CIRCULAR NON - RETURN DAMPERS

This proven range of dampers is in use in many industries. The body is a short circular duct with fully welded flanges. These are normally pre—drilled to customer's requirements. The blades are pivoted such that the axis of the blade is inclined into the direction of flow and outwards at the top. In this way, as the blades swing open at the onset of flow, the centre of gravity of the blades rises, and they naturally fall closed when the flow ceases. For vertical upwards flow, stops are provided to prevent over opening. For flow vertical down, the blades are counter—balanced.

The blades have a Vox: section leading edge for stiffness and aerodynamic efficiency. The shafts turn in sintered phosphor bronze bushes which can be regarded as zero maintenance. In the extremely unlikely event that these need to be changed, they can be replaced without removing the damper from the installation. Direction of flow must be observed : the onset of flow opens the damper. A reverse flow closes the damper.

LOUVRE TYPE NON - RETURN DAMPERS

Similar in construction to our control dampers, the frame or case is made by forming channel sections to give integral flanges. This gives strength with minimum weight, coupled with good rigidity. The blades have a box section leading edge for stiffness and aerodynamic efficiency.

The shafts turn in sintered phosphor bronze bushes which can be regarded as zero maintenance. In the extremely unlikely event that these need to be changed, they can be replaced without removing the damper from the installation.

Direction of flow must be observed the onset of flow opens the damper. A reverse pressure closes the damper. Care must be taken to see that the duct flanges are co - planar so that there is no tendency for the damper frame to be twisted. Unit illustrated has optional blade synchronization linkage.