JP2945872B2 - Spiral wound gasket - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to, for example, LNG
The present invention relates to a spiral-wound gasket that seals between flange portions of a pipeline that circulates (liquefied natural gas) and other gases and liquids.

[0002]

2. Description of the Related Art Conventionally, as the spiral wound gasket of the above-mentioned example, there is, for example, one having a structure shown in FIG. In other words, the hoop member 32a and filler material on the outer peripheral side of the inner ring 31 32 b
Is spirally wound to form a gasket body 33,
An outer ring 34 is arranged on the outer peripheral side of the gasket main body 33. The spiral-wound gasket 35 thus configured
Is used by being interposed between the flange portions 37 and 38 of the pipeline 36 that circulates LNG (liquefied natural gas) and other gases and liquids.

The above-mentioned flange portions 37 and 38 are generally made of a metal material such as carbon steel, stainless steel, aluminum, or aluminum alloy. The above-mentioned hoop material 32a is sometimes made of aluminum tape or the like, but stainless steel is mainly used. , above filler material 32 b is asbestos, graphite, PTF
E, inorganic paper, or the like is used, and the above-mentioned inner and outer rings 31, 34 are generally made of a metal material such as carbon steel or stainless steel.

The above-mentioned flange portions 37 and 38 and the hoop material 32a (metal tape) are not always made of the same material due to economy and difficulty in obtaining the material. The flanges 37 and 38 and the hoop 3
When 2a is composed of a dissimilar metal, a contact potential difference occurs due to contact between dissimilar metals during use.

The term "contact potential difference" as used herein refers to an interface potential difference generated when different kinds of metals are brought into contact with each other. Is recognized as a potential difference (voltaic potential difference) that occurs at

In addition, the outer ring 34 and the flange 3
The gap g exists between the facing surfaces of the 7, 38, battery rainwater collected in the gap g, seawater, electrolytes such as water droplets entering the bimetallic site above result, the contact potential difference between the electrolyte And there is a problem that the flange portions 37, 38 or the spiral gasket 35 are locally corroded by the flow of electric current. In particular, flange portions 37 and 38 having a raised face (stepped surface) as shown in FIG.
In the case of the above, such a problem was remarkable.

[0007]

According to the first aspect of the present invention, an insulating soft member is provided so as to fill a gap between an outer ring located on the atmosphere side and a facing surface of a member to be sealed (a flange portion or the like). By arranging the above, eliminating the above gap,
Rainwater, seawater, preventing the penetration and retention of electrolytes such as water droplets, and by using an electrically insulating member as a soft member,
An object of the present invention is to provide a spiral wound gasket capable of preventing formation of a battery and preventing corrosion of a member to be sealed or a gasket.

According to a second aspect of the present invention, in addition to the object of the first aspect, a PTFE solid body, a porous PTFE, a solid rubber, a sponge rubber or a rubber sealant is used as the insulating soft member. An object of the present invention is to provide a spiral-wound gasket capable of reliably preventing the intrusion of the electrolyte while effectively utilizing an existing material and improving sealing performance.

[0009]

According to a first aspect of the present invention, there is provided a spiral wound gasket having an outer ring on an outer periphery of a gasket main body and interposed between members to be sealed to seal between the members to be sealed. a is, on both sides of the outer ring, the outer ring and the spiral wound gasket insulation soft member Ru fills a gap is disposed between the facing surfaces of the sealing member.

According to a second aspect of the present invention, in addition to the configuration of the first aspect of the present invention, the insulating soft member is made of PTFE solid body, porous PTFE, solid rubber,
Spiral wound gasket set in sponge rubber or rubber sealant.

[0011]

According to the first aspect of the present invention, both outer surfaces of the outer ring located on the atmosphere side are provided with the outer ring.
Since the insulation soft member Ru fill the gap between the surface and the facing surface of the sealing member is disposed, this eliminates the aforementioned gap by insulating soft member, rainwater, seawater, an electrolyte, such as water droplets entering the residence In addition, since the electrically insulating member is used as the soft member, the battery is prevented from being formed due to the contact potential difference, and the sealed member such as the flange portion or the vortex is prevented. There is an effect that the wound gasket itself can be prevented from being corroded.

According to the second aspect of the present invention,
In addition to the effect of the first aspect of the present invention, the above-mentioned insulating soft member is set to PTFE solid body, porous PTFE, solid rubber, sponge rubber or rubber sealant. This has the effect of reliably preventing intrusion of the electrolyte and improving the sealing performance. That is, since each of the above-mentioned materials is softer than the gasket main body and has electrical insulation properties, and has an appropriate density and elasticity inherent to the material, a member to be sealed such as a flange portion due to a change in the ambient temperature. Although the above-mentioned gap also fluctuates when is thermally expanded and contracted, the gap can be satisfactorily followed to fill the gap and the sealing performance is improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. The drawing shows a spiral-wound gasket. The spiral-wound gasket 1 constitutes a gasket body 4 by winding a hoop material 3a and a filler material 3b around the outer periphery of an inner ring 2 in a spiral manner. The outer ring 5 is arranged on the side, and this spiral wound gasket 1 is LNG
(Liquefied natural gas) and other gasses and liquids, and is arranged between flange portions 7 and 8 (members to be sealed) of a conduit 6 for use.

[0014] Here, between the raised de face portion of the opposite surfaces of the flange portions 7 and 8 of the both side surface and the sealing member of the outer ring 5 located on the atmosphere side, specifically from the outer diameter portion of the gasket body 4 The gap (specifically, a gap with a thickness of about 1 mm) between the raised face part and the outer diameter part
Insulating soft members 9 (filling members) are arranged on both side surfaces of the outer ring 5 so as to fill the gap. As the above-mentioned insulating soft member 9, PTFE solid body, porous PTFE, solid rubber,
Sponge rubber or rubber sealant can be used.

In the case of using a porous PTFE tape made of 100% PTFE among the above-mentioned materials, a tape having a density of 0.4 to 0.8 g / cm 3 is selected, and a predetermined portion of the outer ring 5 is provided on a predetermined portion of the outer ring 5, for example, on both sides. Fix with fixing means such as tape. When a PTFE solid body is used, its density is 2.
1 to 2.2 g / cm3 is selected and fixed to a predetermined portion of the outer ring 5 by a fixing means such as a double-sided tape.

That is, when a PTFE-based material is used as the insulating soft member 9, the density is set in the range of 0.4 to 2.2 g / cm3. Further, when solid rubber (silicon rubber or the like) is used among the above-mentioned materials, the density of the rubber is set to 0.1.
A material having a weight of 91 to 1.8 g / cm3 is selected and fixed to a predetermined portion of the outer ring 5 by a fixing means such as a double-sided tape.

When a sponge rubber (such as a sponge rubber tape made of silicone rubber) is used, a sponge rubber having a density of 0.55 to 0.83 g / cm3 is selected. Fix with fixing means.
That is, when a rubber-based material is used as the insulating soft member 9, the density is set in the range of 0.5 to 1.8 g / cm3.

On the other hand, when a rubber sealant is used as the above-mentioned insulating soft member 9, for example, a silicone sealant is applied to a predetermined portion of the outer ring 5, and left to be cured, and after the curing, the spiral wound gasket 1 is attached to the flange portion. It is interposed between 7 and 8. The above-mentioned materials are used for the flange portions 7 and 8, the hoop material 3 a, the filler material 3 b, and the inner and outer rings 2 and 5.

That is, the flange portions 7 and 8 are made of a metal material such as carbon steel, stainless steel, aluminum and an aluminum alloy, the above-mentioned hoop material 3a is mainly made of stainless steel, and the above-mentioned inner ring 2 and outer ring 5 are made of the filler material 3b. It is made of a metal material such as carbon steel, stainless steel, aluminum, and aluminum alloy. In FIG. 1, reference numerals 10 and 11 denote bolts and nuts as fastening members used to fasten the flange portions 7 and 8.

As described above, the above-mentioned insulating soft member 9 is arranged so as to fill the gap when the gasket is tightened between the outer ring 5 located on the atmosphere side and the facing surfaces of the flange portions 7 and 8 as the members to be sealed. Since the insulating soft member 9 eliminates the above-mentioned gaps, it is possible to prevent the electrolyte such as rainwater, seawater, and water droplets from entering and staying therein. Since the battery is used, the formation of a battery due to the contact potential difference is prevented, and the sealed member such as the flange portions 7 and 8 or the spiral wound gasket 1
This has the effect of preventing the corrosion of itself. Note that LNG and other fluids flowing through the pipeline 6 are sealed on the inner ring 2 side.

Further, since the above-mentioned insulating soft member 9 is made of PTFE solid body, porous PTFE, solid rubber, sponge rubber or rubber sealant, the above-mentioned electrolyte is surely prevented from invading while effectively utilizing existing materials. Thus, there is an effect that the sealing performance can be improved.
That is, each of the above-mentioned materials is softer than the gasket main body 4 and has electrical insulation properties, and also has appropriate density and elasticity inherent to the material. When the member to be sealed thermally expands and contracts, the above-mentioned gap also fluctuates. However, the gap can be filled by following the gap fluctuation satisfactorily, thereby improving the sealing performance. Here, the above-mentioned insulating soft member 9 is desirably a porous or sponge-like material such as a porous PTFE tape because of its elasticity and the like.

FIG. 2 shows another embodiment of the spiral-wound gasket. In the previous embodiment shown in FIG. 1, a spiral-wound gasket provided between the raised face type flanges 7 and 8 is used. As shown, the embodiment of FIG. 2 shows a spiral wound gasket interposed between flat face type flange portions 7 and 8.

In this case, as shown in the figure, insulating soft members 9 are fixedly arranged so as to cover the entire upper and lower surfaces of the outer ring 5. Even with such a configuration, the same operation and effect as in the previous embodiment are achieved, such as eliminating the gap at the time of tightening the gasket and achieving both prevention of intrusion / retention of the electrolyte and prevention of battery formation. In FIG. 2, the same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In correspondence between the structure of the present invention and the above-described embodiment, the member to be sealed according to the present invention has flange portions 7 and 8.
However, the present invention is not limited to the configuration of the above-described embodiment.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a spiral wound gasket of the present invention interposed between raised face type flange portions.

FIG. 2 is a sectional view showing a state in which a spiral wound gasket of the present invention is interposed between flat face type flange portions.

FIG. 3 is a cross-sectional view showing a usage state of a conventional spiral wound gasket.

[Explanation of symbols]

 4: Gasket body 5: Outer ring 7, 8: Flange 9: Soft insulating member

Continuation of the front page (56) References JP-A-8-210569 (JP, A) JP 4-32553 (JP, Y2) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16L 23 / 02 F16L 19/04

Claims (2)

(57) [Claims] 1. A has a outer ring on the outer periphery of the gasket body, a spiral wound gasket for sealing between the sealing member is interposed between the sealing member, on both sides of the outer ring, the and the outer ring spiral wound gaskets insulation soft member Ru fills a gap is disposed between the facing surfaces of the sealing member. 2. The soft insulating member is a PTFE solid body,
The spiral wound gasket according to claim 1, wherein the spiral wound gasket is set to porous PTFE, solid rubber, sponge rubber or rubber sealant.