TPL-B 69-B12

Common issues

• Bearing wear (journal and thrust) due to contaminated lube oil, insufficient flow, or prolonged operation at high loads.
• Compressor and turbine fouling, particularly on the turbine side with Heavy Fuel Oil (HFO) operation, leading to reduced efficiency and surging.
• Exhaust gas casing cracks or deformation due to thermal stress cycling or mechanical impact.
• Oil leakage from bearing housing seals (labyrinth seals) into the compressor or turbine side, indicating wear or blockage of drain lines.
• Rotor imbalance caused by uneven fouling, blade damage, or bearing wear, leading to excessive vibration and potential catastrophic failure.
• Nozzle ring and/or diffuser erosion/corrosion, affecting gas flow and turbocharger performance.
• Surging, often indicative of engine issues, severe fouling, or incorrect turbocharger matching/operation.

Inspection checklist

• Visual inspection for oil leaks at bearing housing seals and gas leaks at casing joints. Check for signs of overheating or discolouration.
• Manual check of rotor free rotation (should spin freely with minimal resistance) and axial/radial play (using a dial gauge if possible, comparing to manufacturer's limits).
• Inspect compressor wheel for dirt accumulation, blade damage (nicks, bends), and erosion. Check for rubbing marks on the casing.
• Inspect turbine wheel and nozzle ring (via inspection ports) for heavy fouling, erosion, cracks, or foreign object damage.
• Verify integrity of insulation and lagging on hot surfaces (exhaust casing, gas pipes) to prevent heat loss and ensure personnel safety.
• Check lubricating oil supply and drain lines for proper connection, signs of leakage, and ensure drain is clear and unrestricted.
• Monitor turbocharger speed, boost pressure, and bearing temperatures (if sensors are fitted) against engine load and manufacturer's specifications.
• Inspect air filter condition (if fitted) and ensure compressor wash system is functional and used regularly.
• Verify functionality of turbocharger overspeed trip mechanism (often simulated during surveys) and compressor relief valves.

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 (including associated O-rings/gaskets)
• Bearing housing seals (labyrinth seals, piston rings, or equivalent)
• Set of O-rings and gaskets for casing joints (e.g., compressor casing, turbine casing)
• Lubricating oil filter elements (if turbocharger has a dedicated filter)
• Balancing weights (for rotor re-balancing during overhaul)
• Nozzle ring (especially if operating with high-sulfur fuels or in areas prone to erosion)
• Compressor wheel (if operating in abrasive environments or prone to foreign object damage)

Safety

• High Temperatures: Exhaust gas casing and associated piping operate at extremely high temperatures (300-600°C). Risk of severe burns. Ensure all hot surfaces are properly insulated and lagged.
• High Speed Rotation: The rotor operates at very high speeds (typically 10,000-15,000 RPM for this size). Uncontained failure due to imbalance or component fatigue can be catastrophic, releasing high-energy fragments.
• Noise: Turbochargers generate significant noise levels. Hearing protection is mandatory when working near an operating unit.
• Pressure: High boost air pressure on the compressor side and exhaust gas pressure on the turbine side. Ensure all connections are secure and relief valves are functional.
• Hot Oil: Lubricating oil can be hot and under pressure. Exercise caution during oil system maintenance.

Class survey

A class surveyor will typically focus on verifying the turbocharger's safe and reliable operation. This includes checking service records and maintenance logs, particularly for bearing replacements and major overhauls. They will inspect the overall structural integrity of the casings for cracks, deformation, and secure mounting. Functionality of safety devices, such as the overspeed trip mechanism (often simulated) and compressor relief valves, will be verified. The surveyor will also check the integrity of insulation on hot surfaces, observe the turbocharger's performance during engine load changes (looking for surging, stable boost pressure), and ensure the lubricating oil system (pressure, temperature, alarms) is in good order. Any signs of oil or gas leakage will be noted.

Estimated lifetime: 48,000 hours (before requiring a comprehensive factory-level overhaul or significant component replacement)