| 摘要 |
A heating system comprising a firebox (10) defining a combustion chamber that is substantially sealed from the atmosphere. The system includes a flue (24) for conducting combustion gases from the combustion chamber. A first duct (22) surrounds the flue and defines an inner passageway (26) with respect thereto. A second duct (20) surrounds the first duct and defines an outer passageway (28). An inlet means (34) is provided for introducing ambient air into the outer passageway (28). The air in the outer passageway (28) is drawn through the inner passageway (26) by a negative pressure in the combustion chamber. The ambient air in the inner and outer passageways is heated by heat transmitted from the flue (24). This heated ambient air is then introduced in the combustion chamber to improve the efficiency of combustion. |
