| 摘要 |
A fume hood includes a top, bottom sidewalk, front panel and a back pan el that define an enclosed workspace. The fume hood also includes a movable sas h for opening and closing an access opening and an airfoil disposed proximate an edge portion of the opening to direct airflow through the opening and into the workspace. The airfoil is automatically raised from a down position to an up position when the sash is raised to a predetermined height. In addition, the airfoil may be automatically raised when the velocity of the airflow into the access opening decreases below a predetermined value. Once raised, the airfoil may be automatically or manual ly lowered to the down position. In one embodiment, the airfoil includes one or more fins having an angled portion that extends downwardly below the work surface of the fume hood when the airfoil is in the down position, thereby reducing the possibility of a potential spill when the technician removes an item from the workspace.</S DOAB>
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