When member 215 is forced open by gas pressure, {HEAD ~ the current} flowing between {TAIL ~ electrode} 240 and electrode 242 is interrupted 
flowing between
When member 215 is forced open by gas pressure , { HEAD ~ the current } flowing between { TAIL ~ electrode } 240 and electrode 242 is interrupted
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH