Screw conveyer and furnace

Claim 1

A screw conveyer comprising (a) a rotary shaft carrying screw flite means surrounding and attached to the shaft (b) an imperforate tubular housing surrounding at least the major part of the length of the screw flite means (c) inlet and outlet openings at opposite ends of the housing for products to be heated (d) an inverted U-shaped heat insulation casing over said housing and spaced therefrom, said casing being open at its under part for inlet of ambient air (e) a plurality of pipe burners arranged below the housing extending parallel to the axis of the shaft along said major part of the length of the screw flite means (f) first exhaust duct means (32) connected to the housing and communicating with the interior of the housing for exit of moisture (g) second exhaust duct means (33) communicating with the space between the housing and the casing for exhausting burnt gases (h) the shaft, housing and casing are inclined to the horizontal with the inlet opening lowermost (i) the shaft extends out of the casing at the inlet end and the shaft carries a feed screw at the inlet end outside the casing below the inlet opening (j) the screw flite carries mixing blades (12) (k) at least three side pipe burners are provided spaced apart from each other below the housing.