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DIAGNOSTING THE STEEL PIPELINES BY THE AUTOMATED SCANNING
FLAW DETECTOR «VIKHR» DURING RECOVERY OF PROTECTIVE INSULATION

 

The common task of steel pipelines diagnostics is residual service life (life time) predication for each pipe, which is carried on the results of most dangerous defects linear features evaluation on the basis of officially approved computational and experimental procedures.

Most dangerous defects of metal are stress-corrosion cracks, appearing and expanding in outside surface of steel pipeline, so they are poorly detected by intra-pipeline inspection gauges.

Periodically, every 25-30 years the old protective insulation of steel pipelines is removed and replaced by new, in order to perform it the pipeline is extracted from ground (figure 1). Thus there is some short interval of time when the surface of steel pipeline is turned to open access for outside-of-pipe inspection and ideal conditions are provided for reliable detection of stress-corrosion cracks by the scanning flaw detectors.

Fig.1. Removing of old protecting insulation from main pipeline

 

In the automated scanning flaw detector ASD «Vikhr» the most sensitive inspecting technique is implemented – eddy current, and owing to simultaneous measurement of 3 diagnostic parameters from each of 32 eddy current transducers (ECT) the reliability of inspection results is come close to 100%.

ASD «Vikhr» gage usually operates together with pipe laying machines during removing of old protecting insulation from main pipeline and preparing its surface before new insulation begin to be coated (figure 2).

Fig.2. ASD «Vikhr» gage, closing the chain of the pipe laying machines

 

As scanning of pipeline the ASD «Vikhr» gage transmits results of inspection through wireless communication channel to remote personal computer (figure 3) with software application installed, which performs the automatic analysis of signals measured, classification of defects detected in metal and calculation of their linear features and grade of their danger evaluation.

Fig.3. Remote notebook, performing the automatic analysis of signals measured

 

On the figures 4-6 a number of examples of defects detected in the metal by automated scanning flaw detector «Vikhr» during steel pipelines diagnosing.

 

Fig.4 A stress-corrosion detected by automated scanning flaw detector «Vikhr» during steel pipeline diagnosing and its image on the inspector notebook display

 

 

Fig.5. A group of stress-corrosion defects detected by automated scanning flaw detector «Vikhr» during steel pipeline diagnosing and its image on the inspector notebook display

 

 

Fig.6. A group of stress-corrosion defects detected by automated scanning flaw detector «Vikhr» during steel pipeline diagnosing and its image on the inspector notebook display

 

The results of inspection are accumulated into the computer database, which is used to draw immediately the charts of defects locations and reports as standard Word documents and Excel worksheets formats.

At this time hardware and software solutions accumulated by specialists of «SPECTOR» Sci-Tech LLC and «Molniya» SPC JSC during automated scanning flaw detector «Vikhr» creation are used to create the new generation of multi-channel portable automated scanning flaw detectors, Applicationss of them will be detection, classification and linear features calculation of most dangerous defects of metal in real time.