Twin screw extruder with conical non-parallel converging screws

A twin extrusion screw set comprising:

• first and second elongated screws each having a central shaft presenting a shaft rear end and a shaft front end and a longitudinal axis, outwardly extending helical flighting along the length of the central shaft with the flighting having a flighting rear end, a flighting front end, an outer surface spaced from the central shaft and defining a flighting depth between the flighting outer surface and said central shaft,
• each of said shafts progressively tapering along the length thereof through a first taper angle from a point adjacent the shaft rear end to a point adjacent the shaft front end so that the shaft diameter adjacent the shaft rear end is greater than the shaft diameter adjacent the shaft front end,
• the flighting depth on each shaft progressively tapering along the length thereof through a second taper angle from a location adjacent the flighting rear end to a location adjacent the flighting front end so that the flighting depth adjacent the flighting rear end is greater than the flighting depth adjacent the flighting front end,
• said first and second screws being located in adjacent, side-by-side relationship and each oriented at an angle relative to the adjacent screw so that the longitudinal axes of the first and second screws define an included angle.

A twin extrusion screw set comprising:

• first and second elongated screws each having a central shaft presenting a shaft rear end and a shaft front end and a longitudinal axis, outwardly extending helical flighting along the length of the central shaft with the flighting having a flighting rear end, a flighting front end, an outer surface spaced from the central shaft and a flighting depth between the flighting outer surface and said central shaft,
• said first and second screws being located in adjacent, side-by-side relationship and each oriented at an angle relative to the adjacent screw so that the longitudinal axes of the first and second screws define an included angle,
• the flighting of the first screw being intercalated with the flighting of the second screw along the lengths of the first and second screws, said intercalated flighting of the first and second screws cooperatively presenting a plurality of nip zones along the length of the screws,
• the clearance between said intercalated flighting of the first and second screws at said nip zones being substantially constant along the length of the screws.

An twin screw extruder comprising:

• an elongated barrel presenting an inlet and a spaced outlet and having a barrel opening configured to receive a twin screw set therein;
• and
• a twin screw set within said barrel and including—
• first and second elongated screws each having a central shaft presenting a shaft rear end and a shaft front end and a longitudinal axis, outwardly extending helical flighting along the length of the central shaft with the flighting having a flighting rear end, a flighting front end, an outer surface spaced from the central shaft and defining a flighting depth between the flighting outer surface and said central shaft,
• each of said shafts progressively tapering along the length thereof through a first taper angle from a point adjacent the shaft rear end to a point adjacent the shaft front end so that the shaft diameter adjacent the shaft rear end is greater than the shaft diameter adjacent the shaft front end,
• the flighting depth on each shaft progressively tapering along the length thereof through a second taper angle from a location adjacent the flighting rear end to a location adjacent the flighting front end so that the flighting depth adjacent the flighting rear end is greater than the flighting depth adjacent the flighting front end.

An twin screw extruder comprising:

• an elongated barrel presenting an inlet and a spaced outlet and having a barrel opening configured to receive a twin screw set therein;
• and
• a twin screw set within said barrel and including—
• first and second elongated screws each having a central shaft presenting a shaft rear end and a shaft front end and a longitudinal axis, outwardly extending helical flighting along the length of the central shaft with the flighting having a flighting rear end, a flighting front end, an outer surface spaced from the central shaft and a flighting depth between the flighting outer surface and said central shaft,
• said first and second screws being located in adjacent, side-by-side relationship and each oriented at an angle relative to the adjacent screw so that the longitudinal axes of the first and second screws define an included angle,
• the flighting of the first screw being intercalated with the flighting of the second screw along the lengths of the first and second screws, said intercalated lighting of the first and second screws cooperatively presenting a plurality of nip zones along the length of the screws,
• the clearance between said intercalated flighting of the first and second screws at said nip zones being substantially constant along the length of the screws.

A method of producing an extruded product, comprising the steps of:

• providing an extruder comprising—
• first and second elongated screws each having a central shaft presenting a shaft rear end and a shaft front end and a longitudinal axis, outwardly extending helical flighting along the length of the central shaft with the fighting having a fighting rear end and a flighting front end and an outer surface spaced from the central shaft,
• said first and second screws being located in adjacent, side-by-side relationship and each oriented at an angle relative to the adjacent screw so that the longitudinal axes of the first and second screws define an included angle,
• the flighting of the first screw being intercalated with the flighting of the second screw along the lengths of the first and second screws, said intercalated fighting of the first and second screws cooperatively presenting a plurality of nip zones along the length of the screws,
• the clearance between said intercalated fighting of the first and second screws at said nip zones being substantially constant along the length of the screws;
• and
• passing an extrudable starting material into said barrel inlet and rotating said screw set in order to heat and pressurize said material within the barrel, and extruding the heated and pressurized material from said outlet end.

A method of producing an extruded product, comprising the steps of:

• providing an extruder comprising—
• an elongated barrel presenting an inlet and a spaced outlet and having a barrel opening configured to receive a twin screw set therein;
• and
• a twin screw set within said barrel and including—
• first and second elongated screws each having a central shaft presenting a shaft rear end and a shaft front end and a longitudinal axis, outwardly extending helical flighting along the length of the central shaft with the flighting having a flighting rear end, a flighting front end, an outer surface spaced from the central shaft and defining a flighting depth between the flighting outer surface and said central shaft,
• each of said shafts progressively tapering along the length thereof through a first taper angle from a point adjacent the shaft rear end to a point adjacent the shaft front end so that the shaft diameter adjacent the shaft rear end is greater than the shaft diameter adjacent the shaft front end,
• the flighting depth on each shaft progressively tapering along the length thereof through a second taper angle from a location adjacent the flighting rear end to a location adjacent the flighting front end so that the flighting depth adjacent the flighting rear end is greater than the flighting depth adjacent the flighting front end;
• and
• passing an extrudable starting material into said barrel inlet and rotating said screw set in order to heat and pressurize said material within the barrel, and extruding the heated and pressurized material from said outlet end.

An twin screw extruder comprising:

• an elongated barrel presenting an inlet and a spaced outlet and having a barrel opening configured to receive a twin screw set therein;
• and
• a twin screw set within said barrel and including—
• first and second elongated screws each having a central shaft presenting a shaft rear end and a shaft front end and a longitudinal axis, outwardly extending helical fighting along the length of the central shaft with the flighting having a fighting rear end, a flighting front end, an outer surface spaced from the central shaft and defining a lighting depth between the flighting outer surface and said central shaft,
• the fighting depth on each shaft progressively tapering along the length thereof through a taper angle from a location adjacent the lighting rear end to a location adjacent the flighting front end so that the flighting depth adjacent the flighting rear end is greater than the fighting depth adjacent the flighting front end.

A method of producing an extruded product, comprising the steps of:

• providing an extruder comprising—
• an elongated barrel presenting an inlet and a spaced outlet and having a barrel opening configured to receive a twin screw set therein;
• and
• a twin screw set within said barrel and including—
• first and second elongated screws each having a central shaft presenting a shaft rear end and a shaft front end and a longitudinal axis, outwardly extending helical flighting along the length of the central shaft with the flighting having a flighting rear end, a flighting front end, an outer surface spaced from the central shaft and defining a flighting depth between the flighting outer surface and said central shaft,
• the flighting depth on each shaft progressively tapering along the length thereof through a taper angle from a location adjacent the flighting rear end to a location adjacent the flighting front end so that the flighting depth adjacent the flighting rear end is greater than the flighting depth adjacent the flighting front end;
• and
• passing an extrudable starting material into said barrel inlet and rotating said screw set in order to heat and pressurize said material within the barrel, and extruding the heated and pressurized material from said outlet end.

An extruder comprising

• an elongated barrel presenting a material inlet and a material outlet;
• and
• at least one elongated axially rotatable, helically flighted screw located within said barrel and operable for moving material from said inlet to said outlet,
• said barrel including a section having an outer shell and an inner extraction sleeve disposed within said shell, said sleeve having an inner surface defining an internal, elongated passageway receiving a portion of said screw and an outer surface, with a plurality of slots formed in the sleeve and extending from said inner surface to said outer surface, said slots configured to permit an extracted fluid to pass there-through for collection in said shell,
• said at least one screw and said sleeve cooperatively configured for extraction of fluid from said material during passage through said barrel section, and collection of said fluid within said shell