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:
May. 16, 2000
Filed:
Jul. 10, 1998
Applicant:
Inventors:
Assignee:
Lindab AB, Bastad, SE;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F16L / ; F16L / ;
U.S. Cl.
CPC ...
138129 ; 138122 ; 138143 ;
Abstract
A double-walled structure in a ventilation duct system has an inner tube and an outer tube and, arranged therebetween, a sound-absorbing material. The inner tube is a helically-wound lock-seam tube formed from a sheet metal strip having parallel longitudinal areas of expanded metal.