The _hypocaust_ was a hot-air furnace built in the basement or cellar of the house and from which the heat was conducted by flues to the bath rooms and other apartments. 威廉·亨利·杜利特.世纪发明.
Nathan Read of Salem, Massachusetts, in 1791, invented a tubular boiler in which the flues and gases are conducted through tubes passing through the boiler into the smokestack. 威廉·亨利·杜利特.世纪发明.
Open heat spaces were left between the two flues. 威廉·亨利·杜利特.世纪发明.
This warm fresh air then passes through ordinary flues to the rooms above. 伯莎M.克拉克.科学通论.
The boiler was 30 inches in diameter and had 72 copper flues 1? inches in diameter, 7 feet long. Edward W. Byrn.十九世纪发明进展.
Oliver Evans followed with two longitudinal flues. 威廉·亨利·杜利特.世纪发明.
As the excessively hot water gas passes through the boiler flues it furnishes the necessary heat to generate the steam. Edward W. Byrn.十九世纪发明进展.