Auxiliary engines operating on HFO having a viscosity of max. 380 cSt / 50°C may have a common lubric-
ating oil separator unit. Two engines may have a common lubricating oil separator unit. In installations with
four or more engines two lubricating oil separator units should be installed.
Separators are usually supplied as pre-assembled units.
Typically lubricating oil separator units are equipped with:
•
Feed pump with suction strainer and safety valve
•
Preheater
•
Separator
•
Control cabinet
The lubricating oil separator unit may also be equipped with an intermediate sludge tank and a sludge
pump, which offers flexibility in placement of the separator since it is not necessary to have a sludge tank
directly beneath the separator.
Separator feed pump (2P03)
The feed pump must be selected to match the recommended throughput of the separator. Normally the
pump is supplied and matched to the separator by the separator manufacturer.
The lowest foreseen temperature in the system oil tank (after a long stop) must be taken into account when
dimensioning the electric motor.
Separator preheater (2E02)
The preheater is to be dimensioned according to the feed pump capacity and the temperature in the system
oil tank. When the engine is running, the temperature in the system oil tank located in the ship's bottom is
normally 65...75°C. To enable separation with a stopped engine the heater capacity must be sufficient to
maintain the required temperature without heat supply from the engine.
Recommended oil temperature after the heater is 95°C.
The surface temperature of the heater must not exceed 150°C in order to avoid cooking of the oil.
The heaters should be provided with safety valves and drain pipes to a leakage tank (so that possible
leakage can be detected).
Separator (2S01)
The separators should preferably be of a type with controlled discharge of the bowl to minimize the lubric-
ating oil losses.
The service throughput Q [l/h] of the separator can be estimated with the formula:
where:
volume flow [l/h]
Q =
engine output [kW]
P =
number of through-flows of tank volume per day: 5 for HFO, 4 for MDF
n =
operating time [h/day]: 24 for continuous separator operation, 23 for normal dimensioning
t =
Sludge tank (2T06)
The sludge tank should be located directly beneath the separators, or as close as possible below the sep-
arators, unless it is integrated in the separator unit. The sludge pipe must be continuously falling.
Renovating oil tank (2T04)
In case of wet sump engines the oil sump content can be drained to this tank prior to separation.
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Product Guide Wärtsilä 34DF - 3/2012
Product Guide
7. Lubricating Oil System
