Abstract: An optical timing and A/D conversion method and apparatus for converting analog signals obtained by movement of a plurality of reaction vessels relative to one or more beams of light from analog to digital signals. The sample signals are obtained each time a reaction vessel passes through a beam of light. The converted digital signals indicate the absorbance of the respective vessels and their contents. Each of the reaction vessels or cuvettes has translucent wall portions providing a radiation path therethrough for the light beams which may be monitored by photometer means in a chemical reaction analyzer. The vessels are repeatedly passed through the light beams of the photometer means as chemical reactions take place therein, the purpose being to monitor the changes in the reaction of the fluids therein by measuring the changes in the absorbance of the vessel and fluids.

Abstract: The characteristics of a sample body fluid are determined in a chemical analyzer by sensing the transmittance of light by the sample fluid and reagents during a reaction period. A beam of light is directed onto a cuvette containing the sample body fluid and reagent. A portion of the light is absorbed by the cuvette, the sample fluid and reagent. The remainder of the light is transmitted to a sensor which provides an analog electrical transmittance signal proportional thereto. The analog signal is logarithmically amplified, and is applied to a peak detector. A structure adjacent the cuvette provides a strobe signal such that the analog signal always has a peak amplitude during the strobe signal. The peak detector senses the peak amplitude of the analog signal during the strobe signal and the peak amplitude is converted to a digital value representing absorbance.

Abstract: Disclosed is a method of preparing a blood smear on a microscope slide wherein a diluent is applied to the slide, the slide is spun so as to be coated with a thin layer of diluent, a blood sample then is dispensed on the slide, and the slide is spun a second time to spread the blood sample over the slide.

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: Uniform particles are produced by introducing a laminar stream of a core liquid into a laminar flowing body of an immiscible sheath liquid. The core liquid or the sheath liquid, or both liquids, can contain one or more materials dispersed (dissolved or suspended) in them from which the uniform particles are formed. The two liquids and the dispersed material are expelled from a nozzle to form a liquid jet. The liquid jet is disturbed at a uniform, periodic rate to form liquid droplets which contain a uniform amount of the core liquid, the sheath liquid and the dispersed material. The droplets are collected and held in a catch liquid until the core and the sheath liquid in each droplet have diffused into the catch liquid leaving the uniform particles formed from the dispersed materials. There can be more than one sheath liquid which can also contain one or more materials dispersed in it.

Abstract: A process for preparing whole blood reference controls having long term stability up to six months for devices using electronic means for whole blood determinations including platelet count and mean cell volume and red blood distribution width. The preconditioning diluent for the red blood cells consists essentially of an aqueous solution of lactose, sodium azide, and a non-ionic surfactant and is pH buffered and osmolality adjusted. The media of the whole blood control includes lactose, fungicides and antibiotics, and supplementary agents including purine nucleosides. It also includes additional components which alter red blood cell membranes including bile salts and cholic acid derivatives, phenothiazine compounds and the salts thereof having antihistamine properties, and 4-aminobenzoic acid ester derivatives and their salts having local anesthetic properties.

Abstract: Apparatus and method wherein particles in a liquid stream are hydrodynamically focused to pass through an impedance sensing orifice, a low frequency current source provides a current through the orifice to produce a signal representative of the particle's size, a high frequency source provides a current through the orifice to produce a signal representative of the particle's size and internal resistance, a detector determines the particle's length, and a digital computer correlates the signals for each particle and calculates its shape factor, degree of deformation or natural shape, true volume and internal resistivity.

Abstract: This invention relates to a lytic diluent and a method for rapid lysing of red blood cells in whole blood for a differential determination of lymphoid and myeloid populations of leukocytes, and measurement of hemoglobin, particularly for use in automatic particle counting systems.The diluent is a mixture of at least one quaternary ammonium salt having surface active properties, and an additive in suitable proportions, buffered to an acid pH of 3.5 to 5.0. The additive includes 2-phenoxyethanol and other short chain alkanols substituted by one phenyl or phenoxy, as well as certain polyhydroxy compounds.When the reagent is employed in lower concentrations, an alkaline reagent comprising a quaternary ammonium salt and an alkali metal cyanide, buffered to an alkaline pH, may be added to complete the chromagen formation.

Abstract: In an apparatus in which particles are passed through an optical sensing zone to measure their light scattering characteristics for the purpose of identifying the particles, means and a method are provided for deviating the collected light in accordance with predetermined different paths to a plurality of different photodetecting devices. The deviation is effected simultaneously with collection by optical radiant energy reflecting means. The different photodetecting devices enable the measurement of energy scattered along the particular path which is identified with that device. The paths are established by the combined collecting and deviating means rather than permitted to evolve by the scattering phenomena themselves whereby the photodetecting devices can be located in convenient arrangements and may be conventional in construction.

Abstract: An apparatus and method for illuminating particles, wherein a source of illumination provides a beam of illuminating radiation which perpendicularly intersects a stream of liquid having the particles suspended therein. The illuminator apparatus comprises a concave reflector surface having a center of curvature and an optical axis which is disposed perpendicularly relative to the stream and with the beam being positioned thereon. The stream of liquid defines a cylindrical lens having a focus positioned at the center of curvature. In operation, the illuminating radiation illuminates the particles, is refracted by the stream so as to converge to a focus, passes from that focus to a concave reflector surface, and reflects from the concave reflector surface back to the focus, so as to impinge upon the stream for a second time, to further illuminate the particles.

Abstract: A variable stop syringe for automatically selecting, aspirating and dispensing one of a desired plurality of fluid volumes. The variable syringe includes a plurality of stops in an array each of which defines a particular fluid volume. The array selectively is moved to position the desired stop in the fully aspirated position of the syringe plunger. The stop positions are coded and automatically may be read to select the desired syringe stop for the particular volume of fluid desired to be aspirated and dispensed. The completely dispensed and the fully aspirated positions of the plunger, as well as the speed of the plunger operation, may be monitored to ensure that the plunger is operating properly.

Abstract: By subjecting cells, such as blood cells, tissue cells, and bone marrow cells, to hypotonic solutions having different osmolalities, the cells will rapidly attain a change in volume and electrical resistance parameters, which change is measurable, for example, by a Coulter Counter.RTM. particle measuring instrument. The relationship between change in cell resistance or cell volume and osmolality provides a discriminator between normality, different diseases, and certain inherited differences.

Abstract: A sample and stat feeding system for sequentially supplying a renewable supply of cuvettes with aliquots of sample liquids in a continuous processing mode. The sample liquids are contained in a annular sample tray having a plurality of sample vessels molded into the tray. The sample containers form two or more annular rows on the outer edge of the tray in which routine samples are maintained in an ordered sequence. Emergency samples (stats) and controls (standards) are maintained in separate auxiliary locations or arrays of locations which may be molded or separate cups placed in tray cavities. A sample pick up mechanism has a pick up probe which is rotated to define an arc across at least a substantial portion of the tray and at least one stat location. The tray is rotated to align the sample, stat and control cavities with the arc of the probe.

Abstract: A fluid transfer mechanism for rapidly and accurately picking up or aspirating a fluid quantity or aliquot in one position, moving it to a second position and dispensing the aspirated aliquot. The mechanism includes an arm mounted on a high helix shaft on one end and driven up and down the shaft by a first motor and rotated around the shaft by a second motor. The arm includes at a second end a fluid transfer probe which is moved into and out of the fluids to aspirate and dispense the fluids in precise angular locations. The arm may be accelerated and deaccelerated as it is rotated to avoid vibrations and spilling of the fluid from the probe. The probe may include a level sensing structure for sensing when the probe has contacted a fluid surface. The probe also may be coupled to an oscillator to oscillate the probe in a vessel into which the fluid has been dispensed to mix the fluids therein.

Abstract: System and program for measuring progressively the absorbance changes of a large number of aliquots from a plurality of different samples in a continuous processing mode. A plurality of routine samples are maintained in an ordered sequence in a sample tray which may be moved to a first sample pick up position. Emergency samples (stats) and controls (standards) are positioned in a second plurality of auxiliary positions which may be moved to a second sample position. A first and second plurality of reagents are maintained, moved to respective reagent pick up positions, picked up, moved and dispensed in respective dispensing positions by respective single reagent dispensing arms in a similar manner to the sample operation. The chemical reaction is then monitored by photometer means preferably having a plurality of photometric detectors such that radiation passes through each of the cuvettes and the fluids therein during each cycle of the system.

Abstract: A liquid dispenser system for moving a measure of liquid through a conduit from a source container to a receiving container. A branched flow path is defined between a source of pressurized fluid via a first branch sealingly coupled to the source container and a second branch leading communicatively to said conduit at a location between the intake end and the delivery end. A valve is provided to direct the pressurized fluid along one of said first and second branches. A through coil is interposed between said second branch and said conduit. The first branch terminates above the liquid level of the source container. Pressurized fluid is first directed along said first branch causing liquid flow toward the delivery end of said conduit. When flow of the leading liquid is detected, pressurized fluid is directed to the said location along the second branch to split the flowing column of liquid to deliver the portion above the split to the receiving container and the rest back to the source container.

Abstract: Measurement of the energy and direction of radiation, typically scattered light, produced by particles passing through an optical sensing zone is improved in focusing of the scattered light and flexibility in the choice of focal length for positioning of photoresponsive devices.The improvement is obtained by collimating the collected scattered light entering a deviating device, typically a fresnel prism, and then focusing the emerging separate, independent beams for measurement.Collimation can be obtained using optical elements including lens systems or reflective systems such as those employing parabolic reflection.

Abstract: A method is described for preparing a human platelet analog for use as a reference control in particle analysis instrumentation of the Coulter type. Goat erythrocytes from individual goats which have been selected with respect to age, sex, selective breeding, a controlled environment, prior veterinary treatment, and diet are altered in size and/or combined with samples from several goats, as needed, to obtain a blend for use as a reference control for automated particle counting equipment in which the goat erythrocytes simulate in number, size and distribution the platelets in human whole blood. The controls are useful as a free-standing reference for determination of human platelets only, or can be added to whole blood reference controls for multi-parameter instruments.

Abstract: The invention relates to cuvettes for use in apparatus for the examination of liquid samples, such as automatic chemistry apparatus. Cuvettes are formed as a continuous integral strip, the strip between adjacent cuvettes being made flexible so as to permit relative angular movement of adjacent cuvettes in the horizontal and preferably both the horizontal and vertical planes in use. An apparatus for use with the cuvettes includes a carrier for receiving the cuvette strip in located position, and scanning means for scanning the cuvettes sequentially with appropriate radiation which is transmitted through the samples in the cuvettes.

Abstract: An improved particle sensing transducer apparatus and method for studying the physical properties of particles suspended in an electrolyte solution. The transducer apparatus includes a first chamber, at least a portion of which contains a quantity of the electrolyte solution with a first electrode disposed therein. A second chamber is provided, at least a portion of which contains a quantity of the electrolyte solution with a second electrode disposed therein. The transducer further includes an orifice for establishing a constricted electrical path by providing a passageway for a sample flow of electrolyte solution containing the particles between the two chambers. The improvement comprises a fluid retarding, ion conducting material, such as a gel, frit or membrane, interposed between the sample flow and at least one of the electrodes so as to pass an ionic current while retarding the electrolyte flow from the electrode.