Glass is an amorphous (non-crystalline) solid which is often transparent and has widespread practical, technological, and decorative usage in things like window panes, tableware, and optoelectronics.
- soda ash
- limestone and
- other ingredients, such as iron and carbon which provide colour
Another important ingredient in the glass manufacturing process is cullet or recovered glass, obtained from recycling centres and bottle banks.
Raw materials are stored in large silos, from where they are measured and delivered to batch mixers, according to pre-programmed recipes. batch houses use leading-edge technology to ensure that the mixed material or “batches” delivered to our furnaces meet the stringent quality standards.
The batch is continuously fed into the furnace, which is the beginning of what is known in the glass industry as the “hot end”. And hot it is indeed: the temperature of a furnace is approximately 1 500° C. Operating 24 hours a day, 7 days a week, it is no surprise that a furnace has a limited lifespan, lasting between 8 to 10 years, before requiring a rebuild.
It takes some 24 hours for a batch of raw materials to be converted into molten glass. Red-hot liquid glass is continuously drawn from the furnace through a submerged throat.
From the furnace, the molten glass makes its way to the refiner area, where it is cooled to approximately 1 200° C. Maintaining the correct temperature is extremely important, not just to keep the flow of the molten glass correct, but also because it influences the quality of the end product.
From the refiner, the forehearths deliver glass to the individual bottle-making machines.
The molten glass enters the feeder and flows through cavities in an orifice plate. Streams of glass are cut into gobs of a predetermined weight – exactly as much as is needed to make a single bottle. These gobs are then guided into the individual moulds of the bottle-making equipment, as part of a process known as forming.