JPS6037507Y2 - gasket - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a sealing gasket for use in flanges and joints of transport pipes for liquefied natural gas, which is flammable, explosive, and has an ultra-low temperature.

Conventionally, in equipment that handles flammable and explosive hazardous fluids, static electricity generated can often cause disasters such as fires and explosions, so piping and storage equipment used for transporting and storing hazardous fluids have been In equipment, the generation of static electricity is prevented and, at the same time, the generated static electricity is released to the ground through bonding, while insulating flange joints are often provided at key points of transportation pipes or equipment.

These insulating flange joints were required to have perfect sealing properties in order to handle hazardous fluids.

Generally, asbestos joint seals, which have excellent insulation properties and good sealing properties, are widely used as gaskets for insulating flange joints in such cases.

However, it is difficult to completely seal special fluids such as liquefied natural gas with asbestos joint sheets due to their physical properties, various physical phenomena caused by extremely low temperatures, and the need for large-diameter transport pipes. For this reason, there has been a recent trend toward using graphite sheets that have excellent sealing properties.

However, graphite sheets had the drawback of very poor insulation properties.

The present invention was provided to solve these problems, and is a gasket that combines an asbestos joint sheet and a graphite sheet as a gasket for insulating hazardous fluids that have difficult conditions, such as liquefied natural gas. This effectively satisfies both insulation and sealing properties at the same time.

The present invention will be explained based on the drawings.

FIG. 1 shows an outline of the gasket, and FIG. 2 shows the gasket of the present invention used in a flange joint.

1 is a ring-shaped gasket body, 2 is a ring-shaped thin metal plate, 3 is a ring-shaped graphite sheet, 4 is a bolt hole, and 5
is an asbestos sheet.

Further, 6 is a flange, 7 is a bolt whose surface is covered with an insulating material, 8 is an insulating washer, and 9 is a nut.

That is, the gasket body 1 of the present invention has a ring-shaped thin metal plate 3 surrounded by two ring-shaped asbestos joint sheets 5, and a ring-shaped graphite sheet 2 on the surface of the asbestos joint sheets 5. It is attached with adhesive.

Since the present invention has such a structure, static electricity insulation is provided by the asbestos joint sheet 5, fluid sealing is provided by the graphite sheet 2 and asbestos joint sheet 5, and rigidity is provided by the thin metal plate 3. It is something that

The thin metal plate 3 is used to provide rigidity to the gasket body 1 and facilitate handling, and is preferably made of stainless steel or aluminum alloy steel. Both ends of the thin metal plate 3 are made of asbestos joint sheet 5. It is best to configure it so that it is not exposed.

When the thin metal plate 2 is exposed from the asbestos joint sheet 5, foreign matter adhering to the thin metal plate 3 may cause the insulation to be lost when it comes into contact with the flange 6.

In addition, the thickness of the graphite sheet 2 is preferably about 0.25 to 0.4 mm, and its width is narrower than the sealing surface width of the flange 6 so that the sealing surface force of the flange 6 does not protrude. This prevents the graphite sheet 2 from leaking from the sealing surface of the flange 6.

In addition, by carefully treating the end surface of the asbestos joint sheet 5 in contact with the liquid with epoxy adhesive or gasket paste, leakage of fluid in the pipe (for example, liquefied natural gas) from the end surface of the gasket body 1 can be prevented. At the same time, by sizing the asbestos joint sheet 5 to the outer periphery of the flange 6, damage to the insulation due to foreign matter entering between the surfaces of the flange 6 is eliminated.

The above has described the case of an insulating gasket used for liquefied natural gas transport pipes or equipment, but this insulating gasket is suitable for transporting hazardous fluids such as liquefied natural gas or other equipment.
This is not limited to preventing disasters caused by static electricity in storage equipment.
When used for so-called galvanic corrosion protection to insulate corrosive currents caused by potential differences between dissimilar metals, for preventing electrical leakage from machinery and equipment, when it is necessary to satisfy both sealing properties and insulation properties, and even when sealing properties only are required. It has many effects, such as being able to be used even when the requirements are met.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view of the present invention, and FIG. 2 is a longitudinal sectional front view showing the present invention in use. 1...Gasket body, 2...Graphite sheet, 3...Thin metal plate, 5...Asbestos joint sheet, 6... flange,
7... Covered bolt, 8... Insulating washer.

Claims (1)

[Scope of utility model registration request] A gasket characterized in that an asbestos sheet is adhered to both sides of a thin metal plate, a graphite sheet is further adhered to both surfaces, and a penetration prevention treatment is applied to the end face on the fluid contact side.