US 3,940,855 A · Pipeline pig

Abstract

A pipeline pig is provided which is especially adapted for use in conjunction with laying offshore pipelines in that it detects and indicates dents, and other disconformities in the nominal cross-sectional configuration of the pipeline which may occur as a result of the laying of the pipeline. It employs a plurality of prolate spheroid rollers arranged to secure substantially full circle coverage of the pipeline and yet only a minor portion of the length of the rollers will be normally in contact with the pipeline thereby reducing the wear on the remaining portions of the rollers and increasing the ease with which the pig can be towed along the pipeline. In another aspect, a system is provided in which a pig includes with a means of sensing a condition along the pipeline and a memory means for storing the output of the detecting means. The system also includes a readout means located remotely from the pig and transmission means connecting the memory means to the readout means for periodically reading out the output stored in the memory means within the pig while the latter is within the pipeline.

Claims10

Dependent claims

A pipeline pig for detecting deviations of an inner wall of a pipeline from a nominal cross-sectional configuration, comprising, in combination;

a central pig body;
a plurality of rollers for contacting and rolling along an inner wall of a pipeline as the pig body is moved therethrough;
means mounting the rollers on the pig body for inward and outward movement in a direction generally radially of the pig body and biasing the rollers outwardly for engagement with an inner wall of a pipeline;
said rollers each being of a length as to extend along a substantial portion of an inner periphery of a pipeline for rolling movement therealong and the rollers having substantially the shape of a prolate spheroid with a minor portion of the length thereof being radially enlarged in a manner such that only said minor portion contacts an inner wall of a pipeline when the latter is of nominal cross-sectional configuration and the remaining major portion of the roller is spaced from but sufficiently close to an inner wall of a pipeline to engage inward deviations of such wall and to be moved inwardly thereby;
and means for indicating when a roller is so moved inwardly.

2 more elements

A pipeline pig for detecting deviations of an inner wall of a pipeline from a nominal cross-sectional configuration, comprising, in combination;

a central pig body;
a plurality of groups of rollers spaced longitudinally along the length of said pig body, each group of rollers having a plurality of individual rollers therein with the rollers of one group being offset circumferentially from the rollers of another group so that the rollers of the groups together provide substantially full-circle coverage of an inner wall of a pipeline;
means mounting the rollers on the pig body for inward and outward movement in a direction generally radially of the pig body and biasing the rollers outwardly for rolling contact with an inner wall of a pipeline, said mounting means including a member for each group of rollers carried by the pig body for movement with respect thereto and also includes linkages between the rollers of each group and said member for such group such that inward movement of any roller of such group causes movement of its respective member;
said rollers having the general shape of a prolate spheroid so as to conform generally with the curvature of an inner wall of a pipeline;
means for indicating when at least one member has been moved by a roller;
and means forming a linkage between said indicating means and said members to actuate said indicating means in response to movement of at least one of said members.

3 more elements

Dependencies are inferred from the claim text.

Pipeline pig

Life of this patent

Pipeline pig

Life of this patent

Abstract

Claims10