TPL-B 77-B12

Common issues

• Bearing wear (journal and thrust bearings) leading to increased axial/radial play and potential rotor contact.
• Compressor fouling due to oil carry-over or dirty intake air, reducing efficiency and causing surging.
• Turbine fouling and erosion from exhaust gas impurities (e.g., catalytic fines, unburnt fuel), leading to reduced power and potential blade damage.
• Nozzle ring and cover ring damage/deformation, affecting gas flow and turbine efficiency.
• Oil leakage from bearing housings (air-side or gas-side) indicating seal wear or improper oil drainage.
• Rotor imbalance and vibration, often caused by fouling, erosion, or bearing wear, leading to premature component failure.
• Surging of the turbocharger, characterized by unstable operation and pressure fluctuations, often due to fouling or engine load changes.

Inspection checklist

• Check axial and radial play of the rotor shaft (cold condition) against manufacturer's limits. Look for signs of rubbing.
• Inspect compressor wheel (impeller) for cleanliness, damage (nicks, cracks), and tip clearance. Ensure free rotation without rubbing.
• Inspect turbine wheel for cleanliness, erosion, cracks, and foreign object damage (FOD). Check tip clearance.
• Examine nozzle ring and cover ring for deformation, cracks, or blockage by deposits. Ensure proper fitment.
• Verify integrity of the lubricating oil supply and drain lines; check for leaks, proper oil level, and pressure (if applicable).
• Inspect air filter elements for cleanliness and damage. Ensure exhaust gas casing and insulation are intact.
• Monitor turbocharger vibration levels using onboard systems and compare against baseline/alarm limits.
• Check for any signs of oil leakage from the bearing casing, air intake, or exhaust gas outlets.
• Confirm proper functioning of washing systems (compressor and turbine) and inspect washing nozzles for blockage.

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 bearing cartridge assembly (journal and thrust bearings)
• Set of O-rings, gaskets, and seals for bearing housing and casings
• Air filter elements
• Nozzle ring segments (if applicable, or complete nozzle ring)
• Oil pump (if externally driven or integrated and prone to wear)
• Balancing weights and shims (for field balancing after maintenance)
• Specialized tools for disassembly and assembly (e.g., rotor lifting tools, bearing extraction tools)

Safety

• High surface temperatures of exhaust gas casings and associated piping (burn hazard).
• High-speed rotating machinery (rotor) posing entanglement and projectile hazards if containment fails.
• High-pressure exhaust gas and compressed air within the system (rupture/leakage hazard).
• Hot lubricating oil (burn and fire hazard) during operation and maintenance.
• High noise levels during operation requiring hearing protection in the vicinity.

Class survey

Class surveyors typically verify the overall condition and cleanliness of the turbocharger, inspect for oil/gas leaks, and review maintenance records (including bearing changes, rotor overhauls, and washing logs). They will check the integrity of the casing, insulation, and associated piping. Evidence of proper vibration monitoring and adherence to manufacturer's service intervals are key. The surveyor may also request a functional check of the engine's overspeed protection system, which indirectly protects the turbocharger.

Estimated lifetime: 80,000 - 100,000+ hours with scheduled overhauls, proper maintenance, and component replacement.