Method and device for testing a sealing surface of a container aperture

摘要

The method involved emitting light beams (9) from a light source (5) to the container mouth (4). An optical deflection element (39') is placed in the beam path between the light source and the mouth. This element is transparent at least to light of a particular wavelength and deflects such incident light beams such that they have a directional component which hits the sealing surface tangentially. If faults are present in the surface, the light is scattered. At least some of the scattered beams are detected by a sensor (18). Independent claims also cover an apparatus for carrying out the method.