tailieunhanh - Abrasive Materials_3

Tham khảo tài liệu 'abrasive materials_3', kỹ thuật - công nghệ, điện - điện tử phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Abrasive Particle Size Distribution and Abrasive Particle Diameter 27 Table Particle-size distribution functions Kelly and Spottiswood 1982 Schubert 1988 Function Formula M0 dP Significance of d Equation Logarithmic probability erf dp Ơ Medium particle diameter Rosin-Rammler-Sperling- 1 - exp dp vM J Particle diameter at M0 Bennett RRSB Gates-Gaudin-Schumann Lv nM GGS Gaudin-Meloy 1- 1 - 2 Maximum particle diameter Broadbent-Callcott 1-exp - f 1 exp 1 - Particle Diameter According to regulations in ISO 1117 the particle diameter is defined according to a particle size class . A size class of 140 for example means a particle diameter of mm. If the particle size distribution is known from the sieve analysis several average diameter values of the particle sample can be estimated. The median diameter d50 is the 50 point on any cumulative distribution curve Fig. . For the examples presented in Table and Fig. this diameter is dP50 510 Alumina 700 and dP50 280 MG 65 respectively. The geometric mean diameter dPG is based on the assumption of an even graduation in size from maximum to minimum and it assumes an equal number of particles in each size average dP max dP min dPG ------ 2------ In the examples given in Table and Fig. this diameter is dPG 740 Alumina 700 and dPG 362 MG 65 respectively. A third approach is the definition of a statistical diameter dPSt which follows the equation n 1 mi dPi dPSt --------- For the examples in Table and Fig. the statistical diameter is dPSt 613 Alumina 700 and dPSt 345 pm MG 65 respectively. Alternative Abrasive Particle Size Assessment Methods Particle sizes but also particle size distributions can be assessed also by applying image analysis methods. This alternative approach is not a standard in 28 2 Abrasive Materials a b Fig. Distribution functions for sieve analysis results see Table . a .