Based on the sealing function requirements, structure between blades, blades and frame could be designed differently. The sealing structure with special spring alloy seals could provide 99% sealing rate when the blades are fully closed. 

 

The connection between blade and shaft could use fasteners or welding. Shaft seals and bearings would be installed on the shafts. Shaft seals could provide sound sealing function without leakage and are high temperature resistant. The bearing has the function of self-aligning and self-lubricating, which can automatically compensate the coaxial deviation of the shaft front and rear, ensuring low resistance to closing the damper, no jamming, and flexible rotation. The linkage and the blade have good synchronization. 

 

The selection of the material of the damper is different according to the working conditions and media in contact. For the flue gas damper in FGD system which will be in contact with strong corrosive media, the blades would consider using alloy materials with strong anti-corrosion properties such as C-276.