This type of damper is 100% tight using an air sealing barrier.
The system works by a fan creating a pressure between the discs. This means that no aggressive gas can pass through the damper, since the air sealing pressure is higher than the gas pressure.
Type D consists of two separate dampers, built together in one body, giving
it a high level of security. The function can be viewed as two separate dampers in one unit.
Type DT is a “sandwich” design i.e. two damper blades with one shaft giving maximum strength combined with a low weight and short mounting length.
For air, hot air and flue gases. Max. temperature: 1100° C Max. design pressure: 0,5 bar (g)
The air sealing system give the possibility to worker downstream of the damper. The system can also been used as a barriers for aggressive gases to condensate and give series corrosions problems in the duct and at components in the systems.