| 摘要 |
A control valve (2) for installation in ventilation duct systems (1), comprising first and second tubular sections (2a; 2b), and a body (2c) which can be moved axially therewithin. In order to achieve maximum sound absorption, the mutually facing surfaces of the second tubular section (2b) and the body (2c) define therebetween an acute angle (a), preferably an angle of about 15 DEG . The body (2c) has a perforated downstream end (2c1), wherein the extent of the perforations corresponds to roughly 40 % of the area of said end. The cavity of the body (2c) is filled with sound-absorbent material (5), preferably mineral wool. |
