APPARATUS FOR RETRIEVING HEAT AT RADIANT TUBE OF HEATING FURNACE

摘要

PURPOSE: A heat retrieving apparatus is provided to retrieve heat at a radiant tube of a heating furnace by enlarging a heat exchange area between waste gas generated by combustion gas and combustion air supplied from an exterior. CONSTITUTION: A radiant tube having a burner, which supplies heat for heat-treating a steel plate in a heating furnace by using radiant heat, is provided to retrieve heat of waste gas. An air supplying pipe(13b) is installed in an inner space of an outlet pipe(3b) of the radiant tube. The air supplying pipe(13b) is communicated with an air inlet pipe(14) for receiving exterior air from an atmosphere. A hollow preheating air pipe(13c) is provided in the inner space of the air supplying pipe(13b) so as to supply combustion air towards the burner. An outlet of the hollow preheating air pipe(13c) is communicated with an inlet pipe(3a) of the radiant tube.