US 2004/0166191 A1 · Reservoir reducing screw tip

Abstract

An extruder for extruding extrudate is provided and includes a generally cylindrical barrel portion having an end face. A screw conveyor is rotatably arranged coaxially within the barrel portion and has a downstream end. The screw conveyor has helical flights that define a first flow path with the barrel for the extrudate. The first flow path has a first cross-sectional area. An adapter is arranged on the end face of the barrel portion and defines an exit portion of the extruder. A screw tip is secured to the downstream end of the screw conveyor and extends into the adapter. The screw tip and the adapter define a second flow path for the extrudate with a second cross-section area being at least as large as the first cross-sectional area.

Claims15

Dependent claims

An extruder for extruding extrudate, comprising:

a generally cylindrical barrel portion having a longitudinal axis and an end face;
a screw conveyor rotatably arranged coaxially within the barrel portion, the screw conveyor having a downstream end, the screw conveyor having helical flights that define a first flow path within the barrel for the extrudate;
an adapter arranged on the end face of the barrel portion, said adapter having an opening with varying diameters that defines a second flow path for the extrudate where a downstream end of the opening defines an exit portion of the extruder;
and
a screw tip secured to the downstream end of the screw conveyor and extending into the adapter where the screw tip is designed to reduce dead space in a cross-sectional flow area of the second flow path so that the cross-sectional flow areas of the first and second flow paths remain approximately constant whereby the volume of extrudate flowing through the first flow path is relatively constant with the volume of extrudate exiting the extruder.

2 more elements

An extruder screw tip adapted to be secured to a downstream end of a screw conveyor of an extruder for increasing the output of the extruder, said screw tip comprising:

a base including means for connection with an extruder conveyor screw, the base having a longitudinal axis and a diameter approximately equal to that of the extruder conveyor screw;
a rounded point disposed on an end of the screw tip opposite the base;
a first portion that tapers at an angle from the base toward the longitudinal axis;
and
a second portion that tapers at a slight angle from the first portion to the rounded tip where the second portion is longer in length than the first portion and the tapering angle of the first portion is significantly greater than the slight angle of the second portion.

2 more elements

Dependencies are inferred from the claim text.

Reservoir reducing screw tip

Life of this patent

Reservoir reducing screw tip

Life of this patent

Abstract

Claims15