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AALBORG
INDUSTRIES
NOZZLE SELECTION; OM5560_38#F.1
Nozzle selection
1·
21-28/60
Descriptioll1
The selection
of
a nozzle to a modulating oil burner can be done on basis
of
Table 1
and two calculations. The table shows the nozzle number and oil throughput for max.
and min. load at a specified reference pressure. The supply pressure should be between
25 -
30 bar when running on both
DO
and HFO.
If
the burner only operates on DO,
the supply pressure can be between 20 - 30 bar.
The nozzle is a spill return type nozzle 12-W2 with a spray angle
of
60°. The regulating
range for this type
of
nozzle is between 25 - 100%
of
the total oil throughput.
Note: Ensure
that
the supply pressure does not fall below the above mentioned
settings. The
burner
can only operate
ifthe
pressure
is
sufficiently high
in
order
to withdraw the spring inside the nozzle head.
1.1
Selecting a nozzle size
When a nozzle is selected the required oil throughput must be known. The selection
should be made with regard to the above mentioned supply pressure settings.
If
the gap between two nozzles sizes results in a lower supply pressure than required,
the pressure must be increased to minimum 25 bar for HFO and 20 bar for DO. The
higher oil throughput caused by an increase
ofthe
supply pressure can be reduced by
limiting the oil regulator movement. This is done by adjusting the full load limit switch
in the servomotor to an appropriate lower position. The range
of
regulation is reduced
by this action.
1.2 Nozzle size
selection
Determining the nozzle size and supply pressure can be done either
by
using the charts
in
Figure I or by using Table I and the following formulas.
Language
UK
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