Backup rings in pump packing assemblies prevent packing extrusion into clearance gaps under high pressure preventing catastrophic seal failure and secondary damage. Backup rings manufactured from PTFE, filled PTFE, PEEK, or fabric-reinforced polymers provide extrusion resistance while accommodating reciprocating motion. Ring placement and material selection depend on operating pressur... https://globalsealstech.com/product-category/oil-gas-seals/oil-free-lubricated-pump-seals/