{HEAD ~ Apparatus} for monitoring the accumulation of particulates on {TAIL ~ the lining} of an exhaust duct or the like for a combustion device, comprising: 
{ HEAD ~ Apparatus } for monitoring the accumulation of particulates on { TAIL ~ the lining } of an exhaust duct or the like for a combustion device , comprising :
HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH