Patent ID: 6273266
Filing Date: 2001-08-14
Classification: D21D

Abstract:
A process for the wet screening of stock suspensions in a pressure grader that includes a screen with screen apertures and at least one clearer which is movable relative to the screen, the process comprising:conducting the stock suspension along the screen, whereby break-away eddies are formed on an inflow side of the screen;separating portions of the stock suspensions, wherein a part of the stock suspension passes through the screen apertures as underflow and an other part is rejected as overflow; andmoving the at least one clearer relative to the screen, whereby one of pressure- and suction impulses are produced at the screen apertures to form pre- and back flows,wherein a flow direction of the break-away eddy is reversed by the back flow to rinse a part of the screen lying between the screen aperture with the back flow and an adjacent downstream aperture.