Flue cooling back blowing device

The utility model particularly relates to a flue cooling back blowing device, which belongs to an electric furnace smoke gas afterheat utilization and dust removal system and comprises a flue, compressed air pipes and a temperature measuring thermocouple, wherein a compressed air pipeline formed by a plurality of compressed air pipes is arranged at a bending end part of the flue, the upper ends of the compressed air pipes are communicated with a compressed air valve station, the temperature measuring thermocouple is arranged at the back side of the compressed air pipeline and is connected with a programmable controller, and the programmable controller outputs control signals to an electromagnetic valve of the compressed air valve station. The flue cooling back blowing device adopts a programmable logic controller (PLC) for controlling different combinations of the electromagnetic valves collocated on first to seventh pipelines, different air quantities can be blown in, the strong blowing is adopted when the s