{HEAD ~ A gas blast switch} has a housing which encloses {TAIL ~ an arcing chamber}, an accumulator space and an expansion space 
{ HEAD ~ A gas blast switch } has a housing which encloses { TAIL ~ an arcing chamber } , an accumulator space and an expansion space
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH