The sensing means includes a directing means for directing {HEAD ~ pressurized fluid} to the second reaction chamber upon {TAIL ~ completion} of the dual modulated increases in fluid pressure 
The sensing means includes a directing means for directing { HEAD ~ pressurized fluid } to the second reaction chamber upon { TAIL ~ completion } of the dual modulated increases in fluid pressure
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH