| 摘要 |
An improved aerodynamic shape comprises an essentially planar face portion and leading and trailing edges associated with opposing ends of the face portion to develop a cross-sectionally inverted, pan-shaped enclosure. In conjunction with a damper including a frame and one or more blades pivoted for rotation within the frame, blades provided with the aerodynamic shape of the invention develop increased lift when forced open by escaping air, permitting the blades to be constructed of relatively heavy gauge materials without comprising damper efficiency.
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