the factors affecting sealing rings service time

Factors affecting the service life of sealing rings primarily include material properties, operating environment, installation and maintenance, mechanical stress, and media compatibility. The following analysis focuses on the characteristics of rotating spindle sealing rings:
1. Material Properties
The material composition fundamentally determines a seal’s performance. For instance, rubber compounds may undergo glass transition at low temperatures, diminishing flexibility and resilience. In high-temperature environments, materials like polyurethane may lose elasticity due to thermal decomposition. Consequently, temperature-resistant materials (such as fluorocarbon rubber or metal-reinforced rubber) must be selected based on operating temperatures.
2. Operating Environment
Environmental factors significantly impact seal longevity:
Temperature: Extreme heat or cold can cause material hardening, brittleness, or softening. For instance, EPDM rubber is prone to cracking below -40°C.
Humidity and Chemical Corrosion: Moist environments may accelerate hydrolysis in silicone seals, while strong acids or alkalis can induce material swelling or dissolution.
Mechanical Stress: Prolonged high-pressure friction leads to surface wear, such as deep groove formation in U-seals within hydraulic systems.
3. Installation and Maintenance
Improper installation and maintenance can significantly shorten seal life:
Over-tightening or misalignment: O-ring compression exceeding 30% causes permanent deformation; specialised tools must ensure concentricity during assembly.
Lubricant contamination: Grease containing particulates can scratch seal surfaces.
Inadequate cleanliness: Failure to thoroughly clean sealing surfaces before assembly or striking with sharp tools may cause scratches or deformation.
Media Compatibility
4. Compatibility between seal materials and operating media is critical. Poor compatibility between fluids and seals may accelerate rubber degradation, generate sludge, and lead to seal failure. For instance, nitrile rubber may exhibit up to 300% volume expansion upon contact with kerosene.
5. Mechanical Design Factors
Surface roughness: Inadequate surface finish on shafts or piston rods intensifies seal wear.
Clearance fit: Excessive clearance between the seal and groove causes abnormal localised stress, accelerating ageing.
Movement speed: High rotational speeds may impair oil film formation, increasing frictional resistance.
6. Other Factors
Air or bubbles within the system: Energy released from bursting bubbles can damage seal lip edges.
Radiation damage: In radiation environments such as space or under prolonged solar exposure, molecular chain breakage causes material embrittlement.
 
Summary: The service life of rotating spindle seals results from the combined effects of material properties, operating environment, installation practices, and media characteristics. Correct selection, standardised installation, and regular maintenance are key to extending their operational lifespan.