Crankcase Explosion Page 8 Flashcards
What is the name of the equipment used to warn of conditions that could lead to a crankcase explosion in a diesel engine?
Oily Mist detector
What device is used to relieve excess pressure from a crankcase explosion in a diesel engine?
Spring loaded self-closing valve stops entry of atmospheric air into cylinder.
A strong spring seals the valve during normal conditions; however, in the event of excess pressure caused by an explosion, it overcomes the spring force briefly to allow pressure to escape before re-closing. Oil wetted gauze prevents flame escaping.
What actions should the Engineer Officer of the Watch take when an alarm condition is activated on the oil mist detector?
- Inform the bridge and request the engine to be slowed down, informing Chief Engineer and Master.
- If the engine cannot be stopped, evacuate the engine-room, shut and secure all doors, open skylights, set up boundary cooling, and keep clear from all doors.
- Start Emergency Generator.
- Once the engine is stopped, stop auxiliary blowers.
- Shut off fuel supply.
- Stop all engine room fans.
- Maintain lubrication.
- Maintain cooling.
- Engage turning gear and start.
What are four possible sources of ignition in the crankcase of a large marine diesel engine?
- Overheated bearing (Hot spots)
- Piston blow by (Trunk only)
- Piston skirt seizure
- Scavenge fire overheating diaphragm plate
Piston rod binding on stuffing box is also a source of ignition.
What are two methods to detect a potentially dangerous situation within the crankcase?
- Oil mist detector
- Bearing temperature monitor
3.Plash oil monitor is also a detection method.
What are two indications that could signify a possible dangerous situation within the crankcase?
- Incongruous noise from crankcase
- Irregular running of main engine
3.A smell of oily mist at the bottom deck of the engine room is also an indication.
