Saint-Gobain Oberland AG is one of the leading manufacturers of container glass. Its Wirges/Westerwald factory in Germany produces some 1.5 million bottles per day, using huge quantities of compressed air in various compression stages. The compressed air is generated by extremely durable rotary vane compressors, which as well as requiring little maintenance are highly energy efficient.
After mixing, the powdered batch is introduced into one of two tanks, each with a capacity of some 300 metric tons, where it is melted at a temperature of around 1,600°C and then held at that temperature. The hot stream of molten glass discharged from the tank is divided into portions, and the redhot material is carried - again pneumatically - through ultra-heat-resistant troughs to the forming plant.
The forming process is supported by compressed air and vacuum: the hot material is pressed into the mold by compressed air, while the vacuum - draws - the glass up against the walls of the mold. Together they establish the conditions for uniform wall thicknesses.
The bottles are then cooled under controlled conditions. At the "cold end" - which in the glass container industry refers to temperatures below 600°C! - the bottles and containers are annealed, 100 % inspected, and packaged.