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 ?
When comparing system energy use between series- and parallel-type fan terminals in several different climates, it was found that the leakage of the back-draft damper in parallel FPTUs (required when the fan shuts off to prevent back flow) was a major determinant in the difference in energy use between the two types of devices.
All duct connectors are outfitted with quiet, automatic back-draft dampers, and all units are designed for horizontal, vertical or in-line ducting.
The study by investigators at Texas A&M University's Energy Systems Laboratory tested parallel fan terminals and found average air leakage of between 10% and 20% from back-draft dampers and terminal box seams.