Abrasion test screen

In the most precise commercial grading, the best work being done in some plants in the abrasives industry, the efficiency of the screening does not actually run much over 75 per cent. As shown by hand screens the work is better than this, in some cases over 90 per cent. Hand screens as a means of testing the work of power screens are only better in degree than power screens. With hand test screens of over H-m- size it is possible after shaking out finer particles to pick up the coarse pieces of the test sample and try them in different axial position to see if they will pass the apertures. 

The percent of fines passing the 0.0117-in. screen is considered breakage due to attrition or abrasion rather than shattering, and is reported as dust index. In the above example this.is 20.1 percent. Note that the higher the friability value, the more easily the material under test degradates. 

Fig. 9.9 Agglomerate strength testers top) hydraulic four-column press for the determination of compression strength bottom) from left, rotating tube for measuring degradation at transfer points, drop test arrangement, and drum abrasion tester Fig. 9.10 Laboratory test equipment a) mixers, b) sample splitters and screen,...

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