Polytetrafluoroethylene (PTFE) is a synthetic tetrafluo […]
Polytetrafluoroethylene (PTFE) is a synthetic tetrafluoroethylene fluoropolymer used in a wide variety of applications. It is also known by the generic trade name Teflon. PTFE can be optimized as a gasket material with good chemical resistance. Teflon seals are located inside the flange bolts and along the pipe holes. It sits on the convex side with a convex design. This design requires less material and less cutting, can be assembled without completely disassembling the joint (making it a "plug-in" gasket), but is also more difficult to clamp into place. When determining an annular gasket, only three measurements are required: ID (corresponding to the tube bore), OD (same as the OD of the convex surface), and gasket thickness.
While some elastomers can survive short-term or intermittent use, deterioration over time can cause problems years later, while PTFE's electrical resistance properties remain limitless. Teflon seals do not degrade over time and are not affected by UV light, so ageing controls are generally not required. PTFE ring gaskets have a temperature range of -325°F to +500°F, which is also well beyond the range of most elastomers. Applications in low or high temperature environments such as ovens or combustion processes may also preclude any elastomeric compounds, again making PTFE the best choice. Extremely low temperatures cause most rubber compounds to harden to the point where no elastomeric properties are present in the material anymore. This combined with shrinkage of Ptfe Ball the material may mean it will no longer be effective as a seal. On the other hand, PTFE ring gaskets retain their flex and flexibility even at low temperatures.