Patent ID: 7980927

Claim:
A fume hood for use in accessing the upper end of a container comprising; a) an enclosure having a horizontal floor with a planar work surface and an opening with a first given diameter to receive the upper end of a container, said floor including a raised horizontal surface with a circumferential groove with a second given diameter around said opening and a vacuum port extending around said opening, said groove having an upper edge with a first width and a floor with a second width greater than said first width, whereby vacuum pockets are left on either side of the membrane so that a vacuum can be drawn around the entire groove; b) a vacuum source in communication with said groove through said port; c) a flexible annular membrane having an inner diameter less than said first given diameter and an outer diameter greater than said second given diameter positionable around said opening on said planar surface and over said groove, whereby a vacuum drawn in said groove pulls a part of said membrane into said groove to hold said membrane around said opening; and d) a retainer insertable above said membrane within said groove.