grila gravitationala NRD

NRD

Description


NRD is a gravitational aluminum grille for overpressure with normally closed movable blades.
The grille is recommended for wall or end mounting of rectangular duct.
The product can be used for introducing or evacuating air.

The grille has movable blades parallel to the “L” (length) and mounting holes.
The opening direction of the blades is towards the outside of the frame according to the image.
On request, the blades can be positioned in the opposite direction.

The grille blades open at overpressure.
For lengths > 500 mm, the grille is provided with elements for stiffening.
The grille contains load-bearing sections made of anti-friction plastic and a gasket positioned along the length of the blades.
The product is delivered with fixing screws.
Dimensional limits: minimum dimensions 200×200 mm, the maximum built surface is 1 sqm with the condition H max = 1 m.


Technical drawing



On request, the blades can be positioned in the opposite direction according to the picture.

 

 

Flow selection table for speed of 3m/s.





Note
The optimal speed for choosing the grille size is between 2 and 4 m/s.
The grille dimensions are determined by applying the formula Ak [m²] = Flow [mc/h]/3600 [s]/Veff [m/s] and the selection table.

The legend
Ak [m²] - The free surface of the grille
Veff [m/s] - The effective flow rate of air in the grille
∆Pt [Pa] - Pressure loss

Wire mesh (PS)

The grille can be equipped with a wire mesh with a mesh size of 10x10 mm.

 

The grille is mounted with screws.

Wall mounting

 
Rectangular duct end assembly

Documentation