Particle size measurement electrical sensing zone

Electrical Sensing Zone (Coulter Counter) As a particle passes through an orifice, the electrical resistance measured across the orifice changes as a function of the particle size (volume). This can be proved by considering Figure 37 and deriving the following relationships (7, 8) ... 

Mazdiyasni, K. S., Effects of dispersion of barium titanate powder on measure ments in an electrical-sensing-zone particle size counter. Am. Ceram. Soc. Bull 57, 448 (1978). 

Multiple techniques can be used to measure the particle size distribution, for example electrozone sensing, sedimentation, laser diffraction, and microscopy. With the exception of microscopy, they all require calibration and the results depend on the technique. For example, in a round-robin study reported in Reference 4, the commonly used electrical sensing zone technique (Coulter Counter) was compared to microscopy and sedimentation. The average particle size determined by the electrical sensing zone method was by about 25%... 

The effect of particle shape on particle size distribution was investigated by Naito et al. (1998) with commercial particle size analyzers based on five different measuring principles electrical sensing zone, laser diffraction and scattering, x-ray sedimentation, photosedimentation, and light attenuation. The particles used are blocky aluminum oxide and barium titanate particles, flaky boron nitride particles, and rodlike silicon whisker ceramic powders. Altogether, four commer-... 

If the particle size distributions are characterized by the average diameters at the cumulative masses of 10, 50, and 90%, the data scattering measured by different techniques can be represented by the diameter ratios at the cumulative masses of 10, 50, and 90%, or DRio, DR50, and DR90. Since the particle diameter measured by the electrical sensing zone technique is to be the equivalent volume diameter and is independent of the particle shape, its particle diameter is defined to be one. The particle diameters measured by other techniques are then ratioed with this diameter. The experimental results of DRjo, DR50, and DR90 are summarized in Table 5. It can be seen that the results of particle analysis from different techniques can be quite different. 

T. Allen and K. Marshall, The Electrical Sensing Zone Method of Particle Size Measurement, ... 

B. Goransson and E. Dagerus Image Analysis as a Tool for Calibration of Electrical Sensing Zone Instruments in the Size Measurement of Porous Spherical Particles. Particle Size Analysis 1988 ed. P.J. Lloyd 1988, Wiley Sons, pp. 159-166. 

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