As used herein {TAIL ~ a v notch ball valve} is a valve in which the ball has been modified so that {HEAD ~ only a portion} of the ball is used 
As used herein { TAIL ~ a v notch ball valve } is a valve in which the ball has been modified so that { HEAD ~ only a portion } of the ball is used
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH