Polydros is already working a long time with what they call a ceramic belt. Their last patent was expired in 2008 and is now public domain information, free for everybodyto use.

The idea is to fill a typical lehr belt with clay by pressing the substance in the holes. After a drying time, the clay is fired and becomes a ceramic solid. This solid does not fall out of the belt during turning of the belt. It allows to transport powder or granulates through a high temperature furnace if the used steel for the belt is also temperature resistant. For that reason, it can be used to foam glass like applied by POLYDROS.

The development of this belt by POLYDROS was a fundamental step in the continuous foaming of glass.