TPL-A 73

Common issues

• Bearing wear (journal and thrust bearings) leading to increased clearances, vibration, and potential rotor contact.
• Fouling and erosion of turbine blades and nozzle ring due to combustion byproducts and high temperatures, reducing efficiency.
• Fouling and erosion of compressor wheel blades due to airborne contaminants or oil carry-over, impacting air delivery.
• Oil leakage from bearing casings, particularly at labyrinth seals or drain lines, indicating seal wear or blockage.
• Excessive vibration due to rotor imbalance, bearing damage, or foreign object damage (FOD).
• Exhaust gas leakage from casing joints, expansion bellows, or turbine outlet, posing safety and efficiency risks.
• Ineffective or clogged water washing nozzles leading to persistent fouling and reduced cleaning efficiency.
• Damage to expansion bellows (cracks, thinning) due to thermal cycling and vibration.

Inspection checklist

• Monitor bearing oil inlet/outlet temperatures and pressures for deviations from normal operating parameters.
• Check turbocharger casing for signs of oil leaks, exhaust gas leaks, cracks, or loose fastenings.
• Listen for abnormal noises (e.g., rubbing, whistling, grinding) and monitor vibration levels using onboard systems or portable meters.
• Inspect compressor and turbine sides (via inspection covers) for fouling, erosion, foreign object damage (FOD), and blade integrity.
• Verify exhaust gas and charge air differential pressures across the turbocharger for signs of fouling or restriction.
• Inspect the condition of exhaust gas expansion bellows for cracks, thinning, or signs of leakage.
• Check the functionality and cleanliness of the water washing system nozzles and ensure proper water flow.
• Verify the condition of the turbocharger's foundation bolts and anti-vibration mounts for tightness and integrity.
• Inspect the lubricating oil filter elements and check for metallic particles, indicating bearing wear.

Service intervals

Typical wear limits

Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.

Critical spares

• Complete set of journal and thrust bearings (cartridges or individual components)
• Labyrinth seals (compressor and turbine side)
• Full set of O-rings and gaskets for casing joints and inspection covers
• Water washing nozzles (complete set)
• Lubricating oil filter elements
• Expansion bellows (exhaust gas side)
• Set of balancing weights (for rotor re-balancing during overhaul)

Safety

• Extreme high temperatures of exhaust gas and casing surfaces (risk of severe burns).
• High-speed rotating machinery (rotor) poses a severe risk of injury if covers are removed or maintenance is attempted during operation.
• High pressure charge air and exhaust gas systems (risk of injury from sudden release or leaks).
• Potential for scavenge or exhaust trunking fires due to carbon/oil deposits, which can propagate to the turbocharger.
• High noise levels during operation requiring hearing protection in the vicinity.

Class survey

Class surveyors typically verify the turbocharger's maintenance records (running hours, bearing renewals, cleaning logs). They will visually inspect the external casing for leaks (oil, exhaust gas), cracks, and proper securing. Operational parameters (temperatures, pressures, vibration) are checked against acceptable limits. If the turbocharger has been opened for maintenance, the surveyor will inspect internal components (bearings, rotor, nozzle ring, blades) for wear, damage, and cleanliness. The condition of exhaust gas expansion bellows and the functionality of safety devices (e.g., overspeed trip, if testable) are also key inspection points. Verification of critical spare parts onboard may also be requested.

Estimated lifetime: 24,000 - 32,000 running hours (before major overhaul requiring rotor removal and extensive component inspection/renewal)