Main Engine Scavenging Space Explosion The vessel was drifting when an explosion in the scavenging space occurred right after an “air blow,” resulting in the M/E being unable to start. At that time, the vessel was about to proceed to the pilot station and pick up the pilot. The vessel had started preparing the main engine, but right after the “air blow,” the crew found smoke coming out from the indicator valve and then, found the engine unable to start due to high temperature and low pressure of the scavenging space. An investigation revealed parts of the scavenging space, especially around the non-return valve manifold box, were broken and deformed due to the explosion.
The root cause is assumed as the use of flammable materials such as gas oil and kerosene for scavenging space cleaning while drifting.
1.The remaining flammable liquid vaporized in the scavenging space forming a combustible atmosphere.
2.During “turning” for the M/E preparation, the combustible atmosphere transferred into the cylinder via the scavenging port.
3.The “air blow” moved the shaft and piston, compressing the combustible atmosphere at the same time up to approximately 600 degrees Celsius and the atmosphere self-ignited.
4.The combustion wave in the cylinder propagated to the scavenging space filled with combustible atmosphere, causing an explosion in this space.
Never use flammable materials that may vaporize, such as gas oil or kerosene, to clean inside the scavenging space.
posted 17 May '17, 21:38