TPL-A 91

Common issues

• Bearing wear (journal and thrust bearings), leading to increased axial/radial play and potential rotor contact.
• Fouling and erosion of compressor wheel and diffuser, reducing efficiency and airflow.
• Fouling and erosion of turbine blades and nozzle ring, impacting engine performance and exhaust gas flow.
• Oil leakage from bearing housing seals, indicating seal wear or improper oil drainage.
• Exhaust gas leakage from casing joints or turbine outlet, posing safety risks and reducing efficiency.
• Rotor imbalance or vibration, often due to fouling, damage, or bearing issues.
• Turbocharger surging, caused by insufficient air supply, excessive back pressure, or compressor fouling.
• Overspeed trip activation or malfunction, indicating control issues or actual overspeed condition.

Inspection checklist

• Measure axial and radial play of the rotor shaft (cold and hot if possible) against manufacturer's limits.
• Visually inspect compressor wheel and diffuser for fouling, erosion, cracks, or foreign object damage (FOD).
• Visually inspect turbine blades and nozzle ring for fouling, erosion, cracks, or deformation.
• Check for oil leaks from bearing housing, oil inlet/outlet pipes, and exhaust gas leaks from casing joints.
• Inspect the condition of the air filter and exhaust gas silencer/ducting for blockages or damage.
• Verify lubricating oil pressure and temperature at the turbocharger inlet, and check oil drain for free flow.
• Check security of all mounting bolts, pipe connections, and instrumentation (speed sensor, pressure/temp gauges).
• Listen for abnormal noises (whining, rubbing) and observe for excessive vibration during operation.
• Inspect the turbocharger washing system (water/chemical) for functionality and nozzle condition.
• Confirm proper functioning of the overspeed trip mechanism and alarm settings.

Service intervals

Typical wear limits

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

Critical spares

• Bearing cartridges (complete set: journal and thrust bearings)
• Oil seals (labyrinth and piston ring type)
• Gasket and O-ring sets (for casing joints, oil/air connections)
• Nozzle ring segments or complete nozzle ring
• Diffuser ring
• High-speed balancing kit (if not available ashore or for emergency repairs)
• Speed sensor and overspeed trip mechanism components
• Oil filter elements (for turbocharger dedicated oil system, if applicable)

Safety

• High surface temperatures (exhaust gas casing, turbine outlet) causing severe burns; ensure insulation integrity.
• High rotational speeds (up to 15,000-20,000 RPM for this size) posing a risk of rotor disintegration if bearings fail or foreign object ingress occurs.
• Pressurized hot exhaust gas and compressed air, risk of blow-outs from leaks or improper sealing.
• Hot lubricating oil under pressure, risk of spray fires from leaks onto hot surfaces.
• Noise levels during operation can exceed safe limits; hearing protection is mandatory in the vicinity.

Class survey

Class surveyors typically verify the turbocharger's operational status, maintenance records (logbook entries, service reports from authorized workshops), and spare parts inventory. They will conduct an external visual inspection for leaks, security of mounting, and general condition. During a major overhaul survey, they may witness axial/radial play measurements, inspect critical components (rotor, bearings, casings) for wear and damage, and confirm compliance with manufacturer's specifications and class rules. Functionality of the overspeed trip and alarm systems will also be checked. Evidence of regular cleaning and washing is often requested.

Estimated lifetime: 16,000 - 24,000 running hours (before major overhaul, assuming proper maintenance)