Piston seals in hydraulic cylinders seal the gap between the piston and cylinder bore, retaining pressure on one side while allowing movement. They handle dynamic loads in reciprocating motion, crucial for oilfield hydraulic rams. Single-acting pistons use U-cup designs, while double-acting employ chevron or step-cut profiles. Materials like filled PTFE reduce friction and wear. https://globalsealstech.com/hydraulic-seals/