| 摘要 |
The present invention relates to an adjustable and sound absorptive air restriction device, designed to be mounted in the air ducts of a ventilation system. The air restriction device comprises an insert (1) with sound absorption characteristics and with a substantial flow resistance and which has longitudinal through holes (2), each of which can be closed in a stable way by means of a plug (3) or the like and through which holes (2) the air, which flows through the air ducts of the ventilation system, passes a preselected number of open holes (2) for a desired amount of air. |
