| 摘要 |
PROBLEM TO BE SOLVED: To accurately measure the position of the flaw formed on the inner surface of the inner pipe of a multiple pipe in a short time without using a large-scaled device regardless of whether the multiple pipe is straight. SOLUTION: In this flaw inspection method of the multiple pipe, the electric wave Tx radiated into the inner pipe 2 of the double pipe 1 is propagated in an axial direction to be passed through the flaw D formed on the inner surface of the inner pipe 2 and passed through the spaced 5 in an outer pipe 3 to be returned to one end of the double pipe 1 as an electric wave Rx. When the time lag (the reciprocating propagation time of the electric wave) from the point of time when the electric wave is radiated to the point of time when the electric wave is returned is set toτ; the distance from one end of the double pipe 1 to the flaw D is set to L and the average propagation speeds of the electric wave in the inner and outer pipes 2 and 3 is set to V; the formula,τ=2L/V, is satisfied. When this formula is solved with respect to L, the formula, L=V*τ/2, is given. Accordingly, by measuring the reciprocating propagation time of the electric wave, the position of the flaw D can be calculated. COPYRIGHT: (C)2007,JPO&INPIT
|
