Abstract: A heat exchange flue has a top flue gas chamber, a bottom flue gas chamber, and a heat exchange section located therebetween that includes a heat exchange tube bundle located in the middle and a left side flue and a right side flue located at two sides of the heat exchange tube bundle. The axis of the heat exchange tube bundle is positioned in a vertical plane extending substantially forward and backward, allowing the flue gas to laterally flush against the surfaces of heat exchange tubes. The left and right side flues are in a vertical box shape, and the flues are each provided with a plurality of flue gas dampers (3). Each of the flue gas dampers is provided with a flue gas damper frame for defining a flue gas port and a flue gas port opening/closing device capable of selectively opening and closing the flue gas port.

Abstract: A heat exchange flue, having a top flue gas chamber (1), a bottom flue gas chamber (10) and a heat exchange section (H) located therebetween. The heat exchange section (H) comprises a heat exchange tube bundle (4) located in the middle, and a left side flue (5) and a right side flue (12) which are located at two sides of the heat exchange tube bundle (4). The axis of the heat exchange tube bundle (4) is positioned in a vertical plane extending substantially forward and backward, allowing the flue gas to laterally flush against the surfaces of heat exchange tubes. The left and right side flues (5, 12) are in a vertical box shape, the flues are each provided with a plurality of flue gas dampers (3) which are vertically arranged at intervals in a substantially horizontal alignment. Each of the flue gas dampers (3) is provided with a flue gas damper frame (13) for defining a flue gas port (2) and a flue gas port opening/closing device capable of selectively opening and closing the flue gas port (2).