The top portion 21 of {HEAD ~ the T shaped valve member} 20 forms a sealing surface 30 for selectively substantially preventing {TAIL ~ fluid flow} through the opening 26 
The top portion 21 of { HEAD ~ the T shaped valve member } 20 forms a sealing surface 30 for selectively substantially preventing { TAIL ~ fluid flow } through the opening 26
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH