Wartsila ?31DF Series Product Manual page 114

6. Fuel Oil System
Fuel viscosity
Design temperature
Design flow
Design pressure
Fineness:
- automatic filter
- by-pass filter
Maximum permitted pressure drops at 14 cSt:
- clean filter
- alarm
6.4.5.5 Fine filter, MDF (1F05)
The fuel oil fine filter is a full flow duplex type filter with steel net. This filter must be installed
as near the engine as possible.
The diameter of the pipe between the fine filter and the engine should be the same as the
diameter before the filters.
Design data:
Fuel viscosity
Design temperature
Design flow
Design pressure
Fineness
Maximum permitted pressure drops at 14 cSt:
- clean filter
- alarm
6.4.5.6 MDF cooler (1E04)
The fuel viscosity may not drop below the minimum value stated in Technical data. When
operating on MDF, the practical consequence is that the fuel oil inlet temperature must be
kept below 45°C. Very light fuel grades may require even lower temperature.
Sustained operation on MDF usually requires a fuel oil cooler. The cooler is to be installed in
the return line after the engine(s). LT-water is normally used as cooling medium.
If MDF viscosity in day tank drops below stated minimum viscosity limit then it is recommended
to install an MDF cooler into the engine fuel supply line in order to have reliable viscosity
control.
Design data:
6-30
According to fuel specification
50°C
Equal to feed pump capacity
1.6 MPa (16 bar)
6 μm (absolute mesh size)
(ß = 75, ISO16889)
20
25 μm (absolute mesh size)
(ß = 75, ISO16889)
40
20 kPa (0.2 bar)
80 kPa (0.8 bar)
according to fuel specifications
50°C
Larger than feed/circulation pump capacity
1.6 MPa (16 bar)
34 μm (absolute mesh size)
(ß = 75, ISO16889)
50
20 kPa (0.2 bar)
80 kPa (0.8 bar)
Wärtsilä 31DF Product Guide
DBAE248994