Process unit for drying sawn timber rotating in the ultra high frequency field with a discrete arrangement of magnetrons

Wood is a natural and environmentally friendly construction material widely used in various fields of industrial and civil engineering. Timber drying process has an effect on the consumer properties of the final product and is basic in wood processing technology. Ultra high frequency range is the most effective in drying sawn timber with the use of electromagnetic energy. A process unit comprising discretely arranged magnetrons and a mechanism for rotation of sawn timber along the axis in the chamber is presented in the study. Magnetrons discretely and uniformly arranged ensure better distribution of heat on the sawn timber during rotation and reduces drying time. The engineering solution reduces drying time by 38.75% and increases the volume of dried timber by 27.3%. Variable drying mode control improves efficiency of the process by 8-10% depending on the timber species and initial moisture. Experimental dependences characterizing operational modes of the process unit are obtained. A mathematical model of sawn timber drying in the chamber with discretely arranged magnetrons and a mechanism to ensure rotation of sawn timber along the axis is developed. The mathematical model is made in the object-visual modelling MatLab package (Simulink). The model adequacy is confirmed experimentally, discrepancy between the experimental data and the data obtained from the mathematical modelling is no more than 3%.