Marine Installation Manual
2021-08
4-86
4 Ancillary Systems
4.8 Leakage collection system and washing devices
X72DF
Solution 1: A constantly-drained sludge oil trap with separate sludge accumula
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tion
Solution 1 description
The main function of this system is to reduce the pressure of the sludge emulsion
from scavenge air pressure to just above atmospheric pressure, as well as to sep
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arate the solids from the liquids in the sludge emulsion.
Reducing the pressure prevents the sludge oil tank from becoming pressurised.
This is accomplished by the orifice being fitted onto the drain outlet pipe. To en
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sure a continuous drain flow, some scavenge air flows to the sludge oil trap. The
scavenge air is mainly released on the top of the sludge oil trap by passing
through an orifice to the venting pipe. At the same time, an additional small
amount is directed by an overflow pipe and through another orifice to the sludge
oil tank. This continuous drain flow ensures that the drain pipe will not block
and it will result in a scavenge air loss. The scavenge air loss is especially advan
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tageous compared to the other possible solutions that are described and will not
have any negative impact on the engine performance.
Separating the solids from the liquids will significantly reduce the risk of solid
particles causing the orifice to become blocked. The sludge oil trap collects the
solids from the bottom of the piston underside area. These solids settle at the
bottom of the sludge oil trap. At the same time, the liquid part is drained by an
overflow pipe (which is equipped with an orifice) to the sludge oil tank. As the
solids are separated and since the overflow pipe is located at the upper part of the
sludge oil trap, the risk of blocking the orifice by solid particles is significantly re
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duced. A sufficiently large opening near the bottom of the sludge oil trap is nec
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essary to be able to remove the rather sticky, thick sediment which will have
settled. This sediment will have a consistency closer to that of tar than of oil.
Near the bottom of the sludge oil trap, a large manhole cover is located and is po
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sitioned at the side of the sludge oil trap to enable removal of the sediment. A test
valve with a funnel is also provided to check whether the dirty oil freely flows
from the engine to the sludge oil trap and to make sure that the sludge oil trap
does not become completely filled.
A design proposal for the WinGD sludge oil trap is provided in
. The specific design dimensions for the sludge oil trap are provided in the
sludge oil trap drawings contained in the MIDS relevant for the leakage collec
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tion and washing system,
.