Robotic Crack Detection (ACFM)

Research and Testing

CIA Inspection (CIAI) started the development of its internal coke drum crack detection concept in 2005. Alternating Current Field Measurement (ACFM) was our technology of choice because it requires no surface preparation and allows surface-breaking flaws to be detected and sized through coke and other contaminants. A custom ACFM probe was built, tested and tuned by TSC, the original developers of ACFM technology, specifically for coke drum metallurgy.

Simultaneously, CIAI worked to develop a system for deploying the probe to the coke drum wall. Requirement included being able to fit through a 30 inch manway and deploy a crawler containing the probe to circ welds in drums up to 32 feet in diameter in a potentially explosive environment. Five years of research and development has yielded a system where the robotic crawler is launched from a pneumatically articulated and telescoping boom mechanism that hangs below the existing laser scanner and video capture system. Using remote camera views, the crawler is robotically positioned and magnetically coupled to the drum wall. Once deployed, the crawler moves horizontally along the designated circumferential weld inspecting the complete cross-section including the inconel weld cap and the heat affected zone (HAZ) on both sides of the weld. All controls and probe data are managed in CIAI's building located up to 600 feet from the drum.

As is the case with our existing equipment, the robotic crack detection system is designed to meet or exceed the requirements for operating on line, so the inspection can be conducted in a live vessel without the need to blind or scaffold.

In September, 2009 the prototype system was first deployed during a successful field trial at Pine Bend Flint Hills Refinery, MN. In preparation for the commercial launch of this service, extensive training and testing was conducted in March 2010, under the supervision of Dr. Martin Lugg, of TSC. The results were a resounding success. Using a purpose built, 12-foot section of clad coke drum material, manufactured by CB&I (Chicago Bridge and Iron), with EDM cuts of known length and depth acting as simulated cracks, the system was able to identify and size these flaws with an accuracy of better than +/- 15%, maintained even through coke cover. As a result of this session, CIAI now has a fully vetted system ready to offer for commercial service and six technicians qualified to run and interpret its results in the field.

CIAI is pleased to announce the service is commercially available and are currently scheduling inspections.

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