[icedcappucino]

Early detection of over-heating and the prompt slowing down or stopping of the main engine as circumstances permit, will avoid conditions which might form an explosive mist in the crankcase.
In the majority of cases oil mist detectors are fitted to main engine crankcase to detect any buildup of a potentially explosive oil mist. All alarms from oil mist detectors, no matter how suspect the instrument may be, are to be treated as an emergency situation and the main engine stopped. Operation of a main engine with a positive alarm from a mist detector is only at the jurisdiction of the Master.
Under no circumstances is the alarm to be switched off until the main engine has been stopped. Great care must be exercised if the main engine has been stopped due to a positive alarm from an oil mist detector.
The most likely cause of such an alarm will be overheating of the bearing, or in the case of a trunk piston engine also the possibility of leaking piston rings. Sufficient time must elapse for cooling and mist dispersal before removing a crankcase door for examination.
In some ships bearing temperature sensors or bearing wear down monitoring systems are fitted for monitoring of the main engine bearing temperatures or wear down. Alarms are fitted to indicate high bearing temperatures and/or high bearing wear down. The alarms must be tested every 3 months.
CAUTION: Crankcase doors or inspection doors should not be opened until the engine has cooled down. DO NOT attempt to start the engine until reason of overheating has been ascertained. Ensure the LO flow is normal from all the bearings and LO pressure is normal. Ensure that bearing shells have not shifted or squeezed out.

[Author]

Posts