Abstract: An extrusion head for an extrusion apparatus can include a spider for supporting a central mandrel. A high volume reservoir can be mounted to the spider on a downstream side of the spider. The central mandrel can extend longitudinally into the high volume reservoir. The high volume reservoir can have an axially straight annular conduit with a length L and an outer diameter OD. The annular conduit can have an L to OD ratio of about 1:1. A set of dies can be mounted downstream of the high volume reservoir, whereby the high volume reservoir reduces pressure and promotes homogenization of molten polymer flowing therethrough, before reaching the set of dies.

Abstract: The extrusion head including a conduit with a central mandrel extending within the conduit for supporting an inner die portion of a set of dies that has inner and outer die portions. An upstream spider and a downstream spider are included, and each have webs supporting the central mandrel at axially spaced apart positions. The webs of the upstream and downstream spiders can have web portions that are axially offset from each other to promote mixing of polymer flowing through the conduit.

Abstract: A spider for an extrusion apparatus located upstream from a die, through which a profile is extruded. The spider can have an outer housing with a central flow passage therethrough. An inner hub can be positioned within the central passage for supporting an inner portion of the die. At least one spider leg can be secured to the outer housing and the inner hub, and support the inner hub within the central passage. The at least one spider leg can recess radially rearwardly outwardly in the downstream direction such that molten polymer flowing through the central passage flows around the at least one spider leg, separating and rejoining together earlier in inner radial regions close to the inner hub than in outer radial regions close to the outer housing for reducing spider lines on inside surfaces of extruded profiles.

Abstract: A spider for an extrusion apparatus located upstream from a die, through which a profile is extruded. The spider can have an outer housing with a central flow passage therethrough. An inner hub can be positioned within the central passage for supporting an inner portion of the die. At least one spider leg can be secured to the outer housing and the inner hub, and support the inner hub within the central passage. The at least one spider leg can recess radially rearwardly outwardly in the downstream direction such that molten polymer flowing through the central passage flows around the at least one spider leg, separating and rejoining together earlier in inner radial regions close to the inner hub than in outer radial regions close to the outer housing for reducing spider lines on inside surfaces of extruded profiles.

Abstract: A spider for an extrusion apparatus located upstream from a die, through which a profile is extruded. The spider can have an outer housing with a central flow passage therethrough. An inner hub can be positioned within the central passage for supporting an inner portion of the die. At least one spider leg can be secured to the outer housing and the inner hub, and support the inner hub within the central passage. The at least one spider leg can recess radially rearwardly outwardly in the downstream direction such that molten polymer flowing through the central passage flows around the at least one spider leg, separating and rejoining together earlier in inner radial regions close to the inner hub than in outer radial regions close to the outer housing for reducing spider lines on inside surfaces of extruded profiles.

Abstract: The extrusion head including a conduit with a central mandrel extending within the conduit for supporting an inner die portion of a set of dies that has inner and outer die portions. An upstream spider and a downstream spider are included, and each have webs supporting the central mandrel at axially spaced apart positions. The webs of the upstream and downstream spiders can have web portions that are axially offset from each other to promote mixing of polymer flowing through the conduit.

Abstract: An extrusion head for an extrusion apparatus can include a spider for supporting a central mandrel. A high volume reservoir can be mounted to the spider on a downstream side of the spider. The central mandrel can extend longitudinally into the high volume reservoir. The high volume reservoir can have an axially straight annular conduit with a length L and an outer diameter OD. The annular conduit can have an L to OD ratio of about 1:1. A set of dies can be mounted downstream of the high volume reservoir, whereby the high volume reservoir reduces pressure and promotes homogenization of molten polymer flowing therethrough, before reaching the set of dies.

Abstract: A spider for an extrusion apparatus located upstream from a die, through which a profile is extruded. The spider can have an outer housing with a central flow passage therethrough. An inner hub can be positioned within the central passage for supporting an inner portion of the die. At least one spider leg can be secured to the outer housing and the inner hub, and support the inner hub within the central passage. The at least one spider leg can recess radially rearwardly outwardly in the downstream direction such that molten polymer flowing through the central passage flows around the at least one spider leg, separating and rejoining together earlier in inner radial regions close to the inner hub than in outer radial regions close to the outer housing for reducing spider lines on inside surfaces of extruded profiles.