Screw conveyor apparatus

Claim 1

APPARATUS FOR CONVEYING PARTICULATE MATERIAL COMPRISING A HOUSING DEFINING AN ELONGATED CAVITY, SAID HOUSING HAVING AN INLET PASSAGE COMMUNICATING WITH SAID CAVITY AND AN OUTLET OPENING LONGITUDINALLY SPACED ALONG SAID CAVITY FROM SAID INLET PASSAGE AND COMMUNICATING WITH SAID CAVITY, A CONVEYOR SCREW MOUNTED WITHIN SAID CAVITY TO BE ROTATABLE ABOUT AN AXIS EXTENDING LONGITUDINALLY OF SAID CAVITY, SAID SCREW HAVING A SUBSTANTIALLY UNIFORM OUTER DIAMETER DEFINED BY A HELICAL SCREW THREAD ENCIRCLING A CORE, SAID CORE HAVING A TAPERED PORTION ENCIRCLED BY SAID THREAD WITH THE RADIAL DEPTH OF ADJACENT TURNS OF SAID THREAD INCREASING ALONG THE TAPERED PORTION OF SAID CORE, SAID SCREW HAVING THE LARGER DIAMETER OF THE TAPERED CORE PORTION DISPOSED ADJACENT SAID INLET PASSAGE WITH THE HOUSING ENCLOSING SAID SCREW BETWEEN SAID INLET PASSAGE AND SAID OUTLET OPENING, A GATE FOR CONTROLLING MATERIAL FLOW TO SAID SCREW AND MOUNTED IN SAID INLET PASSAGE TO BE MOVABLE FROM A FIRST POSITION WHEREAT IT CLOSES SAID PASSAGE TO A SECOND POSITION WHEREAT A MATERIAL INLET IS FORMED ADJACENT SAID CONVEYOR SCREW TO ACCOMMODATE FLOW OF MATERIAL TO THE CONVEYOR SCREW, SAID MOUNTING OF SAID GATE PROVIDING FOR MOVEMENT OF SAID GATE FROM SAID FIRST TO SAID SECOND POSITION COMMENCING AT AN INITIAL POINT DISPOSED ADJACENT THE SHALLOW TURNS OF SAID HELICAL THREAD AND CONTINUING TOWARD THE DEEPER TURNS OF SAID HELICAL THREAD WHEREAT SAID MATERIAL INLET IS FULLY OPEN, SAID GATE PREVENTING ACCESS OF PARTICULATE MATERIAL TO SAID SCREW TURNS OTHER THAN THE TURNS IMMEDIATELY ADJACENT THE EXTENT OF OPENINGS OF THE MATERIAL INLET WHEREBY THE RATE OF MATERIAL CONVEYING BY SAID APPARATUS WILL BE DETERMINED BY THE EXTENT OF OPENING OF SAID MATERIAL INLET FOR ANY ROTATIVE SPEED OF SAID CONVEYOR SCREW.