Gap extrusion

External forces acting on the piston rod, reacted by the fluid inside the cylinder, can result in abrupt pressure peaks. These peaks can be far in excess of the system operating pressure and may press a piston seal into the gap between the piston and bore, thereby causing damage to the seal and adversely affecting seal performance and cylinder operation. Seal materials must be carefully chosen to avoid gap extrusion (→ Gap extrusion). This risk of gap extrusion can also be minimized by using seals with anti-extrusion rings (→ Piston seals incorporating anti-extrusion rings).
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