Mapping of ultrasonic fields for dyeing applications

In the last years textile industries have focused their attention on the development of innovative environmental friendly processes and on the improvement of product quality. The use of ultrasounds (US) waves to improve dyeing processes of natural fibers has been investigated since the begin of fifties; it was shown that US are effective to reduce temperature and operative time of the dyeing. In particular this improvement is very important for natural fibers since reduction of temperature and dyeing time helps in maintaining optimal fiber properties. The tests, carried out in the frame of the Piemonte Regional Project INTEXUSA (INnovation in TEXtile productions by UltraSound Application), were aimed at evaluating the influence of the system geometry on the ultrasound waves propagation in a water-based medium. These runs were performed by monitoring the system with an Ultrasonic Energy Meter (by PPB Megasonics) to evaluate the cavitation energy distribution inside a dyeing prototypal equipment operating with different liquor depths. The main goal of this study was addressed to analyze the influence of the liquid depth on the cavitation phenomena, whose output can be useful to determine an optimal geometric configuration in a novel dyeing equipment provided by US transducers and minimize liquor ratios.