Gas-fired radiant tube surface temperature distribution uniformity is an important technical performance indicators, it affects the radiant tube heating capacity, heating quality and the service life of radiant tube.The uniformity of temperature distribution in radiant tube surface can be characterized by its temperature coefficient of inhomogeneous, uneven temperature coefficient is smaller, the temperature distribution more uniform.Often use deviation of radiant tube temperature distribution in engineering to determine the surface temperature distribution uniformity.The traditional u-shaped radiant tube temperature distribution difference usually for plus or minus 20 ~ + 50 ℃.And after the HTAC technology renovation, due to the high temperature air combustion flame itself the uniformity of temperature distribution and preheated air and high temperature flue gas of high frequency switch, make the radiation tube air flow frequent commutation, radiant tube wall temperature distribution more uniform, radiant tube temperature distribution of the difference between the surface temperature distribution of difference can be reduced to plus or minus 10 ℃ or so.