Short length tapered extrusion cooking device

A short length cooking extruder comprising:

• an elongated tubular barrel having a material inlet and a spaced material outlet and presenting an inner surface defining an elongated bore;
• an elongated, helically righted screw assembly positioned within said bore;
• means for axially rotating said screw assembly at a rotational speed of at least 500 rpm;
• and
• an apertured extrusion die disposed across said material outlet,
• said bore being of generally frustoconical configuration for at least 50% of the length of said bore from said inlet to said die and presenting a generally decreasing cross-sectional area as said die is approached,
• said barrel inner surface being configured to present a series of inwardly extending helical rib sections along the length thereof,
• said extruder having a L/D ratio of up to 6.

A short length cooking extruder comprising:

• an elongated tubular barrel having a material inlet and a spaced material outlet and presenting an inner surface with a series of spaced, helical rib sections along the length thereof and defining an elongated bore;
• an elongated, helically righted screw assembly positioned within said bore;
• means for axially rotating said screw assembly;
• and
• an apertured extrusion die disposed across said material outlet,
• said bore being of generally frustoconical configuration from said inlet to said die to present a generally decreasing cross-sectional area along the length of the bore as said die is approached,
• there being an apertured material flow-restricting device within said barrel and intermediate said inlet and outlet, said flow-restricting device presenting an upstream face and an opposed downstream face, said upstream face being closer to said inlet than said downstream face,
• the material displacement per revolution of said screw assembly adjacent said upstream face of said flow-restricting device being smaller than the material displacement per revolution of said screw assembly adjacent said downstream face of said flow-restricting device,
• said screw assembly and flow-restricting device being cooperatively configured for substantially continuously maintaining the apertures of said flow-restricting device full of material during operation of said extruder,
• said rotating means being operable for rotating said screw assembly within said barrel at a rotational speed of at least 500 rpm,
• said extruder having a L/D ratio of up to 6.

A short length cooking extruder comprising:

• an elongated tubular barrel having a material inlet and a spaced material outlet and presenting an inner surface defining an elongated bore which is of general frustoconical configuration over at least a portion of the length thereof;
• an elongated, helically flighted screw assembly positioned within said bore;
• means for axially rotating said screw assembly at a rotational speed of at least 500 rpm:
• and
• an apertured extrusion die disposed across said material outlet,
• there being means defining a material flow-restriction within said barrel and intermediate said inlet and outlet, said flow-restriction defining means presenting an upstream margin and an opposed downstream margin, said upstream margin being closer to said inlet than said downstream margin,
• said extruder having a L/D ratio of up to 6.

A short length cooking extruder comprising:

• an elongated tubular barrel having a material inlet and a spaced material outlet and presenting an inner surface defining an elongated bore which is of general frustoconical configuration over at least a portion of the length thereof;
• an elongated, helically flighted screw assembly positioned within said bore;
• means for axially rotating said screw assembly at a rotational speed of at least 500 rpm;
• and
• an apertured extrusion die disposed across said material outlet,
• said extruder having a L/D ratio of up to 6.

A method of extrusion cooking an edible material comprising the steps of:

• passing said edible material into the inlet of an elongated extruder having a barrel equipped with an endmost extrusion die and an internal, axially rotatable, flighted screw assembly within the barrel,
• said extruder having an L/D ratio of up to 6;
• and
• rotating said screw assembly at a speed of at least 500 rpm for advancing said material from said inlet along the length of said barrel and out said extrusion die for heating and at least partial cooking of the edible material.