How to Prolong the Service Life of Mechanical Seals

1. Reasonable Selection of Mechanical Seal Type & Material

Proper model and material selection is the fundamental premise to extend mechanical seal service life.

• Select seal structure according to working conditions: medium temperature, pressure, rotating speed, viscosity and corrosiveness.

• Match friction pair materials reasonably: such as silicon carbide, tungsten carbide, carbon graphite, ceramic; avoid unreasonable hard-to-hard or soft-to-soft pairing.

• Choose suitable auxiliary sealing materials (O-ring, gasket): EPDM, Viton, PTFE, HNBR etc., adapt to medium corrosion, temperature resistance and aging resistance requirements.

• For high temperature, high pressure, easy crystallization and particle-containing media, adopt balanced mechanical seals or tandem seal arrangement.

2. Strictly Control Installation Accuracy & Standard Operation

Improper installation is the main cause of early failure of mechanical seals.

• Ensure the shaft or sleeve runout, axial displacement and radial clearance comply with technical standards.

• Keep the seal chamber clean without impurities, burrs and welding slag before installation.

• Use special assembly tools; avoid knocking, scratching the seal face and elastic components.

• Control compression amount of the spring properly: too large compression leads to rapid wear and heat; too small causes leakage.

• Install static and dynamic rings in place; ensure sealing face fits closely without deflection.

3. Optimize Operating Working Conditions

Avoid overload and abnormal operation to reduce seal wear and thermal damage.

• Prohibit long-time dry running: mechanical seals must work with liquid film lubrication; dry friction will burn the seal face quickly.

• Control medium temperature: avoid overheating causing material aging, seal face thermal deformation and liquid film vaporization.

• Stabilize working pressure: prevent sudden pressure surge, vacuum negative pressure and frequent start-stop impact.

• Limit allowable linear speed: select high-speed type seal for high rotating speed equipment to avoid excessive friction heat.

4. Effective Flushing, Cooling & Lubrication System

Adopt auxiliary pipeline systems to improve seal operating environment.

• Set up seal flushing (Plan 11 / Plan 21 / Plan 23 / Plan 52 / Plan 53 etc.) to take away friction heat and prevent local overheating.

• Apply cooling and heat preservation for high-temperature and low-temperature working conditions to avoid material cold brittleness or high-temperature aging.

• For media with solid particles, install filter or adopt back flushing to prevent particles from entering the seal face and causing abrasive wear.

• Maintain stable liquid film between seal end faces to ensure lubrication and cooling effect.

5. Medium Treatment & Impurity Control

Solid particles, crystallization and dirt in the medium will seriously shorten seal life.

• Install filters, magnetic separators to reduce solid particles and impurities in the medium.

• For easy crystallization and viscous media, take heat tracing and dilution measures to prevent crystallization deposition on seal parts.

• Control medium pH value and corrosivity; select anti-corrosion materials matching the medium property.

6. Daily Maintenance, Inspection & Periodic Overhaul

Standard daily management can timely eliminate hidden troubles and delay seal failure.

• Regularly check leakage amount, equipment vibration, noise, temperature and pipeline flushing condition.

• Avoid equipment abnormal vibration, shaft misalignment and base loosening which will aggravate seal wear.

• Replace aging elastic elements (O-rings, springs) regularly even without obvious leakage.

• Do frequent inspection after equipment startup and load change; handle slight leakage in time to avoid deterioration.

7. Avoid Frequent Start-Stop & Abnormal Working Conditions

• Frequent start-stop will cause repeated separation and contact of seal faces, damaging the liquid lubrication film and accelerating wear.

• Avoid idle running, low-load long-time operation and medium cut-off operation.

• Carry out soft start and slow down shutdown to reduce mechanical impact on seals.