Patent ID: 8922642
Filing Date: 2014-12-30
Classification: B32B,B44C,G01N

Abstract:
1. An apparatus for monitoring a test medium, the test medium being a powder which is displaceable in position by a magnetic field, said apparatus comprising a test element having an artificial crack, a test medium feed for feeding the test medium to the test element, a test medium return to return the test medium, and a magnetic field generator for generating a magnetic field to be applied to the test element, an image recorder for generating an image of at least one part of the test element which contains at least one portion of the artificial crack, and an image analyzer for rating the image generated by the image recorder, the image analyzer comprising an image comparator for comparing the image generated by the image recorder with a number of previously stored reference images to show a state of the test medium, wherein the artificial crack is introduced by spark or laser erosion into the test element and the dimension of the artificial crack corresponds to lower-limit defects expected in the test element.