Application of Microwaves in Textile Finishing

Title:                   Application of Microwaves in Textile Finishing
Project funding:   Enviromental protection and energy efficiency fund
Project Leader:     Prof. Drago Katović, Ph.D.

Project Summary:

An industrial microwave device was designed at the University of Zagreb, Faculty of Textile Technology (TTF), based on the principle tested on the patented laboratory MW device. Newly designed microwave device completely utilizes the obtained microwave energy in a process. Namely, microwaves make the bipolar water molecules rotate which causes their friction leading to heating i.e. drying. The remaining energy, not used in drying via waveguides, is used for heating the water used as the absorber of microwave energy. This heated water can be used in further processing which enables utilization of the transmitted microwave energy.

Due to the special design of waveguide slot for the textile material there is only minimal leakage of microwave energy into the environment. Namely, passing of the textile material through the waveguides leads to transition of the part of the energy out of the waveguide together with the material. In order to reduce this energy transition as much as possible, waveguide slots are elongated and beveled which enables the return of the microwave energy into the waveguide.

Damp textile material (5) first passes through the slots (3) in the waveguide (2). Redundant energy is guided through the waveguide to the absorber of microwave energy (water) (4). In order to obtain a uniform absorption of microwave energy on the whole material an even number of waveguides must always be used. Number of waveguides used depends on the desired speed of the textile material passing and the amount of water on the material.