Patent ID: 6336983
Filing Date: 2002-01-08
Classification: B29C,B29K,F16L

Abstract:
A method for restoring the burst strength of a pipe having an unbreached weakened region to a level at which the pipe can withstand the forces of a pressure fluid in the pipe having a pressure of at least 500 pounds per square inch, the weakened region comprising at least one depression in the outer surface of the pipe comprising:detecting the weakened region; providing a load-transferring filler material; filling the depression with the filler material; and wrapping around the pipe in the weakened region a strip of high tensile strength material comprising unidirectional high tensile strength filaments in a cured resin matrix and defining a coil band having a length, an inner surface, an outer surface, opposite side surfaces and a plurality of elastic convolutions, the filaments extending parallel to the length of the coil band, the step of wrapping including placing a first elastic convolution around the pipe and placing subsequent elastic convolutions around underlying convolutions on the pipe such that the opposite side surfaces of the band in said subsequent elastic convolutions are in radial alignment with opposite side surfaces of the band in the underlying convolutions, the step of wrapping further including securing the convolutions from movement so that the convolutions do not move relative to one another when the pipe is pressurized, whereby the wrapped pipe has a burst strength of a level at which the pipe can withstand the forces of a pressure fluid in the pipe having a pressure of at least 500 pounds per square inch.