51
Air Flow Adjustment
Oil Flow and Gas Rate Adjustment
Air adjustment
Check that the air swirler setting is in
accordance with the furnace/ combu-
stion chamber geometry and re-set if
required. In order to ensure uniform dis-
tribution, close the air swirler at the air
pipe entry against air inlet. The air curve
of the compound controller is factory-set
so that the air cylinder is closed at mini-
mum settings and open at maximum
settings.
The combustion air ratio (secondary air)
to the fuel can be obtained over the
whole of the output range by turning the
screws, which is then checked by
measuring the exhaust.
Before the compound controller screws
can be adjusted, the lock nuts on the
front face and underside of the com-
pound controller must be loosened. Set-
ting of the primary air is also carried out
via a cam disk and it can be set accura-
tely by adjusting the threaded studs as
required. With a large control range the
minimum combustion output is set by
means of the primary air.
During adjustment care must be exerci-
sed to ensure that over the whole of the
control range the air pressure at the
central pipe (primary side) is 1.5 - 2
mbar higher than the combustion cham-
ber pressure.
Oil adjustment
For taking into operation, the oil control
block with flow control valve in the
return line will be preset. The pump
pressure is set at approx. 28 bar and
the pressure upstream of the control
valve at approx. 5 to 18 bar. After loose-
ning of the lock screws of the socket-
headed studs and sliding ball, the con-
trol curve is adjusted over the whole
control range by means of the cam disk,
after which setting is then locked with
the lock screws.
Heavy fuel oil
Heavy fuel oils must generally be hea-
ted up. On the one hand, this is perfor-
med in the fuel oil storage tank to keep
the oil in a pumpable state because the
temperature must be above the setting
point. Further preheating is required in
the service tank, fluid preheater or elec-
tric preheater to ensure the heavy fuel
oil can be properly atomized and burns
readily. The level of preheating depends
on the viscosity of the fuel oil and can
be determined from the viscosity-tem-
perature diagram. The atomizing visco-
sity is at 12 to 15 cSt.
Gas adjustment
The gas damper is connected to the
mechanical compound controller by
means of a transmission arm.
The gas cam of the compound control-
ler is factory-set so that the gas damper
is closed in its minimum position and
open in its maximum position.
The minimum and maximum positions
and the intermediate positions of the
gas damper are also adjusted with the
electronic compound controller. The gas
pressure must be corrected by means
of the gas pressure controller if neces-
sary. The setting must be checked by
making a combustion analysis.
Spindle-
flame
Long
flame
Average length
flame
Short
flame
Air swirler
position
Flame formation
POS 1
Air swirler angle
Pressure loss
0 - 20°
30 mbar
POS 2
Air swirler angle
Pressure loss
20 - 40°
38 mbar
POS 3
Air swirler angle
Pressure loss
40 - 55°
45 mbar
POS 4
Air swirler angle
Pressure loss
55 - 70°
55 mbar