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. 04, 1977
Filed:
Dec. 08, 1976
Wilhelm Brand, Hannover, DT;
Hermann Berstorff Maschinenbau GmbH, Hannover-Kleefeld, DT;
Abstract
A screw extruder for thermoplastics synthetic materials or elastomers having a screw rotating in a cylinder wherein the screw has a mixing part having a plurality of first grooves at an upstream position thereof inclined in the direction of feed, a plurality of second grooves at a position downstream of the first grooves and also inclined in the direction of feed and a grooveless portion between said first grooves and said second grooves, and the cylinder has a mixing part which surrounds said grooveless portion of the mixing part of the screw and has third grooves therein which extend axially or are inclined in the direction of feed, the number of said first grooves, said third grooves and said second grooves differing. Preferably the number of grooves diminishes in the feed direction that is to say the number of said first grooves exceeds the number of said third grooves and the number of said third grooves exceeds the number of said second grooves. The transitions of said third grooves to the cylinder bore are preferably gradual transitions.