At the Lenzing Fibers mill in Heiligenkreuz, Austria, wireless transmitters from Emerson monitor river water used for cooling to help ensure desired temperatures are maintained. The self-organizing wireless network helps the company meet local government regulations related to the temperature of water discharged into rivers and watercourses.
Lenzing Fibers, winner of the European Awards for the Environment, is the world's largest producer of Tencel fibers. The Heiligenkreuz fibers plant uses water drawn from a local river for cooling purposes. Local environmental regulations require that the water returned to the river must not be more than 5.4°F (3°C) higher than the water extracted. The regulations also stipulate that the company must maintain a constant check and record of the water temperature at both inlet and outlet points.
"Because of the distance of the River Lafnitz from the control room and the fact people are free to walk by the river, we would have had to dig a trench for the cabling, and this would have been expensive," says Wolfgang Gotzi, head of automation and maintenance department at Lenzing Fibers. "The cost of installing wireless is much lower and has made this project possible."
Prior to the regulation being introduced, Lenzing was already monitoring the water temperatures manually, involving daily visits to the river. However, to meet the environmental regulation, there was a need to improve the reliability of the results, and for these measurements to be easily stored and be made readily available for inspection. By implementing a solution that enabled online measurements, Lenzing Fibers was presented with an opportunity to reduce operations costs by eliminating the number of trips to the river and to streamline the reporting.
The wireless network comprises devices manufactured by Austin-based Emerson Process Management. The temperature of the water extracted from the river is transmitted wirelessly via Emerson's Rosemount wireless temperature transmitter, to a Smart Wireless gateway. The gateway is positioned on an external wall of the pump station control room, ~40 yd (200 m) away. A second wireless transmitter is installed where water is returned to the river, and a third transmitter is ~40 yd (200 m) downstream, where it measures the temperature of the remixed water after the return point.
A fourth transmitter is used as a weather station and is situated by a nearby lake that is used as a cooling water reserve. This device acts as a repeater and provides additional paths for the self-organizing network.
"The Emerson technology was both easy to install and integrate and has been extremely reliable in terms of data transfer. When all the transmitters were in place, the network offered us a communications reliability of 100 percent," says Gotzi. "We are currently looking at other applications where Smart Wireless can be applied."