Screw conveyer and furnace

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.