Product category:
Materials and components
News Release from: Furmanite International | Subject: Furmanite composite repair technology
Edited by the Engineeringtalk Editorial
Team on 10 May 2007
Surface treatment repairs vessel without
downtime
Furmanite was able to restore full structural strength and pressure integrity to a vessel on the Leman Alpha platform with a composite repair.
Composite repair technology from Furmanite has allows the repair of a vessel on the Leman Alpha platform in the southern North Sea with no disruption of its operation External corrosion had caused wall thinning, the repair of which would, traditionally, have required shutting it down and welding
This article was originally published on Engineeringtalk on 6 Aug 2007 at 8.00am (UK)
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Instead, Furmanite was able to restore full structural strength and pressure integrity with a composite repair.
The permanent repair was engineered to a design pressure of 5bar and temperature of 40C in line with the vessel operating conditions, was undertaken on-line while the platform remained live, using carbon fibre and epoxy resin composite technology.
These materials provide exceptional strength (up to ten times that of steel at less than a quarter the density), and require no prefabrication or hotwork.
The repair process involved surface preparation using grit blasting to a specified roughness and cleanliness to achieve an optimum bond.
This was followed by an e-glass layer as a tie coat, followed by a number of layers of epoxy resin-impregnated carbon fibre, providing a patch repair less than 6mm thick over a 1.4 x 10.2m area of the vessel underside, with a specified overlap onto sound metal in line with design calculations, and incorporating a taper to the precise ratio specified in the repair design.
A sacrificial peel-ply layer takes up excess resin and provides (when removed after curing) a surface that can be painted or coated as required.
The vessel end caps, 50.8mm nozzles and saddle supports were also incorporated into the repair, requiring varying numbers of carbon plies to achieve the necessary repair strength.
The composites can be applied successfully in challenging conditions, with only a hand's width clearance required.
"Vessel composite repairs involve complex engineering, taking factors such as further erosion, axial loading and vessel content properties into account", Furmanite Business Manager Paul Smith comments.
"The awkward geometries of the nozzles and saddle supports are also challenging to apply.
"Composites technology provides significant advantages but requires skilful application to provide a successful, long-term, high-performance repair", he adds.
"The work was carried out by highly trained technicians, enabling us to provide a fully validated repair".
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