Commissariat a L'energie Atomique

Bernard David

Michel Pigeon

Francis Joffre

Claude Vienot

Remy Besnard

Francois Champonnois

Bruno Benoist

Pascale Attaoui

A system for the processing of signals collected by an eddy current absolute point transducer moving along an inner surface of a conductive material tube and supplying a representative signal concerning the state of the inner surface. The system incorporates a stage for scanning the surface in accordance with a given order or sequence of elementary measurement zones and recording the sampled values of the signal supplied by the transducer for each of the elementary zones, which makes it possible to obtain a three-dimensional image representative of the surface. The system also constructs a background noise surface on the complete image, subtracts the background noise surface from the image and detects a defect or fault on the surface. Such an invention may find particular application to the inspection of steam generator tubes.

Process for processing signals collected by an eddy current absolute

A pulsed eddy current testing system for detecting defects in a part. A probe carries an exciting pulse in one coil and receives a measuring signal in a second coil. The measuring signal is sampled at two instants defined by short and long time lags. The two amplitudes obtained are plotted in a representative plane having two reference axes. The point having the signals as coordinates describes a figure eight, when the part has a defect. The size and orientation of the figure gives information on the defect in the part.

Eddy current testing system using two samples with different time lags

A device for checking bent tubes by means of a probe, such as a pneumatically propelled eddy-current probe. The device comprises a sealing-tight enclosure adapted to communicate with the tube to be checked via a connecting tube. The introduction pressure of the probe is produced by a pneumatic circuit. The probe comprises a checking head and a cable having floaters and is wound on a coil driven by a torque motor. The introduction speed of the probe is controlled by passing it over a drive pulley, to which it is permanently applied by a strap tensioned by a spring, the pulley being mounted on the shaft of a constant-speed motor. Application to the checking of the tubes of heat exchangers, condensers and steam generators, more particularly of nuclear reacters.

Device for checking bent tubes by a probe, such as a pneumatically

The invention relates to a process and to devices for the inspection of the surface of a member by means of an eddy current probe. By scanning the member means of the transducer following a given path, the sampled values of the signal supplied by the transducer are recorded for clearly defined positions of the transducer. By restoring the signals, it is possible to simulate a displacement of the transducer along a different path and/or simulate the displacement of a larger size or different type of transducer. The process may be used in steam generators in nuclear reactors and to the examination of irradiated fuel rods in these reactors.

Process and device for inspecting a surface in simulated manner which

Process and device for non-destructive testing or inspection by eddy currents with correction of the air gap effects. A differential measurement and an absolute measurement are performed and the result of the former is divided by that of the latter, which supplies a signal with respect to which the effects of the air gap separating the probe from the member to be inspected are corrected. Application to the inspection and testing of metal members.

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Gif sur Yvette, France

Bernard David