| 摘要 |
<p>PROBLEM TO BE SOLVED: To extremely easily specify the position of a nail when the nail is driven through a concealed metallic flexible pipe by computing the distance from the end of the pipe to the position of the nail based on a measured current or voltage and the electric resistance of a conductive layer. SOLUTION: When a nail is driven through a gas pipe 1 laid in a house at a point P1 , an alternating or direct current is supplied across the pipe 1 and a conductive layer 3 from supplying points 9 and 10 by means of the supplying means 5 of a measuring instrument 4. In the case where the voltage applied across the pipe 1 and layer 3 from the means 5 is 10V, the current becomes zero when no nail is driven through the pipe 1, but when, for example, the electric resistance of the layer is 100Ω/m and the current detected by means of a current or voltage measuring means 6 is 20mA, the resistance of the pipe becomes 500Ω. Since the resistance value of 500Ωis proportional to the distance from the measuring point from which the current is supplied to the point P1 , the calculated distance from the measuring point to the point P1 becomes 5m.</p> |
