Flue duct for open fires or furnaces - incorporates heat exchanger for liq. or gaseous medium

摘要

The flue gas duct is for use with open fireplaces, or closed furnaces. The flue duct (1) is surrounded by a spiral-shaped heat exchanger (2). This in turn is enclosed by an insulation material (3), and external brickwork (4). The heat exchanger is suitable for a liquid or gaseous exchange medium. Alternately, the flue duct may consist of a double-wall tube, with the intermediate jacket space for the exchange medium. It may be formed from four ducts with a central heat exchanger.