Gas density monitor for gas filled HV switchgear - has bourdon tube enclosed in gas to operate indicator

摘要

The safety device for gas filled high voltage switchgear is an indicator which registers the density of the gas inside the switchgear. The device has a housing (12) mounted on the switchgear housing (14) and containing a Bourdon tube (28) which operates an indicating pointer (50) moving around a circular scale (52). The Bourdon tube has a connection (42) at one end, for the mechanism driving the pointer, and at the other end is attached to a tube (22) screwed into hole (18) through the switchgear housing, and with a hole (24,26) through it, so that the gas can enter the indicator housing. The density of the gas inside the two housings is therefore approximately equal. The indicator can incorporate electrical contacts operated by a fall in density to operate an alarm.