Mechanical strainers

Claim 1

AN APPARATUS FOR SCREENING, CLASSIFYING, DEWATERING OR THE LIKE OF SUSPENSIONS OF SOLID PARTICLES, SUCH AS FIBRES, COMPRISING IN COMBINATION A CASING, A SCREEN DRUM HAVING A SMOOTH OUTER AND INNER MANTLE SURFACE MOUNTED IN SAID CASING WITH ITS AXIS IN A VERTICAL POSITION FOR ROTATION ABOUT SAID VERTICAL AXIS, SAID SCREEN DRUM HAVING A CENTRAL OPENING AT ITS LOWER END, INLET MEANS FORMED BY SAID CASING AND BEING OPERABLE FOR SUPPLYING SUSPENSION TO BE TREATED TO THE OUTER SIDE OF THE SCREEN DRUM AT ONE END THEREOF, FIRST OUTLET MEANS FORMED BY SAID CASING AND BEING OPERABLE FOR REMOVING REJECTED SUSPENSION AT THE OPPOSITE END OF THE SCREEN DRUM ON THE SAME SIDE THEREOF, SECOND OUTLET MEANS COMPRISED BY SAID CASING AND BEING OPERATIVE FOR REMOVING SCREENED SUSPENSION FROM THE INTERIOR OF THE SCREEN DRUM THROUGH SAID CENTRAL OPENING, A PULSATING MEMBER MOUNTED FOR ROTATION IN SAID CASING COAXIALLY WITH THE SCREEN DRUM, SAID PULSATING MEMBER COMPRISING A PLURALITY OF VANES EXTENDING SUBSTANTIALLY AXIALLY ALONG THE OUTER SIDE OF THE DRUM, FIRST DRIVE MEANS OPERABLE FOR ROTATING SAID SCREEN DRUM AT A SPEED SUFFICIENT TO CREATE A ROTATING RING OF SCREENED SUSPENSION ON THE INSIDE OF THE DRUM, AND SECOND DRIVE MEANS OPERATIVE FOR ROTATING SAID PULSATING MEMBER WITH RESPECT TO SAID CASING AND TO SAID SCREEN DRUM, SETTING UP PERIODICALLY IN THE SUSPENSION ADJACENT THE OUTER SURFACE OF THE DRUM SUCTION FORCES AT CONSECUTIVE LONGITUDINAL ZONES OF THE SCREEN SURFACE, THEREBY TO GENERATE A PERIODIC BACK-FLOW OF SUSPENSION THROUGH THE SCREEN.

Claim 2

AN APPARATUS FOR SCREENING, CLASSIFYING, DEWATERING OR THE LIKE OF SUSPENSIONS OF SOLID PARTICLES, SUCH AS FIBRES, COMPRISING IN COMBINATION A CASING, A SCREEN DRUM HAVING A SMOOTH OUTER AND INNER MANTLE SURFACE MOUNTED IN SAID CASING WITH ITS AXIS IN A VERTICAL POSITION FOR ROTATION ABOUT SAID VERTICAL AXIS, SAID SCREEN DRUM HAVING A CENTRAL OPENING AT ITS LOWER END, INLET MEANS FORMED BY SAID CASING AND BEING OPERABLE FOR SUPPLYING SUSPENSION TO BE TREATED TO THE OUTER SIDE OF THE SCREEN DRUM AT ONE END THEREOF, FIRST OUTLET MEANS FORMED BY SAID CASING AND BEING OPERABLE FOR REMOVING REJECTED SUSPENSION AT THE OPPOSITE END OF THE SCREEN DRUM ON THE SAME SIDE THEREOF, SECOND OUTLET MEANS COMPRISED BY SAID CASING AND BEING OPERATIVE FOR REMOVING SCREENED SUSPENSION FROM THE INTERIOR OF THE SCREEN DRUM THROUGH SAID CENTRAL OPENING, A PULSATING MEMBER MOUNTED FOR ROTATION IN SAID CASING COAXIALLY WITH THE SCREEN DRUM, SAID PULSATING MEMBER COMPRISING A PLURALITY OF VANES EXTENDING SUBSTANTIALLY AXIALLY ALONG THE OUTER SIDE OF THE DRUM, FIRST DRIVE MEANS OPERABLE FOR ROTATING SAID SCREEN DRUM AT A SPEED SUFFICIENT TO CREATE A ROTATING RING OF SCREENED SUSPENSION ON THE INSIDE OF THE DRUM, AND SECOND DRIVE MEANS OPERATIVE FOR ROTATING SAID PULSATING MEMBER WITH RESPECT TO SAID CASING AND TO SAID SCREEN DRUM, SETTING UP PERIODICALLY IN THE SUSPENSION ADJACENT THE OUTER SURFACE OF THE DRUM SUCTION FORCES AT CONSECUTIVE LONGITUDINAL ZONES OF THE SCREEN SURFACE, THEREBY TO GENERATE A PERIODIC BACK-FLOW OF SUSPENSION THROUGH THE SCREEN.