50 years of Electric Melting with SORG and HEINZ-GLAS

SORG is proud to continue supporting HEINZ-GLAS to strengthen its sustainable melting capabilities further

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

The partnership between SORG and HEINZ-GLAS is a highly successful one. It started half a century ago, with two local family businesses working closely together to gain global recognition for their pioneering approach to glass melting and manufacturing.

The SORG and HEINZ-GLAS teams, including members of the Sorg and Heinz families, outside the HEINZ-GLAS Glass Museum (European Glass Bottle Museum)

The start of a close partnership
By the end of the 1960s and right up until the 1980s and 1990s, the fossil heated side-fired regenerative furnace was the standard furnace type for most glass makers. The convection patterns of the glass inside the tank and the combustion process could be easily controlled by adjusting the energy input from the multiple burner ports. These provided a good covering of the glass bath surface across the whole furnace.

End-port furnaces were only used for very small units, since sufficient and stable flame coverage was not yet possible for larger furnaces. It wasn’t until a better understanding of the combustion process and heat transfer, together with improved equipment design, that end-port furnaces later made their way to become the most common furnace type in use today.

Making waves in sustainable melting
The glass industry was coming under mounting pressure to seek cleaner alternatives to fossil energy as plants on ‘historical sites’ were 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.

At the time, this was a paradigm change of the complete melting process – as classic furnaces had the main glass current flowing in a horizontal direction, while the cold-top all-electric melter required a vertical process.

The first practical step in this development was the installation of a test furnace in the laboratory building on the SORG site in Lohr am Main. It had a melting area of 1.4 m² and was fully equipped for testing different glass types.

The new furnace concept was introduced as the VSM® – the Vertical Super Melter. There were misgivings and distrust toward using a completely new approach in a very conservative industry. However, SORG persevered in conducting test melts for customers to demonstrate the reliability of the new furnace technology, especially the glass quality, and in 1972, the patent was granted.

It takes courage to create something great
HEINZ-GLAS was the first company to realize the potential of this new melting technology. For its production of opaline 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 fluor.

In 1971, HEINZ-GLAS installed the first full-scale VSM® 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 flaconage.

Glass quality was and still is a critical aspect for customers like HEINZ-GLAS. The VSM® furnace has helped the company become one of the leading manufacturers and finishers of opal glass and glass flacons for the perfume and cosmetics industry.

Fully charged for the future
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 proud to continue supporting HEINZ-GLAS to strengthen its sustainable melting capabilities further. 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 featuring the possibility to operate with high levels of post-consumer recycling glass (PCR).