GUIDE TO MAINTAINING MECHANICAL SEALS IN MARINE PUMPS

I. DAILY INSPECTION AND MAINTENANCE KEY POINTS

- Operation Status Monitoring：
Check for abnormal leakage at the seal position (minor leakage within ≤5 drops/min is acceptable). Observe whether the pump vibration, temperature, and noise are normal to avoid seal failure caused by working condition fluctuations.
- Lubrication and Cooling System：
Ensure smooth circulation of cooling media (such as water or oil) in the seal chamber. Regularly replace or replenish lubricating grease to prevent dry friction damage to the seal faces.
- Seal Face Cleaning：
Clean scale, oil stains, or particulate impurities from the seal end faces when the pump is shut down to avoid hard particles scratching the seal faces.

II. KEY MAINTENANCE STEPS (PERFORM PERIODICALLY)

1. Dismantling and Inspection：
- Dismantle the seal components in the order specified in the pump manual. Check if the dynamic and static rings show signs of wear, cracks, or corrosion. If obvious scratches (depth >0.1mm) appear on the seal faces, grind them or replace the components.
- Inspect elastic elements (springs, O-rings) for aging, deformation, or failure, and replace seal parts promptly.
2. Installation Notes：
- Apply a small amount of lubricant to the seal faces before installation to ensure the dynamic ring moves flexibly. Tighten bolts evenly to avoid uneven stress causing partial wear.
- Adjust the seal compression amount to the value specified in the manual (typically 2-4mm). Excessive tightness accelerates wear, while looseness increases leakage.
3. Trial Operation Verification：
Observe leakage, temperature, and vibration after starting the pump. Put it into use only after 30 minutes of normal operation.

III. COMMON FAILURES AND COUNTERMEASURES

- Excessive Leakage：
Possible causes include worn seal faces, aged O-rings, or installation misalignment. Replace seal parts and re-calibrate the installation position.
- Seal Overheating：
Check if the cooling system is blocked, or if the spring is stuck, causing excessive tightness of the seal faces. Clean the pipeline and adjust the spring tension.
- Abnormal Vibration：
May be caused by shaft eccentricity, bearing wear, or skewed seal installation. Correct shaft alignment or replace bearings.

IV. MAINTENANCE SUGGESTIONS FOR SPECIAL WORKING CONDITIONS

- Seawater Environment：
Select seal components made of corrosion-resistant materials (such as tungsten carbide, fluoroelastomer). Regularly flush the seal chamber with fresh water to prevent seawater crystallization corrosion.
- High-Viscosity Media：
Increase lubrication frequency to avoid media deposition causing seal face adhesion. Flush the seal chamber promptly after shutdown.

V. MAINTENANCE RECORDS AND PREVENTIVE MANAGEMENT

- Establish a maintenance log to record leakage volume, seal part replacement time, and fault handling for traceability of problem patterns.
- Replace seal components according to the manual period (typically 1-2 years) to avoid sudden failures from overdue use.

Regular maintenance can effectively extend the service life of mechanical seals and reduce downtime risks of marine pumps. For complex failures, consult professional maintenance personnel.