Business & Industry
Feb 29, 2016
Glass making technology
Glass making is one of the most ancient arts mastered by mankind. Throughout the centuries the technique of melting sand and other ingredients to make glass has remained virtually unchanged, until the Industrial Revolution. Still, glass making is all about the furnace.
The name SORG is a household name and its technology covers the complete melting and conditioning process, beginning with the arrival of raw materials and continuing until the molten glass is supplied to the forming process.
Currently a group of companies, the SORG name became part of glass industry in Germany after the inception of Nikolaus Sorg GmbH & Co. KG, in 1872. Today the group encompasses four companies, all of them dedicated to glass industry. SORG group technology covers the complete melting and conditioning process, beginning with the arrival of raw materials and continuing until the molten glass is supplied to the forming process. The group is owned and managed by the 4th and 5th generations of the SORG family and Group companies currently have over 430 full-time employees in Germany and China.
There are currently more than 250 SORG melting furnaces in operation throughout the world. Most of these are conventional gas or oil fired units with either regenerative or recuperative waste heat recovery. An increasing number are oxy-fuel melters, and a significant number are all-electric melters.
Most glass furnaces use conventional oil or gas heating with the regenerative system to recover residual heat from the waste gases. Such furnaces can either be end-fired or cross-fired.
Today most SORG furnaces of this type are end-fired. The basic design is very flexible and SORG has built small furnaces with melting areas less than 15 m², whilst the largest SORG furnaces of this type built to date have melting areas greater than 150 m² and produce up to 450 tons per day.
Cross-fired furnaces are generally used for higher tonnages that are not yet possible with end-fired designs. A typical application is for float glass furnaces, but the largest container tanks also use this design.
SORG uses recuperative waste heat recovery on three different types of furnace.
The smallest furnaces (producing less than 35tonnes per day) are often built to an end-fired design using a double shell recuperator. Such furnaces are used, for example, for the small scale production of tableware or fibre for insulating wool (C glass).
Larger furnaces are sometimes built with recuperative waste heat recovery, and with the burners located along the furnace sidewalls. Tube cage recuperators are normally used, that offer a higher air preheat than double shell recuperators. These furnaces are almost always used to melt container glass.