Fiberglass reinforced plastic insulating member submitted to mechanical efforts within a high-voltage switching enclosure containing sulphur-hexafluoride gas
AssigneeSprecher & Schuh AG
InventorHansruedi Zahner, deceased
Life of this patent
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Abstract
The resistance of insulating pieces made of fiberglass reinforced plastics against the decay products of SF.sub.6, such as occur within sealed high-voltage switching devices is unexpectedly enhanced by the use of a reinforcing fiberglass made of a low-alkali silicate glass containing neither boron nor boron-compounds.
Claims1
A fiberglass-reinforced plastic electric-insulating member which is subject to mechanical forces and in contact with decomposition products of SF.sub.6 gas which comprises a fiberglass reinforcement made of a low alkali glass containing neither boron nor boron-containing compounds, said glass having the following composition in percentages by weight:
- 50-65% SiO.sub.2
- 20-30% Al.sub.2 O.sub.2
- 5-20% MgO
- 2-10% CaO
- the sum of the weight percentages of CaO and MgO lying in the range of 15 to 25%,
- the ratio of the weight percentage of SiO.sub.2 to that of Al.sub.2 O.sub.3 being at least 2 and at the most 2.5, and
- the ratio of the weight percentage of MgO to that of SiO.sub.2 not exceeding 0.3.
Dependencies are inferred from the claim text.