The glass tempering requires its heating up to a temperature of 650-700°C and its following speedy cooling up to a temperature of 35-40°C. This process is carried out using furnaces and large fans with the tempering and cooling air control. The glass moves into the furnace by means of ceramic rollers, activated by brushless motors, while the furnace is heated, using electric resistors piloted by SCR groups with close-loop temperature control. The tempering is carry out by investing the glass as it comes. out of the furnace, using room-temperature air at pressure controlled.