Backdraught Dampers (BDD) (also known as Non Return Dampers) supplied by Mole HVAC Equipment Ltd are designed to prevent backflow of air through the ventilation system. These dampers are commonly used within ahi handling units or on fan skids.
Our Backdraught Dampers are supplied with an adjustable counterweight assembly to minimise air pressure drop. Dampers are designed for vertical installation with the horizontal airflow.
Dampers are provided with flanges pre-drilled for installation within the HVAC ductwork. Flanges are drilled in accordance with BS EN ISO15138:2007 unless otherwise specified by Client. All dampers are identified with st/steel nameplates containing relevant information on supplied equipment.
Mole HVAC Equipment Ltd supplies dampers generally in accordance with the following specification:-
2.0 or 3.0mm thick fully welded casing complete with 50 or 75mm own material flanges drilled to BS EN ISO15138:2007 or Client specification. Lifting points are incorporated within damper casing. Minimum damper size is 100x100mm, maximum single unit size 2000x2000mm, larger unit can be supplied as multiple unit assembly. Standard damper casing length is 200mm, other lengths available if required.
2 x 1.0mm double skin construction. Two parts of blade spot welded and bolted to the damper shafts. Longer blades are additionally fitted withstiffening channels for increased rigidity.
Φ14 end shafts. Shafts are removable to allow bearing replacement if necessary. Stainless steel linkage is located out with the airstream and is protected by removable linkage cover.
Maintenance free polymer bearings (suitable for service temperatures between -40 and +80°C and short term temperatures of up to +170°C). High temperature bearings can be provided in necessary.
Our BDDs are gravity operated with the standard control package including an adjustable counterweight assembly.
Backdraught Dampers are fitted with top and bottom stainless steel blade stops as standard. Replacable EPDM/PVC blade edge seals are provided for reducing damper leakage and cushioning of the blades. These dampers are particulary suitable for low noise level applications.
Stainless steel nameplate containing relevant information is attached to the damper casing. Full colour aluminium nameplates can be offered if required.
As standard our dampers are manufactured from 316L St/Steel. Other materials to include 304 St/Steel, pre galvanised mild steel, galvanised after manufacturing mild steel or aluminium can be provided if necessary.