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Introduction |
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Merchant ships are generally constructed from large steel plates welded together either manually or on submerged arc lines. This offers many opportunities for ACFM inspection. The ability of ACFM to inspect through paint, even underwater, means that ship hulls can be inspected without having to enter dry-dock. Using ACFM in conjunction with a rope-access technician or diver also avoids the need for scaffolding or overside staging. |
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| Overview | ||
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As well as inspecting ships hulls, ACFM has been used to inspect storage and ballast tank welds on chemical and gas tanker ships, LPG spheres and propeller blades and thrusters. In most cases large areas require inspection, a process that can be shortened through the use of an ACFM array probe which can be marinised if required. Propeller blades are usually inspected underwater by a diver with an underwater instrument. However this is one example where costs can be reduced through the use of a topside AMIGO instrument and a marinised probe with 50m cable in place of a subsea instrument. Although most of a ship is made from ferritic steel, some components (such as the propeller) may be made from more exotic non-ferrous alloys, for example phosphor bronze or aluminium bronze. ACFM probes can be used to inspect virtually any type of metal, with a simple change in set-up. |
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Projects and Applications
Voith Schneider Propulsor Blades
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Project | Equipment |
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Propulsor blade inspection
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U19 AMIGO system Underwater 40mm flat array probe 5KHz 50m underwater probe extension Standard underwater weld probe 5KHz |
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| Project Overview | ||
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In collaboration with a leading underwater maintenance company in the UK, TSC Inspection Systems developed an ACFM system and underwater array probe to provide accurate and reliable detection of defects in aluminium bronze Voith Schneider propulsor blades and phosphor bronze ships propellers. The array probe is capable of inspecting a width of 40mm at once and detecting defects in all orientations in one pass. It is also capable of differentiating between cracks and cavitational pitting, a common problem on all propulsor and propellor blades. Early detection of defects allows instant decisions to be made on whether components need to be replaced, or condition monitoring carried out. The ability of ACFM to save all scan data allows direct comparison of defects and assessment of any propagation over time. |
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High Strength Steel (HSS) Welds on Submarines
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Project | Equipment | ||||
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Submarine high strength steel (HSS) weld inspection |
U19 AMIGO system Standard weld probe 5KHz |
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Cargo and Chemical Tankers
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Project | Equipment |
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Tanker cargo tank inspection
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U19 AMIGO system Standard weld probe 5KHz Straight mini pencil probe KHz Right angled mini pencil probe 5KHz |
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| Project Overview | ||
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ACFM inspection techniques have been used on a major international shipping company's chemical transport tankers; for the investigation of possible defects, located in cargo tank floors and top and bottom sloping wall welds, as well as leak detection between cargo and ballast tanks in chemical tankers. In one case, inspection was carried out during the time the vessel was in transit between offload and load ports, thus no costly downtime or docking was required. |
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Thruster Inspection
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Project | Equipment | ||||
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FPSO thruster blade maintenance
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U19 AMIGO system Underwater array probe Micropencil probe Mini pencil probe 50m array umbilical Custom build stop hole probe |
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