Wartsila ?31DF Series, Product Manual, Page: 121 / 216

6.4.6.4 Safety filter, HFO (1F03)
The safety filter is a full flow duplex type filter with steel net. The filter should be equipped with
a heating jacket. The safety filter or pump and filter unit shall be installed as close as possible
to the engine.
Design data:
According to fuel specification Fuel viscosity
150°C Design temperature
Equal to circulation pump capacity Design flow
1.6 MPa (16 bar) Design pressure
34
μ
m (absolute mesh size)
(ß
50
= 75, ISO16889)
Filter fineness
Clean filter: 20 kPa (0.2 bar)
Alarm: 80 kPa (0.8 bar) Maximum permitted pressure drops at 14 cSt:
6.4.6.5 Overflow valve, HFO (1V05)
When several engines are connected to the same feeder/booster unit an overflow valve is
needed between the feed line and the return line. The overflow valve limits the maximum
pressure in the feed line, when the fuel lines to a parallel engine are closed for maintenance
purposes.
The overflow valve should be dimensioned to secure a stable pressure over the whole operating
range.
Design data:
Equal to circulation pump (1P06) Capacity
1.6 MPa (16 bar) Design pressure
150°C Design temperature
DBAE248994 6-37
6. Fuel Oil System Wärtsilä 31DF Product Guide