High Pressure Rating PTFE Lined Expansion Bellows: Explosion-Proof Flexible Flanged Joint for Corrosive Industrial Media Explosion-Proof Chemical Containment for High-Pressure Industrial Lines. The High Pressure Rating PTFE Lined Expansion Bellows is an advanced, high-integrity piping component designed for extreme industrial operations where corrosive media and explosive atmospheres intersect. Facilities processing hazardous chemicals, volatile solvents, and high-pressure