JP2001032942A - Spiral gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold highly compressed strength even a large diameter, and hold a sealing performance in a good condition by specifying density of an expanded graphite filler material. SOLUTION: In a gasket main body 3 formed by laminating a hoop material of a tape shaped metallic thin plate having a nearly V-shaped cross section, and a filler material 6 formed by an expanded graphite tape, a thickness t of the hoop material 5 is set to 0.25 to 0.45 mm, the density of the filler material 6 is set to 1.4 to 2.0 g/cm3. Compressed strength is improved comparing with a normal thickness of 0.20 mm by this thickness t. In the case where the thickness t is smaller than it, the hoop material 5 is easily come off when a gasket is wound, the compressed strength is weakened. In the case where the thickness t is larger than it, molding of a cross section is difficult, adhesion between the hoop material 5 and the filler material 6 is wrong, and a sealing performance is reduced. In the case where the density of the filler material 6 is smaller than it, the compressed strength is not increased. In the case where the density is larger, the filler material 6 is excessively hardened, the adhesion between the hoop material 5 and the filler material 6 is wrong, and the sealing performance is reduced. It is thus possible to improve a sealing performance of the gasket having a large diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for joints of high-temperature and high-pressure equipment and pipes, and for the purpose of sealing fluids such as water, oil, steam, gas, etc. A hoop material) and a tape-like filler such as expanded graphite (hereinafter abbreviated as a filler material). Body inner diameter 60 used at high pressure
The present invention relates to a structure useful for a spiral gasket having a large diameter of 0 mm or more (hereinafter, abbreviated as a large spiral gasket).

[0002]

2. Description of the Related Art A spiral gasket has a cross section of approximately V in advance.
It has a configuration in which a hoop material and a filler material of a tape-shaped metal thin plate formed in a letter shape are sandwiched, overlapped with each other and wound in a spiral shape, and this structure is called a basic shape.
In addition, for the purpose of preventing deformation of the gasket body inside due to tightening pressure and centering, metal reinforcing rings are provided inside and / or outside the gasket body, with inner ring, outer ring, inner and outer rings, etc. Various types are known, and are generally widely used as high-temperature and high-pressure gaskets.

As a type of filler material, asbestos tape in which asbestos paper has been slit into strips has been generally used. However, asbestos fibers are natural minerals, and there is a concern that resources may be depleted. Due to the presumed health disorder becoming a social problem and the use of asbestos has been restricted worldwide, currently, non-asbestos paper slitted mainly using inorganic fibers other than asbestos is used It is becoming. Further, an expanded graphite tape having both flexibility and elasticity as a filler material is widely used because of its high heat resistance in a non-oxidizing atmosphere and excellent sealing properties.

Such a spiral gasket is widely used in various industrial piping flanges, pressure vessels, heat exchangers, and the like. It is manufactured up to about 4000mm inside diameter used for containers, etc. Recently, heat exchangers and reactors used in electric power and petrochemicals etc. are becoming higher pressure and larger for efficiency by energy saving. Accordingly, demand for a large-diameter spiral gasket having a main body inner diameter of 600 mm or more has been increasing.

[0005]

However, such a large-diameter spiral gasket is more likely to be deformed when compressed than a small-diameter product, so that the compressive strength tends to be small, and a large-diameter large-diameter gasket has a large distortion. When used for the flange, the gasket cannot follow the distortion of the flange, and leakage may occur.

A large-diameter spiral gasket is shown in FIGS.
As shown in FIG. 4, the inner ring 2 is sandwiched between the formers 7, and the hoop material 5 and the filler material 6 are wound while being pressed by the push piece 8. Therefore, as shown in FIGS. Winding form 7
Compared to the small diameter spiral gasket fixed to
The filler material 6 is not sufficiently pressurized, which also causes a decrease in compressive strength. If the pressing force of the push piece is forcibly increased, there is also a problem that the hoop material 5 comes off during the winding and is separated.

The present invention has been made in view of the above points, and provides a spiral gasket having good sealing properties by maintaining high compressive strength even when the inner diameter of the gasket main body is as large as 600 mm or more. The purpose is to:

[0008]

In order to achieve the above object, a first aspect of the present invention is to overlap a tape-like metal hoop material having a substantially V-shaped cross section with a filler material made of expanded graphite. In the spiral gasket formed by spirally winding, the density of the filler material is 1.4 to 2.0 g / cm.
^The gist is that it is ³ .

According to a second aspect of the present invention, there is provided a spiral gasket comprising a tape-shaped metal thin plate hoop material having a substantially V-shaped cross section and a filler material made of expanded graphite, which are wound in a spiral shape. 0.25-0.4 hoop thickness
5 mm, and the density of the filler material is 1.4 to 2.0 g / c.
and summarized in that set to m ^3.

A third aspect of the present invention is characterized in that, in the first and second aspects, the inner diameter of the main body of the gasket is 600 mm or more.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a preferred embodiment of the present invention, as shown in FIGS. 1 and 2, an inner ring 2 having an inner diameter of 1200 mm and an outer diameter of 1300 mm, an inner ring 1350 mm and an outer diameter of 1
A gasket main body 3 having an inner diameter of 1300 mm, which is formed by superposing a tape-shaped thin metal hoop member 5 having a 400 mm outer ring 4 attached thereto and a filler member 6 formed of expanded graphite tape and spirally forming the same. In the spiral gasket 1 having an outer diameter of 1350 mm, the thickness t of the hoop material 5 is 0.30 mm, and the density of the expanded graphite tape constituting the filler material 6 is 1.7 g / cm ³ .

Here, the thickness t of the hoop material 5 is set to 0.30 m.
In addition to the fact that the hoop material 5 obtained by compressing the gasket has a larger repulsion strength than the hoop material 5 having a thickness of 0.20 mm used in a normal spiral gasket, Since the hoop material 5 having a substantially V-shaped cross section before winding is excellent in shape retention, the hoop material 5 can be wound while being strongly pressed by the push piece 8 during winding. Helps to improve compressive strength.

Then, the thickness t of the hoop material 5 is 0.25 m.
When the thickness is smaller than m, the hoop material 5 is easily detached and loosened when the gasket is wound, and the compressive strength is weakened. When the thickness t of the hoop material 5 is larger than 0.45 mm, the cross section is deformed into a substantially V shape. When the gasket is wound, the hoop material 5 is easily detached and loosened, and the adhesion between the hoop material 5 and the filler material 6 is deteriorated, and the compressive strength is large. Also, the sealing property is reduced.

The present inventors set the thickness t of the hoop material 5 to 0.25 based on the knowledge obtained by the above-described experiment.
mm to 0.45 mm, preferably 0.30 mm to 0.35 mm.

The density of the expanded graphite of the filler material 6 is 1.4 to 2.2 in the case of a large diameter spiral gasket.
0 g / cm ³ , which was higher than that of a product having a normal size.
If the density is less than 1.4 g / cm ³ , the filler material 6 is easily deformed when the gasket is compressed, so that the compressive strength is not increased and the sealing property is reduced. On the other hand, if the density is greater than 2.0 g / cm ³ , the filler material 6 becomes too hard, and conversely, the filler material 6 cannot be formed into a substantially V-shaped cross section of the hoop material 5 during winding, or the hoop material 5 cannot be formed. Of the hoop material 5 and the filler material 6 is deteriorated, and the sealing property is deteriorated.

The thick hoop material 5 as described above is used.
In order to perform winding with a strong pressing force so as to increase the density of the expanded graphite, when the cross-section of the hoop material 5 is formed into a substantially V-shape, the top of the V-shape does not shift from the center of the hoop material 5. Needless to say, a precise forming device is used, and a winding machine designed so that the center of the push piece 8 does not deviate from the center of the gasket is used.

[0017]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

Example 1 Example 1 is a spiral gasket shown in FIGS. 1 and 2 having an inner diameter of 1300 mm, an outer diameter of 1350 mm and a thickness of 6.4 mm. The spiral gasket has an inner diameter of 1200 mm, an outer diameter of 1300 mm and a thickness of 4.
0mm SUS304 inner ring 2 and inner diameter 1350mm,
This is a type with inner and outer rings with an outer ring 4 made of SUS304 having an outer diameter of 1400 mm and a thickness of 4.0 mm.

The method of manufacturing this gasket is as follows. First, a hoop material 5 made of a SUS316 tape-like thin plate having a thickness of 0.30 mm and a width of 8.0 mm is drawn into a substantially V-shape,
As shown in FIG. 3, the hoop material 5 is wound three times while being pressed by the push piece 8, and then the filler material 6 is 0.25 mm thick and 9 mm wide, as shown in FIG.
An expanded graphite tape having a density of 5 mm and a density of 1.0 g / cm ³ is sandwiched therebetween, overlapped with each other, and wound 25 to 35 times. Finally, only the hoop material 5 is air-wound four times. The outer ring 4 is attached and completed. At this time, the density of the expanded graphite tape as the filler material 6 is increased to 1.7 g / cm ³ by being pushed by the push piece 8. However, in FIGS. 1 and 2, the hoop material 5 made of a thin metal plate is used.
The number of turns of the portion where the filler material 6 formed of the expanded graphite tape and the filler material 6 are overlapped and wound is omitted.

Embodiment 2 In Embodiment 2, the density of the expanded graphite tape as the filler material 6 is adjusted to 1.4 g / cm ³ by adjusting the pressing force of the pressing piece 8 in Embodiment 1.

Example 3 In Example 3, the density of the expanded graphite tape as the filler material 6 was adjusted to 2.0 g / cm ³ by adjusting the pressing force of the pressing piece 8 in Example 1.

Embodiment 4 In Embodiment 4, the thickness of the hoop material 5 in Embodiment 1 is set to 0.
It was changed to 20 mm.

Comparative Example 1 In Comparative Example 1, the thickness of the hoop material 5 in Example 1 was set to 0.
The density of the expanded graphite tape as the filler material 6 was set to 1.2 g / cm ³ by changing the pressing force of the push piece 8 to 20 mm.

The results of the sealing test of the spiral gaskets of Examples 1 to 4 and Comparative Example 1 are shown in Table 1 below. However, in the test, as shown in FIG. 7, a spiral gasket 1 as a sample was sandwiched between flanges 9 and 10 having an outer diameter of 1600 mm, and the compressive strength when the gasket was compressed to a thickness of 4.5 mm was measured. Thereafter, a sealing property was evaluated by applying a nitrogen gas of 20 kgf / cm ² G. As shown in FIG. 7, the sealing performance was determined by installing a rubber O-ring 11 on the outer periphery of the flange, collecting gas leakage from the sample, guiding the gas leakage to the water tank 12, and measuring the amount of leakage by water replacement.

[0025]

[Table 1]

When Examples 1 to 4 are compared with Comparative Example 1, all Examples have high compressive strength and remarkably improved sealability. In particular, the hoop material thickness is 0.30 mm and the density of the expanded graphite tape is low. Example 1 and Example 3 with 1.7 g / cm ³ or more did not leak at all.

[0027]

As is apparent from the above description, according to the present invention, the density of the filler material constituting the spiral gasket is 1.4 to 2.5 g / cm ³ and the thickness of the hoop material is 0.1.
By setting the diameter to 25 mm to 0.45 mm, a remarkable effect can be obtained in improving the sealing performance of a large diameter spiral gasket.

[Brief description of the drawings]

FIG. 1 is a plan view of a spiral gasket showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line AA of the gasket.

FIG. 3 is a schematic view of a spiral gasket, a winding die, and a push piece showing a method for manufacturing a large diameter spiral gasket.

FIG. 4 is a plan view of a winding die and a pushing piece.

FIG. 5 is a schematic view of a spiral gasket, a winding die, and a push piece showing a conventional method for manufacturing a small-diameter spiral gasket.

FIG. 6 is a partially cut plan view of a winding die and a pushing piece.

FIG. 7 is a configuration diagram of a test device for a seal test of a spiral gasket.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spiral gasket 2 Inner ring 3 Gasket main body 4 Outer ring 5 Metal hoop material 6 Filler material 7 Winding type 8 Push piece 9 Upper flange 10 Lower flange 11 Rubber O-ring 12 Water tank

Claims (3)

[Claims] A spiral gasket formed by superposing a hoop material of a tape-shaped metal thin plate having a substantially V-shaped cross section and a filler material made of expanded graphite and spirally winding the same, the density of the filler material is reduced. A spiral gasket having a weight of 1.4 to 2.0 g / cm ³ . 2. A spiral gasket comprising a tape-shaped thin metal hoop material having a substantially V-shaped cross section and a filler material made of expanded graphite superposed and spirally wound, wherein the thickness of the hoop material is Is 0.25 to 0.45 mm, and the density of the filler material is 1.4 to 2.0 g / cm ³ . 3. The spiral gasket according to claim 1, wherein an inner diameter of the main body of the gasket is 600 mm or more.