MAGNETIC WALL FLAW DETECTOR Russian patent published in 2000 - IPC

FIELD: non-destructive testing, detection of longitudinal cracks in underground main pipe-lines. SUBSTANCE: flaw detector has cylindrical base with supporting units that carries units of lateral magnetization and fixing of magnetic dispersion fluxes. Lateral magnetization units provide for magnetization of pipe in two ring sections with displacement of one ring relative to another equal to πd/2n, where n is number of pairs of poles. Magnetization is conducted by sections with use of opposite magnetic fields in each section arranged in pairs. Flaw detector is fitted with spacing units made of material having low abrasion factor. Spacing units are reinforce with rods fabricated from magnetically soft material with residual induction equal to residual induction of source of magnetic field. Power supply unit includes turbo-generators. EFFECT: enhanced functional reliability thanks to absence of rotary units. 5 cl, 4 dwg