MET Series

Common issues

• Turbine blade erosion, especially with HFO operation, leading to reduced efficiency and potential imbalance.
• Journal bearing wear and potential failure after extended service (30,000+ hrs), indicated by increased axial/radial play or oil leakage.
• Compressor fouling due to oil carry-over or dirty intake air, reducing air delivery and engine performance.
• Nozzle ring erosion and deformation, impacting turbine efficiency and gas flow characteristics.
• Rotor imbalance caused by uneven deposits or blade damage, leading to excessive vibration and bearing stress.
• Oil leakage from bearing housing seals, contaminating charge air or exhaust gas.
• Exhaust gas leakage from casing joints or insulation degradation, posing burn hazards and efficiency loss.

Inspection checklist

• Visually inspect turbine blades for erosion, pitting, cracks, and heavy carbon deposits. Check for foreign object damage (FOD).
• Examine nozzle ring for erosion, cracks, deformation, and blockage. Ensure free movement if variable geometry.
• Inspect compressor impeller for fouling, damage (e.g., bent blades, nicks), and signs of foreign object impact.
• Check bearing condition by measuring axial and radial play (if accessible/during overhaul). Look for oil leakage from bearing housing.
• Inspect turbocharger casing for cracks, exhaust gas leakage, and integrity of insulation/lagging. Check tightness of mounting bolts.
• Verify oil supply and drain lines for leaks, proper flow, and cleanliness. Check oil filter condition.
• Inspect air filter elements for cleanliness and damage. Ensure proper sealing of air intake.
• Monitor turbocharger speed, exhaust gas temperatures (pre/post turbine), and charge air pressure/temperature for deviations from normal operating parameters.
• Check for signs of oil contamination in the charge air cooler, indicating potential bearing seal failure.

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 journal and thrust bearing assembly)
• Gasket sets and O-rings for casing, oil lines, and air/gas connections
• Nozzle ring (complete assembly or segments, depending on design)
• Oil filter elements and air filter elements
• Bearing housing seals (labyrinth or mechanical seals)
• Overspeed trip sensor (if applicable)
• Turbine blades (if individually replaceable, otherwise complete rotor is a major spare)

Safety

• High surface temperatures of the exhaust gas casing and associated piping (up to 500°C+) pose severe burn hazards. Ensure insulation integrity.
• High rotational speeds (up to 100,000+ RPM) mean catastrophic failure (e.g., rotor burst) can be extremely dangerous. Adhere strictly to maintenance procedures and wear limits.
• Pressurized exhaust gas and charge air lines can cause severe injury if connections fail or are opened improperly.
• Hot lubricating oil under pressure poses burn and fire risks. Ensure oil lines are secure and free from leaks.
• Potential for sudden acceleration or deceleration during operation, requiring caution during any nearby work or inspection.

Class survey

Class surveyors typically check for verification of maintenance records, including service reports for major overhauls, bearing replacements, and routine inspections. They will perform an external visual inspection for oil/gas leaks, casing integrity, and insulation condition. Operational checks for abnormal noise, vibration, and performance parameters (speed, pressures, temperatures) are common. If the turbocharger has been opened for maintenance, the surveyor may request to witness internal inspections of the rotor, bearings, and nozzle ring. Confirmation of overspeed trip functionality and alarm settings is also a key point.

Estimated lifetime: 100,000 - 120,000 hours with regular maintenance, timely component replacement (e.g., bearings, nozzle ring), and adherence to manufacturer's overhaul schedules.