Circuit breakers filled with gas contg. fluorine cpds. - and using glass insulation not attacked by gas decomposition prods.

摘要

An encapsulated electrical device is described in which at least periodic electric discharges and/or arcing occur. The capsule is filled with an electronegative gas contg. a fluorine cpd., e.g. SF6 and also contains a solid electrical insulating material (1) resistant to decompsn. prods. arising in the capsule. The novelty is that the insulant (1) is an alkali-free inorganic cpd. of the alkaline-earth aluminate or aluminophosphate type. The insulant (1) is pref. vitreous and consists of (a) a calcium aluminate glass free from SiO2, B2O3 and alkali but may also contain oxides such as BaO, SrO, MgO, BeO, ZnO, La2O3, Sb2O3, ZrO2, P2O5, Fe2O3, TiO2. Alternatively, the glass may have a compsn. by wt. (b) 75% P2O5, 15% Al2O3, 8% ZnO, 2% PbO. Glass (a) or (b) may form a component or a coating on ceramic or metal, esp. a sintered coating.