Smoke damper doors generally require tightness under the influence of large pressure differences. Smoke damper doors are typically designed with double-layer louvered windows, equipped with sealing elements on each layer. In addition, sealed gas is often introduced into the cavity between the two smoke damper doors to further enhance their sealing properties. The double-sealed single-axis circular damper doors allow for the complete flow/stoppage of a system's pipeline medium or the variation of medium flow according to control. For double-sealed single-axis circular dampers with smaller diameters, they offer both flow interruption and medium flow regulation functions. For large-diameter round dampers, their linear adjustability is not prominent, and they are primarily used for their flow interruption function.