| 摘要 |
A thermally controlled damper construction for a gas fired combustion apparatus such as a furnace or the like is described. A damper is pivotally mounted within the stack or flue of the combustion apparatus for pivotal movement from a closed position, wherein the damper is located at an acute angle with respect to the axis of the stack, to a full open position. One edge of the damper is recessed to provide a vent opening between the damper and the stack to permit the venting of gases generated by operation of the pilot light during periods when the furnace is not operating. The damper is pivotally moved between its closed and open positions by a bi-metallic thermally responsive element which is located upstream of the damper and which is connected to the damper by means of a linkage. The linkage includes means for permitting the unrestrained rotational movement of the bi-metallic element after the damper is in its position thereby preventing stressing of the thermally responsive element at high temperatures. An opening is formed in the stack upstream of the damper and substantially immediately below the recessed portion. A temperature responsive safety switch is positioned at the outside surface of the stack outwardly of the opening formed therein and is operably connected to the gas supply of the furnace. In the event the damper does not open when the furnace is operated or an improper draft is present, the products of combustion spill outwardly through the stack opening onto the temperature responsive safety switch thereby activating the same to terminate the gas supply to the furnace.
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