Abstract: In view of the internal leakage and inflexible switch and adjustment of the air bypass damper and flue bypass damper of the fired heater waste heat recovery system, this paper improves and perfects the drive mechanism, blade seal, and adopts the four-bar linkage parallel contact soft seal to realize near-zero internal leakage of the damper. In addition, in terms of the control mode, the sealing and regulating functions are integrated on one damper, it can accurately control the regulating blades at the opening angle and the rapid response of the sealing blades to the on-off signal, so as to meet the on site process requirements.

Key words: fired heater, duct, damper, seal, drive mechanism