It is designed not to be fully sealing, but with sealing air connection could be zero leakage when applied sealing air. It is designed with inspection hatches for manual soot cleaning when required.
TD-M 3-way flue gas damper is designed with two sets dampers and double mechanical linkages to ensure when one damper is in "close'' position, another damper is in "open" position. The atmosphere damper is operated by manual clutch or single pneumatic actuator (FO position when power failure). To close the damper, damper discs touch the sealing rings (two couple of malposed half rings) to get the plane sealing effect; the damper shaft and half rings are unique designed for surface sealing. The air sealing connection for sealing air (sealing air pressure is slight higher than the flue gas pressure) is option according to customer’s requirement.