During a switching off operation, the moveable contact member moves out of the arcing chamber and {HEAD ~ quenching gas} flows from {TAIL ~ the accumulator space} into the expansion space, through the arcing chamber, i.e. the nozzle 
flows from
During a switching off operation , the moveable contact member moves out of the arcing chamber and { HEAD ~ quenching gas } flows from { TAIL ~ the accumulator space } into the expansion space , through the arcing chamber , i.e. the nozzle
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH