TPL-A 85

Common issues

• Compressor fouling (due to dirty intake air or oil carry-over), leading to reduced efficiency and surging.
• Turbine fouling (due to poor fuel combustion or exhaust gas bypass), causing increased back pressure and reduced power.
• Bearing wear or failure (plain journal and thrust bearings), indicated by increased axial/radial play, high oil temperature, or vibration.
• Rotor imbalance or vibration, often caused by blade erosion, foreign object damage, or uneven fouling.
• Nozzle ring and/or turbine blade erosion/corrosion, leading to reduced turbine efficiency and potential blade failure.
• Oil leakage from bearing housings or seals, indicating seal wear or incorrect oil pressure.
• Casing cracks, particularly in the hot gas path (turbine inlet/outlet) due to thermal cycling and stress.
• Surging, often due to compressor fouling, incorrect engine load, or issues with the air intake system.

Inspection checklist

• Check for any visible oil or exhaust gas leaks from casing joints, bearing housings, and drain lines.
• Verify axial and radial clearances of the rotor (if accessible or during planned maintenance) against manufacturer's limits. Typical new axial play: 0.15-0.25 mm; radial play: 0.20-0.35 mm.
• Inspect compressor wheel for dirt accumulation, erosion, foreign object damage, or bent blades. Ensure free rotation without rubbing.
• Inspect turbine blades and nozzle ring (if accessible) for erosion, cracks, foreign object damage, or excessive carbon deposits.
• Check condition of air filter elements and ensure proper sealing of the air intake system.
• Monitor lubricating oil pressure and temperature at the turbocharger inlet/outlet. Ensure oil quality is within specifications.
• Inspect mounting bolts, chocks, and anti-vibration mounts for tightness and integrity.
• Verify operation of water washing systems (compressor and turbine) and ensure proper drainage.
• Check functionality of overspeed trip device and associated alarms during scheduled tests.

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 (thrust and journal bearings, seals)
• Gasket and O-ring sets for casing openings and bearing housings
• Lubricating oil filter elements
• Air filter elements (if applicable to specific intake design)
• Nozzle ring segments or complete nozzle ring (depending on design and wear)
• Overspeed trip bolt/pin
• High-temperature bolts and nuts for turbine casing
• Oil pump (if external and critical for lubrication)

Safety

• High rotational speeds (up to 15,000-20,000 RPM for TPL-A 85), posing a severe risk of rotor disintegration if overspeed occurs or due to catastrophic bearing failure.
• Extremely high temperatures (up to 550-600°C) in the turbine casing and exhaust gas piping, requiring proper insulation and caution during inspection/maintenance.
• High-pressure compressed air (up to 4-5 bar gauge) in the compressor discharge, requiring safe depressurization before opening.
• Hot lubricating oil under pressure, posing burn and slip hazards if leaks occur.
• Noise levels can exceed 100 dB(A) in the vicinity of the turbocharger, necessitating hearing protection.

Class survey

Class surveyors will primarily focus on verifying that the turbocharger's maintenance has been carried out in accordance with the manufacturer's recommendations and the vessel's approved planned maintenance system. They will check maintenance records, logbook entries, and service reports for bearing replacements, rotor overhauls, and cleaning operations. A visual inspection will be conducted for any signs of leaks, excessive vibration, or external damage. They may request to witness the operation of safety devices, such as the overspeed trip, and verify alarm functions. If the turbocharger is opened for inspection during a special survey, the surveyor will typically check bearing clearances, rotor condition, and the integrity of the compressor and turbine sections.

Estimated lifetime: The main rotating assembly (rotor shaft, compressor wheel, turbine wheel) can achieve 48,000 - 72,000 running hours before requiring major reconditioning or replacement, assuming regular maintenance and component replacements (bearings, seals). The robust casings can last significantly longer, often the lifetime of the vessel with proper care.