As shown in FIG 1, the valve member 20 preferably has {HEAD ~ a generally T shaped cross section} with {TAIL ~ the top portion} 21 of the T being disposed adjacent the opening 26 and the bottom 23 of the T being disposed within the opening 28 
As shown in FIG 1 , the valve member 20 preferably has { HEAD ~ a generally T shaped cross section } with { TAIL ~ the top portion } 21 of the T being disposed adjacent the opening 26 and the bottom 23 of the T being disposed within the opening 28
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH