Coated Spiral Wound Gaskets
The spiral wound gaskets are used to replace the plastic gaskets (asbestos-free or graphite) when their limits of application are exceeded.
This gasket are manufactured by winding of metallic strip, preformed V, alternated with inorganic fillers, can be made on specific standards (ASME, API, UNI EN) or customer's design.
There are many materials used for gasket manufacturing, starting from common stainless steel (AISI 316/304) up to the alloys of nickel or titanium, while the fillers used are standard based on expanded pure graphite or PTFE.
In order to improve the seal they can be coated with a softer material, usually graphite.
Another characteristic of these seals is the presence of containment and/or centering ring with standardthickness of 3.2 mm which are defined as follows:
- Inner Ring, Usually made of the same metal material of the spiral; has the function of preventing the radial deformation of the seal and to protect the internal spirals from any turbulence and erosion by the fluid contained.
- Outer/centering Ring standard gasket are manufactured in carbon steel material with anticorrosive treatment (tropicalization). Its function is to center the gasket during the assembly phase and protect the gasket from excessive compression