This eliminates the problem of {HEAD ~ diffusion} of the lighter gas through {TAIL ~ the soap film} as it travels from the gas flow inlet 25 to the sensor assembly 20, which in turn ensures that the soap film transits across the sensing region at the same rate as the gas 
through
This eliminates the problem of { HEAD ~ diffusion } of the lighter gas through { TAIL ~ the soap film } as it travels from the gas flow inlet 25 to the sensor assembly 20 , which in turn ensures that the soap film transits across the sensing region at the same rate as the gas
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL 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