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Glass Melting Furnaces

Glass Melting Furnaces

Date posted: May 3, 2016 // Glass Melting

The Evolution of Glass Making and the Melting Furnace

Although the primitive humans, at that time, could have had no idea of how it was made, they had already recognised the value of the natural form of glass that we know as obsidian. Archaeologists have uncovered evidence that as far back as 4 000BC, prehistoric man was using this hard material to fashion arrowheads and tools for a variety of purposes. Formed not in a melting furnace as in modern times, the natural product was created as the result of volcanic activity. Not long after, however, a simple formula for glass was invented and, with the aid of fire, the first attempts to produce this material artificially spelled the birth of what would eventually become a gigantic industry.

Some 2 500 years later, Egypt and Mesopotamia became the site of the first vessels to be created from this valuable new material. This was achieved by wrapping the molten material around a core made from earth and animal dung, which was later removed once the glass had cooled. Although, at this stage, there was still nothing resembling the type of melting furnaces in use today, the technique of glassblowing was invented by the Syrians at some point during the third century BC.

The Syrian blowpipe was quickly adopted by the Romans who, in turn, adapted its use to create new shapes and patterns, whilst also experimenting with and perfecting new formulae to create colour. At about the same time, manufacturers in Egypt and the Middle East were perfecting the technique of enamelling. With the dawn of the Dark Ages, most of the knowledge gleaned from Rome was lost to European countries until the beginning of the 14th century.

Although the term is often used as a synonym for kiln and, in America, to describe the wood, coal or oil burning source of a household heating system, it is more appropriate to refer to the devices used for melting steel and other metals or glass as furnaces. Although originally fired by burning various combustible materials in a controlled stream of air, today their heat energy tends to be derived less often from combustion and more commonly by means of an electric arc or induction. Typically, they operate under pressures of up to 200MPa and at anything up to 2 000°C. Whatever the power source and capabilities, the use of these devices has made it possible to produce quantities of this versatile raw material on an industrial scale and the demand for the many varied products in which it is used shows no sign of abating.

New formulae have resulted in versions of this material that are impervious to all forms of ionising radiation, are resistant to fire and even direct contact with flames, reflect almost no ambient light, and that can even stop a bullet in its track with little or no sign of damage. None of these products could be produced without the support of high performance glass melting furnaces and these, in turn, depend upon components that have been designed to tolerate the extreme conditions encountered within them.

At LIT Africa, we are a leading local supplier of specialised glass and also undertake the design and manufacture of precision components for use in selected types of glass-making furnace.