JP2000205412A - Sealing structure of valve casing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing structure for a valve casing, capable of easily performing attachment of a seal ring, lightening assembly operation of a valve casing and a valve cover, and improving the watertightness. SOLUTION: A ring-inner wall 13 is formed on a valve casing body 10, a ring-outer wall 22 is formed on a valve cover 20, and a seal ring 30 is put between both the walls 13, 22. The seal ring 30 is formed into a sectional form having a bottom face 31 abutting on the valve casing body 10, a vertical inner peripheral surface 32 abutting on the ring-inner wall 13, a conical outer peripheral surface 33 abutting on the ring-outer wall 22, and a top face 34 abutting on the valve cover 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal structure for a valve box, and more particularly, to a seal structure for ensuring watertightness between a valve box body and a valve cover in a valve box such as a soft seal gate valve. .

[0002]

2. Description of the Related Art A valve box such as a soft seal gate valve has a seal ring (profile ring) made of an elastic material such as rubber between a valve box body having a valve seat and the like and a valve lid holding a valve rod and the like. Are formed in a state in which water tightness is secured by flange connection.

FIGS. 4 and 5 show an example of a conventional sealing structure between a valve body and a valve cover. FIG. 4 is a sectional view of a main part showing a state before assembly. FIG. 5 is a sectional view of a main part showing a state after assembly.

In this conventional sealing structure, a stepped portion 3 serving as a seal ring contact surface is provided on the inner periphery of a flange 2 of a valve body 1 and a seal ring 6 is fitted on an inner periphery of a flange 5 of a valve cover 4. The valve housing 1 and the valve cover 4 are assembled by inserting the seal ring 6 into the annular groove 7 of the valve cover 4 and then mounting the two flanges 2. This is done by butting 5 and tightening it with bolts and nuts.

[0005]

Therefore, it is necessary to fit the seal ring 6 into the annular groove 7 on the lower surface side of the valve cover 4 when assembling the two. Since the dimensional relationship between the two is set so as not to drop, the force required for the fitting operation is large, and the seal ring must be securely and firmly fitted. Further, the shape of the seal ring 6 itself is also deformed to the shape shown in FIG. 5 under the internal pressure, and when the outer peripheral surface thereof is pressed against the gap between the flanges 2 and 5, a predetermined watertight performance is exhibited. It was formed into a shape.

[0006] Therefore, there is a problem in workability in fitting the seal ring 6 and assembling the valve cover 4, and there is a limit in improving watertightness.

Accordingly, the present invention provides a valve box sealing structure that can easily mount the seal ring, reduces the work of assembling the valve box body and the valve cover, and improves the watertightness. It is intended to be.

[0008]

To achieve the above object, a seal structure of a valve box according to the present invention is a seal structure between a valve box main body and a valve cover attached to the valve box main body. An annular inner wall having an outer peripheral surface formed of a cylindrical surface parallel to the axis is formed on the valve box mounting surface of the valve box main body, and has a larger diameter and an axial line than the annular inner wall on the valve box main body mounting surface of the valve cover. The dimension in the direction is large, the inner peripheral surface forms an annular outer wall composed of a conical surface whose diameter is increased in the direction of the valve box body, and a seal ring disposed between the annular inner wall and the annular outer wall is provided with a seal ring of the valve box body. A planar bottom surface in contact with the valve box mounting surface, a vertical inner peripheral surface which rises vertically from the inner peripheral side of the bottom surface and contacts the outer peripheral surface of the annular inner wall, and the annular outer wall from the outer peripheral side of the bottom surface A conical outer peripheral surface rising in the direction in which the valve lid side reduces in diameter corresponding to the conical surface of
It is characterized in that it is formed in a cross-sectional shape having a flat top surface bent in the inner circumferential direction so as to abut on the valve box body mounting surface of the valve lid from the upper end of the conical outer peripheral surface.

[0009]

1 to 3 show one embodiment of a valve box sealing structure according to the present invention. FIG. 1 is a sectional view of a main part showing a state before assembly, and FIG. Is a sectional view of a main part showing a state after assembly, and FIG. 3 is a partial sectional front view showing an example of an internally threaded gate valve to which the seal structure of the present invention is applied.

First, a gate valve includes a valve body 10 having a valve seat and a flange for connecting pipes, and a valve cover 2 having a valve rod and the like.
0 and a seal ring 30 made of an elastic material such as rubber.
The valve lid 20 is flange-connected via
The valve body is attached to the valve box main body 10 in a state where the valve body is mounted on a valve stem penetrating the valve cover 20.

A flange 11 is provided on the outer periphery of the valve cover main body 10 on the side where the valve cover is mounted, and a valve cover mounting surface 12 is formed on the upper surface of the flange. An annular inner wall 13 having an outer peripheral surface formed of a cylindrical surface parallel to the axis is provided on an inner peripheral portion of the valve cover attaching surface 12 so as to protrude toward the valve lid 20.

A flange 21 is provided at a lower portion of the valve cover 20 so as to face the flange 11, and an inner peripheral portion of the flange 21 is provided with the annular inner wall 13.
And a valve box main body mounting surface 23 corresponding to the valve lid mounting surface 12.

The annular outer wall 22 has an inner diameter of the annular inner wall 13.
Are formed to be larger than the outer diameter of the annular inner wall 13 and the annular outer wall 22 when the valve body 10 and the valve cover 20 are assembled.
And a space for sandwiching the seal ring 30 therebetween. The dimension (height) of the annular outer wall 22 in the axial direction is set to be larger than the dimension (height) of the annular inner wall 13, and the tip (lower end) of the annular outer wall 22 abuts on the valve cover attaching surface 12. When in contact with each other, an appropriate space S is provided between the tip (upper end) of the annular inner wall 13 and the valve box body attaching surface 23.
(See FIG. 2). further,
The inner peripheral surface of the annular outer wall 22 is formed as a conical surface whose diameter is increased on the lower side of the valve body 10.

The seal ring 30 mounted between the annular inner wall 13 and the annular outer wall 22 formed as described above has a flat bottom surface 3 abutting on the valve box mounting surface 12 of the valve box body 10.
1, a vertical inner peripheral surface 32 which rises vertically from the inner peripheral side of the bottom surface 31 and contacts the outer peripheral surface of the annular inner wall 13, and a conical surface of the annular outer wall 22 from the outer peripheral side of the bottom surface 31. A conical outer peripheral surface 33 rising in a direction in which the valve lid 20 side is reduced in diameter, and the valve lid 20 from the upper end of the conical outer peripheral surface 33.
A top surface 34 which is bent in the inner circumferential direction so as to contact the valve body body attaching surface 23 of the valve case main body, and further has an inner peripheral end of the top surface 34 and an upper end of the vertical inner peripheral surface 32. The cross-sectional shape has a curved arc surface 35 provided on the outer peripheral side between them.

The inner diameter of the seal ring 30 is formed to be the same as or slightly smaller than the outer diameter of the annular inner wall 13.
The seal ring 30 is securely attached to the annular inner wall 13. Further, the height of the seal ring 30 (the distance between the bottom surface 31 and the top surface 34) depends on the valve box mounting surface 12 and the valve box main body mounting surface 23 when the valve box body 10 and the valve cover 20 are assembled. Is set to be larger than the interval between Therefore, the seal ring 30 is mounted in a compressed state between the valve box mounting surface 12 and the valve box main body mounting surface 23.

With this configuration, the seal ring 30 can be attached when the valve box body 10 and the valve cover 20 are assembled together, with the valve box body having the valve box mounting surface 12 facing upward. It is only necessary to put the seal ring 30 on the outer circumference of the annular inner wall 13 of the tenth embodiment. Further, since there is no possibility of falling as in the conventional case, there is no need to firmly fit the annular inner wall 13 and the seal ring 30. This can be easily performed with a lighter force as compared with a conventional one that is firmly fitted into the annular groove.

Moreover, the annular outer wall 22 of the valve lid 20 abuts against the conical outer peripheral surface 33 of the seal ring 30 attached to the valve box body 10 on an inclined surface.
Of the seal ring 3 in a predetermined position.
0 can be inserted.

When the flanges 11 and 21 are tightened with bolts and nuts, the seal ring 30 is positioned between the valve box mounting surface 12, the annular inner wall 13, the valve box body mounting surface 23 and the annular outer wall 22. In use, the internal pressure is applied from the space S to the seal ring 3 during use.
0, it is further compressed, and is pressed against the valve box attaching surface 12 and the annular outer wall 22 by a strong force, so that the watertightness (water stoppage) can be greatly improved.

In particular, as shown in the present embodiment, the portion facing the gap S is formed into an arcuate surface 35 curved to the outer peripheral side, so that the internal pressure can be reliably applied to the seal ring 30 to the valve box mounting surface 12 and the annular outer wall 22. , So that the valve box mounting surface 12 and the bottom surface 31 and the annular outer wall 22 and the conical outer peripheral surface 33 can be brought into close contact with each other, and between the valve box mounting surface 12 and the tip of the annular outer wall 22. Can be made more reliable.

[0020]

As described above, according to the seal structure of the valve box of the present invention, the seal ring can be easily mounted and the valve box can be easily assembled. In addition to greatly improving the performance, the watertightness of the valve box can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part showing an example of a seal structure of a valve box of the present invention before assembly.

FIG. 2 is a cross-sectional view of a main part, similarly showing a state after assembly.

FIG. 3 is a partially sectional front view showing an example of an internally threaded gate valve to which the seal structure of the present invention is applied.

FIG. 4 is a sectional view of a main part in a state before assembling showing an example of a conventional sealing structure.

FIG. 5 is a cross-sectional view of a main part, similarly showing a state after assembly.

[Explanation of symbols]

10: valve body, 11: flange, 12: valve cover mounting surface,
13: annular inner wall, 20: valve lid, 21: flange, 22 ...
Annular outer wall, 23: Valve box body mounting surface, 30: Seal ring, 31: Bottom surface, 32: Vertical inner peripheral surface, 33: Conical outer peripheral surface, 34: Top surface, 35: Arc surface

Claims (1)

[Claims] 1. A sealing structure between a valve box body and a valve cover attached to the valve box body, wherein a cylinder whose outer peripheral surface is parallel to an axis is provided on a valve box attaching surface of the valve box body. An annular inner wall consisting of a surface is formed, and the valve case body attachment surface of the valve lid is larger in diameter and larger in the axial direction than the annular inner wall, and the inner peripheral surface is expanded from the conical surface in the direction of the valve box body. And a seal ring disposed between the annular inner wall and the annular outer wall, a flat bottom surface abutting the valve box mounting surface of the valve box body, and an inner peripheral side of the bottom surface. A vertical inner peripheral surface that rises vertically and abuts against the outer peripheral surface of the annular inner wall; and a conical outer peripheral surface that rises from the outer peripheral side of the bottom surface in a direction in which the valve lid side is reduced in diameter corresponding to the conical surface of the annular outer wall. And a planar shape bent in the inner circumferential direction so as to contact the valve box body mounting surface of the valve lid from the upper end of the conical outer peripheral surface. A valve box sealing structure formed in a cross-sectional shape having a top surface.