| 摘要 |
A fire damper with mounting structure which permits the dampers easy installation in a building ventilation duct or passage without the use of conventional, external flanges which must be bolted on at the installation site. The damper includes a peripheral frame having internally threaded, tubular elements secured to the inside of the frame and aligned with apertures extending through the frame. Threaded studs in the elements have self-boring, conical noses so that the studs may be advanced into gripping engagement with the proximal building wall.
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