Extrusion die with external and internal cooling means

摘要

This invention relates to apparatus for controlled cooling of an extruded plastic product. As the product exits the extrusion die, it passes through an elongated shell. The shell surrounds the die at its inner end and extends outwardly along the extrusion. A seal ring at the outer end of the shell engages the exterior of the extruded product; the shell, seal ring, and product define an annular cooling chamber through which a coolant is circulated through the cooling chamber, the coolant exiting through an annular cooling chamber extension in the die. For a hollow extruded product, the apparatus further includes an internal cooling tube that extends axially through the interior of the hollow product. The tube ends at a seal cap that engages the internal surface of the hollow product. The tube and seal cap define a second, internal cooling chamber through which coolant circulates; the coolant enters throught the end of the tube opposite the seal cap and exits through an annular recess in the die.