Gasket Compression Calculations for Pressure Transducer Port Glands
Optimizing transducer port sealing demands balancing 15 to 25 percent gasket squeeze against volumetric fill below 85 percent to prevent mechanical die offset.
Anti Extrusion Backup Ring
Clearance Geometry
Sealing hardware components of rigid high-modulus polymers or metals sit adjacent to elastomeric O-rings to block fluid pathways under pressure. An anti extrusion backup ring prevents the flexible elastomer from flowing into the clearance gap between mating metal parts when differential pressure increases. System pressure forces the ring against the low-pressure side of the gland, closing structural clearances.
Pressure Limit
Continuous operation above elevated pressures causes seal degradation without secondary structural support. Installing an anti extrusion backup ring increases the effective pressure rating of an elastomeric seal assembly up to fourfold. High system fluid forces press the ring tightly against the seal boundary, suppressing extrusion clearance flow.
Material Hardness
Polythermal polymers like polytetrafluoroethylene and filled polyamides provide dimensional stability across dynamic thermal cycles. Choosing an anti extrusion backup ring made from a material with high Young modulus prevents mechanical deformation under shear stress. Harder backup materials resist cold flow while maintaining low friction against moving shaft surfaces.
Softer materials risk shear failure under peak pressure spikes, whereas overly rigid metals can scour adjacent housing walls during assembly or thermal expansion.
Failure Mode
Mechanical degradation occurs when high differential pressures force elastomeric material around or through backup interfaces. A damaged anti extrusion backup ring exhibits localized nibbling along the trailing edge where fluid forces concentrate stress. Inspecting removed seals confirms whether clearance gap dimensions exceeded manufacturing tolerances during high pressure excursions.
Proper hardware alignment preserves seal integrity and maintains predictable calibration parameters across extended operational cycles.