Patent ID: 6783667
Filing Date: 2004-08-31
Classification: B01D,B29C

Abstract:
A screen unit for removing solid particles from a viscous mass, the screen unit comprising:a housing having a supply channel and a discharge channel for the viscous mass; a screen element in the housing between the supply channel and discharge channel, the screen element being operable to screen solid particles from the viscous fluid during a screening phase during which the viscous mass flows through the housing from the supply channel to the discharge channel; means for cleaning the screen element by backflushing the viscous mass through the screen element during a backflushing phase, the cleaning means comprising a backflush channel for discharging during the backflushing phase the solid particles screened by the screen element during the screening phase, an outflow channel through which the solid particles exit the housing during the backflushing phase, a shut-off valve between the backflush channel and the outflow channel, and pressure-generating means for causing the viscous mass to backflush through the screen element at a pressure higher than a pressure in the supply channel; a shutter element disposed along the screen element; and means for moving the shutter element with respect to the screen element, the moving means being operable to increasingly expose more of the screen element to the viscous mass substantially throughout the screening phase, and to decreasingly expose less of the screen element during the backflushing phase.