PROCEDE ET DISPOSITIF POUR DETERMINER L'EMPLACEMENT DE DEFAUTS PRESENTS DANS DU VERRE PLAT

The locations of defects in flat glass (1) are detected during conveyance through a detection station where the glass is scanned by a radiation beam (11). The beam sweeps transversely across the path of the glass through a distance in excess of the glass width so that the beam sweeps through both side edges. Beam deflection occurs when the beam encounters a side edge boundary of the glass (1) and beam deflection or attenuation occurs when the beam encounters a defect. Photodetectors (22,23) are located so that their irradiation or non- irradiation by the beam after it has passed through the glass depends on beam defections or attenuations by the glass, in particular detector 23 receives the beam when undeflected and detector 22 when deflected. Pulses of light are received by a detector 15 from a striped mirror 13 to indicate the position of the beam. The photodetectors are connected to a signal processor from which output signals are obtained indicative of the locations of the defects in the lengthwise direction of the glass and indicative of the transverse distances between such defects and a side edge of the glass.