Patent ID: 6426969
Filing Date: 2002-07-30
Classification: F27D

Abstract:
Discharge screw (6) for a moving hearth, and in particular for an annular rotary hearth (2) of a reheat furnace for the heat treatment of loose materials, comprising a cylinder (61) arranged above and substantially radially with respect to the said annular hearth (2) and turned by suitable actuators (15) so as to discharge the materials from the edges of the said annular hearth (2), the said cylinder (61) comprising on its lateral surface a first series of helicoids (62) beginning in an area close to its outermost end with respect to the furnace and a second series of helicoids (63) beginning at its innermost end with respect to the furnace, and the inclination of the helicoids (62) of the said first series being essentially symmetrical to the inclination of the helicoids (63) of the said second series, which screw is characterized in that each helicoid (62, 63) of one series comprises an inward end that meets the inward end of a corresponding helicoid (63, 62) of the other series in such a way that at at least one of the said ends a free final section is left for the removal of loose materials from an area underneath it on the annular hearth (2).