improved.

The O-ring case (17) shown in FIGS. 1 to 5 has the same diameter in the diameter direction from one end to the other end, but is separated from the seat ring (11) as shown in FIGS. The outer shape of the protruding end (20) protruding in the direction may be reduced. As a result, the width of the convex portion of the seat ring is reduced, which is advantageous. In addition, the portion to be integrally vulcanized is on four sides and the surface area is larger than that shown in FIGS. In the O-ring case shown in FIG. 7, the O-ring insertion portion is formed of two parts having an L-shaped cross section, and is united to form one O-ring case. This facilitates the processing of the groove for inserting the O-ring, and improves the dimensional accuracy and reduces the cost because it can be formed into a mold.

An oil groove (21) is formed at least above or below, preferably up and down, the O-ring insertion groove of the O-ring case (17), and a lubricant such as grease is sealed in the groove (21). As a result, the smoothness of the rotation of the valve stem and the durability of the O-ring can be improved, and a load in the radial direction can be effectively borne particularly when the valve stem is arranged in a horizontal position. The shape of the oil groove (21) may be any of a quadrangular section, a triangular section and the like.

[0017]

According to the present invention, the thickness of the seat ring shaft, that is, the position of the O-ring case can be kept constant, and elastic deformation can be suppressed. The O-ring prevents the inner ring from leaking outside by the O-ring, and the outer diameter prevents the leakage from the outside by vulcanization integrally with the seat ring. The O-ring case and valve stem are synchronized regardless of fluid pressure,
There is no danger of the sealability being impaired without the shaft hole being deformed. Since the O-ring case protrudes outward from the seat ring, the valve body and the valve stem do not move to the secondary side regardless of the fluid pressure. Since the O-ring case is built into the seat ring and is integrally vulcanized, the O-ring case does not fall off or rotate, so that assembly is easy and man-hours can be reduced. The integral vulcanization of the O-ring case eliminates leakage from inside and outside of the case, prevents pressure from staying on the outer periphery of the seat ring, and prevents compression of the seat ring in the inner diameter direction. The cost can be reduced by combining the O-ring case with a plurality of components. Since the O-ring case extends outward in the axial direction, the adhesive surface is enlarged by the extent of the extension, and a stronger adhesive effect can be achieved. The lubrication and durability can be improved by the oil groove. And so on.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a butterfly valve according to the present invention.

FIG. 2 is an enlarged sectional view of a main part of a valve stem.

FIG. 3 is an enlarged sectional view of a main part at a position orthogonal to a valve stem.

FIG. 4 is an enlarged perspective view of a valve stem.

FIG. 5 is an enlarged perspective view of a seat ring.

FIG. 6 is a sectional view showing one modification.

FIG. 7 is a sectional view showing another modification.

FIG. 8 is a sectional view showing a conventional example.

FIG. 9 is a plan view showing a deformation of a conventional shaft hole.

[Explanation of symbols]

 (10) Valve body (11) Seat ring (12) Valve body (13) Valve stem (14) Valve stem (15) Gasket (16) Bottom cover (17) O-ring case (18) O-ring (19) Primary seal (20) Protruding end (21) Oil groove (22) Concave groove

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16K 1/16-1/226 F16K 41/00-41/08

Claims (5)

(57) [Claims] 1. A disc-shaped valve element having an outer peripheral surface contacting and separating from a seat ring made of an elastic sealing material is fixed to an inner peripheral surface of a valve body penetrating a hollow cylindrical fluid passage. rotatably journaled within the valve body, the O-ring for shaft seal mounted attachment, into the O-ring case by integrally vulcanization molding the O-ring case made of rigid material on the valve stem shaft hole of the seat ring
In the butterfly valve shaft sealing device, the entire inner peripheral surface of the valve body
An annular groove is formed on the inner surface of the valve body,
Extending toward the inner circumference of the valve body
A projecting projection is formed in an annular shape, and the projection is fitted into the groove.
Together with the O-ring with the casing is extending out until the height diameter outwardly of the convex portion, the shaft seal device of the butterfly valve, characterized in that fitted into the groove of the valve body inner peripheral surface. 2. The device according to claim 1, wherein the width and height of the O-ring case extending outward are made to match the width and height of the convex portion formed on the outer peripheral surface of the seat ring. Shaft sealing device. 3. The shaft sealing device according to claim 1, wherein the O-ring case is formed of a non-metallic material. 4. The shaft sealing device according to claim 1, wherein an oil groove is formed on an inner peripheral surface of the O-ring case. 5. The shaft sealing device according to claim 1, wherein a portion of the O-ring case extending outward in the diameter direction is formed to have a smaller diameter than the O-ring insertion portion.