Regulating dampers for round spiral ducts

The DAR dampers for round ducts are available in
the diameters of 80 mm to 630 mm.
The damper closure has two chord-cut edges to provide
20% of the rated air flow in the closed position.

The dampers 450 mm in diameter and larger have the damper
closure pivot braced additionally with a single steel bar
across the opening. The damper mechanism can be provided
with up 50 mm thick insulation and features a control dial
to show the opening ratio. The dampers of diameter 450 mm
or greater also feature the KIT-DS-H damper mechanism control
lever for easier operation.