Spiral Wound gaskets
General guide to spiral wound gaskets
Used in very high pressure applications or in very corrosive or high temperature environments such as pipelines in the chemical and petroleum industries.
Construction of the sealing part of the gasket is a strip of high grade metal, commonly stainless steel, wound in a spiral. (known as the winding).
This spiral (or winding) is wound together with a "filler" strip such as, PTFE, Graphite, or a non-asbestos jointing depending on the application. Graphite is a good general purpose choice.
The spiral can have inner or outer guide rings to assist in location or to increase performance. These guide rings can be of several metals but the standard is Carbon Steel zinc plated and passivated.
The winding material, filler material, guide ring material and the guide ring configuration can all be varied to fit the application.
The winding is generally 4.5mm thick compressing to about 3mm with the guide rings at 3mm thickness.
A frequently specified configuration is:
Spiral winding of stainless steel
Filler of graphite
Outer guide ring in carbon steel zinc plated
Note: Graphite is not suitable for operation above about 440 centigrade in the presence of oxygen.
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