dunphy TAD4, Operating Manual

Page: 46 / 165

Operating Instructions For TD/TAD4 Dual Fuel Burner
June 13 46 of 165 TD/TAD4 Manual Rev 4
4.3.4 Oil Operating System Modulating Burners ART 106 Nozzle
Atomisation of the oil is by means of a single nozzle which works on the spill-back principle.
From the schematic diagram below it can be seen that when the oil supply is admitted to the
nozzle by the two main oil valves, the flow can either pass through the nozzle into the furnace or
can return down the spill line to the pump return.
The control of the oil volume is achieved by a metering valve in the spill line restricting the amount
of `spilled` oil and therefore increasing the volume that passes through the nozzle for combustion.
Control of both the metering valve and the air shutter is achieved by means of a modulating
motor which is positioned by potentiometer according to the control signal.
On burner shutdown both the main safety shut off valves and the return safety shut off valves
close simultaneously to isolate the nozzle and reduce any possibility of oil spillage into the furnace.