WÄRTSILÄ 46F Series, Product Manual

Page: 75 / 208

6.3.5.1 Circulation pump, MDF (1P03)
The circulation pump maintains the pressure at the injection pumps and circulates the fuel in
the system. It is recommended to use a screw pump as circulation pump. A suction strainer
with a fineness of 0.5 mm should be installed before each pump. There must be a positive
static pressure of about 30 kPa on the suction side of the pump.
Design data:
Allowed range at 2 cSt: see chapter Technical Data Capacity
1.6 MPa (16 bar) Design pressure
1.2 MPa (12 bar) Max. total pressure (safety valve)
see chapter "Technical Data" Nominal pressure
50°C Design temperature
90 cSt Viscosity for dimensioning of electric
motor
6.3.5.2 Flow meter, MDF (1I03)
If the return fuel from the engine is conducted to a return fuel tank instead of the day tank,
one consumption meter is sufficient for monitoring of the fuel consumption, provided that the
meter is installed in the feed line from the day tank (before the return fuel tank). A fuel oil cooler
is usually required with a return fuel tank.
The total resistance of the flow meter and the suction strainer must be small enough to ensure
a positive static pressure of about 30 kPa on the suction side of the circulation pump.
There should be a bypass line around the consuption meter. For mechanical flowmeter, the
bypass line should open automatically in case of excessive pressure drop.
6.3.5.3 Fine filter, MDF (1F05,1F10)
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:
according to fuel specifications Fuel viscosity
50°C Design temperature
Larger than feed/circulation pump capacity Design flow
1.6 MPa (16 bar) Design pressure
34
μ
m (absolute)
(ß
50
= 75, ISO16889)
Fineness
Maximum permitted pressure drops at 14 cSt:
20 kPa (0.2 bar) - clean filter
80 kPa (0.8 bar) - alarm
DAAB605814 6-19
6. Fuel Oil System Wärtsilä 46F Product Guide