Methods for using a high tensile strength reinforcement to repair surface defects in a pipe

A method for repairing a pipe having a raised region on an outer surface thereof and having a defective region defined by at least one cavity extending from said outer surface of said pipe toward the center of said pipe, said method comprising the steps of:

• providing a filler material having a workable uncured state and a rigid cured state,
• filling said cavity to at least said outer surface of said pipe with said filler material in said workable state,
• applying said filler material in said workable state to said outer surface of said pipe adjacent said raised regions,
• providing at least one band having a plurality of elastic convolutions of a high tensile strength material,
• while said filler material is in said workable state, wrapping said plurality of convolutions of said high tensile strength material about said pipe to form a coil overlying said filler material, said step of forming said coil creating void spaces between said outer surface of said pipe and said coil,
• tightening said coil about said pipe so that filler material completely fills that portion of said cavity underlying said coil and said void spaces,
• securing at least one of said convolutions to an adjacent one of said convolutions, and
• permitting said filler material to cure to said rigid state.

A method for repairing a pipe having a defective region defined by at least one cavity extending from an outer surface of said pipe toward the center of said pipe, said defective region being in a portion of said pipe curved in the axial direction, said curved portion having an outer radius of curvature and an inner radius of curvature, said method comprising the steps of:

• providing a filler material having a workable uncured state and a rigid cured state,
• filling said cavity to at least said outer surface of said pipe with said filler material in said workable state,
• providing at least one band having a plurality of elastic convolutions of a high tensile strength material,
• while said filler material is in said workable state, wrapping said plurality of convolutions of said high tensile strength material about said pipe to form a plurality of coils overlying said filler material so that adjacent ones of said coils are spaced from one another along said outer radius of curvature to define unwrapped regions,
• tightening said plurality of said coils about said pipe so that said filler material completely fills that portion of said cavity underlying said plurality of coils,
• securing at least one of said convolutions to an adjacent one of said convolutions in each of said plurality of coils, and
• permitting said filler material to cure said rigid state.

A method for repairing a pipe adapted to carry an internal load directed radially outward therefrom, said pipe having a defective region defined by at least one cavity extending from an outer surface of said pipe toward the center of said pipe but not extending completely through the wall of said pipe, said method comprising the steps of:

• providing a filler material having a workable uncured state and a rigid cured state,
• filling said cavity to at least said outer surface of said pipe with said filler material in said workable state,
• providing an adhesive having an uncured fluid state and a cured adhesive state,
• while said filler material is in said workable state, applying a layer of said adhesive in said uncured fluid state over a circumferential portion of said pipe including said cavity, said adhesive being compatible with said filler material so that said adhesive does not prevent said filler material from curing to said rigid state,
• also while said filler material is in said workable state, wrapping a band of composite material about said pipe to form a coil overlying said filler material and said adhesive layer, said band defining a spiral terminating in an inner end and an outer end and having a plurality of elastic convolutions for encircling and engaging said pipe, each convolution having an inner surface and an outer surface bearing against corresponding surfaces of adjacent convolutions, said composite material comprising a plurality of continuous, high tensile strength filaments encapsulated in a resin matrix and extending through said spiral parallel to the direction of spiral,
• simultaneous with said wrapping step, applying a layer of said adhesive in said uncured fluid state between adjacent ones of said plurality of convolutions,
• tightening said coil about said pipe so that said filler material completely fills that portion of said cavity underlying said coil, and
• permitting said filler material to cure to said rigid state and said adhesive to cure to said adhesive state, whereby a load carried by said pipe is transferred substantially instantaneously from said pipe to said coil.

A method for repairing a pipe adapted to carry an internal load directed radially outward therefrom, said pipe having a defective region defined by at least one cavity extending from an outer surface of said pipe toward the center of said pipe but not extending completely through the wall of said pipe, said method comprising the steps of:

• providing a filler material having a workable uncured state and a rigid cured state,
• filling said cavity to at least said outer surface of said pipe with said filler material in said workable state,
• providing at least one band having a plurality of elastic convolutions of a high tensile strength material,
• while said filler material is in said workable state, wrapping said plurality of convolutions of said high tensile strength material about said pipe to form a coil overlying said filler material,
• tightening said coil about said pipe so that said filler material substantially completely fills void spaces in a portion of said cavity underlying said coil and between said outer surface of said pipe and said coil,
• securing at least one of said convolutions to an adjacent one of said convolutions, and
• permitting said filler material to cure to said rigid state, whereby a load carried by said pipe is transferred substantially instantaneously from said pipe to said coil.