| 摘要 |
PURPOSE:To achieve a higher quality of a glass tube by a method wherein light is made to hit a glass tube used for a fluorescent lamp or the like along the length thereof through a slit to detect a striae of the glass tube accurately depending on an electrical signal of a quantity of light sensed passing through the glass tube. CONSTITUTION:A box body 3 having specified dimensions of a slit 2 in front thereof and a light source 4 comprising a halogen bulb or the like with a high output housed therein are provided along a glass tube 1 with a specified value of a tube diameter during a tube drawing. Likewise, a box body 6 having a light receiving slit 5 in front thereof and a sensor 7 housed therein are arranged. The light source 4 and the sensor 7 are arranged in a positional relationship of facing each other and a recorder and an automatic selector 8 are connected to the sensor 7 through a photoelectric conversion circuit. Then, a constant DC voltage is applied to a light source 3 and light lit is made to hit the glass tube 1 through the light slit 2 and light from the glass tube 1 enters the sensor 7 by way of the slit 5 to convert a quantity of the light into an electrical signal. Thus, a striae of the glass tube 1 is detected depending on a size of the electrical signal. |
