In high-pressure hydraulic and pneumatic systems, the primary seal faces a relentless enemy: extrusion. Under extreme pressure, the sealing material is forced into the microscopic gap between the piston and the cylinder wall (or the rod and the housing). This deformation, known as extrusion, leads to nibbling, tearing, and ultimately, seal failure. This is where the critical role of a back-up ring comes into play.

The sole purpose of a back-up ring is to act as a rigid barrier, preventing seal extrusion in these demanding environments. Manufactured from tough, incompressible materials like PTFE, or PEEK, the back-up ring is installed on the low-pressure side of the primary seal. It fills the clearance gap, providing physical support that blocks the softer seal material from being forced into it. This simple component is what enables standard seals to function reliably in high-pressure applications far beyond their normal operating range.

The advantages of specifying back-up rings extend far beyond preventing failure. By effectively supporting the seal, they drastically extend its service life, reducing downtime and maintenance costs. They also enable the use of more cost-effective sealing materials in situations that would otherwise require exotic, expensive compounds. For engineers designing systems operating above 1,500 PSI, especially with large clearance gaps or pressure spikes, extrusion prevention isn't optional—it's essential. Our expertise lies in providing the right custom backup rings, tailored to your specific pressure, temperature, and fluid compatibility requirements to ensure total system integrity.