Fire protection device e.g. fire damper, for closing ventilation duct, has blade including side edges having curved portion whose distance relative to pivot axis varies such that blade gradually closes passage during pivoting of blade

摘要

The device (100) has an rectangular outer support (2) fixed in a ventilation duct and a trapezoid blade (3) mounted to pivot with respect to the support according to a pivot axis (X-X) for selectively sealing a complementary-shaped passage in the support. The blade includes side edges (9a, 9b) extending parallel to the axis of the blade on two sides of the axis. Each side edge comprises a curved portion representing a quarter of length of the side edges, and a distance between the portions to the axis varies such that the blade gradually closes the passage during the pivoting of the blade.