What are the common failures of mechanical seals?

Common failures of mechanical seals mainly focus on leakage, abnormal wear, and functional failure, with clear causes and characteristics:

1. Leakage (most frequent failure)

- Main manifestations: Continuous dripping or seepage at the seal face, or leakage from auxiliary seal rings (O-rings, V-rings).
- Core causes: Seal face damage (scratches, cracks), improper spring pressure (too loose/tight), auxiliary seal aging (hardening, deformation), or shaft eccentricity.

2. Seal face wear/abrasion

- Main manifestations: Rough, frosted, or grooved seal faces (moving/stationary rings), leading to reduced sealing performance.
- Core causes: Solid particles in the medium (abrasive wear), insufficient lubrication (dry friction), or mismatched material hardness (e.g., soft graphite paired with unpolished hard materials).

3. Spring failure

- Main manifestations: Spring deformation, breakage, or jamming (failure to provide stable axial pressure).
- Core causes: Corrosion (from aggressive media), fatigue (long-term high-speed operation), or foreign matter blocking the spring cavity.

4. Auxiliary seal ring damage

- Main manifestations: Sealing ring cracking, swelling, or losing elasticity.
- Core causes: Incompatible with the medium (e.g., oil swelling rubber), excessive temperature (high temp hardens/softens seals), or improper installation (twisting during assembly).

5. Vibration/noise abnormal

- Main manifestations: Abnormal noise (squeaking, grinding) or excessive vibration at the seal, accompanied by accelerated wear.
- Core causes: Shaft misalignment, poor surface finish of the seal face, or loose fit between the moving ring and the shaft.