Abstract: A piston is disposed inside a tube having an inner cross sectional size and shape uniform along its length. The tube has an open end. The piston is free to move linearly inside the tube and preferably may move out of the tube through the open end. If the tube is cylindrical, for example, it has a constant inner diameter. The open end of the tube is neither tapered or flaring. Liquid samples are aspirated into the device by pulling the piston back. The sample is then ejected by accelerating the piston to a minimum velocity to force the liquid sample out of the open end of the tube. The velocity of the sample is sufficient to render negligible the effects of surface tension forces. The volume of the liquid sample dispensed is determined by the inner diameter of the tube and the piston displacement. Accurate positioning of the piston provides samples of accurate volumes. A specific embodiment of the present invention uses a tube with an inner diameter of 0.5 mm, resulting in a volume displacement of 1.

Abstract: An apparatus for holding reagent and sample vessels. The apparatus has reagent and sample vessel racks, a carousel supporting the racks, guiding pins that serve to guide the racks as they are mounted on the carousel and also serve to attach the racks to the carousel. Each of the racks has a handle that is used to lift the racks from the carousel. The grip of the handle is located above the center of gravity of its corresponding rack when the rack is lifted by the grip.

Abstract: The invention presents a system for automatically identifying labware and sample containers. Labeled sample containers are inserted into the reception slots of a labeled labware. A sample condition label is affixed below each reception slot. The sample condition label is covered by the sample container when the sample container is inserted into the reception slot. An exposed sample condition label indicates the absence of a sample container in that reception slot. The labware containing the sample containers is installed on a labware holder having a labware condition label affixed to its surface. The labware condition label is covered by the labware when the labware is installed on the labware holder. An exposed labware condition label indicates the absence of a labware on the labware holder. The label information is read by an optical reader attached to a motorized track. Both the optical reader and the motorized track are connected to a data processor.

Abstract: A cover effective to releasably seal a multiwell container, such as a microtitration plate, is disclosed. The cover contains a pad, fashioned from a flexible polymer sheet, and a plurality of resiliently compressible ridges formed on the sheet. The ridges are deformable, such that application of pressure applied to the cover is effective to form a fluid-tight seal between the pad and the well openings. The ridges extend from the pad sufficiently to break the seal upon release of the pressure.