Making the cross sectional shape of {TAIL ~ the channel} 46 a segment of a true circle also contributes to the functional characteristics of {HEAD ~ the valve} 
Making the cross sectional shape of { TAIL ~ the channel } 46 a segment of a true circle also contributes to the functional characteristics of { HEAD ~ the valve }
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 HEAD HEAD HEAD HEAD HEAD HEAD