Patent ID: 7048212
Filing Date: 2006-05-23
Classification: B02C

Abstract:
1. In a reduction mill susceptible to damage by a non-frangible foreign object included within reducible material fed into the reduction mill along a predetermined path via a conveyor means, protective apparatus for providing a signal indicative of the presence of the non-frangible foreign object at a predetermined location along the predetermined path, comprising: at least one sensing surface for traversing the flow of reducible material in said reduction mill and for receiving impactions of reducible material and foreign objects; means for mounting said at least one sensing surface in operative relationship to said conveyor means and including means for vibrationally isolating said sensing surface from said reduction mill; piezoelectric transducer means attached to said at least one sensing surface for providing output signals representative of the impactions of the foreign objects and the reducible material; means coupled to said piezoelectric transducer means for selecting said foreign object impact signal from other signals coupled thereto; and means coupled to said selection means responsive to said foreign object impact signal for generating a utilization signal useful for indicating the presence of said foreign object.