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:
Mar. 18, 2003
Filed:
Oct. 04, 2001
Applicant:
Inventors:
Tom Jacobsen, Trondheim, NO;
Lars Jenssen, Trondheim, NO;
Assignee:
Leiv Eiriksson Nyfotek AS, Trondheim, NO;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
E21D 1/100 ; F15C 1/00 ;
U.S. Cl.
CPC ...
E21D 1/100 ; F15C 1/00 ;
Abstract
A method for reducing frictional loss in unlined tunnels or other tunnels with a rough wall surface and/or irregular cross section. A flexible or rigid pipe with a cross section similar to or somewhat less than the largest circular open cross section of the tunnel is introduced into the tunnel and attached continuously or at certain points to parts of the tunnel wall. Apparatus for ensuring that a superpressure occurs within the pipe relative to its outside during flow are also introduced.