ZENITH SAFETY GLASS CO

Primary float Glass

Primary float Glass

We at Zenith Safety Glass co. offer as wholesalers Flat glass which is formed in a flat shape, such as for cutting into window panes, and glass formed flat and then bent or curved, such as for fabrication into automobile windshields. Float glass is flat glass made by a float process as described below. Almost all of the flat glass currently made and sold throughout the world is float glass.

This natural glass is composed of three elements of the earth-sand, soda and lime. These same elements in varying forms also make up the basic composition of manufactured glass products ranging from containers and glassware to windshields and windows for high-rise commercial buildings. About 50 other chemical elements are used in modern glassmaking, in major and minor ways, to affect color, viscosity or durability, or to impart some desired physical property. But nature's original ingredients are still basic elements in the formulation of glass.

Glass largely is an open chain of silicon atoms with atoms of various oxides occupying the spaces between. It is this loose structure that permits transparency. Silica, or sand, is the most important ingredient in glassmaking since it is the source of, and provides the structure for, transparency. But sand requires soda and lime for practical glassmaking.

Today, an average batch mix used to manufacture flat glass products contains about 70 percent silica sand, 13 percent lime, 12 percent soda and small amounts of other materials. About one-quarter of the batch is in the form of cullet, or cleaned and crushed glass recovered from previous glassmaking operations.

Silica or silicon dioxide, which is converted into glass by the action of heat is very difficult to fuse, requiring extremely high temperatures. Ancient scientists discovered that other materials such as soda, when melted in close contact with sand, would permit the melting of silica at much lower temperatures. Such materials are known as fluxes, and soda was probably the first flux.

Clear Float Glass

Clear Float Glass

Float glass processes involve placing molten glass on the surface of a pool of molten tin or other metal. The molten glass forms a flat layer that floats on this surface of molten metal, as oil floats on the surface of a pool of water. This flat layer of floating glass is allowed to cool until it is sufficiently rigid to retain its flat shape, and is then removed from the surface.

In a float glass plant, the float glass process proceeds uninterruptedly: a stream of molten glass is delivered continuously to one end of the molten metal surface, forming an endless, cooling ribbon of glass that is continuously removed from the opposite end of the surface when sufficiently cooled. The ribbon of glass is then subjected to further processing, including annealing, inspection, and cutting to desired dimensions.

The glass, which is highly viscous, and the tin, which is very fluid, do not mix so that the contact surface between these two materials is perfectly flat. When leaving the bath of molten tin the glass has cooled down sufficiently to pass to an annealing chamber called a lehr. Here it is cooled under controlled temperatures, until it is essentially at room temperature.

Tinted / Coloured Float Glass

Tinted / Coloured Float Glass

It is a normal float-clear glass into whose melt colorants are added for tinting and solar-radiation absorption properties. This reduces heat penetration in buildings. Coloured glass is an important architectural element for the exterior appearance of façades. It is also used in interior decoration (doors, partitions, staircase panels, mirrors

Production is the same as in float glass production. The only variation is the colorants mixed at the beginning with the standard raw materials. Different additives may produce differently coloured glasses. Some of the most-used colorants and colours they produce are listed below:

Reflective Float Glass

Reflective Float Glass

This is an ordinary float glass with a metallic coating to reduce solar heat. This special metallic coating also produces a mirror effect, preventing the subject from seeing through the glass. It is mainly used in façades. Production Pyrolitic (On-Line): in this process, semi-conducted metal oxides are directly applied to the glass during the float glass production while the glass is still hot in the annealing lehr. These are hard coatings which are relatively harmful to the environment. Vacuum (magnetron) Process (off-line):in this process one or more coats of metal oxide are applied under a vacuum to finished glass. The coatings applied by this technique are soft and must be protected against external influences and are therefore used for the interior side of glass panes. There are some other techniques for the OFF-LINE coating: