FILTER MEDIUM WITH A MULTIPLICITY OF DIFFERENT FILTER LAYERS AND USE FOR TESTING FILTER MEDIA

摘要

Fluid flows along a fluid path (14) to pass through a filter element (12). The filter element (12) is preceded by an obstacle (24). This creates an eddy region (40) in which fluid flow along the path (14) is reduced, reversed or zero. This is found to improve the performance of the filter elements (12) in removing particulate material from fluid.