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:
Sep. 03, 1991
Filed:
Dec. 08, 1989
Manfred Dienst, Burgdorf, DE;
Hermann, Berstorff Maschinenbaum GmbH, Hanover, DE;
Abstract
A single or twin-screw device is used to incorporate additives in a thermoplastic plastics material melt. The or each barrel of the extruder includes a first feed aperture for the introduction of the melt and a second feed aperture downstream thereof for the introduction of the additives. A screw is mounted on a shaft in each barrel and includes a core and a helical flight. In the region of the second feed aperture, the flight is replaced by alternating disc members and spacer members mounted on the shaft. The diameter or major dimension of the disc members is approximately equal to the combined diameter of the screw core and its flight while the diameter of the spacer members is approximately equal to that of the screw core. The disc members have profiled downstream faces. The disc and spacing members increase mixing and consequently throughput in the region of the second feed aperture.