초록 ▼

A multi-stage extruder apparatus comprising at least two extruder units operatively joined together in series for the progressive sequential working of plastic molding material moving continuously therethrough. The apparatus comprises an improved extrusion screw for a succeeding extruder unit of the

A multi-stage extruder apparatus comprising at least two extruder units operatively joined together in series for the progressive sequential working of plastic molding material moving continuously therethrough. The apparatus comprises an improved extrusion screw for a succeeding extruder unit of the multi-stage apparatus which prevents adverse effects attributable to an imbalance of the rate or volume of molding material moving continuously through the multi-stage apparatus.

대표청구항 ▼

An apparatus for the continuous blending and plasticizing of a heat softenable and curable molding compound comprising plasticizable polymeric material and continuously extrusion molding the blended and plasticized compound, comprising, (a) a preceding extruder unit comprising an extruder barrel hav

An apparatus for the continuous blending and plasticizing of a heat softenable and curable molding compound comprising plasticizable polymeric material and continuously extrusion molding the blended and plasticized compound, comprising, (a) a preceding extruder unit comprising an extruder barrel having an upstream inlet and a downstream outlet, and containing therein a rotatable extruder screw; (b) a connection comprising a passage leading from the outlet of the barrel of the preceding extruder unit to an inlet in an intermediate portion of a succeeding extruder unit; (c) a succeeding extruder unit comprising an extruder barrel having an inlet positioned intermediate its upstream end and its downstream end and a downstream outlet, and containing therein a rotatable screw, said extruder barrel of the succeeding extruder uNit having a surplus discharge outlet located upstream from its intermediate inlet; and (d) the rotatable screw of said succeeding extruder unit comprising a shaft extending from beyond the upstream end of the extruder barrel substantially through the length of said barrel towards the outlet and having a portion therein intermediate its length of substantially reduced cross-section located adjacent to the intermediate inlet of the succeeding extruder unit and extending downstream therefrom and an adjoining portion providing an enlarged cross-section extending upstream from said portion of reduced cross-section with an interface between the adjoining portions of reduced and enlarged cross-sections of the shaft forming a generally radial extending shoulder located upstream from said intermediate inlet, said shaft being provided with a helical screw flight extending downstream from the interface shoulder having a pitch to advance molding compound from the intermediate inlet downstream toward the outlet, and a helical screw flight extending upstream from the interface shoulder having an opposite pitch to advance surplus molding compound upstream toward the surplus discharge outlet.