Abstract: A low air volume exhaust hood is based on the concept of zone laminar flow through the hood as the hood sash is raised to different levels. Laminar flow is achieved through a plurality of plenum zones constructed at the rear of the cabinet. Preferably the zones are created by utilizing different sized openings in a rear baffle of the cabinet which presents the plenum chamber. Alternatively, distinct independent plenums may be formed and coupled with a common exhaust structure. By utilizing laminar flow which is directed through different zones corresponding to different open positions of the sash, a lower volume of air can be moved through the hood while achieving desired levels of evacuation. Performance of the hood is further enhanced by a novel air foil design at the floor of the hood which promotes a sweeping flow of air across the floor.

Abstract: An improved laboratory fume hood is the subject of the present invention. A cabinet structure presents an enclosed work area defined by sidewalls, a back wall, and an access opening. Each of the sidewalls presents first and second planar surfaces disposed in spaced parallel planes and interconnected by a third surface disposed at an acute angle relative to the plane of one of the first two surfaces. This third surface provides a mounting area for hose connectors which increases the effective work area and reduces the danger of clothing catching on the hose connectors. A vertically mounted sash covers the access opening and is movable between a lowered closed position and a raised open position. A fixture mounted in front of the sash provides means for mounting a light source. A removable cover on the side of the sash opposite the work area cooperates with the sash to define an air duct for directing add air into the access opening.