Oil Mist Detector is equipment which monitors the environment inside a crankcase space of an internal combustion engine and thus tells the engineer, in case of formation of any type of explosive vapors occurring in the crankcase of engine. This is a preventive step avoiding crankcase explosion taking place. Here is the step by step procedure, to be followed in case of an alarm.
What Causes Oil Mist Detector Alarm
This piece of equipment is needed to monitor the environment inside the crankcase. Oil vapors of lube oil are constantly formed inside crankcase and they possess a hazard of crankcase explosions. So, to avoid that, OMD (Oil Mist Detector) will keep taking samples of air, from the connected space at an interval of 1.5 sec to 2 seconds. Then after this it will measure it with the standard value, plus the values from other units as well. If the reading is out of limit, alarm comes in.
Measures to be taken After Oil Mist Detector Alarm
Following is the step by step procedure for the same:
1) First thing, first, accept the alarm from the panel.
2) Inform the bridge and chief engineer and side by side initiation of Slow Down the engine.
3) Press Engineers alarm, to call the required manpower for the same.
4) Check that alarm which has come is true or not. Just reset it and see if it comes again. Sometimes, false alarms also come in engine room.
5) Next step is to increase the lubrication of the main engine, by starting the standby lubrication pump.
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6) As soon as bridge gives you command for stopping engine, you are ready to stop it. Bridge can also do that, depending on the situation.
7) Indicator cocks of the units needs to be opened.
8) This will be followed by one man engaging the turning gear and start turning the engine. This is a counter measure to avoid piston getting stuck.
9) In the mean time, this is happening; other manpower can keep the fire extinguishers ready. Lubrication should be kept on all the times.
10) As a precautionary measure, make sure that nobody is standing near or close to the crankcase relief door. As pressure relieve by them can be too much, which may prove fatal.
11) When the alarm has gone, you can switch off the lube oil pump. With the back of your hand, feel the crankcase door. If they are cool, then we can proceed further, otherwise wait for them till the time, they are cooled. You may also look for any sign of paint color change on the doors.
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12) When it is cooled down to normal temperature, open the crankcase door. Two, three ventilation blower are to be kept for ventilating the crankcase space.
13) Now it is time to go inside and make few checks. But before that, make sure that, the light that you are using
is flame proof. Also, you boiler suit is clean and free of any oil. Both the sleeves needs to be rolled down, as there might be hot surface inside.
is flame proof. Also, you boiler suit is clean and free of any oil. Both the sleeves needs to be rolled down, as there might be hot surface inside.
14) Check for any sign of local hot spot. Try to see for any sort of metal particles etc. Rectify the same.
15) Now again start the lube pump and see the flow.
Note: This was all, which you need to do, during an OMD alarm. The procedure might differ from people to people, as different people have different approaches. This is just a general approach.
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15 ) Start the pump with crankcase door open ?