| 摘要 |
PURPOSE:To measure the depth of corrosion into a cast iron pipe in a non- destructive manner, by paring a table against which a detection output as obtained from an LC oscillation circuit is checked when a coil of the oscillation circuit used as sensor is brought into contact with the cast iron pipe. CONSTITUTION:An oscillation circuit 10 is determined by a coil 10a used as sensor, other resistances and a capacitor 10b and oscillates a fixed oscillation frequency. When this sensor is put on a sound part and a part to be inspected to produce an oscillation output, a detection circuit 20 detects and smoothes changes in the amplitude of the oscillation circuit 10 as DC voltage and an A/D converter 30 converts an output of the detection circuit 20 into digital from analog. A CPU40 judges the material of the case iron pipe from an output of the detection circuit for the sound part at the initialization according to a flowchart and during the measurement,it computes the depth of graphatic corrosion utilizing a material-wise detection output table stored in an internal memory and the results are displayed 50. This enables the measurement of the depth of corrosion into a cast iron pipe non-destructively in a short time.
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