Method for producing a steel underwater pipe that is able to carry a corrosive fluid
AssigneeSaipem S.P.A.
InventorRaymond Hallot
Life of this patent
Estimating the term…
Abstract
A method for producing a steel underwater pipe for carrying a corrosive fluid, includes the successive steps: applying a layer of corrosion-resistant steel alloy on a terminal part of the internal wall of each pipe element from its end to be welded; the application of a plastic coating, on the internal wall of each pipe element; covering only a first part of the layer of metal alloy, a terminal part of the layer of metal ally on the side of the end to be welded of each pipe element not being covered by the plastic coating; the coaxial insertion and the crimping of a compression ring against the terminal part of the plastic coating; and the assembly by welding directly together the ends of two pipe elements by a corrosion-resistant steel alloy weld.
Claims13
A method for producing a steel underwater pipe that is able to carry corrosive fluids, the internal wall of which is partially lined by a protective coating of plastic material of the liner type wherein the assembly by welding directly together the ends of at least two pipe elements is provided for, comprising the following steps successively:
- a) applying a layer of corrosion-resistant steel alloy on a terminal part of length L1 of the internal wall of each pipe element from its end to be welded;
- b) machining, on the pressure side surface, of the layer of corrosion-resistant steel alloy,
- c) applying said protective coating of plastic material directly on the internal wall of each pipe element;
- and covering a first part of length L2 of said layer of corrosion-resistant steel alloy, a second, adjacent part of length L3 of said layer of corrosion-resistant steel alloy on the side of the end to be welded of each pipe element not being covered by said protective coating of plastic material,
- d) coaxially inserting a compression ring of corrosion-resistant steel alloy inside said terminal part of each pipe element and the crimping of a first annular part of length L4 of said compression ring against the pressure side face of the terminal part of said protective coating of plastic material covering a first part of said layer of corrosion-resistant steel alloy, and the welding of the free end of a second annular part of said compression ring against a second part of said layer of corrosion-resistant steel alloy not covered by said protective coating of plastic material, said first annular part of the compression ring comprising an outer side face which is corrugated, over a part at least of its length said second annular part of said compression ring continuing said first annular part, said second annular part being applied against a part of said second part of the layer of corrosion-resistant steel alloy not covered by said coating of plastic material and extending over a length L5 less than L3, from and against the end of said coating of plastic material until said free end of said compression ring closest to the end to be welded of the pipe element, and
- e) assembling, by welding directly together, the ends to be welded of two pipe elements by a corrosion-resistant steel alloy weld.
Dependencies are inferred from the claim text.