Consolidation of the packing material in chromatographic columns under dynamic axial compression .2. Consolidation and breakage of several packing materials

The consolidation of packing materials under dynamic axial compression is studied for one irregular and two spherical shaped particles. When the total axial compression stress is raised from 1 to 80 kg/cm(2), a long column of initial length 25 cm shrinks by nearly 25%, while a short column of initial length 4 cm decreases by nearly 35%. This result illustrates the lack of homogeneity of the stress distribution during the compression. While the extent of consolidation is nearly the same with all three materials, its kinetics is different. The spherical materials consolidate rapidly and smoothly. The material made of irregular-shaped particles consolidates more slowly, in several decreasing steps. Finally, almost no breakage is observed with the spherical materials, while for the irregular-shaped material fragmentation and chipping takes place to a significant extent under an axial compression stress of 80 kg/cm(2).