A method, device, and system for controlling a flow of {HEAD ~ a fluid} moving through {TAIL ~ a pipe} are presented 
A method , device , and system for controlling a flow of { HEAD ~ a fluid } moving through { TAIL ~ a pipe } are presented
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH