Observing and sensing an interlaced yarn.
Bertolla M., Scotoni M.
Interlacing is used in textile industries to impart cohesion to multi-filament yarn, blowing compressed air on a yarn running in a channel. The underlying physical processes are complex and far from being understood. The distance between cohesion points (knots) is almost periodic. However, it shows irregularities, so that online monitoring is required. The process is deemed to be linked to shock waves that form in the channel. Acoustically sensing these waves via pressure and acceleration probes, in combination with high speed video analysis, might be used to implement a reliable online knot-counting and monitoring technique.