Control requirements for gas burners at work

1. Pre-blowing.

Before ignition, the low-nitrogen gas burner must have a pre-blower for a period of time to blow off or dilute the residual gas in the furnace and flue. Since there will inevitably be residual gas in the working furnace of the burner, if it is ignited without pre-blowing, there is a danger of explosion. The residual gas must be blown and diluted to ensure that the gas concentration is not within the explosive range. The pre-blowing time is related to the furnace structure and blowing volume, and is generally set to 15-60 seconds. the

2. Automatic ignition. 

Gas burners should be ignited by electric sparks for easy automatic control. The high-voltage ignition transformer can be used to generate arc ignition, and its output energy is required to be: voltage ≥ 3.5KV, current ≥ 15mA, and the ignition time is generally 2~5 seconds. the

3. Combustion state monitoring.

Combustion status must be monitored dynamically. Once the flame detector senses the flameout signal, it must feed back to the burner in a very short time, and the burner immediately enters the protection state and cuts off the gas supply. The flame detector should be able to perceive the flame signal normally, neither sensitive nor dull. Due to the 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. The response time from the flameout to the flame detector sending out the flameout signal is generally not more than 0.2 seconds. the

4. The protection point does not catch fire. 

When the burner is ignited, gas is introduced, and the gas ignites and burns. The ignition action requires the formation of an ignition temperature field before the gas enters, which is convenient for ignition and combustion. If there is no fire, the flame detector cannot perceive the flame signal, and the burner will enter the protection state. The time from ignition to protection should 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, the fire will not ignite, causing a large amount of gas to enter the furnace. Usually the burner is required to judge the flame signal sensed by the flame detector within 2-3 seconds after the gas is turned on, enter the protection state when it is not on fire, and maintain combustion when it is on fire. the

5. Flameout protection.

During the combustion process, if the burner goes out unexpectedly, the burner will enter the protection state. Because the furnace is hot, the gas is easy to deflagrate when it enters, so it needs to enter the protection state in a short time to cut off the gas supply. From flameout to burner entering protection state, the response time of the process shall not exceed 1 second. 

6. Air pressure high and low limit protection.

The gas burner has a certain stable combustion range, and only allows the gas pressure to fluctuate within a certain range. The purpose of limiting the high and low pressure of gas is to ensure the flame stability: no flameout, no flameout, no backfire, and at the same time limit the output heat power of the burner to ensure the safe and economical operation of the equipment. When the air pressure exceeds this range, the burner should be locked out.

www.burners-china.com