Applicant: Qinetiq Ltd, UK
An eddy current sensor for use as a dynamic proximity sensor, particularly for monitoring blade-tip timing and clearance in turbo-machinery, has been developed. It has a common coil (6) for use in both generating a magnetic field (in a proximate region) and detecting the effect of eddy currents generated by this field in electrically conductive objects passing through that region. The coil is wound on a rectangular or other elongate former so that it is elongated. This can improve the resolution of the device when used for sensing the passage of objects elongate in section <em dash> such as a turbine blade tip (11) <em dash> when the sensor coil is oriented with its shorter cross-sectional dimension aligned with the shorter cross-sectional dimension of the respective object. Also described is a method of processing a signal wave form such a device to derive ‘trigger’ points for blade-tip timing.
Patent number: WO/2009/004319
Inventor: K.S. Chana
Publication date: 8 January 2009
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