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:
Jan. 16, 1996
Filed:
Mar. 30, 1995
Paul Tersi, Altenstadt, DE;
Wolfgang Briegel, Hanau, DE;
Dieter Cermak, Friedrichsdorf, DE;
Michael Schulze, Offenbach am Main, DE;
Zimmer Aktiengesellschaft, , DE;
Abstract
A process for filtering polymer melt which minimizes the generation of dead zones in the filter and provides uniform residence time and accurate temperature control. The process is carried out in an apparatus comprising a plurality of heat exchanger pipes, each enclosing a filter cartridge surrounded by an annular space which terminates at its upper end in a plurality of narrow channels. The molten polymer is charged into the annular space and divided into primary and secondary streams. The primary stream flows through the filter cartridge and the secondary stream, which constitutes 0.03 to 3.0 weight percent of the weight of the combined streams, flows through the narrow channels, whereupon the streams are combined and discharged from the apparatus. The discharge temperature of the polymer is maintained within .+-.1.degree. C. of the charging temperature and the heat exchanger fluid enters the apparatus at a temperature within 1.degree. and 5.degree.C. of the temperature of the melt.