A New Low Stress to Seal Conformable ePTFE Gasket Tape for Large Diameter Glass Lined Steel Equipment

Glass lined steel (GLS) vessels and piping is widely used in the chemical industry primarily for processing harsh chemicals at elevated temperatures. GLS flanges have delicate surfaces that can be easily damaged by too much bolt force, yet the connection must provide a tight seal to minimize leakage of the harsh and often dangerous chemicals. This application provides a unique sealing challenge as gaskets must be chemically and thermally resistant, seal at low loads, and accommodate the rounded and wavy nature inherent of glass lined steel flange sealing surfaces. Sealing solutions made of 100% polytetrafluoroethylene (PTFE) give the broadest chemical resistance. Such solutions are commercially available to reliably seal GLS piping. This paper explores more deeply the challenges of sealing large GLS vessels and presents a new 100% PTFE sealing solution based on fundamental technical understanding of the application using finite element analysis (FEA) and confirmed by laboratory tests. This paper also provides an overview of the gasket properties and gives a brief technical review of the principle technology.