| 摘要 |
A fabric air duct with main discharge openings includes additional, much smaller openings that help ventilate the surface of the duct. Ventilating the surface of the duct with a slight yet even amount of airflow helps inhibit the accumulation of condensate and dust on the surface of the duct. In some embodiments, the duct includes a pliable sheet consisting of a rather porous fabric base material. To achieve an appropriately low level of airflow, a coating on the fabric reduces, but does not eliminate the fabric's porosity. A calendering process then reduces the porosity even further. In some embodiments, the calendering process occurs before the coating process. In other embodiments, the pliable sheet is substantially air impermeable, except for its main discharge openings. The sheet is then perforated with numerous smaller openings to achieve the desired amount of surface ventilation. In yet other embodiments, an emorizing or sueding process is used to abrade or nap the surface of a porous or non-porous base material to create a pliable sheet having a desired amount of porosity. From any of these processes, air ducts of various shapes may be formed, including air ducts that are circular, ½ round, and ¼ round in shape, as well as air ducts having a non-uniform cross-sectional shape across their lengths.
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