{HEAD ~ a pressure sensor} connected in line with said distribution trunk tube and adapted to sense and indicate {TAIL ~ normal and abnormal operating pressures}; and 
{ HEAD ~ a pressure sensor } connected in line with said distribution trunk tube and adapted to sense and indicate { TAIL ~ normal and abnormal operating pressures } ; and
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL REL OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH