Seals & Sealing Engineers [I] offers Polytetrafluoroethylene Lined Pipes and Fittings. Seals & Sealing Engineers [I] supplies a wide range of mechanical seals and sealing systems. The Polytetrafluoroethylene Lined Pipes and Fittings find applications in chemical process industries where highly corrosive materials are used, product purity is critical, environmental pollution is to be avoided and pipe replacement is difficult or impossible.