Abstract: The aspiration system with positive pressure includes a fluid flow network having a vacuum source at one end and a suction instrument at another end. Suction is regulated by a control valve that can be actuated by a foot pedal. Suction communication between the vacuum source and the suction instrument can be prevented by placing the control valve in the closed position. A positive pressure input device is included in the fluid flow network and is also actuatable by the foot pedal to provide an impulse of positive pressure at the suction instrument. The positive pressure impulse is provided when the aspiration process is being hindered by blockage of the suction inlet end of the suction instrument. A puff of positive pressure is used to expel material from the suction inlet end of the suction instrument. The use of a positive pressure impulse at the suction end of a suction instrument is also applicable to release material transported by the suction instrument from one location to another.

Abstract: The nestable case is generally box-shaped with four side walls and a base. The side walls include upper fixed wall portions that are rigidly joined together to define a mouth portion of the case. The side walls also include moveable wall portions that are hinged to corresponding foldable sections of the base. When the case is fully loaded with containers the moveable wall portions and foldable sections of the base are in an expanded limit position. When the case is emptied the moveable wall portions and the foldable sections of the base can be moved to a contracted condition, which permits nesting of similarly empty cases. Fully loaded cases in the expanded limit position can be stacked one upon the other or arranged in a pinwheel configuration. A further embodiment of the invention includes provision of a shield at corner clearance openings to protect bruising of any portions of the containers that project from the corner clearance opening.