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Description
Supagraf® Furnasele gasket comprises a solid metal support ring with a relatively thick layer of Supagraf® expanded graphite bonded (and often mechanically fixed) to each face.
The support ring allows the the graphite sealing faces to be positioned accurately on large vertical flanges. Without the support ring, large gaskets of regular graphite sheet would have to be supplied and transported in segments, leading to on-site handling and installation problems.
The graphite layers of Supagraf® Furnasele are thicker than those used on some other semi-metallic gaskets. Thicker graphite enables the gaskets to seal when lightly loaded and/or when applied to uneven or distorted flanges.
Typical applications
Supagraf® Furnasele was initially developed to solve sealing problems on blast furnace ducts with warped flanges. Long-term reliability and sealing performance has made it a standard fitment at many metallugical plants. It also solves flange sealing problems in other industries when a large conformable one-piece gasket is needed for medium or high temperatures duties - especially on vertical flanges.
Gasket design features
Each Supagraf® Furnasele gasket is custom-designed to suit the specific application. In general, two thickness variants cover most applications:
Alternative thickness combinations are available to suit operating conditions as required.
Gaskets can be designed to fit inside the bolt circle, or have full-face profiles with bolt holes, or a slot-leg configuration to assist location on the bolts where these are outboard of the raised-face region of the flange. Face widths can be almost any dimension to suit a specific duty, but are usually in the region of 40mm to 50mm on gaskets of 500mm to 2m diameter that fit within the bolt circle.
Graphite layers are factory-bonded to the metal ring using a special non-volatile adhesive. When the gaskets are to be fitted on hot flanges, specially developed clips are used to retain the the graphite layers in position on the metal ring in case the adhesive softens during installation.
Paddle-type handles, lifting lugs or eyes can be fitted on request to simplify gasket handling.
Materials of construction
Graphite layers
Metal support ring
Refractory gasket
On particularly hot flanges, an additional inner gasket of refractory material can be supplied as a thermal barrier to prevent oxidation of the graphite by hot gases. This is unnecessary on many metallurgical applications where large valves are watercooled and, with refractory lining of the pipe, the temperature at the graphite is substantially lower than the main process temperature.
How supplied
Circular and non-circular gaskets of virtually any size are custom-designed and manufactured to suit specific requirements.
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