The improvement 4, wherein each said pressure responsive device includes {TAIL ~ means} for driving said valve therefor toward open position upon {HEAD ~ an increase} in the pressure signal thereto 
The improvement 4 , wherein each said pressure responsive device includes { TAIL ~ means } for driving said valve therefor toward open position upon { HEAD ~ an increase } in the pressure signal thereto
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH