this is normal for smaller perforations but the effects are magnified by the large plastics in the reject stream which are sufficiently large to drop the freeness and sufficiently light to change the consistency referring to fig6 the pressure drop verses the accept flow is illustrated for both screens the upper limit on both screens was the pump capacity and not the screen the 0 055 34 curve is almost at the maximum while the 0 078 34 curve shows that additional capacity is available referring to fig7 the debris removal for both screens is illustrated with respect to the percent rejects by weight as shown the 0 055 34 screen provided better debris removal thab the 0 078 34 screen at a reject rate of 5 5 rejects by weight the debris removal was 52 for the 0 078 34 screen and was 71 for the 0 055 34 screen the debris content was measured using an image analyzer four one gram view sheets were made from each pulp sample the analyzer was set to count as large a section as possible of the sheet which amounted to about 80 of the sheet sensitivity was set such that the particles which were visible to the eye were counted the magnification amounted to about 1 4 u00d7 to achieve the visual to analyzer correlation the results of these tests are tabulated below in table 3 showing the debris area measured for each inlet accept and reject sample the debris removal is calculated from the equation equ1 table 3______________________________________test 1 test 2 test 3 test 4______________________________________in 0 01318 0 00681 0 00512 0 00620acc 0 00473 0 00222 0 00251 0 00182rej.