| 摘要 |
<p>An airflow regulating device for regulating the airflow through an opening comprises one or more vanes (7) extending across an aperture (5) and movable between a first position in which the airflow through the aperture (5) is reduced to a minimum and a second position in which the airflow through the aperture (5) is a maximum. A surface of said vane(s) (7) is acted on by the airflow to move the vane(s) (7) towards the first position. Control means (21) are provided comprising non-linear compression spring means (23) acting on the vane(s) (7) so as to bias the vane(s) towards the second position and adjustment means (33) are provided for varying the action of the spring means (23). The non linearality of the spring means (23) is such that spring strength increases when the compression force acting thereon increases and vice versa. <IMAGE></p> |
