JP6883496B2 - gasket - Google Patents

Description

The present invention relates to gaskets.

For example, as a sealing material used for a valve body or a valve seat of a butterfly valve or the like, a gasket made of a laminated sheet in which an expanded graphite sheet and a metal plate are bonded and laminated is known (for example, the figure of Patent Document 1). 2 (C)). Since such a gasket uses expanded graphite, it has better compatibility with the mating material than a gasket composed of only a metal plate, and exhibits high sealing performance even when used under high temperature and high pressure conditions. To do.

Japanese Unexamined Patent Publication No. 6-101763

For example, the conventional gasket is provided on the valve seat of the butterfly valve, and when the valve body rotating with respect to the valve seat rotates to a closing position that closes the flow path, the sealing surface formed on the outer periphery of the gasket is formed. When the outer peripheral surfaces of the valve body are brought into contact with each other for sealing, there are the following problems. That is, when an excessive tightening load (axial load) is applied to the gasket from the outside when the valve body is in the closed position, the outer peripheral surface of the expanded graphite sheet and the metal constituting the sealing surface of the gasket are formed. Among the outer peripheral surfaces of the plate, there is a problem that the outer peripheral surface of the metal plate bites into the outer peripheral surface of the valve body, which is the mating material, and the valve body cannot be rotated from the closed position.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a gasket having a new structure capable of suppressing the sealing surface from biting into a mating material.

(1) In the gasket of the present invention, a first sheet portion composed of a first expanded graphite sheet and a second sheet portion containing metal are laminated, and a sealing surface is provided on an outer surface extending in the lamination direction of these sheet portions. The second sheet portion is made of the formed laminated body, and the second sheet portion covers the second expanded graphite sheet, at least both end surfaces of the second expanded graphite sheet in the lamination direction, and the surface on the sealing surface side. It is composed of a metal mesh as a metal mesh.

According to the present invention, in the second sheet portion containing metal, the surface of the second expanded graphite sheet on the sealing surface side is covered with a metal mesh, so that, for example, when an excessive load is applied to the gasket, the second sheet portion is second. By allowing the surface of the expanded graphite sheet 2 on the sealing surface side to bite into the voids of the metal mesh, the surface on the sealing surface side can be brought into contact with the mating material. As a result, the area in which the expanded graphite having excellent familiarity comes into contact with the mating material can be increased, so that the sealing surface can be prevented from biting into the mating material.

(2) It is preferable that the metal mesh also covers the surface of the second expanded graphite sheet opposite to the surface on the sealing surface side.
In this case, when an excessive load is applied to the gasket, the deformation of the opposite surface of the second expanded graphite sheet can be suppressed by the metal mesh.

(3) In the laminated body, a plurality of the first sheet portions and a plurality of the second sheet portions are alternately laminated, and the first sheet portion is arranged on the outermost side of one of them in the stacking direction. It is preferable that the outermost end surface of the first sheet portion arranged on the outermost side in the stacking direction is the attachment surface to be attached to the member to be attached.
In this case, when the gasket is attached to the member to be attached, the outermost first sheet portion can also be used as a sealing member interposed between the member to be attached and the gasket, so that the gasket can be attached. The structure can be simplified.

According to the gasket of the present invention, it is possible to prevent the sealing surface from getting caught in the mating material.

It is a perspective view which shows the gasket which concerns on one Embodiment of this invention. It is a perspective view which shows the 1st sheet part of a gasket. It is a perspective view which shows the 2nd sheet part of a gasket. It is a perspective view which shows the 2nd expanded graphite sheet of the 2nd sheet part. It is a perspective view which shows the metal mesh of the 2nd sheet part. It is an enlarged sectional view of a gasket.

Next, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a perspective view showing a gasket according to an embodiment of the present invention. This gasket 1 is, for example, an annular sealing material used by being attached to the valve seat of a butterfly valve, and includes a plurality of (four sheets in the example) first sheet portion 2 made of expanded graphite and metal. It is composed of a laminated body in which a plurality of (4 sheets in the illustrated example) second sheet portions 3 are alternately laminated.

FIG. 2 is a perspective view showing the first sheet portion 2 of the gasket 1. In FIG. 2, each first sheet portion 2 of the gasket 1 is composed of, for example, a first expanded graphite sheet 21 which is compression-molded by pressing expanded graphite powder. The first expanded graphite sheet 21 of the present embodiment is formed in an annular shape (endless annular shape) having no end, for example, and the density of the first expanded graphite sheet 21 is, for example, 1.4 to 1. It is said to be 8 g / cm ^3.

FIG. 3 is a perspective view showing the second sheet portion 3 of the gasket 1. In FIG. 3, each second sheet portion 3 of the gasket 1 is composed of a second expanded graphite sheet 31 and a metal mesh 32 as the metal that covers the second expanded graphite sheet 31.

FIG. 4A is a perspective view showing the second expanded graphite sheet 31 of the second sheet portion 3. In FIG. 4A, the second expanded graphite sheet 31 is, for example, one formed by pressurizing expanded graphite powder and compression molding. The second expanded graphite sheet 31 of the present embodiment is formed, for example, in an annular shape (ended annular shape) having an end portion, and is formed to have substantially the same size as the first expanded graphite sheet 21. The density of the second expanded graphite sheet 31 is, for example, 1.4 to 1.8 g / cm ³ .

FIG. 4B is a perspective view showing the metal mesh 32 of the second sheet portion 3. In FIG. 4B, the metal mesh 32 is formed in a mesh shape by metal wires, and has a plurality of voids 32a formed between adjacent metal wires. The metal mesh 32 of the present embodiment is formed, for example, in an elliptical cylinder shape.

When manufacturing the second sheet portion 3, one end in the circumferential direction of the second expanded graphite sheet 31 shown in FIG. 4A is directed from one end in the axial direction of the metal mesh 32 shown in FIG. 4B to the other end in the axial direction. And insert it inside. Then, as shown in FIG. 3, the metal mesh 32 is bent in an annular shape according to the outer shape of the second expanded graphite sheet 31, so that the entire second expanded graphite sheet 31 is inside the metal mesh 32. It will be in the inserted state. Thereby, the second sheet portion 3 can be easily manufactured.

In the state shown in FIG. 3, the metal mesh 32 has an axial (lamination direction) end surface 31a, an end surface 31b (see also FIG. 5), and an outer peripheral surface (a surface on the sealing surface 1b side described later) of the second expanded graphite sheet 31. ) 31c and the inner peripheral surface (the surface opposite to the surface on the sealing surface 1b side) 31d are covered with the second expanded graphite sheet 31 in close contact with the second expanded graphite sheet 31.

In the present embodiment, the second expanded graphite sheet 31 is formed in an endless annular shape and the metal mesh 32 is formed in an elliptical cylinder shape, but the second expanded graphite sheet 31 is formed in an endless annular shape. At the same time as forming, the metal mesh 32 may be formed in a sheet shape. In this case, the second expanded graphite sheet 31 having an endless annular shape may be wrapped with a sheet-shaped metal mesh 32 to cover it.

FIG. 5 is an enlarged cross-sectional view of the gasket 1. For convenience of explanation, in the present specification, one side in the axial direction of the gasket 1 (lower side in FIG. 5) is referred to as "lower side", and the other side in the axial direction of the gasket 1 (upper side in FIG. 5) is referred to as "upper side". However, this description does not limit the arrangement direction of the gasket 1.

In FIG. 5, in the gasket 1 of the present embodiment, four first sheet portions 2A to 2D and four second sheet portions 3A to 3D are alternately laminated on the same axis C. It is formed by pressing with a mold (not shown) from both sides in the stacking direction (vertical direction). By the press molding, in the second sheet portions 3A to 3D, the surfaces (end surfaces 31a, 31b, outer peripheral surface 31c, and inner peripheral surface 31d) of the second expanded graphite sheet 31 are formed in the plurality of voids 32a of the metal mesh 32. It will be in a state of biting. Therefore, the second expanded graphite sheet 31 and the metal mesh 32 are integrally formed.

In the present embodiment, the adjacent first sheet portion 2 and the second sheet portion 3 are fixed to each other by using an adhesive (not shown) so as not to separate from each other before press molding. By forming the metal mesh 32 of the second sheet portion 3 in a coarse mesh shape without limitation, the metal mesh 32 is formed in the adjacent first sheet portion 2 (first expanded graphite sheet 21) at the time of press molding. It may be bound by an anchor effect.

The first sheet portion 2D is arranged on the lowermost side of the gasket 1 (one outermost side in the stacking direction). The lower surface (outer end surface in the stacking direction) of the first seat portion 2D is a mounting surface 22 that is mounted in contact with the outer surface of the valve seat (attached member) 50 of the butterfly valve. The mounting surface 22 is blasted so that it can be easily fitted to the outer surface of the valve seat 50.

On the outer peripheral surface (outer surface extending in the stacking direction) of the gasket 1, in the cross-sectional view of FIG. 5, a flat surface 1a formed parallel to the axis C and an inclined surface formed inclined with respect to the axis C. The sealing surface 1b is formed.
The flat surface 1a of the present embodiment is composed of two outer peripheral surfaces of the first sheet portions 2C and 2D and two outer peripheral surfaces of the second sheet portions 3C and 3D, which are the lower halves of the gasket 1. ing.

Further, the sealing surface 1b of the present embodiment includes two outer peripheral surfaces of the first sheet portions 2A and 2B and two outer peripheral surfaces of the second sheet portions 3A and 3B, which are the upper halves of the gasket 1. , It is configured by forming the inclined surface. The sealing surface 1b is inclined so as to gradually reduce its diameter from the lower end to the upper end.

The seal surface 1b contacts and presses against the valve seat 50 of the butterfly valve when the valve body (counterpart material) (not shown) rotates to a closing position that closes the flow path. By doing so, the outer peripheral surface and the sealing surface 1b are sealed. At that time, on the outer peripheral surfaces of the second sheet portions 3A and 3B constituting the sealing surface 1b, the outer peripheral surface of the second expanded graphite sheet 31 that bites into the gap 32a of the metal mesh 32 and the metal mesh 32 form a valve. Contact the outer peripheral surface of the body.

Although the sealing surface 1b of the present embodiment is formed on a part of the outer peripheral surface of the gasket 1, it may be formed on the entire outer peripheral surface of the gasket 1. Further, the sealing surface 1b does not necessarily have to be an inclined surface, and may be formed flush with, for example, the flat surface 1a.

As described above, according to the gasket 1 of the present embodiment, the second sheet portions 3A and 3B constituting the sealing surface 1b of the gasket 1 cover the outer peripheral surface 31c of the second expanded graphite sheet 31 with the metal mesh 32. Therefore, when an excessive tightening load (axial load) is applied to the gasket 1 from the outside, the second expanded graphite sheet 31 bites into the gap 32a of the metal mesh 32 in the second sheet portions 3A and 3B. The outer peripheral surface 31c of the above can be brought into contact with the mating material (valve body). As a result, the area in which the expanded graphite having excellent familiarity comes into contact with the mating material can be increased, so that the sealing surface 1b can be suppressed from being bitten into the mating material.

Further, since the metal mesh 32 also covers the inner peripheral surface 31d of the second expanded graphite sheet 31, the inner circumference of the second expanded graphite sheet 31 when the excessive tightening load is applied to the gasket 1. The deformation of the surface 31d can be suppressed by the metal mesh 32.

Further, since the first seat portion 2D having the mounting surface 22 is arranged on the lowermost side of the gasket 1, when the gasket 1 is mounted on the valve seat 50, the first seat portion 2D is referred to as the valve seat 50. It can also be used as a sealing member interposed between the gasket 1 and the gasket 1. This makes it possible to simplify the mounting structure of the gasket 1.

The overall shape of the gasket 1 in the above embodiment is not limited to an annular shape, and may be another shape such as a rectangular shape, a semicircular shape, or a fan shape. Further, although the gasket 1 in the above embodiment is attached to the valve seat 50 of the butterfly valve, it may be attached to the valve body of the butterfly valve or to a member other than the butterfly valve.

In the gasket 1 in the above embodiment, the first sheet portion 2 is arranged on the lowermost side, but the second sheet portion 3 may be arranged on the lowermost side. In this case, a seal member made of expanded graphite sheet may be separately interposed between the second seat portion 3 arranged on the lowermost side and the outer surface of the valve seat 50. Further, the gasket 1 in the above embodiment is composed of a plurality of first sheet portions 2 and a plurality of second sheet portions 3, but at least one first sheet portion 2 and one second sheet portion. It suffices if it is composed of 3.

In the above embodiment, the plurality of metal meshes 32 of the second sheet portions 3A to 3D cover both end faces 31a and 31b, the outer peripheral surface 31c, and the inner peripheral surface 31d of the second expanded graphite sheet 31. At least, the metal meshes 32 of the second sheet portions 3A and 3B constituting the sealing surface 1b may cover both of the end surfaces 31a and 31b and the outer peripheral surface 31c.

In the above embodiment, on the outer peripheral surfaces of the second sheet portions 3A and 3B constituting the sealing surface 1b, the outer peripheral surface 31c of the second expanded graphite sheet 31 bites into the voids 32a of the metal mesh 32 during press molding of the mold. However, when the excessive tightening load acts on the gasket 1, the outer peripheral surface 31c of the second expanded graphite sheet 31 may be made to bite into the gap 32a of the metal mesh 32.

If the gasket 1 is not used under high temperature and high pressure conditions and the operability of the member to which the gasket 1 is attached is required, instead of the metal mesh 32, polytetrafluoroethylene (PTFE) or the like is used. A mesh made of an organic fiber such as a fluororesin or a carbon fiber, or an inorganic fiber may be used.

The embodiments disclosed this time should be considered to be exemplary in all respects and not restrictive. The scope of the present invention is indicated by the scope of claims, not the above-mentioned meaning, and is intended to include the meaning equivalent to the scope of claims and all modifications within the scope.

1 Gasket 1b Sealing surface 2 1st sheet part 3 2nd sheet part 21 1st expanded graphite sheet 22 Mounting surface 31 2nd expanded graphite sheet 31c Outer peripheral surface (surface on the sealing surface side)
31d Inner peripheral surface (surface opposite to the surface on the seal surface side)
32 Metal mesh 50 Valve seat (attached member)

Claims (2)

It is composed of a laminated body in which a first sheet portion composed of a first expanded graphite sheet and a second sheet portion containing metal are laminated, and a sealing surface is formed on an outer surface extending in the laminating direction of these sheet portions.
The second sheet portion
With the second expanded graphite sheet,
It is composed of a metal mesh as the metal that covers at least both end surfaces of the second expanded graphite sheet in the lamination direction and the surface on the sealing surface side .
In the laminated body, a plurality of the first sheet portions and a plurality of the second sheet portions are alternately laminated, and the first sheet portion is arranged on the outermost side of one of these in the stacking direction. ,
A gasket in which the outermost end surface of the first sheet portion arranged on the outermost side in the stacking direction is a mounting surface to be mounted on a member to be mounted. The gasket according to claim 1, wherein the metal mesh also covers a surface of the second expanded graphite sheet opposite to the surface on the sealing surface side .

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