US 5,205,048 AGranted

Pipeline bend detector pig

AssigneeTDW Delaware, Inc.

InventorsDanny D. Toomey, Gene R. Ralls, Johnny M. Manley

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Abstract

A pipeline bend detector pig for measuring a bend in pipeline is disclosed, the pig having an elongated flexible body for transposition through the pipeline. The body has an imaginary central axis that substantially remains coaxial with the pipeline cylindrical axis as the body transverses the interior of the pipeline. First and second length-measuring cables are supported to the body, each in a radial plane of and spaced from the body central axis and spaced angularly from each other. Each length-measuring cable has one end affixed to the body and a free end. Each cable has spring tension applied to the free end thereof to keep the cable taunt. A variable electrical resistance element is actuated by the free end of each cable as the free ends of the cables are moved by bends in the pipeline. An odometer for measuring the distance of travel of the pig is provided. A solid state memory records the distance traveled and the occurrence of bends in the pipeline.

Claims23

Dependent claims

An apparatus for measuring a bend in a length of cylindrical pipe having a cylindrical axis, comprising:

an elongated flexible body for transposition through the length of cylindrical pipe having a first and a second end, said flexible body having a central substantially cylindrical core portion and a plurality of spaced apart radial integral enlarged diameter disc portions, the external cylindrical surface of said disc portions forming a body external cylindrical surface slidably received in and closely conforming to the cylindrical pipe internal surface, said flexible body having an imaginary central axis that substantially remains coaxial with the pipe cylindrical axis as the body traverses the interior of the pipe, said flexible body central core and said integral disc portions being formed of flexible plastic, said body substantially cylindrical with said body central opening therein at least substantially coincident with said body central axis and including a reinforcing cable received in said body central opening and secured to said body first and second ends;
a first length-measuring means carried by said body in a first radial plane of said body central axis and spaced from said body central axis;
a second length-measuring means carried by said body in a second radial plane having said body central axis therein, the second length-measuring means being spaced from and substantially parallel said body central axis, the second radial plane being angularly spaced from said first radial plane;
the first and second length-measuring means responding to bending of said flexible body as it traverses the interior of a pipeline having at least one bend therein;
means of converting length as measured by said first and second length-measuring means to bend signals;
means for providing a distance signal indicating the distance travelled by said flexible body;
means providing a record of said bend signals and said distance signals;
and
means to move said body through a length of cylindrical pipe.

6 more elements

An apparatus for measuring a bend in a length of cylindrical pipe having a cylindrical axis, comprising as at least a portion of such apparatus:

an elongated flexible body for transposition through the length of cylindrical pipe having a first and a second end, and an external cylindrical surface slidably receivable in and closely conforming to the cylindrical pipe internal surface, the body having an imaginary central axis that substantially remains coaxial with the pipe cylindrical axis as the body traverses the interior of the cylindrical pipe;
a first length-measuring cable carried by said body in a first radial plane of said body central axis and spaced from said body central axis, the first cable having one end affixed to said flexible body adjacent said first end and a free end adjacent said flexible body second end;
a second length-measuring means carried by said flexible body in a second radial plane having said body central axis therein, the second length-measuring means being spaced from and substantially parallel said body central axis, the second radial plane being angularly spaced from said first radial plane, the second cable having one end affixed to said flexible body adjacent said first end and a free end adjacent said body second end, the first and second length-measuring cables responding to bending of said flexible body as it traverses the interior of a pipeline having at least one bend therein by displacement of said cables free ends;
a first and a second potentiometer supported to said flexible body at said second end, each potentiometer having a rotatable shaft extending therefrom;
a spool received on each said potentiometer shaft;
a spring member coiled around each said spool and having a free end, the free end of said spring coiled around said spool on said shaft of said first potentiometer being affixed to said second end of said first length-measuring cable and the free end of said spring coiled around said spool on said shaft of said second potentiometer being affixed to said second end of said second length-measuring cable, whereby the displacement of said cables free ends are converted to bend measurement signals;
means for providing a distance signal indicating the distance travelled by said flexible body;
means providing a record of said bend signals and said distance signals;
and
means to move said flexible body through a length of pipe.

7 more elements

Dependencies are inferred from the claim text.