26 to the next vertically the slots 40 may have opposite orientations that is for one screen plate the slots 40 may slant up left to right from top to bottom and the other right to left from top to bottom as shown in fig6 the slots 40 in each slot region 34 have a narrow opening at the inner surface 44 of the plate 36 and a wide opening at the outer surface 42 of the plate the width w of a slot may be taken the narrow dimension of the slot as compared to the length l of the slot as shown in fig4 the thickness t of the slot is the thickness of the plate 36 if the slot is tapered along its thickness t the angle of the taper may be beta u03b2 fig6 e g 30 degrees in a specific embodiment the width w may be measured at the narrowest opening of the slot such as at the outer surface 42 of the plate 36 generally all slots 40 in a slot region 34 and even in a screen plate have uniform widths w lengths l thicknesses t and tapers u03b2 however the slot width w may vary from slot region to region from screen plate to plate and or from screen section to screen section within a screen assembly fig7 and 8 are a front and a cross sectional side views respectively of a first embodiment of a screen plate 50 having diagonal slots with rounded inlet edges the screen plate shown in fig7 and 8 are most suitable for continuous digesters in which the pulp slurry moves past the slots in a downward direction the plate 50 may also be applied in a batch digester the slots.