| 摘要 |
PURPOSE:To cool material to be heat treated to the aimed temp., by exhausting combustion exhausted gas generated at temp. control zone for heating material to be heat treated from duct for exhausting gas so that passing of exhausted gas through inside of temp. control zone for lowering temp. is prevented. CONSTITUTION:A steel pipe P is held to the aimed temp. between temp. control zones 1-i in a heat treating furnace 10, and cooled to a prescribed temp. between temp. control zones i+1-n. In this time, a total combustion exhausted gas quantity Q1 is obtd. by a prescribed formula from combustion exhausted gas generation quantity at zones 1-i by an arithmetic unit 18, and a total combustion exhausted gas quantity Q2 at zones i+1-n is similarly obtd. Further an opening degree theta1 of a damper 14 and an opening degree theta2 of a damper 15 are obtd. from a pressure P1 in furnace and Q1 value and a pressure P2 in furnace respectively. The obtd. theta1, theta2 are given to opening degree controllers 16, 17 respectively to control opening degrees of the dampers 14, 15. In this way, combustion exhausted gases at zones 1-i are exhausted mainly from the duct 14 at furnace inlet side, and that from zones i+1-n are exhausted from the duct 15 at furnace outlet side, flowing of exhausted gas at zones 1-i into zones i+1 side is prevented, and temp. of the pipe P is lowered by a prescribed rate.
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