back-draft damper

back-draft damper

[′bak ‚draft ′dam·pər]
(mechanical engineering)
A damper with blades actuated by gravity, permitting air to pass through them in one direction only.

back-draft damper

A damper, 1 having blades which are actuated by gravity, permitting air to pass through them in one direction only.
References in periodicals archive ?
All duct connectors are outfitted with quiet, automatic back-draft dampers, and all units are designed for horizontal, vertical or in-line ducting.