Positive pressure backwash strainer

Claim 1

A ROTARY DRUM STRAINER COMPRISING AN ENCLOSING CASING, A DRUM OF INVERTED TRUNCATED CONICAL SHAPE IN THE CASING HAVING STRAINER OPENINGS IN THE PERIPHERY THEREOF AND STRAINER ELEMENTS IN SAID OPENINGS, THE DRUM BEING CLOSED AT THE TOP AND HAVING AN OPEN BOTTOM, MEANS IN THE BOTTOM OF THE CASING ENGAGING THE LOWER END OF THE DRUM PROVIDING A SEAL, MEANS FOR SUPPLYING LIQUID TO BE STRAINED TO THE CASING AROUND THE EXTERIOR OF THE DRUM, AN OUTLET FOR CARRYING AWAY STRAINED LIQUID FROM THE LOWER END OF THE DRUM, A SHAFT ON WHICH THE DRUM IS CARRIED, SAID SHAFT PASSING THROUGH THE TOP AND BOTTOM OF THE CASING, A BACKWASHING SHOE ON THE INTERIOR OF THE CASING HAVING AN INCLINED FACE PARALLEL WITH THE OUTER FACE OF THE DRUM WHICH IT CONFRONTS AND AGAINST WHICH IT BEARS, A POSITIVE PRESSURE BACKWASHING SHOE INSIDE THE DRUM BEARING AGAINST THE INNER WALL OF THE DRUM IN CONFRONTING POSITION TO THE SHOE ON THE CASING AND HAVING ITS FACE INCLINED PARALLEL TO THE INNER WALL OF THE DRUM AND THE FACE OF THE SHOE IN THE CASING, A THRUST BEARING AT THE OUTSIDE OF THE BOTTOM OF THE CASING FOR SUPPORTING SAID SHAFT ON WHICH THE DRUM IS MOUNTED, SAID POSITIVE PRESSURE SHOE HAVING A PIPE-LIKE EXTENSION AT ITS LOWER END EXTENDING OUT THE OPEN BOTTOM OF THE DRUM AND THROUGH THE BOTTOM OF THE CASING ECCENTRICALLY TO THE SHAFT, COOPERATING MEANS AT THE EXTERIOR OF THE BOTTOM OF THE CASING AND ON SAID EXTENSION FOR ADJUSTABLY RAISING OR LOWERING THE POSITIVE PRESSURE SHOE AND SUPPORTING IT AGAINST RADIAL MOVEMENT, AND A PIPE CONNECTION FOR SUPPLYING LIQUID UNDER PRESSURE TO THE POSITIVE PRESSURE SHOE FROM A SOURCE OF SUPPLY, SAID FIRST BACKWASHING SHOE HAVING A DISCHARGE OPENING FOR THE OUTFLOW OF BACKWASH LIQUID THEREFROM, SAID POSITIVE PRESSURE SHOE HAVING INTEGRAL BRACING THEREON SLIDABLY ENGAGING THE DRUM SHAFT FOR HOLDING THE SHOE AGAINST THE INTERIOR OF THE DRUM AND CONFINING THE SAME AGAINST RADIAL MOVEMENT RELATIVE TO THE DRUM.