1. A MATERIAL HANDLING HOPPER CONSTRUCTION COMPRISING A CONICAL STORAGE STRUCTURE HAVING AN APEX PORTION AND A DISCHARGE PASSAGE COMMUNICATING WITH THE APEX PORTION, SAID APEX PORTION PROVIDED WITH AN UPPER FLUID CIRCULATING MEANS, SAID CIRCULATING MEANS HAVING AN ANNULAR RING MEANS DISPOSED WITHIN THE APEX PORTION AND DEFINING AN ANNULAR PERIPHERAL PASSAGE OF GRADUALLY DECREASING CROSS SECTION IN THE DIRECTION OF FLUID FLOW, AND A CENTRAL WHIRLPOOL CHAMBER, SAID ANNULAR RING MEANS BEING PROVIDED WITH A PLURALITY OF TRANS-RADIAL PASSAGES COMMUNICATING THE ANNULAR PASSAGE WITH THE INTERIOR OF THE CENTRAL WHIRLPOOL CHAMBER, A LOWER FLUID CIRCULATING MEANS INCLUDING A VENTURI MEANS DISPOSED WITHIN SAID APEX PORTION AND BELOW SAID ANNULAR RING MEANS MEMBER AND COM-