Self-organizing network of Rosemount® wireless temperature transmitters, Smart Wireless gateway works reliably to protect assets despite harsh plant conditions
AUSTIN, TEXAS (October 15, 2008) – Usiminas (Usinas Siderúrgicas de Minas Gerais S.A.), one of the world's top steel producers, is using a Smart Wireless network from Emerson Process Management to protect valuable plant assets and to avoid unscheduled stoppages at its heavy plate mill in Ipatinga, Brazil.
Eight Rosemount® wireless temperature transmitters installed on the "backup" rolls that are part of the facility's process to produce steel plates measure the temperature of the roll bearing oil. A Smart Wireless gateway collects this critical information and transmits it to the company's distributed control system (DCS). Operators use this wireless data, along with the rolls' return oil temperatures collected by a hard wired network, to automatically monitor the state of bearing health and to keep the steel plate-making process running smoothly.
"This more accurate and redundant data allow us to better maintain the roll bearings and to avoid unscheduled shut downs," said Carlos Augusto Souza de Oliveira, Usiminas instrumentation supervisor. "Previously, we would have experienced from one to two unplanned shut-downs a year because of damage to overheated bearings."
When roll bearings are damaged, it takes at least six hours to shut down the steel plate-making process and replace the set of backup rolls. Usiminas pays from $40,000 to $175,000 to repair each bearing. The company can also lose a minimum of 600 metric tons in production during such an event.
The self-organizing wireless network consistently provides Usiminas with data even though the temperature transmitters are subjected to extreme heat, water, oil and grease. The company wanted to know if the new technology could endure such an abusive environment and whether the network could communicate with its DCS.
"The wireless equipment is reliable and robust despite the harsh conditions under which it is operating," said Oliveira. "We have had no problems with the devices, their batteries or communications since installation."
Installation and commissioning of the new technology was quick and easy.
"We performed the installation as we were doing regular maintenance over the course of 15 days. But if we could have scheduled it all at once, it would have taken about two days," Oliveira said. "We spent four hours commissioning these devices. It would have taken two or three days to commission wired instruments."
The hot, dirty conditions are also rough on the hard wired temperature sensors and their cables, and the sensors are very difficult and dangerous to access during regular maintenance. Usiminas plans to replace these wired monitors with wireless temperature transmitters.
"In addition, we plan to use temperature, pressure and vibration monitors at measurement points throughout the plant, and a field wireless network has become an option for us. These measurements are now being read and recorded manually," Oliveira said. "We would also like to use wireless pH transmitters to monitor wastewater effluent in each area where it's generated. Currently these data are collected only at the main outfall."