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Louver Dampers :

Louver dampers are best applied to balance or control flow.  The normal leak path of 0.7% of duct area produces a three to five percent leak rate in average applications.

As a general rule , a damper should be used in the middle third of the control range for best results.  This gives equal percentage in either direction should the need arise.  Your DDI representative can advise you the way your control requirements can be met.

A variety of options are available.  Metallic spring seals, sealed (dust tight) blade ends, shear seals, and many materials are available.  This custom equipment is designed specifically to fit your application.

Leakage performance of a louver depends on ratio of flowing to shutoff pressure, design temperature, number of blades, and blade edge treatment.  Since the first two are system related, the last two are the usual areas of improvement.  Reduction of number of blades reduces leak path to the limit that a single blade has only perimeter leakage.

DDI louver dampers are full welded equipment designed for long service, low maintenance, and easy repair.

Damper Operators will be specified, supplied, mounted, and tested when requested.  A wide variety of operators can be specified-electric, pneumatic, hydraulic or manual - you choose the one best suited for your particular application.