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.