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