| 摘要 |
PURPOSE:To prevent outdoor noises from entering a room, by defining a plurality of chambers by partitions, and communicating the chambers through passages, with the first chamber being in communication with the outside air and the last chamber being in communication with the room, in a silencer to be attached to a ventilating opening of a building. CONSTITUTION:A silencer 10 is attached to a ventilating tube 24 of an outdoor side opening that is attached to a building wall 22 and a room side opening 18 is attached to a chamber 14b. The chamber 14b is divided by a partition 30 and is in communication with a chamber 14a through the passage 12. The chamber 14a is in communication with the open air through an outdoor side opening 16. According to this arrangement, the sound waves entering from the outdoor side opening 16 are expanded in the chamber 14a, then compressed in the passage 12, and then again expanded in the chamber 14b. Accordingly, the energy is reduced, and part of the sound waves moving toward the opening 18 via the passage 12 bounds back from a wall 20 to cause the resonance and also are absorbed by a sound absorbing material 32 thereby the energy is further reduced. Thus noises can be prevented from entering the room. |
