Desirably said second valve includes a bleed path which opens prior to full opening of the second valve so as to effect {HEAD ~ a controlled release} of pressure through {TAIL ~ said gas outlet} 
Desirably said second valve includes a bleed path which opens prior to full opening of the second valve so as to effect { HEAD ~ a controlled release } of pressure through { TAIL ~ said gas outlet }
OTH OTH OTH OTH OTH OTH OTH 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 TAIL TAIL TAIL TAIL TAIL TAIL TAIL