APPLICATION OF UHF INSTALLATIONS FOR THE MANUFACTUREOF MOLDED THERMAL INSULATION PRODUCTS BASED ON LIQUID GLASS

Abstract

The article investigates the processes of swelling of liquid-glass compositions and the production of heat-insulating materials based on them under convective and microwave heating. In the work, it was established that the nature of the swelling curves of liquid-glass compositions under the conditions of microwave radiation and convective heating are significantly different. Thus, during convection heating, there is an induction period, but then the speed increases sharply and then the process gradually slows down. In the case of microwave radiation, there is no induction period, and the process proceeds at a high speed from the very beginning, and then slows down as the concentration of gas-forming substances decreases. In contrast to the swelling process under the influence of microwave radiation, during convective heating, the process proceeds uniformly with gradual release of water, as a result of which the material is mostly dried, and not swollen. A comparative analysis of the processes of swelling of liquid-glass compositions under convective and microwave heating showed a higher efficiency of swelling with the help of microwave radiation. The necessary duration of such heat treatment is 8-10 minutes. The materials obtained by convective heating at a temperature of 300 0C are the closest to such materials in terms of the swelling coefficient, the duration of such heating lasts more than 15 minutes. In addition, the calculated efficiency of the microwave installation is almost two times higher than the efficiency of the drying installation, for example, it is 0.79 for the microwave installation, and only 0.46 for the drying installation. Therefore, under the influence of microwave radiation, it is possible to produce effective heat-insulating materials based on liquid glass at lower temperatures and during a significantly shorter heat treatment time, compared to traditional convective heating. The work presents industrial microwave installations that can be used for the swelling process. These are chamber microwave installations of periodic action, which are used mainly for drying or heating large-sized products.