| 摘要 |
PURPOSE:To detect a defect securely by deciding the number of peaks of spectral intensity of a percussion generated by striking a specific part of a glass bottle gently with a hammer, etc. CONSTITUTION:The glass bottle 50 to be inspected is conveyed by a conveyor 1 in a tunnel type sound insulating wall 2 and its specific part which has a defect with high possibility is struck gently with the hammer 3 provided in the sound insulating wall 2. The percussion generated by the glass bottle 50 is passed through a microphone 4, amplifier 5, and fast Fourier transformer 6 to make a spectrum analysis by frequencies, and a proper threshold voltage is sent by a threshold voltage generator 7 and a computing element 8 decides the number of peaks exceeding the threshold voltage, so that when there are plural peaks detected, it is decided securely that the glass bottle has the defect. |
