About the Company
Nucor (nucor.com) is one of North America’s largest steel and steel products companies, priding itself on safety, quality, and productivity. Their facility in Louisville, Kentucky is one of the few plants in the country that produces hot dip galvanized conduit. This galvanized conduit, which protects electrical wiring, is invaluable to the construction industry.
The facility’s mechanical engineer must assess the mechanical integrity of all of the plant’s equipment to keep it operational. In particular, losing the facility’s kettle, which heats molten zinc to 760° F (404° C), would cripple the plant and could take up to six months to repair. This unexpected shutdown would drastically impact the construction industry’s supply chain of galvanized conduit and cost Nucor millions of dollars.
Previously, determining the mechanical integrity of the kettle’s flue was very difficult. The long, narrow flue measures only 20” (50 cm) wide by 30” (76 cm) high. The longest channel of the flue spans up to 90’ (27 m), with various turns across the four different channels that supply heat to different areas of the facility. The flue is buried underground and lined with 12” (30 cm) thick concrete, rebar, and soil, and they only shut the kettle down for maintenance one month every four years.
The plant’s mechanical engineer used SuperDroid Robot’s compact inspection robot (GPK-32 4WD), to assess the flue’s structural integrity. He traversed all four channels of the flue totaling over 170′ (52 m) in 30 minutes, allowing the engineer to see the interior of the structure on the remote control’s video monitor. The robot rolled over the ash debris and climbed over broken concrete panels. After the inspection, the mechanical engineer viewed a high-definition (HD) video of the inspection stored on the robot’s SD card on his computer to get a better view to determine their maintenance game plan.
The inspection robot provided engineers with their first full visual inspection of the flue system. The robot helped them to identify a number of locations with minor damage and no signs of major damage. Using the inspection robot provided the mechanical engineer with better data about the integrity of the flue to make better decisions about the required maintenance including when to do longer shutdowns. The mechanical engineer noted that this inspection video also gives him a benchmark to compare future inspections against.