A185-L 185-L37

Common issues

• Bearing wear and failure (thrust and radial bearings), often indicated by increased vibration or high bearing temperatures.
• Fouling of compressor wheel and diffuser, leading to reduced efficiency, surging, and increased charge air temperature.
• Fouling, erosion, or corrosion of turbine blades and nozzle ring, causing reduced turbine efficiency and potential imbalance.
• Exhaust gas leakage from casing joints, gland seals, or turbine inlet/outlet connections, posing safety and efficiency concerns.
• Lubricating oil system issues, such as low oil pressure, high oil temperature, or oil contamination, leading to premature bearing wear.
• Rotor imbalance due to fouling, damage, or manufacturing defects, resulting in excessive vibration and potential catastrophic failure.
• Surging of the turbocharger, often caused by engine load changes, exhaust gas boiler operation, or severe fouling, leading to mechanical stress.
• Air filter clogging, restricting air intake and causing reduced compressor efficiency and potential cavitation.

Inspection checklist

• Monitor and trend bearing temperatures (radial and thrust) and vibration levels for any abnormal deviations.
• Visually inspect compressor wheel and diffuser for fouling, erosion, foreign object damage (FOD), and tip clearance.
• Inspect turbine wheel and nozzle ring for fouling, erosion, corrosion, and FOD. Check for free movement of nozzle ring segments if variable geometry.
• Check for any signs of lubricating oil leakage (especially at bearing casings) and exhaust gas leakage from casing joints or seals.
• Verify lubricating oil pressure and temperature at the turbocharger inlet and outlet, ensuring they are within manufacturer's specifications.
• Inspect the condition of the air filter elements and clean/replace as necessary to ensure unrestricted air flow.
• Check the integrity of the turbocharger casing, insulation, mounting bolts, and support structure for cracks, looseness, or damage.
• Listen for unusual noises (e.g., rubbing, whistling, grinding) during operation, which may indicate internal damage or wear.
• Periodically test the overspeed trip mechanism and verify the functionality of the speed sensor and associated alarms.
• Inspect the charge air cooler (if applicable) for cleanliness and signs of leakage, as its condition directly impacts turbocharger performance.

Service intervals

Typical intervals for this design class, not the manufacturer’s figures for your model. The manufacturer’s manual is binding.

Typical wear limits

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

Critical spares

• Complete bearing set (thrust pads, radial bearings, and associated seals/O-rings).
• Gland seals (air and gas side) and sealing rings.
• O-rings and gaskets for casing joints and inspection covers.
• Lubricating oil filter elements (if applicable to the turbocharger's dedicated oil system).
• Air filter elements (if applicable).
• Nozzle ring segments or complete nozzle ring (depending on design and common failure modes).
• Speed sensor and associated wiring/connectors.
• Set of mounting bolts and nuts for critical connections.

Safety

• High surface temperatures of the turbine casing and exhaust gas piping, requiring adequate insulation and guarding to prevent burns.
• Extremely high rotational speeds (up to 15,000-20,000 RPM for large units), posing a severe risk of disintegration in case of catastrophic failure.
• High pressure charge air within the compressor casing and discharge piping, requiring secure connections and pressure relief mechanisms.
• Presence of hot lubricating oil under pressure, which can cause burns or create fire hazards if leaks occur.
• High noise levels during operation, necessitating hearing protection in the vicinity of the turbocharger.

Class survey

Class surveyors typically focus on the overall operational integrity and safety aspects. They will check for general cleanliness, absence of oil and exhaust gas leakages, and the security of mounting arrangements. The integrity of insulation and guarding for hot surfaces is critical. Surveyors often review maintenance records, particularly for bearing overhauls, cleaning cycles, and any reported operational issues. They may request to witness an overspeed trip test (or review records of recent tests) and verify the functionality of safety devices. Any signs of excessive vibration or unusual noises will be investigated. Compliance with IMO NOx regulations, if applicable, might involve checking records related to engine tuning and turbocharger performance.

Estimated lifetime: 24,000 - 36,000 hours (before major overhaul, assuming regular maintenance and component replacement)