AUTOMATED INSTRUMENT TO QUANTIFY D3241 ABSOLUTE DEPOSIT USING INTERFEROMETRY (INTERFERENCE METHOD)

摘要

In the early 1990's Robert E. Morris and Robert Wagner of the US Navy developed and patented (Patent Number 5,293,298 - March 1994) a technique that used interferometry to measure the thickness distribution and volume of jet fuel thermal oxidation deposit by scanning the length of the tube with an optical probe. At that time, the technique showed limitations in measuring deposit thickness thinner than 100 nm. The technique was abandoned because studies showed that the critical thickness corresponding to an ASTM D3241 "3" failing visual rating was in the range of 80 to 100 nm. Based on the combination of this technique and the latest UVVIS spectrometer available at present, AD Systems has developed an automated instrument that precisely quantifies the D3241 deposits from 0 up to 1200 nm. This paper describes the technique and details the results obtained with the ASTM / EI interlaboratory study. Based on these results, Energy Institute published the IP 597 test method -Rating of heater tubes — Interferometric method. In addition, the paper presents results on specific heater tubes for which visual tube rating (VTR) approach generates much debate.