said first opening providing a valve inlet for connection to a source of {TAIL ~ high pressure gas}, an inlet flow passage leading from said first opening into said axial bore and {HEAD ~ inlet pressure passage} also leading from said first opening, 
said first opening providing a valve inlet for connection to a source of { TAIL ~ high pressure gas } , an inlet flow passage leading from said first opening into said axial bore and { HEAD ~ inlet pressure passage } also leading from said first opening ,
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH