The labelling of shaker screens has been a problem. Existing mesh count designations do not adequately describe a shaker screen's potential separation performance. Consequently, it is difficult to make an informed decision when selecting shaker screens. The establishment of a standardized, performance-based designation system has been hindered largely by the time, expense and difficulty in deriving absolute screen separation efficiencies from full-scale laboratory testing.
This paper introduces a technique which overcomes this problem by relating the separation efficiency potential of a shaker screen to a volume-equivalent distribution of its hole sizes. Magnified, computer-enhanced visual images of screen apertures were measured using a PC-based image analyzer system. An equivalent volume distribution was then derived from this data to yield a curve corresponding to a grade efficiency or percent-separated function. These equivalent volume distributions were compared to experimental percent-separated values for square, oblong and layered mesh screens to confirm the viability of the image analysis technique.