Role of contamination in static seals performance

This thesis presents an investigation of the effect of particulate contamination on the sealing performance of static, ladder-frame gaskets in hydraulic systems. Aluminium particles(600–1600 µm) were deposited on the elastomeric lip bonded to a metal-backed gasketand subjected to controlled clamping and pressurisation in a custom test rig. Leakage wasquantified by measuring the oil absorbed onto filter paper; evaporation losses were characterised separately and corrected using an exponential evaporation model. Single-particletests revealed an exponential increase in leakage with particle size, whereas assembliesof ten particles produced approximately 40% less total leakage than a single particle ofequivalent size. This reduction may be due to blockage of capillary pathways beside thegasket lip, though further investigation is required. Line-laser triangulation (LLT) was evaluated for particle detection and characterisation. LLT demonstrated the potential for rapid, large-area scanning, but with the drawbacksof oil-induced noise if oil is present on the surface. Future work should explore automatedscanning protocols for comparing trends in deviation and the detection of particles. Whendeveloped, it can be used as a measuring technique for large-scale production.Based on the experimental findings, this thesis provides design recommendations forladder-frame gaskets. It is advised to characterise the contaminants in both manufacturing and service environments, identifying particle types, size distributions, and occurrence frequencies. Then, use the most frequently damaging particle as the design metricfor a new design of a gasket. Such a targeted design will enhance gasket robustness inreal-world hydraulic.