RH RH-30

Common issues

• Bearing wear (journal and thrust bearings) leading to increased play, vibration, and potential rotor contact.
• Fouling of compressor impeller and diffuser, reducing efficiency, causing surging, and increasing exhaust gas temperature.
• Carbon buildup on turbine nozzle ring and blades, restricting gas flow, reducing engine power, and increasing back pressure.
• Oil leakage from bearing housing seals (compressator or turbine side), indicating seal wear, blocked drain lines, or excessive crankcase pressure.
• Rotor imbalance due to uneven fouling, minor blade damage, or bearing issues, causing excessive vibration and potential catastrophic failure.
• Cracks in the turbine casing or exhaust gas manifold connections due to thermal stress and cycling.
• Damage to compressor or turbine blades (erosion, foreign object damage, rubbing) leading to efficiency loss and imbalance.

Inspection checklist

• Operational Check: Listen for abnormal noises (whining, grinding, surging) and check for excessive vibration (manual feel or accelerometer).
• Oil System Integrity: Inspect oil inlet/outlet lines for leaks, proper pressure/flow (if gauges available), and ensure oil quality is good.
• Air Filter Condition: Check cleanliness and integrity of the air intake filter element (if fitted) to prevent foreign object damage and maintain efficiency.
• Casing Integrity: Visually inspect compressor and turbine casings for cracks, especially around hot sections, mounting points, and welding seams.
• Rotor Play Measurement: Perform axial and radial rotor play measurements (cold) as per IHI manual specifications to assess bearing wear.
• Internal Visual Inspection (if accessible): If possible (e.g., through inspection ports or after opening), visually inspect compressor impeller and turbine blades for fouling, erosion, or foreign object damage.
• Exhaust Gas System: Check exhaust gas manifold connections, expansion bellows, and drain lines for leaks or blockages.
• Performance Monitoring: Verify boost pressure, exhaust gas temperatures (inlet/outlet), and engine load against normal operating parameters and logbook records.
• Drain Lines: Ensure oil drain lines from the bearing housing are clear and unobstructed to prevent oil accumulation and leakage.

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 (or individual journal and thrust bearings)
• Oil sealing rings (labyrinth or piston ring type, depending on design)
• Full gasket and O-ring set for overhaul
• Impeller nut (often left-hand thread, single-use)
• Air filter element (if external filter is part of the turbocharger system)
• Nozzle ring (if prone to heavy fouling/erosion in specific applications)
• Set of mounting bolts/nuts (for casing connections)

Safety

• High Rotational Speed: The rotor operates at extremely high RPMs (e.g., 50,000 - 100,000+ RPM). A catastrophic failure (rotor burst) due to severe imbalance or bearing failure poses a significant hazard.
• High Temperatures: The turbine casing and exhaust gas piping operate at very high temperatures (e.g., 400-600°C); severe burn risk. Always allow sufficient cooling time before inspection or maintenance.
• Pressurized Systems: Compressor discharge air and exhaust gas are under pressure; ensure systems are depressurized before opening any connections.
• Hot Lubricating Oil: The lubricating oil can be very hot; take precautions against burns during oil system checks or draining.
• Noise Levels: Turbochargers generate significant noise during operation; hearing protection is essential when in close proximity.

Class survey

For the IHI RH-30, a class surveyor typically checks the following: 1. Operational Verification: Observation of the turbocharger in operation, checking for abnormal noise, vibration, and verifying performance parameters (boost pressure, temperatures) against engine logbook entries. 2. External Condition: Thorough visual inspection for oil/gas leaks, cracks in casings, loose connections, and general cleanliness. Special attention to exhaust gas manifold connections and expansion bellows. 3. Maintenance Records: Review of maintenance logbooks, especially records of bearing inspections, overhauls, and any repairs. Verification of compliance with manufacturer's recommended service intervals. 4. Spare Parts: Verification of critical spare parts availability onboard, particularly bearing cartridges, seal kits, and gaskets. 5. Safety Devices: Confirmation of any fitted safety devices (e.g., overspeed trip, if applicable to this model/installation) and their last test date. 6. Opening for Inspection: If the turbocharger has been opened for maintenance (e.g., bearing renewal) prior to the survey, the surveyor may request to witness the reassembly or inspect the internal components (bearings, rotor, nozzle ring) for wear and damage.

Estimated lifetime: 24,000 - 36,000 hours before considering major component replacement (rotor, casings) or full unit replacement, assuming strict adherence to maintenance schedules and regular overhauls.