Quantifying Water Vapor Diffusion across Elastomer Pressure Sensor Seals
Water vapor diffusion across elastomer seals causes reference cavity pressurization and dielectric drift, requiring coulometric ISO 15105-2 verification.
Gland Design
Sealing Configuration
A mechanical interface defines the cavity and compression surfaces that contain a gasket or O ring to prevent fluid leakage. Proper gland design ensures that the sealing element remains under sufficient stress to block leak paths while avoiding excessive deformation. This structure must account for the thermal expansion of both the seal material and the housing to maintain integrity across the full temperature range.
The depth and width of the groove determine the volume available for the elastomer to expand under load.
Mechanical Stress
The geometry of the groove controls how the seal reacts to system pressure and prevents the elastomer from extruding into the clearance gap. Within a gland design, the surface finish of the mating components must be smooth enough to prevent abrasion but textured enough to hold a thin film of lubricant. Sharp edges or burrs in the machining process can damage the seal during installation and lead to premature failure.
Calculating the total volume of the seal at its maximum swelling point is a requirement to avoid overfilling the cavity.
Material Compatibility
Engineers select dimensions based on the expected compression set and chemical resistance of the specific elastomer chosen for the application. A gland design for high pressure gas must incorporate backup rings to support the primary seal and prevent extrusion.
Installation Tolerance
Minor variations in machining can lead to insufficient compression or excessive friction on moving parts. Standardized tables from organizations like the Society of Automotive Engineers provide the basic dimensions for most industrial applications. Each assembly is verified through pressure testing to confirm that the seal functions as intended under simulated field conditions.