Make electricity, coal, gas or fuel oil as heat source, thermal radiation as work principle to dry or roast material. The circulate hot wind of draught fan can make the material being heated evenly and keep the material into the situation of good quality, color and taste. It is composed by feeding device, speed regulating motor, drive mechanism, circulating fan, electric cabinet and other parts. Control blowing rate and set the temperature of the material being heated by regulating running speed to ensure best roasting effect.