| 摘要 |
Method and apparatus is disclosed for heat treating coiled, metal strip in bell shaped annealing furnaces employing an annealing stand upon which coils of strip are vertically stacked. An inner cover removably sealed to the stand surrounds the coil and an outer cover surrounds the inner cover. A vacuum is drawn within the inner cover while the work is being preheated to volatize oil on the coil into hydrocarbon vapors and permit the hydrocarbons to be drawn off prior to annealing so that carbon soot formation does not occur. A unique concentric, two seal arrangement is disclosed which provides for drawing a vacuum between the seals to positively seal the inner cover to the base while providing a fail safe mechanism for monitoring the process thus permitting a potentially explosive reducing atmosphere, such as pure hydrogen, to be used in the annealing furnace in a safe manner.
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