English 
The radiant tube is the key equipment in the heating section of the continuous annealing furnace of the galvanizing unit. It is used to radiate the strip steel, eliminate the internal stress of the strip steel, improve the plasticity, and achieve the purpose of annealing. However, if the radiant tube leaks, it will cause great harm to the production and operation of the unit. The consequences may even affect the normal operation of production.To prevent the radiant tubes from being burned and to extend the service life of the radiant tubes, certain measures need to be taken.
1. Adjust the combustion ratio of combustion gas and combustion air. Because in a nitrogen protective atmosphere, excess oxygen will undergo strong nitriding and oxidation, causing corrosion and damage to the radiant tube, so the O2% content in the combustion exhaust gas is controlled below 2%. .
2. The gas pressure control valve and air pressure control valve should be sensitive in action and should not lag behind to ensure the stability of gas pressure and air pressure during combustion and ensure complete combustion of the gas.
3. The exhaust fan rotates smoothly to reduce the fluctuation of the combustion flame.
4. There should be no leakage in the heat exchanger of the combustion air to prevent the air from being sucked away by the exhaust fan and affecting the mixed combustion ratio of gas and air.
5. There should be no leakage in the connecting flange and seal of the heat exchanger to avoid the entry of outside cold air and to increase the temperature of the combustion air as much as possible.
6. If conditions and funds permit, a large heat exchanger should be installed to use the waste heat of the exhaust gas discharged outside the factory (up to 390°C) to preheat the air for the first time. After the air enters the heat exchanger in the burner radiant tube Secondary preheating air to increase the temperature of combustion air.
7. When the temperature of the radiant tube is >400°C (furnace temperature), it is strictly prohibited to open the furnace cover and disassemble the burner and heat exchanger to avoid cracks caused by shrinkage of the high-temperature radiant tube when exposed to cold air.
8. Try to arrange centralized production of strips with the same heating requirements.
9. Try to maintain the uniformity of the working temperature during production, and avoid quickly igniting the burner to heat up and stopping the burner for purging and cooling operations.
