MEHRSCHICHT-SCHAUMGLAS MIT DICHTER GLASOBERFLAECHENSCHICHT UND HERSTELLVERFAHREN DAFUER

摘要

The invention relates to a foam glass block provided with a dense glass surface layer. To solve a problem that adhesion of the dense glass layer to the foam glass layer is insufficient, a relatively thin intermediate layer of porous glass is interposed between the basic foam glass layer and the dense glass layer. The intermediate layer has apparent specific gravity of 0.8-1.8, whereas the basic foam glass layer is lower than 0.8 in apparent specific gravity. The multilayer foam glass block is produced by simultaneously firing a granulated material of the basic foam glass, a granulated material of the intermediate porous glass and a particulate material of the dense glass in layers, or by firing a granulated material of foam glass and a particulate material of dense glass in layers and pressing the upper surface of the dense glass during or soon after firing. The outer surface of the dense glass layer may be formed with a number of fine cracks or a number of small semispherical protuberances to produce an ornamental effect.