Abstract: A flow cytometer sorting mechanism is operative to controllably sort successively generated fluid droplets in accordance with the contents of a plurality of contiguous precursor regions of the carrier fluid which are contained within a target droplet of interest and precursor regions for droplets on either side of the target droplet. This multi-region sorting window scheme is particularly useful in reducing the time required to harvest a highly purified quantity of a particular type of cell, as not only are droplets containing only desired cells sorted to a highly purified collection store, but should an undesired cell be detected within a predefined proximity of a desired cell, rather than being simply aborted, the droplet is sorted into an auxiliary enrichment container, whose contents may then be reclaimed for resorting. Since all droplets are sorted to one of a plurality of droplet reclamation containers, substantially no detected/target cells are lost.

Abstract: A single instrument for photometrically determining hemoglobin content and electronically determining white blood cell count of a single sample suspension of blood. The instrument is provided with a calibration mode of operation independent of the run or normal operational mode of the instrument.A vacuum system is described where vacuum is generated during the operating cycle only at periods when vacuum is required with an adjustable volume vacuum chamber interposed in the vacuum system to assure proper vacuum levels.Carryover of one liquid to a next introduced second liquid in the test vessel is reduced by successive draining of said second liquid and reintroduction into said vessel of a replacement amount of said second liquid. The second liquid can be a sample of rinse liquid.An hydraulic system is described as operating in conjunction with the pneumatic or vacuum system.

Abstract: An aperture module for obtaining signals from microscopic particles suspended in a sample blood solution which passes through a scanning aperture. A module housing including an aperture holder is mounted on a container or bath containing a body of the particulate liquid suspension to be tested. The aperture holder with aperture formed therein extends into the vessel to permit passage of the sample through the aperture to an outlet chamber immediately behind the aperture. The chamber is connected to a source of clean electrolyte and has a narrowed or reduced dimension portion positioned immediately behind the aperture. A vacuum is applied to the chamber to cause the sample to be drawn through the aperture for testing thereof. An optical hemoglobinometer is positioned in association with the bath to measure the hemoglobin content of the solution to be tested.