Improved Capabilities to Detect Incipient Bearing Failures.
Final rept. 1 May 78-31 Mar 80,
PRATT AND WHITNEY AIRCRAFT GROUP WEST PALM BEACH FL GOVERNMENT PRODUCTS DIV
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A methodology using safe, low level radiation technique for the detection of wear in gas turbine engine mainshaft bearings has been developed and evaluated in a simulated gas turbine engine bearing environment. In conjunction with spectrometric analyses of engine oil samples, the radioactive tag will detect low levels of wear and will simultaneously indicate whether the tagged bearing is the source of the wear. Iron-55 is employed as the active tag owing to its low radiation levels, long half-life, and homogeneity of the isotope in the bearing rollers. The low levels of radiation existent in the tagged wear particles requires the separation of wear debris from the oil. Test results showed that the tagging method would provide a means of identifying the tagged rollers experiencing abnormal wear at the or - 0.5 part per million iron level. Safe, low-level radioactive bearing roller tagging was achieved by waiting six months after neutron irradiation for the decay of the iron-59 and the chromium-51 gamma emitting radioisotopes. Wear measurements are conducted using the long half-life, low energy emitting X-rays from iron-55. The technique used for tagging, debris concentration, debris measurement, and bearing testing is given. Author
- Machinery and Tools