TOOL-DEFECTOSCOPE FOR DETECTING OPENINGS IN PIPELINE Russian patent published in 2005 - IPC

FIELD: non-destructive testing.

SUBSTANCE: tool-defectoscope has pickups for converting variation of local stress of pipe metal field into electrical signal. The pickups are secured to the flexible plates and is additionally provided with phase-sensitive amplifier. Each bridge circuit of the pickup has three inductive coils and three fixed reference resistors and two variable resistors. The inductive coils are connected in series with plates. The first reference resistor is connected in series with the intermediate plate and inductive coil. The values of inductivities of the inductive coils and capacities of plates provide their reactivity resistance to be equal and signs to be opposite. The fixed and variable resistors are connected in the bridge arms whose leads are signaling ones and connected with the inputs of the electronic unit. The leads of the first reference resistor are connected with the first input of the phase-sensitive amplifier. The second input of the first reference amplifier is connected with the output of the generator of high-frequency voltage.

EFFECT: enhanced reliability.

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