How the 8 Inch Back Draught Damper Seals an Idle Duct
Galvanized sheet steel housing, spring-loaded aluminium flaps, rubber seal at the seat. The flaps are held closed by spring pressure and opened by the fan, which means there is nothing to wire and nothing to fail electrically. On an 8 in duct it is the simplest way to stop reverse flow through an idle run.
Mounting a Backdraft Shutter in the Right Place
Because the flaps are sprung rather than gravity-hung, it works mounted horizontally or vertically. Put it downstream of the fan with the flaps opening the way the air goes. The honest cost is a small static pressure penalty, which on an 8 in run is usually irrelevant but is real. Check the rubber seat for dust when you service the fan; that is what makes a damper leak. If the flaps chatter at low speed, the fan is running below the pressure they need to stay open. Nudge the speed up a step.
Key Features
- Spring-Loaded Aluminium Flaps: Open on airflow and close under spring pressure, with nothing to power.
- Rubber Seal: Closes the gap at the seat so a stopped duct actually stays shut.
- Galvanized Steel Housing: Corrosion-resistant in the damp air an exhaust run carries.
- Horizontal or Vertical Mounting: Spring loading means it does not depend on gravity to close.
- 8 in Duct Fit: Matches Ruck 8 in components and standard 8 in ducting.
- Fully Mechanical: No wiring, no actuator and no control signal to lose.
Technical Specifications
| Specification | Value |
|---|---|
| Duct Size | 8 in |
| Housing | Galvanized sheet steel |
| Flaps | Spring-loaded aluminium |
| Seal | Rubber |
| Mounting | Horizontal or vertical |
| Operation | Airflow-opened, spring-closed |