Understanding fundamental pump maintenance simplifies preventive care. Most pump repairs require in-depth knowledge during inspections, as root causes often extend beyond visible failures. Below are critical maintenance methods and best practices:

1. Packing (Stuffing Box)

Inspection:

· Check for excessive leakage at the stuffing box gland. Tighten the gland if necessary, but never fully eliminate leakage—water acts as a coolant for the packing.

· Ideal Leakage: ~20 drops per minute. If adjustment fails, repack with appropriate packing material (consider pressure and shaft speed).

Repacking Procedure:

1. Safety First: Isolate the pump and motor; follow lockout/tagout protocols.

2. Remove Old Packing: Use proper tools (avoid screwdrivers) to prevent damage. Clean the stuffing box and inspect the shaft sleeve for wear.

3. Install New Packing:

· Ensure full contact with the shaft, no gaps at joints.

· Stagger packing joints by 90° (prevents fluid bypass). Align the liquid seal ring with the coolant port.

4. Adjust Gland: Tighten the gland gradually (3/4 turn every 30 minutes). Monitor for overheating or uneven pressure.

Figure 1: Improperly adjusted gland with no leakage

Figure 2: Excessive leakage at the stuffing box gland

2. Bearings

Overheating Causes:

· Friction from inadequate lubrication or contamination.

Maintenance Steps:

1. Clean Lubrication Points: Remove dirt from grease nipples and cups before refilling.

2. Lubrication Guidelines:

· Follow manufacturer recommendations for grease type and quantity.

· Over-lubrication causes overheating. Purge old grease by removing overflow plugs during refilling.

3. Debris Inspection: Check expelled grease for metal particles, indicating wear.

3. Couplings

Lubrication & Alignment:

1. Safety Precautions: Remove the coupling guard and isolate power before servicing.

2. Elastomer Inspection: Check for wear or metal debris (signs of misalignment).

3. Reassembly:

· Clean all components thoroughly.

· Install elastomers between the motor drive end and pump driven end.

· Lubricate coupling bolts until new grease exits overflow ports. Avoid over-lubrication to prevent seal damage.

4. Routine Inspections

Key Checks:

· Visual: Blocked discharge lines, excessive packing leakage, or bearing overheating.

· Auditory: Unusual noises (e.g., bearing rumbles, cavitation).

· Vibration Analysis: Address vibrations immediately to prevent catastrophic failure.

Checklist Tips:

· Compare current findings with historical data to identify trends.

· Document issues and prioritize repairs with supervisors.

Figure 3: Properly adjusted gland with controlled leakage

Preventive Maintenance Best Practices

1. Follow Manufacturer Guidelines: Adhere to lubrication intervals and torque specifications.

2. Use Correct Tools: Avoid improvised tools that damage components.

3. Monitor Trends: Track temperatures, pressures, and vibration levels.

4. Safety First: Always isolate equipment before maintenance.