2.
2.
Burner operation
Burner operation
2.1.
2.1.
Burner operation 3-stage ( T ) burners
Burner operation 3-stage ( T ) burners
2.1.1
2.1.1
Combustion air
Combustion air
A burner device has been provided with a fan that is tailored to produce high and steady
enough air pressure that is required to get a flawless ignition and good combustion in a
modern combustion chamber. A servomotor controls the amount of air feeded according
to the amount of fuel combusted.
2.1.2
2.1.2
Pre-ventilation, purging and ignition
Pre-ventilation, purging and ignition
Before ignition the burner runs through the pre-ventilation and purging periods.
During the pre-ventilation period the burner fan is ran with full load settings to exhaust
explosive fumes from the boiler.
Purging period flushes the nozzle valves and the utilisation circuit. The nozzle valve is
preheated and the oil temperature controller ensures adequate temperature has been
reached for fuel atomizing.
During purging period solenoid valves (NC) are closed and solenoid valve (NO) is open.
During this time oil flows through the stage-1 nozzle control circuit but as not wnough
pressure to open the nozzle since the solenoid valve (NO) is open allowing a return flow
to the tank.
After the end of the purging period servomotor turns the air dampers to stage-1 position
and solenoid valve (NO) closes. The oil pressure begins to take effect on the nozzle
piston and the spring-loaded nozzle valve opens. Oil flows from nozzle 1. Spark between
the ignition electrodes ignites oil spraying from the nozzle. Burner operates at stage 1.
2.1.3
2.1.3
Atomizing
Atomizing
To get a sufficient viscosity for the fuel atomizing the oil temperature is raised with a
preheater device. The temperature of the heated oil is controlled electronically.
In-let oil pressure to the pump varies case-specificly; See 'Pump adjustments'.
Atomizing pressure is provided by the burner oil pump.
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RPMARINES 30840641GB
2. Burner operation