Oil/air regulation
The oil and air regulation for the burner are handled by two servomotors. The oil flowis regulated bya valve, which is regulated by a servomotor. The air damper is regulatedby a second servomotor.Figure 1 illustrates the regulator system.The servomotorsare controlled by the control system during start-up/stop and operationof the burner.
The oil quantity burned is determined by nozzle size and oil pump pressure. The oilregulator regulates the return oil flow according to the capacity demand. At partial loadthe oil regulator is open so that the oil throughput in the valve is at maximum and thereturn oil flow pressure at minimum. At full load the oil regulator is closed whereuponthe oil throughput is at minimum and the pressure at maximum.
The air quantity is matched to the fired oil quantity by means of the control system, which controls the servomotor for the air dampers.
Start sequence for burners with microprocessor control systems.
1) Pre-purge takes place with the air quantity of full load. During pre-purge period solenoid valves (4), (5), and (8) are closed and solenoid valve (15) is open, see Figure 1 and Figure 2.
2) Flushing period-At the end of the purging period the servomotors turn to the position of ignition load, solenoid valve (5) and (8) opens and a flushing sequence will take place, the nozzle valve is purged (pre-heated) during this period. The oil temperature regulation controls that the oil temperature is adequate during purging and atomising periods.
3)Atomizing period-After the flushing period is completed the solenoid valve (5) will close and the oil in the pre-heater will be heated. The burner will then go into the ignition step; solenoid valves (4) and (5) are opened and solenoid valve (3) closed. The electric arc between the ignition electrodes ignites the oil spraying from the nozzle.
4)Burner operation- The oil quantity to be fired is regulated by means of the oil regulator (12) by throttling the return flow. At partial load the oil regulator is open and at full load closed. During burner operation the control system drives the servomotors, which again drives the oil regulator and the air dampers between partial load and full load according to the steam demand.
5)Shut down- If the burner shuts down, solenoid valves (4), (5), and (8) close, and solenoid valve (3) opens. The oil pressure is released from the nozzle valve. The nozzle valve spring-back closes the needle valve in the nozzle and closes the oil flow in the nozzle. At full load the atomising pressure is approx. 20-25 bar when operating on MDO or MGO and approx. 25-30 bar on heavy fuel oil. The return pressure of the oil measured at manometer position 2 can vary from the lowest possible for the nozzle at low load and up to max 30 bar(g) at full load. The return flow pressure is determined according to the position of the oil regulator.
The oil and air regulation for the burner are handled by two servomotors. The oil flowis regulated bya valve, which is regulated by a servomotor. The air damper is regulatedby a second servomotor.Figure 1 illustrates the regulator system.The servomotorsare controlled by the control system during start-up/stop and operationof the burner.
The oil quantity burned is determined by nozzle size and oil pump pressure. The oilregulator regulates the return oil flow according to the capacity demand. At partial loadthe oil regulator is open so that the oil throughput in the valve is at maximum and thereturn oil flow pressure at minimum. At full load the oil regulator is closed whereuponthe oil throughput is at minimum and the pressure at maximum.
The air quantity is matched to the fired oil quantity by means of the control system, which controls the servomotor for the air dampers.
Start sequence for burners with microprocessor control systems.
1) Pre-purge takes place with the air quantity of full load. During pre-purge period solenoid valves (4), (5), and (8) are closed and solenoid valve (15) is open, see Figure 1 and Figure 2.
2) Flushing period-At the end of the purging period the servomotors turn to the position of ignition load, solenoid valve (5) and (8) opens and a flushing sequence will take place, the nozzle valve is purged (pre-heated) during this period. The oil temperature regulation controls that the oil temperature is adequate during purging and atomising periods.
3)Atomizing period-After the flushing period is completed the solenoid valve (5) will close and the oil in the pre-heater will be heated. The burner will then go into the ignition step; solenoid valves (4) and (5) are opened and solenoid valve (3) closed. The electric arc between the ignition electrodes ignites the oil spraying from the nozzle.
4)Burner operation- The oil quantity to be fired is regulated by means of the oil regulator (12) by throttling the return flow. At partial load the oil regulator is open and at full load closed. During burner operation the control system drives the servomotors, which again drives the oil regulator and the air dampers between partial load and full load according to the steam demand.
5)Shut down- If the burner shuts down, solenoid valves (4), (5), and (8) close, and solenoid valve (3) opens. The oil pressure is released from the nozzle valve. The nozzle valve spring-back closes the needle valve in the nozzle and closes the oil flow in the nozzle. At full load the atomising pressure is approx. 20-25 bar when operating on MDO or MGO and approx. 25-30 bar on heavy fuel oil. The return pressure of the oil measured at manometer position 2 can vary from the lowest possible for the nozzle at low load and up to max 30 bar(g) at full load. The return flow pressure is determined according to the position of the oil regulator.
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