| 摘要 |
PURPOSE:To measure the thickness of minute faults by pulse-driving a ultrasonic probe to make it emit ultrasonic wave in the vertical direction of a thickness and then measuring its reflection wave voltage or the sound pressure of transmission wave. CONSTITUTION:An object 18 to be tested is submerged in a water bath 17. A pulser 1a generates a transmission wave by pulse driving, from a transmission terminal 12 to a probe 16, and a receiver part 1b detects the echo reception signal with a reception terminal 13 out of the probe 16, and then transmits the one within the set gate range to an A/D conversion circuit 2. The circuit 2, responding to the connection signal of an MPU 5, makes about 1000 samplings of the echo reception signal demodulated by an envelop detector, at a high frequency, about the fault wave, bottom surface wave, etc., coming from a flaw detection part 1, and sends them to a waveform data memory 3. Measurement data is picked up here. The MPU 5, obtaining the max. peak value of the data, stores it along with the voltage data at that time in a RAM 6. This process is repeated several times with different voltages. These multiple max. peak values are processed to obtain the gap thickness within the to-be tested object. By this, the thickness of minute fault is measured. |
