Furnaces for Glass Tempering / Glass Tempering Furnaces

Glass has many applications in construction, electronics, optics, safety glass for the automotive industry, aerospace, photovoltaics, solar glass and also in art. Today glass is found in almost every field.

Glass is made from ingredients such as silica sand, the main component, and dolomite or limestone powder — without these elements the glass would not be stable. Adding sulfate powder prevents the formation of bubbles and soda is added to lower the melting point. All these ingredients are heated together in the melting furnace to around 1600°C until a glass melt is formed.

Afterwards the glass is brought into the desired shape by various other processes.

To remove stresses and make the glass resistant to breakage, the glass must be tempered. JTEKT Thermo Systems (formerly Koyo Thermo Systems) from Japan, a Toyota Motors subsidiary, is one of the largest furnace manufacturers worldwide and also supplies tempering furnaces for glass. The long-standing experience in glass tempering and the high quality of the equipment have established JTEKT Thermo Systems as one of the leading suppliers in this field.

Roller conveyor furnaces for glass tempering

JTEKT offers different furnace designs, either batch-type or continuous furnaces. Ultimately the furnaces are customized to customer requirements.

The RH furnace, or "Roller Hearth type furnace", is a continuous furnace specifically developed for tempering glass and can of course be adapted to customer requirements.

Specification
Technical features Product data
Contact with glass Ceramic rollers with >99.5% SiO2 content
Heating elements Special elements with low thermal conductivity for energy savings and reduced environmental impact
Furnace design Glass muffle to avoid substrate contamination
Processable glass sizes Min. W300 × L300 mm up to max. W2800 × L1900 mm
Temperature range 150-650 °C
Temperature stability Very good stability
Cleanroom class Class 1000
Roller furnace

Roller conveyor furnaces were developed to temper extremely large and heavy glass panels in the production of plasma display panels. Transport within these clean, horizontal, continuously operating furnaces is carried out by rotating steel rollers. To avoid metallic contamination, ceramic tubes made of pure alumina are fitted over these steel rollers. This combination of steel core and ceramic surface has proven to be the best solution to combine high throughput with high yields. Due to its stability, this construction allows simultaneous processing of two layers of glass panels that are connected by a special spacer system. All rollers are driven by a special chain system to prevent slip between the glass panels and the drive rollers. The furnace itself is built from a special glass muffle and remote infrared Moldatherm™ heaters. An elaborate temperature control system ensures temperature uniformity of less than 1 °C across the entire glass panel.

JTEKT Thermo Systems and Crystec look forward to building a cost-effective system for you that meets your most demanding requirements.