An HT gas burner with very high turndown ratio was developed and utilized specially for low and moderate temperature furnaces. The burner was equipped with a combustion chamber of dual swirlers design. Therefore, an intensive recirculation zone was formed to stabilise its flame. A turndown ratio of its load could reached as high as 50: 1. The burner could also operated at very high efficiency of combustion. In order to get a longer life of the burner a combined cooling method had been employed to protect its flame tube successfully so that the highest wall temperature was no more than 850 K, well below the material's oxidising temperature.