Adjustable Counterbalanced Backdraft Damper
The BD-84 backdraft damper employs counterbalanced gravity operated triple-V style blades and a rugged channel frame to restrict reverse airflow and to permit the forward flow of air in the intended direction. Adjustable counterbalances attached to the blades axles permit field adjustment to regulate start-to-open and full blade operation. The BD-84 damper is intended to be mounted vertically in either exhaust or intake installations for medium to high velocity and pressure applications.
Frame: 8" x 2" X 14 ga. (203 x 51 x 2.0) galvanized steel channel.
Blades: 6" x 16 ga. (152 x 1.5) galvanized steel - triple-V
Axles: 1/2" (13) diameter plated steel.
Linkage: Concealed in frame.
Bearings: Steel ball bearing, press fit into frame.
Counterbalances: On-blade axle, crankarm and weights - adjustable.
Minimum Size: 6" x 6" (152 x 152)
Maximum Size: 48" x 96" (1219 x 2438)
70 cfm/ft2 @ 4 in. wg. (0.36 m3/s/m2 @ 1.00 kPa) with no seals.
40 cfm/ft2 @ 1 in. wg. (0.21 m3/s/m2 @ 0.25 kPa) with no seals.
-25oF to 250oF (-32oC to 121oC) with no seals.
-10oF to 150oF (-23oC to 66oC) with seals.