Abstract: A fluid delivery device wherein the traditional quasi-planar doors or gates are replaced by one or more plugs of approximately inverted teardrop cross sectional shape. Said plugs rest and bear against a sealing surface to effect sealing of the tank shut, and are actuated in a direction contrary to the direction of fluid outflow, into the interior cavity of the tank or hopper plenum in order to effect opening and dispensing of the contained fluid. Exit flow is markedly more laminar and uniform that that attainable with conventional quasi-planar door or gate systems, providing an improved exit flow characteristic, and greater accuracy in placing the working fluid onto a target.