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:
Aug. 01, 2000
Filed:
Sep. 03, 1997
Applicant:
Inventor:
Shailesh Doshi, Kingston, CA;
Assignee:
E. I. du Pont de Nemours and Company, Wilmington, DE (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B23P / ;
U.S. Cl.
CPC ...
29890043 ; 29890044 ;
Abstract
Plastic tube-type heat exchanger structures are made with partially crystallized partially aromatic polyamides of high glass transition temperature. The structures are then annealed to further crystallize the polyamides, causing shrinkage and building up residual tensile stresses. These stresses counteract the swelling caused by water absorption and temperature rise during use of the heat exchanger and keep the structures dimensionally stable.