Know about the reason for crankcase explosion

An overheated bearing or hot spot causes oil droplets to evaporate inside the crankcase, leading to the formation of an oil mist.
  • Higher concentration of oil mist causes crankcase explosion.
  • An oil mist detector or OMD senses oil mist concentration inside the crankcase of all the units.

  • If the concentration of mist increases in any unit above the limit, it activates an alarm.
  • When you heard the alarm, reduce the speed of engine to dead slow.
  • Ensure that the alarm is not false. Note the unit in which the mist concentration has gone up.
  • Request permission from the bridge to stop the engine.
  • Stop the engine and the fuel supply. Switch off the auxiliary blowers.
  • Keep lubricating oil pumps and jacket cooling water pumps running.
  • Open the skylight to ventilate the engine room and prepare the fire fighting equipment.
  • Stop the lubricating oil circulating pump. Cut off the starting air and engage the turning gear.

  • Twenty minutes after the engine has stopped, open the crankcase doors and inspect the unit indicated by the OMD.
  • While opening, stay clear of possible spurts of flame.
  • Locate the hot spots using power lamps.
  • Check the temperatures of main bearings, piston rods, stuffing boxes, crossheads, and telescopic pipes using a remote handheld thermometer.

  • Look for squeezed out bearing metal and discolouration caused by heat such as blistered paint, burnt oil, or oxidized steel.
  • Prevent further 'hot spots' by permanent repair.
  • Start the circulating oil pump. Check the oil flow through all bearing.
  • Disengage the turning gear and start the engine.
  • Stop the engine after 15 minutes and inspect the crankcase.
  • Run the engine for one hour and inspect the crankcase again.
  • Run the engine on full load and inspect the crankcase to ensure that there are no Hot spots.

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