JPH0972425A - Spiral wound gasket and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To improve the sealing property of a spiral wound gasket. SOLUTION: A gasket body 1 is formed by stacking a hoop 2 of a tape-shaped thin metal plate and a filler 3 and forming a spiral winding. The filler 3 protrudes from the hoop 2, and the protrusion amount A is 0.10 mm to 0.50 mm.
Within the range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape-shaped metal corrugated thin plate (hereinafter referred to as a hoop), which is used for a joint portion of high-temperature and high-pressure equipment and pipes, for the purpose of sealing fluids such as water, oil, steam and gas. And a tape-shaped filler (hereinafter abbreviated as filler) such as asbestos or expanded graphite, which are wound in a spiral shape a plurality of times in a state of being overlapped with each other, and a manufacturing method thereof Is.

[0002]

2. Description of the Related Art In a spiral wound gasket, a tape-shaped metal hoop previously formed in a substantially V shape and a filler such as an asbestos tape are sandwiched and wound by superposing each other. Note that the filler is generally wider than the hoop width so as not to damage the flange to be sealed by the hoop, and the structure is such that the filler protrudes from the hoop.

The one in which a hoop and a filler are sandwiched and wound only by overlapping each other is referred to as a basic form of a spiral wound gasket, and other than that, it is made of a metal for preventing the gasket body from being deformed inward by tightening pressure. With an inner ring with a reinforcing ring attached to the inside of the gasket body, with an outer ring with a metallic reinforcing ring attached to the outside of the gasket body for the purpose of preventing deformation and centering to the outside of the gasket body, with inner and outer rings, etc. Various types referred to are known and are generally widely used as high-temperature and high-pressure gaskets.

As a type of filler, asbestos tape obtained by slitting asbestos paper into strips is generally used.
For applications requiring corrosion resistance such as acid and alkali, unbaked P
TFE tape was used, but asbestos fiber is a natural mineral, and there is concern about resource depletion, and health problems that are presumed to be due to asbestos fiber have become a social problem, and asbestos is used worldwide. Since there is a tendency to be restricted, non-asbestos paper mainly made of inorganic fibers other than asbestos (hereinafter referred to as NA tape) has been used. In addition, expanded graphite tapes (Graseal tapes, hereinafter abbreviated as GR tapes) having both flexibility and elasticity are used as fillers for applications requiring extremely low temperature conditions or particularly high sealing properties.

[0005]

As is well known, this spiral wound gasket has a structure in which a substantially V-shaped metal hoop and a filler having a cushioning property are alternately superposed and wound, so that they are elastic. It is considered to be one of the ideal gaskets because it has excellent sealing property because it is rich in heat and can cope with expansion and contraction due to heat. In particular, the one using GR tape as the filler has good compatibility with the flange to be sealed and can reduce the leakage from the contact surface. Known as an excellent gasket.

However, even in the conventional spiral wound gasket using such a GR tape as a filler, the gas cannot be completely sealed. On the other hand, nitrogen gas or the like is used in the completion inspection of the plant or the like. In many cases, leaks occurred and sometimes became a problem.

For this reason, a method of applying an organic binder or the like on the entire surface or a part of the filler or a method of using an auxiliary filler has been proposed to improve the sealing property.
There is concern about the sealability at high temperatures when using organic substances,
Further, the method using the auxiliary filler has a problem that the productivity is remarkably reduced. In addition to this, recently, as represented by the American Air Purification Act (CAA), there is a movement to regulate even a minute amount of leakage as a part of environmental problems, and a spiral wound gasket with good sealing properties. Is needed.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a spiral wound gasket which has a good sealing property and is inexpensive.

[0009]

In order to achieve the above-mentioned object, the invention of claim 1 forms a spiral shape by superposing a hoop of a tape-shaped thin metal plate and a filler and allowing the filler to protrude from the hoop. In the spiral wound gasket formed by winding, the gist is that the amount of the filler protruding from the hoop is in the range of 0.10 mm to 0.50 mm.

A second aspect of the present invention is characterized in that, in the spiral wound gasket of the first aspect, the filler is formed of expanded graphite tape.

Further, in the method of manufacturing a spiral wound gasket according to the invention of claim 3, a hoop of a tape-shaped thin metal plate and a filler having a width slightly larger than the width of the hoop are superposed by a predetermined winding die. It is wound in a spiral form and the amount of protrusion from the hoop of the filler is 0.10 mm by sandwiching the hoop and filler with a pair of side plates during this winding.
The main idea is to cut it within the range of 0.50 mm.

Here, presuming the mechanism of maintaining the sealing property of the spiral wound gasket having the above-mentioned characteristics, the conventional spiral wound gasket has a hoop flange due to the filler protruding from the hoop. The filler's cushioning property fills the gaps in the contact surface due to scratches and bending of the flange, and prevents leakage from the contact surface of the flange. However, the amount of filler protruding from this hoop was not specified.

As a result of intensive studies, the present inventors have found that if the amount of the filler protruding from the hoop is small and not sufficient, leakage from the contact surface cannot be completely prevented, and the filler does not protrude. If too large an amount is used, leakage from the contact surface at room temperature can be prevented, but when used in an environment that deteriorates the filler material such as heating, the expanded graphite and organic substances in the filler that have protruded will deteriorate and disappear, tightening the gasket. It was found that the pressure was lowered and the leakage from the contact surface could not be prevented, and the sealing property was deteriorated, and the present invention has reached the present invention in which the range of the amount of the filler protruding from the optimum hoop for improving the sealing property is clarified.

It has been confirmed that the sealing property is best when the protrusion amount of the filler protruding from the hoop is 0.10 mm to 0.50 mm, and the sealing property is inferior regardless of whether the protrusion amount of the filler is large or small. Was done.

[0015]

1 and 2, a spiral wound gasket 1 is a tape-shaped metal corrugated thin plate hoop 2 and a filler 3 as shown in FIGS. It is composed by stacking and and forming a spiral winding. The filler 3 is made of, for example, an expanded graphite tape and slightly protrudes from the hoop 2, and the protrusion amount A
Is in the range of 0.10 mm to 0.50 mm.

As an embodiment of the invention of claim 3, a method of manufacturing a spiral wound gasket as shown in FIG. 3 is proposed. That is, the hoop 2 of the tape-shaped thin metal plate is wound by the winding form 6.
Then, the filler 3 having a width slightly larger than the width of the hoop is overlapped and wound into a spiral shape. During this winding, the hoop 2 and the filler 3 are sandwiched by the pair of side plates 7a and 7b so that the protrusion amount A of the filler 3 from the hoop 2 is 0.
Grind so that it is within the range of 10 mm to 0.50 mm.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention shown in the drawings will be described below. Embodiment 1 FIG. 1 is an embodiment of a spiral wound gasket 1 according to the present invention, and shows a transverse sectional view of the left half thereof. FIG. 2 is an enlarged view of a part B thereof. In the figure, 2 is a tape-shaped thin metal plate hoop, which is drawn into a substantially V shape. Reference numeral 3 denotes a filler, which is made of, for example, expanded graphite tape, and is overlapped with the hoop 2 and wound in a spiral shape to form the gasket 1. Amount A of the filler 3 protruding from the hoop 2 is 0.2
4 mm. In addition, 4 is an inner ring and 5 is an outer ring. Example 2 The amount A of protrusion of the filler 3 from the hoop 2 is 0.12 mm.
It is. Example 3 The amount A of protrusion of the filler 3 from the hoop 2 is 0.48 mm.
It is.

Comparative Example 1 Comparative Example 1 is a spiral wound gasket manufactured in substantially the same manner as in Example 1 and the amount of protrusion of the filler is 0.06 mm. Comparative Example 2 Comparative Example 2 is a spiral wound gasket manufactured in substantially the same manner as in Example 1, and the amount of protrusion of the filler is 0.60 mm.

The results of the sealing properties of Examples 1 to 3 and Comparative Examples 1 and 2 are shown in Table 1. However, in order to measure the sealing property,
Using the actual 100A, RF flange, the gaskets of Examples 1 to 3 and Comparative Examples 1 and 2 were attached thereto, and the temperature was kept at room temperature and 5
H after heating at 00 ℃ for 5 hours and cooling to room temperature
The leakage from each gasket for 1 hour when e-gas of 42.0 kgf / cm ² G was applied was indicated by the amount of gas collected by the water displacement method.

[0020]

[Table 1]

From Table 1, it can be seen that the leakage amount of Comparative Example 1 is larger than that of each Example at room temperature and after heating. Further, in Comparative Example 2, the sealing property at room temperature is as good as that of the Example, but it is also found that the sealing property after heating is poor.

FIGS. 3 and 4 show an embodiment of a method for manufacturing a spiral wound gasket according to the present invention. In the figure, 6 is a rotatable winding die, and 7a and 7b are a pair of side plates. First,
After a tape-shaped metal (for example, SUS304) thin plate is drawn into the winding form 6 into a substantially V shape, it is set as shown in the drawing, and only the hoop material 2 is wound around once and then spot welded. After that, the coil tape is continuously wound around for two rounds, and the GR tape filler is sandwiched between them, and wound for 15 to 17 rounds. Then, only the hoop material is wound around for three rounds and spot-welded again. At this time, the protrusion amount of the filler 3 protruding from the hoop 2 is, for example, 0.2
Since the widths of the hoop 2 and the filler 3 are set so as to be 4 mm, the side plates 7a and 7b are wound so that the hoop 2 and the filler 3 are sandwiched so as not to shift during winding. As a result, the filler 3 is scraped by the side plates 7a and 7b, and the protrusion amount of the filler can be adjusted with high accuracy. It seems that in order to get the filler out of the hoop, the width of the filler only needs to be larger than the width of the hoop.
The amount of protrusion is only adjusted by the width of the hoop and the filler, and the amount of protrusion is 0.10 mm to 0.
It could not be adjusted to the range of 50 mm.

FIG. 5 shows the overall structure of the gasket body 1 manufactured by the method of the present invention.

[0024]

As described above, according to the present invention, the protrusion amount of the filler from the hoop is 0.10 mm to 0.5.
By setting the thickness within the range of 0 mm, it is possible to provide an inexpensive spiral wound gasket having the best sealing property.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged view of a portion in which a filler is sandwiched between the hoops of the embodiment of FIG.

FIG. 3 is a schematic diagram showing the method of the present invention.

FIG. 4 is a partial schematic view showing the method of the present invention.

FIG. 5 is a plan view of a gasket according to the present invention.

[Explanation of symbols]

 1 Whirlpool type gasket 2 Hoop 3 Filler 4 Inner ring 5 Outer ring A Amount of filler protruding from hoop 6 Rolling type 7a, 7b Side plate

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[Procedure amendment]

[Submission date] February 2, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 3

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction contents]

[0002]

2. Description of the Related Art In a spiral wound gasket, a tape-shaped metal hoop previously formed in a substantially V shape and a filler such as an asbestos tape are sandwiched and wound by superposing each other. Incidentally, the width of the filler so as not to damage the flanges to be sealed hoop wider than the width of the hoop, the filler is in the protruded structure from the FOUP is common.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

Further, in the method of manufacturing a spiral wound gasket according to the invention of claim 3, a hoop of a tape-shaped thin metal plate and a filler having a width slightly larger than the width of the hoop are superposed by a predetermined winding die. The roll is wound into a spiral shape, and the amount of protrusion of the filler from the hoop is 0.10 by sandwiching the hoop and the filler with a pair of side plates during the winding.
The gist is to cut so as to be in the range of 0.5 mm to 0.50 mm.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

Comparative Example 1 Comparative Example 1 is a spiral wound gasket manufactured in substantially the same manner as in Example 1, and the amount of protrusion A of the filler is 0.06 mm. Comparative Example 2 Comparative Example 2 is a spiral wound gasket manufactured in substantially the same manner as in Example 1, and the protrusion amount A of the filler is 0.60 mm.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction contents]

From Table 1, it can be seen that the leakage amount of Comparative Example 1 is larger than that of each Example at room temperature and after heating. Further, in Comparative Example 2, the sealing property at room temperature is as good as that of the Example, but it is also found that the sealing property after heating is poor.

Claims (3)

[Claims] 1. A spiral wound gasket formed by superposing a hoop of a thin metal plate in the form of a tape and a filler and forming a spiral wound so that the filler protrudes from the hoop. A protrusion of the filler protruding from the hoop. A spiral wound gasket characterized in that the amount is in the range of 0.10 mm to 0.50 mm. 2. The spiral wound gasket according to claim 1, wherein the filler is formed of expanded graphite tape. 3. A hoop of a tape-shaped thin metal plate and a filler having a width slightly larger than the width of the hoop are overlapped by a predetermined winding form to form a spiral form, and at the time of forming the form, By sandwiching the hoop and filler with a pair of side plates, the amount of protrusion from the filler hoop is 0.10 mm.
A method of manufacturing a spiral wound gasket, characterized in that it is ground to a range of 0.50 mm to 0.50 mm.