Our range of spiral duct grilles have been designed for fitting directly to circular ducts without the need for a special take-off.
For supply grilles the angled hit and miss sliding damper acts as an air turn as well as a damper.
RGS grilles are manufactured from hot galvanized steel plate and are assembled without welding. This means that the grille can be used without further surface treatment and the exterior of the grille matches the surface of the spiral duct onto which it is mounted.
RGS-1 Double deflection grille without damper
RGS-7 Double deflection grille with angled hit and miss damper - Supply Grilles
By self tapping screws (provided) through pre-drilled holes in grille frame.
A grille designed for supply air applications must have an angled hit and miss damper (code RGS-7) .
Please give required length first followed by height and ensure that an appropriate height has been selected for the duct diameter (see table)