Marine LNG Compressor Series (Vertical/V-Type)

Visually inspect piston rings for wear grooves; measure radial and axial clearances with feeler gauges every 6000 running hours. Replace if remaining step cut overlap is 1/3 or less of full overlap. Check discharge gas temperature for early sign of leaking piston rings.

Remove and dismantle suction/discharge valves for inspection; check sealing surfaces for wear using valve plate testing. Carbonized valves indicate oil carryover. Replace worn valve plates immediately; do not reuse. Test relief valve opening pressure with hydraulic tester.

Record cylinder pressure profiles for all stages; measure rod runout with dial indicator at stroke extremes (max deviation ±0.00015 mm/mm of stroke or 0.064 mm absolute per API 618). Perform 4-hour unloaded mechanical running test at rated speed; record bearing temperatures, vibration amplitudes, and lube oil viscosity.

Measure bearing clearances with precision gauges and record all readings. Inspect crankcase interior thoroughly with lint-free cloth for metal particles and sludge. Gauge major components (piston, liner, rod, crosshead bearing); replace if outside tolerance. Renew piston rings, gudgeon pin, and top-end bearing as preventive measure.

Monitor cooling water inlet and outlet temperatures continuously (target rise: 10-15°C). Check inlet pressure (0.07-0.3 MPa) and flow rate (1-2 m/s). Inspect intercooler and jacket passages for scale/blockage. Drain condensate from intercoolers every 8-24 hours via automatic drain valve. Verify cooling pump belt and impeller condition. Check expansion tank water level.