What recuperative glass tanks
does IWG Glasofenbau supply?

A recuperative end-fired glass tank is a gas-fired melting furnace with burners at one or both ends. The combustion air is preheated in a recuperator: Hot exhaust gases transfer their heat to the supply air. This reduces gas consumption, ensures stable flame ignition, and increases efficiency.

End-firing creates a clear heat axis from the burner to the fining zone. This supports the fining process, ensures high homogeneity, and maintains uniform temperatures across the glass surface, breast walls, and crown. Crucial factors are well-controlled flame length, burner pressure, and draft control. NOx emissions can be reduced by operating with a slightly lean mixture; with a moderate excess of air, reduction effects in the glass remain low.

Where emission limits are strict, low-NOx burners, exhaust gas recirculation, or moderate O₂ enrichment are available as equipment options. The result is a robust, energy-efficient furnace solution for small to medium pull rates – with reliable product quality, a compact design, and an attractive investment.
With the recuperative end-fired glass melting tank from IWG, you can produce the following types of glass, for example:

A recuperative side-fired glass tank is a gas-fired melting furnace with burners arranged staggered along the side walls. The combustion air is preheated in the recuperator by the hot exhaust gases – gas consumption is noticeably reduced, the flames ignite stably, and the overall efficiency increases.

Applications: Fused silica is the material of choice for high-power lasers, UV lithography in microchip manufacturing, and optical components in space research. In industrial metrology, it is used for windows and lenses that must withstand extreme temperatures or chemically aggressive environments without losing their optical integrity.

Side-firing ensures uniform cross-heating: Heat is introduced across the width of the bath and into its depth, which supports fining and homogeneity and creates stable temperature profiles across the glass surface, breast walls, and crown. Crucial factors are well-controlled flame length, burner pressure, and draft control. NOx emissions can be reduced by operating with a slightly lean mixture; with a moderate excess of air, reduction effects in the glass remain low.

With the recuperative side-fired glass melting tank from IWG, you can produce the following types of glass, for example:

Our recuperative furnaces can be equipped with precisely matched electric boosting systems, depending on the product and pull rate. Melting boosting increases the available power directly in the bath, shortens start-up times, and creates reserves for high cullet ratios.

A thermal barrier stabilizes the heat balance in the transition to the refining zone, smooths out temperature peaks, and supports bubble removal. The electric throat heating acts specifically at depth, maintains the target viscosity, and ensures reproducible temperature profiles right up to the outlet.

Additionally, we use bubbling systems – tailored to your recipe – which can be operated with either compressed air or oxygen. The finely dosed gas promotes convection, accelerates refining, and reduces striae as well as inclusion defects, without altering the glass chemistry.

We adjust the proportion of melting and refining through the design of walls and throats: Geometry, position, and flow are selected so that heat is introduced into the bath in a targeted manner and the flow forms the desired circulation patterns. Optional integrated air or furnace cooling provides additional control reserves at critical points.