Repotenciación del sistema tipo araña mediante tracción magnética para inspección ultrasónica de espesores en tanques, conforme a API 653

Abstract

The main objective of this Degree Project is to upgrade a spider-type semi-automatic ultrasonic system (MFD-800B), originally designed for pipeline evaluation, by integrating the technological application of magnetic traction to inspect thicknesses in storage tanks under the API 653 standard. Manual inspection in large structures involves high occupational risks due to working at heights, extended execution times, and the generation of inconsistent data with broad blind areas. To overcome these geometric and adherence limitations, the original clamp was replaced by a sandwich structural chassis (acrylicrubber-acrylic) equipped with 16 N52 neodymium magnet modules configured in series. With an air gap calibrated at 2 mm to protect the epoxy coating, this array provides a normal force of 240 N and a dynamic Factor of Safety of 5.33, facilitating a stable orthogonal displacement. The mechatronic reengineering included the adaptation of commercial 6515 wheels, TT and N20 gear motors to optimize torque, and wireless Bluetooth control using an Arduino Uno R3. The experimental validation contrasted discrete manual sampling (5 points) against the prototype’s continuous high-density scanning. The results demonstrated that the upgraded system reduces the total operational time by 30.63% and minimizes the margin of error to +0.03 mm (an 88% improvement). Backed by experimental evidence, its high-density matrix scanning significantly increased the probability of detection (POD) of critical zones of localized corrosion (10.15 mm pitting) conventionally omitted, improving the reliability of structural integrity assessments.