Method and apparatus for separating paper from cardboard

A screen for classifying material by size comprising:

• a receiving section having a front end and a rear end, the receiving section inclining upward from the front end to the rear end at a given angle;
• a plurality of shafts mounted on the receiving section substantially parallel with one another, the shafts extending up from the front end to the rear end of the receiving section in a substantially coplanar alignment at the given angle;
• and
• discs mounted on the shafts, each of the discs having an arched perimeter shape that maintains a space between discs substantially constant during rotation while moving material on said discs up and down, the discs at the front end of the receiving section interdigitized between discs extending from adjacent shafts and discs behind the front end of the receiving section aligned in the same longitudinal positions on each shaft.

A method for classifying material by size comprising the steps of:

• defining a receiving stage of a conveyer including a plurality of shafts arranged to define a substantially array extending at a given inclined angle;
• mounting noncircular discs on the shafts in substantially parallel rows;
• rotating the shafts in the same direction;
• dropping material on the shafts at a first end of the receiving stage so that shaft rotation causes the material to be pushed by the discs up the receiving stage;
• shaping a parameter of the discs so that the discs agitate the material in an up and down motion while pushing the material up the receiving stage in a forward direction;
• carrying the material on the conveyor from the given inclined angle of the receiving stage to a downwardly sloping angle;
• and
• dropping the material from the receiving stage while moving in the downwardly sloping angle and forward direction thereby causing the material to drop or flipover in a vertically downward and forward direction.

A screen for classifying material by size comprising:

• a receiving section having a front end and a rear end;
• a discharge section including a front end located below the rear end of the receiving section, and a rear end,
• a plurality of shafts mounted on the discharge section substantially parallel with one another, the shafts extending from the front end to the rear end of the discharge section in a substantially coplanar alignment;
• and
• discs mounted on the shafts, each of the discs having an arched perimeter shape, the discs at the front end of the discharge section interdigitized between discs extending from adjacent shafts and discs behind the front end of the discharge section aligned in the same longitudinal positions on each shaft.