A circular valve is used in a circular air transport system to control and/or adjust air flow rates. The valve can also be used to shut off air flows completely if it is equipped with a rubber sealing ring around the valve blade.
Material quality and thicknesses
For normal comfort ventilation, adjustment valves are manufactured from the following materials:
- Casing: Sendzimir galvanised steel;
- Valve blade: Sendzimir galvanized steel or plastic, possibly with a rubbersealing ring;
- Adjusting and/or locking device: Sendzimir galvanized steel or plastic;
- Other choice of material, depending on the application, in consultationwith the supplier.
The valve has circular connections with a rubber sealing ring for an air tight connection to the ductwork.
The available nominal dimensions of the intermediate adjustment valves are standardised to NEN-EN 1506 (circular connections) and can be selected as indicated in the tables for standard dimensions given in this guide under section 126.96.36.199 (circular connections). They refer to internal dimensions with a tolerance of +0 to -5 mm. The dimensions depend on the manufacture.
Adjustment valves must be fitted in accordance with the manufacturer's instructions. If present, they must at least comply with the requirements of section 3.1.4.
A minimum distance from or to a bend, fan, valve, etc. must be taken into account. For round dampers a minimum distance of 2 x the connection diameter is recommended.
Circular valves with rubber sealing rings can be efficiently connected to air ducts and contribute to the airtightness of the air duct system, if the fittings have sufficient airtightness in accordance with NEN-EN 1751.