Abstract: A method of correcting first approximation data obtained from a conventional electrozone particle sensing apparatus includes steps for calculating factors for correcting for binary and tertiary coincidences, from the raw data and from physical characteristics of the sensing equipment, to yield an accurate measure of particle distribution within the sample.

Abstract: A suction chamber and at least one sample chamber are located in relatively shiftable operating adjacency. The suction chamber may have a plurality of orifices and the sample chamber a single port for selective registration with the orifices. On the other hand, the suction chamber may have a port or an orifice, and a plurality of sample chambers may have either respective ports or orifices, and the chambers mounted for relative shifting for effecting selective port/orifice registration. A sample depletion detector may be provided in association with the sample chamber. The sample chamber may have a minimum volume residual sample well for maintaining a filled system with the suction chamber to facilitate recurrent sample analyzing function.

Abstract: A method of and means for controlling orientation of particles through a sensing zone in a particle analyzing system, which facilitates particle shape determination, comprises laminar flow orientation of the particles in a stream moving through an elongate straight passage coaxially aligned with an elongate sensing zone longer than the longest particle to be sensed and analyzed. The particles are carried through the sensing zone in an isokinetic laminar flow sheath of fluid.

Abstract: A method of and means for controlling orientation of particles through a sensing zone in a particle analyzing system, which facilitates particle shape determination, comprises laminar flow orientation of the particles in a stream moving through an elongate straight passage coaxially aligned with an elongate sensing zone longer than the longest particle to be sensed and analyzed. The particles are carried through the sensing zone in an isokinetic laminar flow sheath of fluid.

Abstract: A digitally controlled variable impedance, preferably for use in a current normalizer for particle analysis apparatus, includes a variable resistance connected to a counting register by a plurality of opto-isolaters in the form of light emitting diode-light responsive transistor combinations. The register is reset (or preset) to a predetermined count and operates to change the impedance value in response to receipt of each pulse of a pulse train. A circuit is provided to terminate counting in response to an interpulse interval of greater than a predetermined interval to indicate a null condition between pulse amplitude, the pulses traversing the impedance, and a reference amplitude.