SF6
circuit breaker
Sulphur hexafluoride (SF6) is an inert, heavy gas having good dielectric and
arc extinguishing properties. The dielectric strength of the gas increases with
pressure and is more than of dielectric strength of oil at 3 kg/cm2. SF6 is now
being widely used in electrical equipment like high voltage metal enclosed cables;
high voltage metal clad switchgear, capacitors, circuit breakers, current transformers,
bushings, etc. The gas is liquefied at certain low temperature, liquefaction
temperature increases with pressure.
Sulphur hexafluoride gas is prepared by burning coarsely crushed roll sulphur in the fluorine gas, in a steel box, provided with staggered horizontal shelves, each bearing about 4 kg of sulphur. The steel box is made gas tight. The gas thus obtained contains other fluorides such as S2F10, SF4 and must be purified further SF6 gas generally supplier by chemical firms. The cost of gas is low if manufactured in large scale.