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Non-return Damper New Line Type RK-E20

Self acting non return dampers will close at reverse airflows in HVAC systems and will lock ducts or air handling units automatically.


They are installed e. g. often on the positive pressure side of parallel arranged ventilators and will prevent reverse airflows at a stop of one ventilator. When the ventilators are running the lamellae are open due to the airflow energy.

Non return dampers are optimal if the pressure drop should be low with open lamellae and the leakage should be very small in closed position. Krantz is producing non return dampers since many years and these have been installed in HVAC systems with good success. Based on practical experience and many laboratory tests Krantz non return dampers have been optimized. The result is a non return damper with a very low pressure drop and especially small leakage rates.


  • The robust damper housing made from optional stainless or galvanized steel can contain up to seven lamellae.
  • Non return dampers with more than one lamella additionally have crossbars made from U-profile, welded to the damper housing. These cross-bars are serving as fixing for the lamellae and as supporting surface for the sealing.
  • The lamellae are made from ageing resistant reinforced elastic material with a non-breakable inlet. A solid reinforcement and stabilization of the damper blade sealing is done by aluminum reinforcement angles on incoming flow side of the damper and aluminum plates on the back side.
  • The elastic lamellae are heat resistible up to 90 °C. For higher requirements lamellae with higher heat resistance are available as an option (additional price).
  • The flow-separating plates at back side of damper housing are creating single ducts behind each lamella to avoid transmission of impulse between partial air flows.



from 200 mm x 200 mm to 1 400 mm x 2 000 mm

Total depth of damper:

360 mm

Admissible design temperature:


Adm. leakage rate of damper housing acc. DIN 25 496

(outer leak tightness):

<10 l/(h·m2) at 1 bar, 20°C and Δp = 2 000 Pa

Adm. leakage rate of damper blade acc. DIN 25 496 (inner leak tightness):

2 % of nominal air flow rate at 1 bar, 20 °C and Δp = 2 000 Pa

Material Damper housing / separating plates Reinforcing angle and back plate Lamellae:

galvanised steel or stainless steel aluminium silicone

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