{TAIL ~ Axial forces} acting on the check are balanced during {HEAD ~ movement} between the sealing and open positions so that direct control over the check position may be accomplished through the use of a low force actuator 
{ TAIL ~ Axial forces } acting on the check are balanced during { HEAD ~ movement } between the sealing and open positions so that direct control over the check position may be accomplished through the use of a low force actuator
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH