It was found that during the mechanical cycles, packing friction was very low so that the friction of the combined two part packing assembly with PTFE and graphite material is significantly less than the friction of {HEAD ~ a sole graphite packing system} with {TAIL ~ similar leakage characteristics} 
with
It was found that during the mechanical cycles , packing friction was very low so that the friction of the combined two part packing assembly with PTFE and graphite material is significantly less than the friction of { HEAD ~ a sole graphite packing system } with { TAIL ~ similar leakage characteristics }
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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL