| 摘要 |
<p>The device has an aspiration chamber (12) placed in upstream of a ventilating fan (14), and a filter (16) placed in the chamber. The chamber has an access opening (18) whose transversal section is composed of an aspiration part (20) and a filter part (22). The aspiration part is opened or closed based on needs for admitting fresh air (24) into the chamber. The filter part is closed by a wall (26). The aspiration part is opened and the wall is displaced from its operating position for releasing the filter part during changing of the filter, such that the parts are opened and form the opening.</p> |
