{HEAD ~ The valve} is closed by swinging the valve element through {TAIL ~ 90 degrees} thus moving the valve element passage out of registry with the ports 13 13 of the chamber 
{ HEAD ~ The valve } is closed by swinging the valve element through { TAIL ~ 90 degrees } thus moving the valve element passage out of registry with the ports 13 13 of the chamber
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH