This eliminates the problem of diffusion of {HEAD ~ the lighter gas} through 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 {TAIL ~ the same rate} as the gas 
This eliminates the problem of diffusion of { HEAD ~ the lighter gas } through 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 { TAIL ~ the same rate } as the gas
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD 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 TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH