{TAIL ~ The valve element} also has {HEAD ~ a through passage} 23 which, when arranged in an open position as shown in FIG 1, enables passage of gas through the valve 
{ TAIL ~ The valve element } also has { HEAD ~ a through passage } 23 which , when arranged in an open position as shown in FIG 1 , enables passage of gas through the valve
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH