Full electrical furnaces, cold top furnaces, are normally used for production ranges of 5- 50 t/d. In these furnaces the energy input is not done by means of fossil energy, but exclusively by means of electrical energy through electrodes. Rod electrodes with specially developed water-cooled electrode holders, top electrodes or block electrodes can be used.
The electrodes can also be arranged in the bottom of the tank or in the basin side walls. The suitable location and wiring of the electrodes lead to diminished corrosion of the refractories and a longer furnace lifespan. The batch is charged by a cold top batch charger through an open sidewall of the furnace superstructure directly onto the glass bath, forming a homogenous and even batch layer. The melting, refining and homogenization processes take place vertically in the cold top melter.
HORN full electric furnaces are typically used in the production of table ware, fibre glass or special glass (e.g. Opal).