Abstract: An extruder head made up of several segments including a first section made up of at least two plates bolted together. At least one plate is hingeably mounted to another plate in the first section to provide access to an extrudate passage defined by the plates. Downstream of the first section is a pair of mating blocks bolted to the first section further defining the extrudate passage. Inserts of hardened steel are provided and held by the plates and blocks forming the extruder head and the inserts define parts of the extrudate passage. A cooling liquid chamber is provided in at least one insert to cool the wall forming the passage. Although the passage is continuously restricted in the downstream direction, to increase the pressure of the elastomeric melt, intermittent portions of a slightly greater cross-sectional area are provided to allow expansion and thus intermittent lower pressure of the melt as it passes through the passage.

Abstract: An extruder for elastomeric material has an axial screw in an extruder chamber defined by a cylindrical housing. Two radial planes of vented kneading pins are provided upstream of the extruder housing succeeded by spaced-apart planes of non-vented kneading pins. Each vented kneading pin includes small apertures at the inlet end of the pin which communicate with a stepped bore of gradually increasing crosssectional area from the inlet to the outlet thereof whereby gases within the elastomeric material can be vented through the apertures communicating with the stepped bore to the exterior of the extruder housing.