Abstract: A method and apparatus for removing foreign matter, including debris and deposits and air bubbles from a flow cell of a particle study device. The apparatus includes a chamber with an aperture containing unit at one end and sample and sheath introduction mechanisms at the other end to supply respectively, a sample suspension of particles and a particle free liquid. The chamber has a waste orifice positionally disposed to provide a turbulent flow of particle free liquid within the chamber upon simultaneous injection and exhaustion of the particle free liquid into and out of, respectively, the sheath introduction mechanism and the waste orifice, to remove any air bubbles in the chamber and its adjacent aperture area.

Abstract: Method of and apparatus for handling a microsample comprising a probe for aspirating a sample and a cleaning mechanism having a passageway within which the probe is movable. The passageway has a cleaning chamber having opposite ends, one end being open to the atmosphere and proximate the sample. The cleaning mechanism further includes a fluid directing means and two vacuum applying means, the vacuum applying means being disposed at opposite ends of the chamber and the fluid directing means being disposed between them. During a cleaning mode the fluid directing means directs a wash fluid against the probe and the vacuum applying means removes the wash fluid, prevents exiting of the wash fluid and drys the probe, the later two by permitting gas from the atmosphere to flow into the cleaning chamber.

Abstract: Disclosed is a flow-through, particle analyzer and sorter apparatus for simultaneous optical and electrical impedance measurements on a stream of particles, comprising a flow cell having a pair of channels fluidly connected by a particle sensing aperture, through which the particles pass and are analyzed; a nozzle mounted at the end of the downstream channel so as to define a flow chamber; a sheath liquid which is introduced at the bottom of the flow chamber to hydrodynamically focus the particle stream and to jet the same in a liquid jet from the nozzle; and a system for creating droplets from the liquid jet and for thereafter sorting the droplets.

Abstract: The containment of biohazardous substances, which may exist in the streams of sample material that are being separated in air into droplets in a testing chamber of equipment, such as cell sorters and cytofluorometers, is attained by subjecting the testing chamber to negative air pressure, so that inward air flow at the open face of the chamber is sufficient to inhibit biohazardous substances from exiting out from the face of the chamber. A region of air stagnation is created around the sample streams so that the streams are not deflected from their paths, such paths being pertinent to their testing of the biological sample material. The air stagnation region is formed by interposing an air diverter between the sample streams and the air flow exhaust port at the rear of the testing chamber.

Abstract: Disclosed is a tool for use in spreading soft, malleable materials along an inner corner formed by angular surfaces. The tool has a relatively hard core and an elastomeric covering on the core together forming a spreading nose for the tool. The tool has a handle for the spreading nose. The elastomeric covering is a soft, resilient material so that it will seal against the angular surfaces of the inner corner where the material is being spread, even if those surfaces are somewhat irregular, for confining the soft spreading material and inhibiting it from spreading around a working edge of the tool except at a tip where a bead is formed.