If the gas flow inside the burner decreases continuously, which means that the air flows more slowly and the blue cone is lower and lower, the flame will become smaller inside the burner at last because of the air flow is slower than the flame propagation. It is called gas hob tempering.
When it is burning to temper, it will appear a tempering noise and the burning in the pipelines near the nozzles will continue to produce noises. The sudden closure of the valve also will cause the tempering noise with the fire extinguishing. And coal oven gas is more prone to tempering noise than natural gas and liquefied petroleum gas.
The opening of air regulating plate is too large so that the primary air coefficient will be too large too, which is easy to cause tempering. Adjusting the air regulating plate can exclude it.
Gas pipeline, valve, burner nozzle and fire-L are blocked by food scums, carbon black and other materials, add in the lack of gas pressure in the liquefied gas cylinder, which will lower gas flow velocity to cause tempering. Cleaning the dirts and inflating gas into the liquefied gas cylinder can avoid it.
The nozzle is eccentric or not positive and it will hamper the gas emission that causes tempering. At this time, it should correct the center line of gas nozzle or replace it.
Gas burning time is too long and the ejector tube and nozzle temperature is too high, which will accelerte the burning speed to cause tempering. At this time, turn off the gas and cool the ejector tube and nozzle before reignition.