C1.4 - A Wireless Sensor for Ingot Mold Temperature Monitoring

SENSOR+TEST Conferences 2011
2011-06-07 - 2011-06-09
Proceedings SENSOR 2011
C1 - Wireless Sensors I
S. Mamaschew, M. Vossiek - Technische Universität Clausthal (Germany), I. Hüllen, J. Schlüter - SMS Siemag AG, Düsseldorf (Germany)
381 - 385


A rupture of a metal strand is one of the most severe disruption that can happen during steel production. To avoid this accident, it is essential to measure the temperature profile of the metal strand in order to identify the development of cracks. For this task a matrix of up to 120 spatially distributed sensors is used. The sensor matrix is located at the inner side of the ingot mold that is oriented to the molten metal strand. The cabling of the numerous sensors causes notable problems with respect to installation efforts and reliability. In addition, if the ingot mold needs to be re-arranged, the required adjustment of the cabling leads to long and thus costly downtimes.

To overcome this problem, a concept for a wireless sensor solution has been developed that will be described subsequently. In addition to the setup of the wireless sensor different powering concepts were investigated. Beside battery based powering energy harvesting concepts for powering the sensors based on thermo converter were investigated. A simple low power transmission protocol with a low probability of collision was used for the radio transmission. The extreme temperature conditions, pollution by settled dust, the potential mechanical forces and the need for easy installation and handling were considered in the sensor design.

Measurements show that the developed thermoelectric powered sensor can obtain every second up to 28 bits of user data in addition to the 32 bit unique sensor id with a temperature difference of 20 °C between a hot surface and the ambience. The field tests have shown that the sensor was easily able to obtain messages in a distance of about 3 m from the receiver. Despite the rather unfavorable multipath cannel a reliable data transmission was obtained. The temperature changes during the casting process can be displayed in real time and are suitable to control the casting process.