In {HEAD ~ order} to move the valve pin 31 to {TAIL ~ its closed, middle and open positions}, a three position actuator 34 is provided 
In { HEAD ~ order } to move the valve pin 31 to { TAIL ~ its closed , middle and open positions } , a three position actuator 34 is provided
OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH