Safety control requirements for gas burners

Safety control requirements for Low NOx gas burners

1.Pre-blowing
Before the burner is ignited, there must be a period of pre-blowing to blow away or dilute the remaining gas in the furnace and flue. Because there is inevitably residual gas in the working furnace of the burner, if it is ignited without pre-blowing, there is a risk of explosion. The residual gas must be blown away or diluted to ensure that the gas concentration is not within the explosion limit. The pre-blowing time is related to the furnace structure and air blowing volume and is generally set to 15-60 seconds.
2. Automatic ignition
Gas burners should use electric spark ignition to facilitate automatic control. A high-voltage ignition transformer can be used to generate arc ignition, and its output energy is required to be: voltage ≥3.5K V, current ≥15mA, and the ignition time is generally: 2 to 5 seconds. ​
3. Combustion status monitoring
The combustion state must be dynamically monitored. Once the flame detector senses a flameout signal, it must be fed back to the burner in a very short time. The burner will then enter the protection state and cut off the gas supply. The flame detector must be able to sense flame signals normally and should not be sensitive or slow. Because of its sensitivity, if the combustion state fluctuates, it is easy to cause malfunction and become slow, and the feedback flame signal lags behind, which is not conducive to safe operation. It is generally required that the response time from the flameout to the flame detector sending out the flameout signal does not exceed 0.2 seconds. ​
4. Protection against fire
When the burner is ignited, gas is introduced and the gas ignites and burns. The ignition action is required to occur before the gas is introduced, and an ignition temperature field is formed first to facilitate ignition and combustion. If the ignition fails, the flame detector cannot detect the flame signal, and the burner enters the protection state. The time from ignition to entering the protection state must be appropriate, neither too short nor too long. If it is too short, there will be no time to form a stable flame; if it is too long, a large amount of gas will enter the furnace when the fire cannot be ignited. It is generally required that the burner will judge the flame signal sensed by the flame detector after 2-3 seconds of passing the gas. If it is not on fire, it will enter the protection state, and if it is on fire, it will maintain combustion. ​
5. Flameout protection
During the combustion process of the Low Nitrogen Gas Burner, if it accidentally flames out, the burner will enter the protection state. Because the furnace is hot. Deflagration is likely to occur when gas enters, so it must enter the protection state in a very short time and cut off the gas supply. From the occurrence of flameout to the burner entering the protection state, the response time of this process is required to be no more than 1 second.www.burners-china.com

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