The analyzer being programmed to derive, from {HEAD ~ the velocity measurement} made within {TAIL ~ the single chamber}, information relating to the level of the gaseous substance to be monitored 
made within
The analyzer being programmed to derive , from { HEAD ~ the velocity measurement } made within { TAIL ~ the single chamber } , information relating to the level of the gaseous substance to be monitored
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH