Heating system adjustable exhaust damper - has butterfly with spindle working in flange plate against outside of flue

摘要

The lockable or electrically-adjustable heating system exhaust damper has a butterfly (6) with spindle (7) working at one end in a flange plate (1) fitting against the outside of the flue, and inserted via a slot in the latter so that the centres of butterfly surface and flue cross-section coincide. The flange plate can have a hollow hub (5) at the centre extending to either side, acting as a bearing for the butterfly spindle, while the butterfly and pointer (8) acts against opposite ends of the hub. A plate with a curved elongated hole (12) is fixed to the hub outer end.