Fuel oil filter
Continuously automatic backflushing fuel oil filter
The automatic filters are designed specifically for full-flow
filtering of fuel oils for trunk piston and crosshead engines.
Unique features
" Robust disc-type filter elements.
" Continuous backflushing driven by filtered oil.
" Constant pressure drop across the filter.
" Filtered oil drives the backflushing process.
" Compact and lightweight.
" Refiltration of backflushed oil and removal of particles
collected from the system at the filter.
Key benefits
" Robust design reduces risk of filter element cracking.
" Continuous backflushing significantly prevents adhesion
of retained solids to filter surfaces, which results in:
 No manual cleaning of filter elements.
 Low and constant pressure drop across the filter
elements, which further reduces the risk of cracking.
" Use of filtered oil for backflushing process eliminates the
need for compressed air.
" Constant pressure drop across the filter, combined with the
pressure drop indicator, facilitates detection of malfunction
in the fuel oil system. Automatic fuel oil filter shown with electrical motor.
" Easy to install and to retrofit as an upgrade to existing
installations.
Rib Filter frame
Upper half
Filter element
}
Lower half
Filter screen
Figure 1. Full-flow element.
Diesel engine protection Distributor drive
The fuel oil conditioning system includes filters to remove The distributor, which creates the backflushing and self-
solid particles that may have entered the system after the cleaning feature of the filter, is driven by either an electrical or
separator, which is installed in the cleaning system. The filter hydraulic motor. This selection will depend on your application
hence prevents any potentially dangerous particles from and the location of the fuel oil filter in the fuel oil conditioning
reaching the sensitive parts of the diesel engine fuel system. system. Above 120°C the electrical motor is mandatory and
standard on the Alfa Laval booster units.
Diversion filter
elements
Electric motor
Distributor
Diversion filter
elements
Diversion chamber
Drain for
Full-flow chamber
diversion
chamber
Full-flow filter
elements
Full-flow
elements
Figure 2. Filtering unit. Figure 3. Fully assembled filter showing full-flow and diversion
chambers and electric motor.
Key: QCP = Circulation pump capacity P1 = Filter inlet pressure
Q1 = Maximum capacity of the filter P2 = Filter outlet pressure
QE = Fuel oil flow to the engine P3 = Backflushed oil outlet pressure
Q3 = Flow of backflushed cleaned oil PD = Pressure in deaerator
Engine pressure
control valve
Return from engine
From diesel
engine
G3
To diesel
engine
P3
PD
V21
QE
= P2
P3 Drain
P1
Q1
Recommended for
certain engines
Deaerator Heater
Circ.
pump
Filter
QCP
Figure 4. Protector automatic fuel oil filter, shown on the hot side of the booster module.
Operating principle The driving force for the automatic backflushing is the differ-
The unfiltered oil entering the filter is fed by the distributor ence in pressure between the clean-oil outlet (P2) and the
to seven of the eight full-flow filtering columns. Solids are backflushed oil outlet (P3) of the filter. A flow sheet illustrating
collected on the filter surface and the filtered oil flows to the the pressures, flow and capacity is shown in Figure 4.
engine. Solids previously collected are removed in the eighth
column by backflushing with a small amount of the filtered A pressure drop indicator, drain cock and counter flanges are
oil and taken through a passage in the distributor to the provided as ancillary equipment. Options exist for additional
diversion chamber. features, such as an automatic timer drain valve. In addition,
the Alfa Laval fuel oil filter is also available with a changeover
The distributor, which is driven by the hydraulic motor on valve, and built-in bypass filter (see Figure 5). This allows un-
top of the filter housing, rotates regularly to feed oil for filtra- interrupted operation during routine maintenance.
tion in seven columns and backflushing in the eighth. In this
way, all the columns are backflushed once per full rotation
of the distributor which corresponds to every one to two
minutes.
The backflushed oil with solids entering the diversion
chamber is filtered in seven of the eight columns and led
back to the deaerator. At the same time backflushing by
clean oil takes place in the eighth column and solids settle
to the bottom of the diversion chamber, where they are
periodically discharged through the drain cock.
The pressure drop indicator is connected between the inlet
and outlet of the full-flow chamber. It provides a reading and
signals an alarm condition if, for any reason, the pressure
drop reaches the alarm level. Figure 5. Duplex automatic/manual fuel oil filter.
Other Alfa Laval filtration products
Alfa Laval also manufactures filters for other engine room
applications, such as automatic filters both with and without
diversion chamber for lubricating oils, and manual indicator
and bypass filters.
After-sales support
Replacement components and after-sales service are
provided through a network of Alfa Laval subsidiaries and
representatives worldwide, including Marine Service Centres
in all major ports.
Technical data
Data Value
Filter outlet pressure (P2)
 Min. 2 Bar above pressure (P3)
 Recommended 3 5 Bar above pressure (P3)
Max. filter inlet pressure (P1) 15 Bar
Test pressure 30 Bar
Max. viscosity in the filter
at normal operation (hot side) 75 cSt
Guidelines to overall dimensions Max. temperature in the filter 160°C
For flow rates up to 20 m3/h: Alarm "p (P1 P2) 0.8 Bar
Height × Length × Width (mm): 900 × 250 × 250 Backflushing flow 15 20% of circulating
or with the built on bypass: 900 × 660 × 250 pump capacity (QCP)
Housing material Nodular cast iron
For flow rates from 20 to 30 m3/h: Filter screen material Stainless steel
Height × Length × Width (mm): 1620 × 500 × 450 Heating method Steam/hot water/thermal oil
or with the built on bypass: 1620 × 1130 × 450 Supply 110/220 V, 50/60 Hz,
single phase
Consumption 0.20 A (110 V), 0.10 A (220 V)
Filtration fineness Protection Class F, IP55, tropicalised
This can be defined depending on diesel engine requirements
and the specific application.
Technical documentation
Complete information and documentation for the main
Installation components and the installation, operation and maintenance
All Alfa Laval automatic fuel oil filters are designed for of the filter is contained in the Instruction Book that accom-
installation in the engine room. Flanges are according to panies delivery of each Alfa Laval filter. Your local Alfa Laval
DIN standards. company will be able to provide more details on the applica-
tion and sizing of Alfa Laval automatic filters.
The control of the electric motor of the fuel oil filter should be
installed on the booster module. When fitted with a hydraulic
motor, no external controller or energy supply is required.
EMD00046EN 0406 Alfa Laval reserves the right to change specifications without prior notification.
How to contact Alfa Laval
Contact details for all countries are
continually updated on our web site.
Please visit www.alfalaval.com to
access the information direct.
Height
Width
Length