As a mechatronic equipment with a high degree of automation, the burner can be divided into five major systems based on its functions: air supply system, ignition system, monitoring system, fuel system, and electronic control system. These five major systems will not be discussed here. We will mainly explain the detailed working process of the burner. Only by understanding the working process of the burner can we perform maintenance and troubleshooting when the burner fails.

Introduction to the working process of the burner

Let’s take the most complex proportional gas burner as an example. Its working process has four stages: preparation stage, pre-purge stage, ignition stage and normal combustion stage.

gas burner

Preparation stage: After the program controller is powered on, it starts the internal program self-test. At the same time, the servo motor drives the damper to the closed state. After the program self-test is completed, it is in the standby state. When the thermostat, over-high or low gas pressure switch, steam boiler steam pressure When the limit switch such as the switch is allowed, the program controller starts and enters the pre-purge stage. If the solenoid valve group is equipped with a leakage detection system, the system will first perform valve leakage detection when the above-mentioned limit switch allows it. After the detection passes, it will enter the pre-purge stage.

Pre-purge stage: The servo motor drives the damper to the high-fire opening state. At the same time, the fan motor starts and starts to supply air for 13 seconds to blow in air for pre-purge. Depending on the program controller, after about 20 to 40 seconds of purging, The servo motor drives the damper to the ignition opening state, ready for ignition. During the entire pre-purge stage, the air pressure switch measures the air pressure. Only when the air pressure is maintained at a high enough level can the pre-purge process continue.

Ignition stage: After the servo motor drives the damper to the ignition opening state, the ignition transformer works and outputs high voltage to the ignition electrode to generate ignition sparks. After about 3 seconds, the program controller sends power to the safety solenoid valve and proportional solenoid valve. , after the valve is opened, the gas reaches the combustion head, mixes with the air provided by the fan, and then is ignited. Within 2 seconds after the valve is opened, the ionization electrode should detect the presence of flame. Only in this way, the program controller will continue the subsequent program. Otherwise, the program controller will lock and disconnect the solenoid valve to stop the gas supply and alarm at the same time. (Ignition within the motor starting time)

gas burner

Normal combustion stage: After a few seconds of normal ignition and stable combustion, the servo motor drives the damper to the high fire opening state (the oil pump of the fuel engine is opened to start fuel injection). At the same time, the servo motor of the proportional gas regulating valve cuts in, and adjusts the valve according to the air pressure. and furnace back pressure to adjust the gas pressure behind the gas valve to adjust the gas volume to achieve stable and efficient combustion. Thereafter, the burner automatically switches between small and large fires and shuts down according to the requirements of each limit switch.

In addition, an ionization electrode and an air pressure switch monitor the burner throughout the combustion process.