Measuring Fan-Blade-Tip Displacements

Abstract

Magnets and Hall-effect transducers used to monitor tip-to-shroud clearances. Mounting permanent magnet in end of fan blade and monitoring tip-to-shroud distance by use of output of Hall-effect transducers affixed to surface of shroud. Transducers provide real-time information. By placing magnets in each fan-blade tip, complete set monitored sequentially as each blade rotates past sensor. Application in many rotating machines, providing surrounding materials nonmagnetic and temperatures not severe.