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:
Sep. 14, 1993
Filed:
Jul. 22, 1991
Campbell H Steketee, Jr, Salem, OR (US);
NuPipe, Inc., Memphis, TN (US);
Abstract
A thin, flexible tubular membrane provides a heat containment tube for inserting into and inflation within an underground conduit to be repaired. Folded rigid thermoplastic pipe is inserted into the tube while hot and flexible. The tubular membrane is pressurized to exclude unwanted fluids from within the existing conduit. Hot steam is injected into the tube to heat the pipe full-length externally and internally until flexible. The pipe is then rounded and expanded against the walls of the conduit with the tube therebetween. The rounding and expanding of the pipe is carried out progressively by moving a plug through the pipe and by injecting hot steam under pressure behind the plug.