Glass technology

In the glass sector, the microwave applications are used not only for varnish drying but also for the actual material processing. At room temperature, the glass is almost transparent to microwave radiation but it becomes sensitive to these particular frequencies when heated up at a suitable temperature.

Combining the infrared technology with the hot air and microwave technologies, it is possible to optimize, for instance, the curving process of glass sheets. In fact, with monomodal microwave and infrared applicators, the energy can be applied only along the line indicating where the glass is supposed to be curved. In this way not only the energy consumption is reduced drastically but also the result is better and safer for it helps to avoid defects and deformations in the marginal zones of the glass sheet, which are typical for traditional methods where the entire glass sheet surface is heated up.

In this same application field, Microglass has recently launched a research project focused on the glass extrusion using the microwave technology.

At first, the silica mixture is heated in a melting-pot, combining the IR and microwave radiation; subsequently, the melt-spinning of glass fiber is obtained by dropping through an opening. The fiber passes into special autoresonant applicators, inside which the microwave energy is directly focalized on the fiber itself, without heat losses, so as to reach a precise temperature appropriate for obtaining a desired viscosity and thus diameter.

Following the first successes of the application, an automatic control system of the microwave power is currently being developed, in order to be able to regulate with extreme precision the diameter of the glass fiber, thus reducing the energy consumption of the plant and optimizing the product quality.

From the first results, the introduction of the microwaves in this process proves to be successful in time reduction and therefore in economic and energy saving.