The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 22, 1985
Filed:
May. 12, 1983
Granville J Hahn, Big Spring, TX (US);
Raleigh N Rutledge, Big Spring, TX (US);
Cosden Technology, Inc., Dallas, TX (US);
Abstract
Apparatus is disclosed for the formation of pipe comprising one or more layers of thermoplastic resin. The apparatus comprises a die housing having a bore therethrough with a mandrel longitudinally supported within the bore by radial members extending from the inside surface of the bore to provide an annular extrusion passageway defined by the inside surface of the housing and the outer surface of the mandrel. The housing includes therein a plurality of electrically resistive heating elements longitudinally positioned parallel to the extrusion passageway to selectively heat the thermoplastic material flowing therethrough in proximity to the heated section thereby increasing the laydown of thermoplastic material. Also included in the housing is plurality of radially adjustable elements having electrically resistive heating elements therein to radially reposition a moveable discharge sleeve held therebetween thereby controlling the wall thickness of the thermoplastic material passing in proximity thereto. The extrusion passageway is constricted downwstream of the radial support but prior to the annular sequentially positioned feed rings to reunite the thermoplastic material after the flow disruption created by the radial support members. Also included in the mandrel is a central longitudinal passageway in communication with the inlet section of the bore for the transportation of thermoplastic material therethrough to one or more of the annular feed rings. The mouth of the mandrel bore includes a restrictor orifice therein to balance the pressure differential created therein by the constriction in the extrusion passageway.