Pepperl Fuchs VDM28-15 laser sensor effectively detects steel at 1400 DegF

A leading Hot Strip Mill in the midwest US was found to have serious problems with detecting hot slabs of steel at 1400 Deg F. Using an...

A leading Hot Strip Mill in the midwest US was found to have serious problems with detecting hot slabs of steel at 1400 Deg F. Using an inductive prox sensor or mechanical limit switch was just not going to happen, because a slab of steel at 1400 °F will render them useless at less than an inch away. Infrared radiation (IR)detectors seemed most appropriate but are usually housed in heavy-duty housings, are water-cooled, and cost thousands of dollars besides running the risk of exposure to very high temperatures that could melt the IR detectors. Engineers at the mill were looking for a way to detect the presence of the strip or slab of steel at certain points of the process between the roughing mills, which start shaping the roll, and the finishing mills, which complete the process. Pepperl Fuchs implemented the VDM28-15 laser sensor which operates based on the (PRT)Pulse rating technology.The VDM28-15 laser sensor emits extremely high bursts of light periodically rather than a continuous emission of lower light energy. These high-energy bursts of light are emitted from the sensor to the steel and reflected back to the sensor at long distances, which reduces the ambient temperature at the sensor’s location. Using this technology, the VDM28-15 laser sensor effectively detected the hot slab of steel at temperatures of 600 °F to 1400 °F. Being a distance measurement sensor it can also precisely measure the thickness of steel all this at a fraction of the cost of IR detectors.