In addition, the bias means control deformation of the valve member so as to prevent {HEAD ~ undesirable, excessive opening} of {TAIL ~ the valve} 
In addition , the bias means control deformation of the valve member so as to prevent { HEAD ~ undesirable , excessive opening } of { TAIL ~ the valve }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL