Method and apparatus for detecting checks in glass tubes

摘要

A method and apparatus for inspecting glass tubes for fire checks and other defects is disclosed. Each tube is positioned on transport equipment and moved through an inspection area as it is rotated about its longitudinal axis by a spinner mechanism. A broad source of diffused light illuminates each tube in the inspection area. A camera is positioned above the moving line of tubes and includes an array of photosensitive diodes arranged parallel to the longitudinal axes of the tubes. A check in a tube will reflect a higher intensity light to the camera than a non-defective portion of the tube. By averaging the signals from the first few diodes for each longitudinal scan of the camera, a reference voltage level can be electronically determined for each scan. Any signal generated by a diode element of the camera which is greater than the sum of the reference signal and a predetermined signal indicates the presence of a defect in the tube.