Abstract: In a blood analyzer, improved calibration is provided. First and second photodetectors sense energy supplied directly from a source and from the source through a sample respectively. A log ratio amplifier provides an analog output indicative to the log of the ratio of the outputs of the photodetectors to a control circuit. When a blank sample is measured, a programmable voltage source operates to set the analog output to a selected level. A reference sample having optical density corresponding to a preset value is next measured, and a variable gain amplifier is set by the control circuit to cause the analog signal to correspond to the preset value.

Abstract: A hematology analyzer provides a pulse signal in which the number of pulses manifests the number of blood cells in a sample volume of blood and the magnitude of each pulse manifests the size of each such blood cell. The analyzer also provides an analog voltage manifesting the hemoglobin content of the blood sample. Means responsive to the pulse signal provide an analog voltage manifesting the hematocrit of the blood sample and an analog voltage manifesting the number of cells. An analog-to-digital converter is switchably responsive to the analog hemoglobin, hematocrit and cell count signals to provide required ratios reflecting the mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration of the blood sample.

Abstract: In an automatic chemical testing apparatus calibration values obtained from readout signals of analysis means must be stored for use in prior art calculating means for processing of subsequent readout signals of samples containing unknown quantities of substances in a medium. Improved means are provided for selecting the calibration values, namely a blank value and a reference value. A plurality of pairs of blank and reference samples are processed. The blank samples have known zero or baseline levels or concentrations of substances, and the reference samples have known concentration levels of each substance. These known values are stored for comparison to processed values obtained by processing the readout signals obtained in response to analysis of the blank and reference samples. The validity of each such readout signal as a calibration value is determined by the successfulness of the comparison. The most current successful blank and reference signals are selected as the calibration values.

Abstract: A method and apparatus for correcting the output count of an electronic particle counting system in which additional correction pulses are added to the pulses generated by the electronic counting system as a result of detecting particles flowing through an orifice. The correction pulses are added in accordance with a curve which is generated by statistical computation determined by the size of the orifice and the character of the particles being detected therein and their quantity per unit volume. The improved apparatus comprises the addition of a second counter chain to the system which includes digital counters having outputs at various frequencies which are dividends of the frequency of the input pulses. The various-frequency outputs are combined through logic circuitry to generate individual correction pulses at frequencies such that when the pulses are added to the detected pulses, the total of the pulses corresponds to the actual number of particles flowing through the orifice.

Abstract: In an automatic chemical testing apparatus, a reaction loop conveyor carries rows of reaction containers in a path including an upper, forward path in a direction normal to the rows. Samples for analysis are provided to the reaction conveyor from a sample source. An improved system is provided in which sample source means synchronized with the reaction conveyor index successive sample containers to an aspiration station adjacent to one row in the forward path of the reaction conveyor. The sample source means may be a sample conveyor consisting of sample container holders linked together.

Abstract: In an automatic chemical testing apparatus including a reaction conveyor carrying rows of reaction containers from a sample dispensing station through a reaction station and to an analysis station, the improvement is provided in which slats containing the reaction containers are linked together to form a reaction loop conveyor without the need for a separate chain. The loop path includes first and second apexes and a forward path between the apexes. Guideways are provided to maintain the reaction container slats in an upright disposition between the forward path and the apexes. Further, a conveyor housing assembly is provided housing incubation means, reaction container washing means and means for driving the conveyor directly.

Abstract: There is disclosed apparatus for aspirating and dispensing a liquid sample which includes a storage cylinder within which is included a freely moving solid cylinder. Attached to the storage cylinder is an aspirating cylinder or needle, which is inserted into the sample. Both the storage cylinder and needle are initially filled with water. Before aspirating the sample, a slight amount of water is removed from the storage cylinder resulting in air being aspirated through the needle. Then, the needle is inserted in the sample and water continues to be removed from the storage cylinder, resulting in the sample being aspirated through the needle. The aspirated sample and water are separated by the previously aspirated air, which creates a bubble in the storage cylinder. This bubble lifts the movable solid cylinder in the storage cylinder as the sample is aspirated.

Abstract: A mold formed reaction container includes a lower portion having four sides forming an open top parallelepiped structure and an upper portion in the shape of a threaded hollow cylinder over which a cap may be screwed. The lower portion is inserted in a square opening of an automatic chemical analyzer so that two of the sides thereof are in a radiant energy path. The opening of the analyzer has two slot indentions removed from two opposite sides thereof and the lower portion of the container has two corresponding key extensions therefrom to insure the proper two sides of the container are placed in the energy path. Further, one of the sides of the container not having a key extension has a label on a portion thereof and that portion intersects and blocks a second radiant energy path through the opening in such a manner that the insertion of the container can be detected.