| 摘要 |
PURPOSE:To prevent bedewing on the surface of a steel strip in an annealing furnace and to prevent deterioration of product quality by heating low humidity air with waste hot blast at the forced convection preheating zone and blasting this heated air to the steel strip at the upstream side of inlet of the annealing furnace to execute the initial preheating. CONSTITUTION:The waste hot blast at the forced convection preheating zone 5 in the annealing furnace 2 is introduced into a heat exchanger 8 through a flue 7 and the low humidity air is heat-exchanged with the waste hot blast to be raised in temperature. This air is sent into a duct 9a and is blasted to the steel strip 1 from a blowing nozzle in a bedewing preventing device 10 at the outside of the annealing furnace 2 in the upstream of the inlet 2a of the steel strip into the annealing furnace 2. By this method, by initially preheating the steel strip 1 prior to the preheating at the forced convection preheating zone 5, even if the hot blast from the radiant preheating zone 4 is blasted to the steel strip 1 at the forced convection preheating zone 5, the surface of the steel strip 1 is not bedewed.
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