Experimental Study on the Precision Quantification of a Flexible Caliper Sensor for Oil & Gas Pipelines

Abstract

Caliper pigs are essential devices for ensuring the safe operation of oil & gas pipelines. However, traditional caliper pigs cannot detect multiple pipe deformations at one time, and the equipment components are complex and cannot be reused. With the continuous improvement of detection performance requirements in practical application fields, there is an urgent need for a detector that can accurately quantify deformation along the pipeline with a simple structure. To this end, a new type of flexible caliper PIG with strain sensors embedded in polyurethane caliper discs was designed, which is less disturbed by the internal environment of the pipeline. In this paper, the theoretical model of the flexible gauging disc for the quantification of deformation is first presented. Then, the whole process of the flexible gauging disc through the dent is simulated by finite element method, and the theoretical analysis is carried out by the dynamic model. Moreover, a flexible caliper sensor motion test bench is established to verify the feasibility and rationality of the proposed flexible detection method. Four experiments are designed to explore the factors affecting the precision of flexible caliper sensors. The experimental results demonstrate that the flexible caliper sensor can effectively detect the deformation defects in the pipe. The thickness, outer diameter and material hardness of the flexible gauging disc have no significant impact on the detection accuracy, and the detection error increases with increasing running speed. Overall, this research provided a theoretical basis for the development of intelligent and efficient pipeline deformation inspection system.

Keywords: Flexible caliper sensor, Flexible gauging disc, Strain gauge, Deformation detection, Oil & gas pipeline, Defect