magnetic flux leakage inspections 8th International Conference on - - PowerPoint PPT Presentation

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8th International Conference on flat bottom tanks

Laser scanning as a complement to magnetic flux leakage inspections

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Introduction

 Since 1997 the storage tank operators

and refineries have been inspecting tanks floors by Magnetic Flux Leakage method, and we have seen a lot of inspection companies use these system. This method has been a great innovation for the tank inspection.

• Quick inspection for a large area.
• Recognize by any code repair
• Discriminate internal and external defects.
• New maintenance practice

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magnets Plate sensor

 A important corrosion area top side plate.

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 Cylindrical pits less 15mm diameter

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 The volume loss of the metal for these both pits

are similar

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 Plate curvature or

bulges can prevent the sensor head from remaining in close proximity to the inspection surface.

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 False echo

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 These systems don't have to detect defects in

welds

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• Following HSE Research Report 481, for the

inspection of storage tanks there needs to be a team of operators. This inspection team should consist of at least two individuals and possibly

• three. The roles required of the inspection team can

be described as:

• Team Leader (TL)
• MFL Technician (MT)
• Ultrasonic Technician (UT)

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• Report all indications marked on the floor

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• Scanning by laser-scanner of tank floor :

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 Defects measurements

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• We complete our inspection by a drawing:

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• The floor geometric deformations

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• The annular geometric deformations

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• The result of the planar tilt

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• Out of verticality of the shell

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• Out of roundness of the shell

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• Dome roof inspection

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• The beam Inspection

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• The scanner laser has to carry out:
• A complete inspection report of the bottom

tank

• A complete geometrical analysis of tank
• A monitoring deformations in time

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« Observe is our job »