TOPICS FOR SPEAKING
the viscosity of the oil is often so high that the transfer pump is unable to suck the
oil up from the tanks.
The transfer pump which can, for example, be a gear pump or a screw pump, sucks
fuel oil through a coarse filter and feeds it to one of two settling tanks. The fuel oil
is heated in the settling tanks up to 80 - 90º C to allow some water and sludge to
settle out by gravity and be drained off.
The fuel is then passed through the purification system and discharged to a service
tank. Two centrifuges are required to be used in a large engine. The first acts as a
purifier to remove water, soluble, sludge etc while the second acts as a clarifier to
remove solids.
From the service tank the oil flows to one of the electrically driven booster pumps.
From there it is fed through the preheater, and the fine filter to the engine fuel
pumps.
LUBRICATING SYSTEM
When two solids are in contact and move in relation to each other, there arises a
resistance to this movement known as friction, i.e
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