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2.06
, Gas
1011 BC
Pipe Materials/Velocities and
pressure Losses
Steel pipes are normally used for the fresh water
systems and aluminum-brass for the sea water
systems.
Types and materials of standard coolers are, based
on fresh water, as follows:
Jacket water cooler, plate type:
Plates of stainless steel if cooled by freshwater.
Plates of titanium if cooled by seawater.
Lubr. oil cooler, plate type:
Plates of stainless steel.
Charge air cooler, tubular type:
Tubes of CuNi.
Gear oil cooler:
Type and material according to supplier
specifications.
Central cooler, plate type:
Plates of titanium (sea water).
In order to prevent excessive pressure losses and
erosion in the piping systems the water velocities
should not exceed the following:
Fresh water systems w. steel pipes:...............4.0 m/s
(Closed system)
Sea water systems with aluminum-brass pipes:
.............................................(in a pressure pipe) 3.0 m/s
...............................................(in a suction pipe) 2.0 m/s
Very low water velocity may cause deposits in the
piping system.
The velocity in fresh water as well as in sea water
systems should not be lower than:................1.0 m/s
Normal pressure losses are:
0.40 bar in the high temperture stage of
charge air cooler
0.20 bar in the engine‘s water jacket
Very low pressure may cause pitting in the engine‘s
water jacket. Jacket water pressure should not be
lower than:...............................................................1.5 bar
0.4 bar in low temp. stage of charge air cooler
0.4 - 0.6 bar in lubricating oil cooler
0.3 - 0.4 bar in jacket water cooler
For pressure losses in the different coolers,
the suppliers have to be consulted.
Thermostatic valves,
high temperature system
In the high temperature cooling water system, a
thermostatic valve (65HT) is being used. This is a
diverting application where the valve directs the
water either to cooling or returns it to the suction
side of the built on HT cooling water pump, ref.
pumps and capacities.
The Bergen Engine standard is a wax element type
valve.
The wax element valve type has a temperature
range of:...............................................................82 - 91 °C
For good temperature control,the pressure
loss in the valve should be:....................0.14 - 0.5 bar
As an option, we can supply a electrical/pneumatical
valve with a temperature sensor on the engine and a
control unit.
The electrical/pneumatical valve is operated by the
engine control system which reads temperature
from the sensor on the engine. It has a programable
set-point, and works to keep the temperature stable
at 90 °C.
Thermostatic valves,
low temperature system
Recirculation of the the low temperature fresh water
with a thermostatic control valve, is important in
order to obtain a good combustion and to prevent
water condensation in charge air coolers at low
engine load.
For the low temperature cooling water system a
mixing valve is used to mix cooled water from the
fresh water cooler (central cooler) with hot by-pass
water from the engine to get an optimal inlet
temperature to the engine suction side.
In the low temperature cooling water system,
a thermostatic valve (65LT) is being used.
The Bergen Engine standard is a wax element type
valve.
The standard wax element type valve has a
temperature range of: ....................................29 - 41 °C
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