Expansion chamber for oil-filled cable - has diaphragm between oil gas with metered gas quantity inserted in non-gaseous form

摘要

Expansion chambers are fitted to an oil-filled cable allowing pressure regulation to compensate for temp. variations due to load or changed environmental conditions. The gas side of the expansion chamber is sealed. To ensure that the correct quantity of gas is put into the chamber to give the required pressure compensation the gas is inserted in the non-vapour phase. The application of heat after sealing the chamber then gasifies it. For example, the gas can be inserted in liq. form, typically methyl chloride, in a heat insulated capsule which bursts when the sealed chamber is subsequently heated. Alternatively, the gas is evolved by mixing two chemicals after sealing the chamber, again by the application of heat.