Hopper structure

Claim 1

AN OUTLET STRUCTURE ADAPTED TO BE SECURED BENEATH A HOPPER STRUCTURE COMPRISING A PAIR OF OPPOSITELY FACING SIDE WALLS SLOPING DOWNWARDLY TOWARD EACH OTHER IN A GENERALLY SMOOTH RELATION AND HAVING SPACED LOWER PORTIONS EACH TERMINATING IN A LIP, MENS CONNECTING THE ENDS OF THE SIDE WALLS TO FORM A GENERALLY TROUGH-SHAPED OUTLET STRUCTURE, A CONDUIT STRUCTURE EXTENDING BETWEEN AND BELOW THE SPACED LOWER PORTIONS OF THE SIDE WALLS TO FORM A DEPRESSED TROUGH BOTTOM BETWEEN THE LIPS IN WHICH PARTICLES ARE REMOVED PNEUMATICALLY FROM THE OUTLET STRUCTURE, SAID CONDUIT STRUCTURE INCLUDING AN ELONGATE METERING TUBE BETWEEN THE SPACED LOWER PORTIONS EXCEEDING 1/8 INCH, SAID PERMEABLE SHEET HAVING TORTUOUS OF THE SIDE WALLS AND ROTATABLE IN ONE DIRECTION FROM A CLOSED POSITION TO AN OPEN POSITION, SAID METERING TUBE HAVING A SLOT EXTENDING LONGITUDINALLY THEREOF TO RECEIVE PARTICLES FROM THE OUTLET STRUCTURE FOR PNEUMATIC UNLOADING WHEN POSITIONED BETWEEN THE LIPS, EACH OF SAID LIPS BEING CLOSELY SPACED FROM THE ADJACENT METERING TUBE AND EXTENDING LONGITUDINALLY IN A DIRECTION GENERALLY PARALLEL TO THE ROTATIONAL AXIS OF THE METERING TUBE, SAID CONDUIT STRUCTURE BEING CUT BACK IMMEDIATELY BELOW EACH LIP TO DEFINE AN INCREASED CLEARANCE WHEREBY A RESTRICTION IS PROVIDED BETWEEN EACH LIP AND THE ADJACENT METERING TUBE, MEANS FORMING WITH AT LEAST A PORTION OF THE LWER SURFACES OF SAID SIDES A PLENUM CHAMBER, AND MEANS FOR INTRODUCING FLUID WITHIN THE PLENUM CHAMBER, EACH OF SAID SIDE WALLS COMPRISING A PERMEABLE SHEET HAVING SPACED PARALLEL FACES WITH ONE OF THE FACES FORMING A PARTICLE SUPPORTING SURFACE AND A PERFORATED SUBSTANTIAL RIGID PLATE GENERALLY COEXTENSIVE WITH AND ADJACENT THE OTHER OF SAID FACES OF THE SHEET, THE THICKNESS OF THE PLATE RELATIVE TO ITS PLANAR DIMENSION BEING GREAT ENOUGH TO SUPPORT PARTICLES WITHOUT SUBSTANTIAL DEFLECTION, SAID PLATE AND SAID SHEET BEING SECURED TO EACH OTHER ALONG SUBSTANTIALLY THEIR ENTIRE FACING SURFACES TO FORM AN INTEGRALLY BONDED RIGID SANDWICH, SAID PERMEABLE SHEET HAVING A RELATIVELY HARD AND SMOOTH PARTICLE SUPPORTING SURFACE THEREBY TO PERMIT THE PARTICLES TO MOVE EASILY ALONG THE SURFACE AND THE SURFACE TO BE EASILY CLEANED.