Microwave heating drying technology uses microwave selective heating and penetration to realize material drying. Microwave is an electromagnetic wave with a wavelength of between 1mm~1 m and a frequency of 300MHz~300GHz. When wool fiber is dried by microwave drying equipment, polar water molecules can absorb microwave, accelerate the speed of rotation and spin, increase the internal energy and convert it into heat, resulting in thermal effect. Compared with the traditional hot air drying mode, the wool fiber tunnel type microwave drying mechanical microwave oven has the advantages of high heating efficiency, good uniformity, energy conservation, environmental protection, low operation cost, easy control and the like. The microwave drying technology is applied to the wool spinning industry, and meets the requirements of the current low-carbon energy-saving environment-friendly and social development.
The advantages of the wool fiber tunnel type microwave drying equipment are as follows:
1.Wool tunnel microwave drying equipment has little effect on the surface morphology and structure of wool. The surface of the untreated wool fiber has a complete scale structure, and the edge of the scale is quite clear. The scale structure of the wool surface treated by microwave drying at 100 w is slightly damaged and the edge of the scale becomes blurred. With the increase of microwave power to 800 W, the scale structure of wool fiber surface is more damaged, and the fragments attached to the scale surface are also increased. Cracks and scale edge warping appear in some areas, but the scale structure is still relatively complete. The surface scale structure of wool fiber dried by hot air oven is the most seriously damaged.
After the microwave drying treatment of the hot air oven and the tunnel type wool fiber microwave drying equipment, the surface morphology structure of the wool fiber is affected, and the effect of the hot air oven drying treatment is large, and the drying treatment on the different microwave power has different influence on the wool fiber. The greater the power, the greater the damage to the surface morphology of the wool fiber.
2.The effect of wool fiber tunnel type microwave drying equipment on the strength of wool single fiber is small.
The breaking strength of the single fiber after drying decreased, and the elongation at break did not change much. By comparing the single fiber strength of wool after drying, it can be found that the strength loss of wool fiber after microwave drying of tunnel type microwave drying wool fiber equipment is 3%~5%, while the strength loss of wool fiber after drying in hot air oven is about 9%, which is 23 times of microwave drying. It can be seen that the strong damage of hot-air oven drying on wool fiber is larger than that of microwave drying, that is, the drying mode of wool fiber tunnel type microwave drying equipment has less damage to wool fiber.
Compared with 100w and 800w microwave drying data, the higher the power, the lower the breaking strength of the wool single fiber, and the lower the elongation at break. At the same time, it can be seen from the comparison of the coefficient of variation that the coefficient of variation of the microwave drying of the wool fiber tunnel type microwave dryer is less than the coefficient of variation of the drying of the hot air oven, which indicates that the data obtained by the microwave drying is more stable and the effect on the wool fiber itself is small.
The hot air oven drying treatment has great influence on the surface morphology and structure of wool fiber. The more power the microwave drying treatment, the greater the damage of wool fiber surface morphology and structure. The strength of wool fiber after drying in both ways is damaged, and the damage after drying in hot air oven is much greater, but for microwave drying of microwave wool fiber tunnel drying equipment, the higher the power, the greater the strength damage of wool fiber.
The color fastness of the wool fiber treated by the two methods has no change, that is, the drying treatment of the hot air oven and the microwave drying treatment of the wool fiber tunnel type microwave drying equipment have no influence on the color fastness of the wool fiber. Combined with the continuous microwave dryer in wool fiber industry, the continuous microwave dryer has high efficiency, energy saving and environmental protection, which has little effect on the structure and properties of wool fiber, and the cost is also low, which is very beneficial to improve the benefit of wool textile enterprises.