New apparatus for determination of size distribution of particles in fine powders

Every year a greater need for accurate analysis of size distribution of subsieve material is being by the engineer, because of the increasingly vital it plays in the manufacture of cement, pigments, and powdered products. Sieves are a satisfactory means obtaining this information as long as the material is relatively coarse, but when from 70 to 95 per cent of the sample passes the 200-mesh screen (the finest one giving consistent reading), some new scheme of analysis must be used. methods of analyzing this fine fraction have developed. For example, Professor Work at has perfected an excellent microscope technic. and sedimentation methods employing various media have been shown to be feasible, and methods are constantly being developed, but of them are slow and tedious.