Container glass furnaces provide large-scale production of beer bottles, wine bottles, glassware, and other food containers. In these furnaces, the glass will be carried to IS machines via forehearths. Some designs will utilize the regenerator concept (either cross fired or end fired), whereas others will utilize oxy-fuel firing, which eliminates the need for regenerators.
Regenerators utilize checker brick to improve efficiencies by taking advantage of the excellent heat exchange properties inherent in ceramic materials. As the furnace exhausts through the checker packing, the bricks are preheated by the waste gases, providing a source of energy to preheat the combustion air when the cycle is reversed. Regenerator efficiencies can be affected by a variety of factors, from pack design to regenerator size. The materials utilized by the regenerators must be able to withstand many different forms of attacks, such as corrosion by alkalis, silica, and sulfates, as well as thermal shock and creep. The selection of refractories is critical to the operation and life cycle of the regenerator.
Combinations of the NARMAG® family of products, NIKE family of products, and KALA® are used to provide the best-performing regenerator. In the melter construction, the paving consists of AZS materials like VISION®, zircon ram like TZ® 748 RAM MIX, and zircon brick like TZB®, with a clay flux backup material like CRYLA® XXL and insulation like GREENTHERM. Since the sidewalls and breast walls most commonly consist of fused-cast AZS and the crown of silica, zircon is required as a buffer between the possible reaction of the AZS and the silica. TZB® is the industry’s benchmark brand for zircon brick. Forehearths can be either gas fired or electric melted, and some forehearths have the ability to change the color of the glass as it is passed from the melter to the forming machines. Variations in the firing, color, and even the length of the forehearth greatly impact the refractory selection, and zoning is often used to provide the best performance in an economic manner.