Non-preloaded lip seal
Non-preloaded lip seals (commonly referred to as U-cups or Y-rings) are the cornerstone of high-efficiency hydraulic rod sealing. Unlike spring-energized designs, these seals utilize their inherent geometric flexibility and fluid pressure to achieve a "self-sealing" effect. At Carlock Sealing, we optimize the interference fit of the lip to ensure low breakout friction while maintaining a leak-free interface during reciprocating strokes.
Q: Why does my PU rod seal turn hard and fail in water-based fluids?
A: Standard polyurethanes suffer from hydrolysis. Carlock Sealing recommends our MDI-based Red H-PU for these environments. It is specifically designed to resist chemical aging and hardening, significantly extending the service life of your rod sealing system.
Q: Can a non-preloaded FKM seal handle high pressure?
A: FKM has excellent chemical and heat resistance but is softer than PU. For high-pressure applications (>250 bar), Carlock Sealing recommends using a high-hardness grade or adding a Back-up Ring to prevent material extrusion into the clearance gap.
Technical Disclaimer: Material compatibility and pressure ratings are dependent on the specific fluid and operating temperature. Always consult our technical team to verify if a non-preloaded design is suitable for your specific cylinder speed and surface roughness (Ra).
