Greene, Tweed recommends that back-up systems be used for pressures above 1,500 psi, dependent on temperature, extrusion gaps and surfaces finish. Anti-extrusion rings can be supplied in a wide variety of standard or special designs. Standard materials held in stock are listed below.
A high-strength, 482°F (250°C) thermoplastic capable of withstanding steam and the aggressive conditions found downhole, Arlon resists virtually all organic and aqueous chemicals over a wide temperature range, with the exception of concentrated inorganic acids at high temperature. Arlon is highly wear resistant and tough while retaining its mechanical properties over a wide temperature range to 482°F (250°C). Greene, Tweed supplies virgin grade Arlon and grades reinforced with glass, carbon fiber and TFE. Greene, Tweed has back-up systems working at up to 40,000 psi or more with its GT Seal configuration.
Chemically inert at elevated temperatures and pressures, reinforced TFE has outstanding resistance to nearly all oilfield environments. Temperatures from -450°F to 600°F (-268°C to 315°C) can be achieved; however, TFE has only fair resistance to deformation under load. Greene, Tweed utilizes fillers such as graphite or glass fiber to improve TFE’s resistance to cold flow.