PolyTetraFluoroEthylene (PTFE) felt is an inert felt with excellent hydrophobic properties and resistance to chemical attacks along with a 260°C maximum service temperature.
PTFE felt is designed to easily handle extreme conditions like high acid gas concentrations (HCL, H2SO4, and HF), high humidity, and chemically aggressive operative conditions.
However PTFE is very expensive material, should only be used when everything else fails.
It has poor abrasion resistance hence a minimum of 20-vertical wire supported cage is recommended.
PTFE Felt with PTFE membrane lamination is also available to enhance filtration efficiency.