摘要 |
A clean air duct device comprises a duct (11) having a positive-pressure air channel (21), and a filter (12) provided between the inlet (24) and the outlet (31) of the duct. The filter (12) comprises a filter medium (41), and a frame (43) surrounding the medium (41) and having an upstream mount flange (45) along an edge portion thereof defining an upstream opening (44) and a downstream mount flnage (47) along an edge portion thereof defining a downstream opening (46). The duct (11) comprises an upstream duct member (22) and a downstream duct member (23). The upstream duct member (22) is provided at an outlet end thereof with an upstream communication opening (26) shaped in conformity with the shape of the frame upstream opening (44), and the downstream duct member (23) is provided at an inlet portion thereof with a downstream communication opening (33) shaped in conformity with the shape of the frame downstream opening (46). The upstream communication opening (26) has an upstream joint flange (28) along its edge portion, and the downstream communication opening (33) has a downstream joint flange (35) along its edge portion. The upstream mount flange (45) and the upstream joint flange (28) are connected together with an upstream packing (51) interposed therebetween, and the downstream mount flange (47) and the downstream joint flange (35) are connected together with a downstream packing (52) interposed therebetween.
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