Full definition
Sealing elements designed specifically for compressed air and gas systems, characterized by low friction (essential for smooth, controllable cylinder movement at the low pressures and low lubrication typical of pneumatics) and fast response (minimal breakaway friction for quick start/stop actuation). Operating pressure: typically 4-10 bar (versus 70-350 bar for hydraulic). Materials: NBR (standard — good air and oil compatibility), PU polyurethane (best wear resistance for high-cycle applications), PTFE (lowest friction for precision/clean applications), and silicone (wide temperature range, food-grade). Key difference from hydraulic seals: pneumatic seals operate with minimal lubrication (air line lubricator or grease — not flooded oil bath), so they must have inherently low friction to avoid stick-slip behavior. Seal profiles: lip seals (PU or NBR — most common), piston rings (PTFE or filled PTFE), and O-rings with backup rings. Pneumatic cylinders per ISO 6432 (round), ISO 15552 (profile), and ISO 21287 (compact). Per ISO 6195 for pneumatic cylinder seal groove dimensions. Cycle rates up to 1,000+ cycles/min in high-speed automation. Brands: Parker, Trelleborg, SMC, Festo, Hallite.