| 摘要 |
PROBLEM TO BE SOLVED: To provide a filter for a ventilation opening using a filter material for collecting dust, which has the sound insulation property of equivalent level to the case where a shutter is closed, even during the operation of a ventilation. SOLUTION: The filter for the ventilation opening A has a dust removal part 1 and a sound insulation part 2, which are arranged to be spaced in a filter frame 10-12, wherein the sound insulation part 2 has a plurality of porous sound absorbers 4, 5 having a plurality of penetration holes 6, 7, and consists of a multistep structure where these porous sound absorbers 4, 5 are arranged to be spaced. COPYRIGHT: (C)2007,JPO&INPIT |
