Flexible graphite is used as a sealing material. Compared with traditional sealing materials (such as asbestos, rubber, cellulose and its composite materials), flexible graphite has a wide available temperature range, the available range in the air is -200℃-450℃, in a vacuum or reducing atmosphere can reach 3000℃, and the coefficient of thermal expansion is small, at low temperatures do not brittle, do not burst, at high temperatures do not soften, do not creep, so it is dubbed "sealing king. At present, it has been widely used in petrochemical, machinery, metallurgy, atomic energy and other industries.
According to its use, flexible graphite sealing materials are mainly divided into two categories: one is used for sealing fillers on various pumps, valves and reactors; The other is the graphite gasket for various pipe flanges.
① Sealing packing
Sealing packing is the expanded graphite strip cut into the appropriate width and length wound in different specifications of metal molds, directly formed in the press of the pre-formed packing, suitable for a variety of globe valves, gate valves, regulating valves, ball valves, valves and so on.
② Sealing gasket
Usually can be divided into two kinds, one is pure graphite gasket, which is directly pressed with expanded graphite particles in the metal mold, and can also be directly blanked or cut by expanded graphite sheet; The other is the graphite winding pad, which is made of metal tape and expanded graphite overlapping and rolled, and can be used at higher pressures.
③ Graphite packing
Graphite packing is a sealing material made of cotton fiber or graphite fiber woven with graphite roll foil. The graphite coil with cotton fiber as the core (SPM type) is suitable for the sealing of pipelines, valves, machines and pumps with a pressure of 12MPa and a temperature below 200℃. The contact medium can be river water, tap water, groundwater, seawater, oil, etc. Graphite fiber as the core of the graphite disc (SPS type) is suitable for pressure 12MPa, temperature 350℃ below the pipe, valve, pump and other sealing, contact media in addition to a variety of water, oil, but also can contact acid and alkali substances.
According to its use, flexible graphite sealing materials are mainly divided into two categories: one is used for sealing fillers on various pumps, valves and reactors; The other is the graphite gasket for various pipe flanges.
① Sealing packing
Sealing packing is the expanded graphite strip cut into the appropriate width and length wound in different specifications of metal molds, directly formed in the press of the pre-formed packing, suitable for a variety of globe valves, gate valves, regulating valves, ball valves, valves and so on.
② Sealing gasket
Usually can be divided into two kinds, one is pure graphite gasket, which is directly pressed with expanded graphite particles in the metal mold, and can also be directly blanked or cut by expanded graphite sheet; The other is the graphite winding pad, which is made of metal tape and expanded graphite overlapping and rolled, and can be used at higher pressures.
③ Graphite packing
Graphite packing is a sealing material made of cotton fiber or graphite fiber woven with graphite roll foil. The graphite coil with cotton fiber as the core (SPM type) is suitable for the sealing of pipelines, valves, machines and pumps with a pressure of 12MPa and a temperature below 200℃. The contact medium can be river water, tap water, groundwater, seawater, oil, etc. Graphite fiber as the core of the graphite disc (SPS type) is suitable for pressure 12MPa, temperature 350℃ below the pipe, valve, pump and other sealing, contact media in addition to a variety of water, oil, but also can contact acid and alkali substances.