The present invention relates to a fluid conduit, and to a multi-conduit umbilical for use in the transportation of chemicals with small molecular size and shape e.g. methanol ethanol and other hydrocarbon fluids used in the oil industry. The conduit comprises a flexible fluid hose encapsulated by at least one metallized layer which is formed and arranged to minimize permeation of a fluid being transported in the fluid hose. In use in a multi-conduit umbilical the metallised layer minimizes permeation into adjacent fluid hoses containing chemicals. The invention is characterized in that the fluid hose(s) have differing levels of encapsulation and thereby permeation, along a given length according to the operational requirements of the fluid conduit/umbilical. Typically such fluid conduits/umbilicals will have lengths in excess of 100 km.
1. A variably permeable conduit for the long distance conveyance of fluids comprising:
a flexible plastic hose of multiple kilometer length;
a metallized encapsulating layer disposed over the outside surface of said hose wherein the metal of said metallized layer is selected from the group consisting of copper, nickel, chrome, aluminum and alloys thereof and is of a thickness between about 2 microns and 2 millimeters and is applied by a step selected from the group consisting of spraying, depositing, plating and wrapping; and
said metallized layer exhibiting long length variations in effective permeability to the molecules of said fluid whereby at least one substantial and continuous length of said hose has different permeability to said fluid molecules than other substantial and continuous lengths.
2. A fluid conduit according to claim 1 wherein said metallized layer (or layers) is applied to the fluid hose in the form of a metallized tape.
3. A fluid conduit according to claim 1 wherein said fluid hose material is selected from the group of materials including polyethylene, cross-linked polyethylene, polyamide or fluoropolymers.
4. A fluid conduit according to claim 1 wherein said fluid hose is a unitary single hose formed by a continuous extrusion process.
5. A fluid conduit according to claim 1 wherein said fluid hose is a one piece extrusion having a length in excess of 50 km.
6. A fluid conduit according to claim 1 wherein said fluid hose is a one piece extrusion having a length in excess of 100 km.
7. A fluid conduit according to claim 1 wherein the metallized layer is formed by electroplating.
8. A fluid conduit according to claim 1 wherein the metallized layer is applied by spraying.
9. The conduit of claim 1 further including a diagonally braided reinforcing layer over said encapsulating layer.
10. A variably permeable multi-conduit umbilical for the long distance conveyance of fluids in offshore drilling application comprising:
a plurality of flexible plastic hoses of multi-kilometer length and gathered together to form a bundle;
at least one of said plastic hoses further having a metallized encapsulating layer disposed over said hose wherein the metal of said metallized layer is selected from the group consisting of copper, nickel, chrome, aluminum and alloys and is applied by a step selected from the group consisting of fraying, depositing, plating and wrapping, each said metallizing layer exhibiting a variation in effective permeability to the molecules of said fluid whereby at least one substantial and continuous length of said bundle has a different permeability to said hydrocarbon fluid molecules than other substantial and continuous bundle lengths.
11. A multi-conduit umbilical according to claim 10 which includes at least one of a power cable; fiber optics cable, and other fluid transportation hoses.
12. A multi-conduit umbilical according to claim 10 having a length in excess of 50 km.
13. A multi-conduit umbilical according to claim 10 having a length in excess of 100 km.
14. An umbilical as defined in claim 10 further including a reinforcing layer over said bundle and a plastic sheath over said reinforcing layer.