The wireless network includes 32 Emerson Rosemount wireless temperature transmitters, 28 for control and four for monitoring. The transmitters send data to a Smart Wireless Gateway, interfaced to the mill’s transformer-regulation and burner-control system. Based on this initial experience, Northstar Bluescope intends to implement a similar wireless solution for a second electric arc furnace.

Northstar Bluescope’s Smart Wireless system collects data used to control cooling panel and water-cooled burner temperatures on the mill’s electric arc furnace—data critical for safe furnace operation. Overheating cooling panels can lead to major furnace damage, with a blown-out panel costing as much as $20,000 to repair.

“Better temperature control through wireless has allowed us to add up to one additional batch per day,” said Rob Kearney, maintenance supervisor for Northstar Bluescope Steel. "With each batch worth as much as $200,000, that's a significant advantage."

Emerson’s wireless solution replaced a hard-wired monitoring network with hundreds of wiring junctions. Wiring fared poorly in the mill's harsh environment, with its high electromagnetic field, flying slag, vibration, moisture and temperatures as high as 3,000 degrees Fahrenheit.

“Between nine and 12 measurements per week would fail due to high temperatures or physical damage to sensors, cable or conduit," said Kearney. "And when a measurement point fails, the furnace must be shut down. The new wireless solution eliminated almost 100 percent of the cable and conduit, reducing annual maintenance costs by $200,000. The new wireless solution has been up and running for four months without a single failure.”

“Safety has also been improved,” Kearney said. “The furnace’s cooling panels are operating consistently at a safe temperature, and there is less maintenance required around the hot furnace shell, where ambient temperatures can be 140 degrees.”