The Pilkington Glass company was founded in 1826. It was then known as the St Helens Crown Glass Company founded with the technical knowledge of John William Bell and funded by three local families, the Bromilows, the Greenalls and the Pilkingtons.
The company was renamed in 1829 to Greenall & Pilkington and again renamed in 1849 to Pilkington Brothers when Peter Greenall withdrew from the company. Today the company is one of the leading manufacturers of flat glass in the world, selling to over 130 countries worldwide. Pilkington Glass is now part of the NSG Group with manufacturing operations in 27 countries they were reported to have more than 35,000 employees in 2007.
Sir Alastair Pilkington invented the float glass process in 1952 which has set the global standard for the manufacture of high quality glass. The original process was only able to produce glass of 6mm thick, however, over the years technical advances have allowed for the manufacture of float glass to be as thin as 0.4mm up to a thickness of 25mm.
Raw materials are mixed and melted in a furnace, the molten glass is poured continuously from the furnace onto a shallow bath of molten tin (within a chemically controlled atmosphere). The molten glass spreads out and forms a level surface which is cooled and cut into panels. The thickness of the glass is controlled by the speed at which the solidifying glass is drawn off from the bath. Special coatings can be added to the glass either during the float process or later in a secondary process.
The use of float glass in the construction industry has escalated in recent years as architects are constantly seeking ways to make their high tech glass buildings more environmentally friendly. The use of glass allows light to flow from room to room. It also allows the natural rays of sunshine to warm rooms. The use of special energy saving and solar control products allows architects to control heat loss as well as solar gain resulting in an energy efficient building.
Over the last few years motor vehicle designers have also increased the glazing in cars resulting in better viewing and with the addition of sun roofs to many models this has led to an overall increase in sales to the automotive industry.
Two different types of glass are used in cars. Laminated glass, where layers of glass are bonded together to appear as a single sheet of glass. If an accident occurs and the glass is broken then the layers are held together and are less likely to cause an injury. It is used in windscreens and for some side windows. Toughened glass is used normally for side and rear windows. This glass has been heated then quickly cooled. If broken this glass breaks into small blunt fragments which again cause less injury to passengers.
The glass used in cars needs to be shaped or curved. To do this the glass is heated until it is almost like plastic. It can then be left to bend under its own weight. Where a more precise shape or curve is required then a press bending process can be used.