Fifty years ago the glass industry was coming under mounting pressure to seek cleaner alternatives to fossil fuel energy as plants on established sites became surrounded by growing towns.

The SORG concept for this challenge was to create an all-electric furnace. Due to the direct energy input into the glass, it would also show a much higher efficiency.

Without the necessity to have heat transfer from a combustion space, the logical solution was to cover the entire surface area of the glass bath with raw materials, forming an insulating blanket, while this cold-top all-electric melter also required a vertical process.

The new furnace concept was introduced as the Vertical Super Melter (VSM). SORG conducted test melts for customers to demonstrate the reliability of the new furnace technology, especially the glass quality, and in 1972, the patent was granted.

Heinz-Glas was the first company to realize the potential of this new melting technology. For its production of opal and flint glass flacons and jars, the VSM was the ideal choice.

It provided perfect glass quality without emissions of NOx or CO2 from combustion, along with nearly zero evaporation of highly volatile components like boron and fluorine.

The company installed the first full-scale furnace from SORG for its facility in Kleintettau, Germany. Featuring a 2.85m² melting surface, the furnace had a target capacity of 14 tpd, mainly producing opal glass and flint glass for high quality flaconnage.

For SORG, this was the start of a real success story, with 26 VSM furnaces being delivered worldwide and going into full operation in the following decade.

Today SORG is supporting Heinz-Glas to strengthen its sustainable melting capabilities.

The latest project is to develop a new all-electric furnace, fuelled by renewable energy, with the flexibility to increase the tonnes per day of speciality glasses like opal and flint, as well as with high levels of post-consumer recycling glass.

The November/December 2021 issue of Glass Worldwide will feature an exclusive interview with Carletta Heinz. To subscribe, visit https://www.glassworldwide.co.uk/subscription-choice

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Image: The first SORG VSM furnace at the HEINZ-GLAS facility in Kleintettau, Germany