As one of the important equipments in the rotary kiln system, the cooling machine materials in which have full heat exchange with the air in the barrel. The material temperature will be below 200 ℃ and all the air for cooling materials gets into the kiln so as to improve the thermal efficiency of the kiln. The structure of the cooling machine is reasonable, of simple operation and high efficiency. Mainly composed by the cylinder, the raising plate, reducer, hot air channel and the cooling water, the cooling machine is widely used in metallurgy, building materials, light industry, chemical industry and coal industry etc..