Speed Measurement & Speed Control
Mass Flow Regulation in a Rolling Mill with a C-frame and an integrated LSV
In order to meet the dimensional accuracy and tolerance specified by automotive and industrial consumers, modern rolling mills employ a technique called Automatic Gauge Control (AGC), which utilizes mass flow calculations to meet the precision tolerances on thickness. Due to their high processing speed, Polytec's LSVs offer an almost immediate response to thickness variations, making the LSV a perfect sensor for precision AGC.
Non-Contact Speed Sensor Reduces Breaks in Paper Mill
In response to a significant number of breaks during splicing operations on a continuous coater, a paper mill installed a Polytec LSV on its high-speed paper unwind. By integrating the LSV's surface speed signal into the control loop, the mill now consistently matches parent reel speeds to within ±5 ft/min-1 at about 5,000 ft/min-1 (±0.1%). The result was a significant reduction in tension variation during the splice, which eliminated breaks due to mismatched speeds. The ROI from the installation at the mill was less than one year.
Speed Synchronization in an Aluminum Mill
Automated Gauge and Elongation Control
Cold band is re-rolled in temper mills to produce the final degree of levelness and surface quality. The gauge is determined by the difference in the strip speed when arriving at and leaving the roll stand. Until now, the gauge has been measured using encoded contact wheels. By replacing contact speed measurement with laser surface velocimetry, measurement errors caused by slippage and contact problems can be eliminated. At a large stainless steel manufacturer, an LSV was used to used to measure strip speed and to control the strip gauge to 0.02%.
High-Precision Real-Time Measurement of Car Speed
A novel application of LSV technology is being investigated by Renault, which is incorporating an LSV as an on-board reference sensor to measure real-time vehicle ground speed with better than 0.1 km/h accuracy. This accuracy is superior to other methods commonly used for ground speed measurement, including GPS.
Non-destructive Testing of Steel Tubes
This innovative non-destructive test line for steel tubes uses two LSV-1000 Laser Surface Velocimeters. The first LSV provides a millimeter “clock” to determine the length of test pieces and to log and mark flaw locations. A second velocimeter is integrated downstream and is used to recognize speed variation of test pieces.