Electricity: conductors and insulators – Combined fluid conduit and electrical conductor
Reexamination Certificate
2000-05-24
2003-03-25
Reichard, Dean A. (Department: 2831)
Electricity: conductors and insulators
Combined fluid conduit and electrical conductor
C174S096000, C174S101500, C174S11000P, C138S111000, C138S118000
Reexamination Certificate
active
06538198
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to marine umbilicals, and more particularly to a marine umbilical incorporating composite inner tubing for the conveyance of fluids and the enclosure of optical fibers and electrical conductors.
2. Description of the Related Art
The efficient manipulation of subsea wellheads requires an interface between a control or processing facility, such as a platform, a land base facility, a servicing vessel or and the subsea wellhead. It is frequently desirable to be able to remotely manipulate valves and other equipment as well as inject various servicing fluids into the wellhead and to transmit and receive signals and electrical power. Umbilicals are frequently used to provide this necessary interface.
Dynamic umbilicals are used to interface moveable objects, such a submersibles, floating platforms and servicing vessels with other structures, such as wellheads, other platforms or other structures. As the name implies, dynamic umbilicals are designed to withstand stresses due to bending, tension and torsion. The majority of these dynamic loads are due to ocean currents and wave action. Static umbilicals are designed largely for stationary deployment.
Many conventional umbilicals incorporate a plurality of internal steel tubes shrouded by an external plastic jacket. The steel tubes are designed to carry hydraulic fluids, hydration inhibitors, such as methanol, or other servicing fluids. In some cases, electrical conductors are positioned around the steel tubes. Steel as an internal tube material presents several disadvantages associated with fatigue strength limitations, bending capacity, weight and cost. Fatigue strength places confines on the operation of the umbilical, particularly in dynamic contexts, such as connections to semi-submersible and fully submersible vehicles. In circumstances where high internal pressures are required within these steel tubes or high external hydrostatic pressures are present, the effect of fatigue loading can be more severe. As a consequence, the strain in the steel must be kept relatively low at normal operating conditions, and below the elastic limit of the steel even in the most extreme operating conditions.
Bending capacity is another limitation associated with umbilicals incorporating steel internal tubes. In order to maintain fatigue life and allowable stress levels within acceptable limits, the diameters of the internal steel tubes are restricted. Thus, the steel internal tubes may have relatively small diameters which translate into high head losses for fluids flowing therein.
Shear weight is another disadvantage associated with steel internal tubing in umbilicals. As the weight of the umbilical goes up, more of the total stress capacity of the umbilical must be devoted to tension and thus less is left over for bending stresses. In addition, heavier umbilicals require more robust handling equipment, such as winches, spools and the structures holding them, such as servicing vessels and/or platforms.
Material cost is another drawback associated with conventional steel umbilicals. Most conventional steel umbilical tubing is fabricated from sophisticated alloys that require complex hot and cold working. As many types of umbilicals may be thousands of feet in length, material costs due to the steel can soar.
Another type of conventional umbilical incorporates conventional hydraulic hoses within a plastic jacket. The hoses consist of a plastic tube reinforced externally by a wrapping of aramid and an outer wrapping of rubber or plastic. One disadvantage associated with this conventional internal tubing design is that aramid fiber jacketing is, like steel, prone to fatigue failure. In addition, there is typically no chemical bond between the aramid fibers and the core plastic tube. Thus, if the core plastic tube is perforated, or vice versa, if the outer plastic jacket is perforated, leakage may readily cascade through the perforation, through the aramid reinforcement and either into or out of the core plastic tube depending upon the pressure differential between the inside of the hose and the outside of the hose. A final disadvantage associated with conventional hydraulic internal tubing is a diminished ability to withstand the large external compressive forces due to hydrostatic pressure in deep water environments. In such circumstances, the conventional umbilical must be wrapped with a significant amount of armor wiring to protect the enclosed hydraulic hoses.
One conventional umbilical design proposed the incorporation of a composite center tube surrounded by a plurality of hydraulic lines and a number of power and signal conductors. The design advocated the use of a composite center tube only along with conventional hydraulic and conductor lines. Thus, the problems associated with steel tubing noted above remain.
The present invention is directed to overcoming or reducing the effects of one or more of the foregoing disadvantages.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, an umbilical is provided that includes a first tube and a second tube. The first tube and the second tube each have a polymer sleeve and an outer sleeve of fibers in an epoxy matrix positioned around the polymer sleeve. A third tube is provided that surrounds the first tube and the second tube.
In accordance with another aspect of the present invention, an umbilical is provided that includes a first tube and a second tube. The first tube and the second tube each have a polymer sleeve and an outer sleeve of carbon fibers in an epoxy matrix positioned around the polymer sleeve. A third tube is provided that surrounds the first tube and the second tube.
In accordance with another aspect of the present invention, an umbilical is provided that includes a first tube, a second tube positioned in the first tube and a plurality of third tubes positioned in the first tube. Each of the plurality of third tubes has an inner polymer sleeve and an outer sleeve of carbon fibers in an epoxy matrix positioned around the polymer sleeve.
REFERENCES:
patent: 4196307 (1980-04-01), Moore et al.
patent: 4336415 (1982-06-01), Walling
patent: 4476923 (1984-10-01), Walling
patent: 4630970 (1986-12-01), Gunderson et al.
patent: 4726314 (1988-02-01), Ayers
patent: 5044826 (1991-09-01), Forster
patent: 5052444 (1991-10-01), Messerly et al.
patent: 5170011 (1992-12-01), Martucci
patent: 5188872 (1993-02-01), Quigley
patent: 5192167 (1993-03-01), da Silva et al.
patent: 5285204 (1994-02-01), Sas-Jaworsky
patent: 5330807 (1994-07-01), Williams
patent: 5483022 (1996-01-01), Mar
patent: 5570437 (1996-10-01), Kluth et al.
patent: 5580626 (1996-12-01), Quigley et al.
patent: 5688571 (1997-11-01), Quigley et al.
patent: 5764835 (1998-06-01), Rubin et al.
patent: 5828003 (1998-10-01), Thomeer et al.
patent: 5888601 (1999-03-01), Quigley et al.
patent: 5902958 (1999-05-01), Haxton
patent: 5904445 (1999-05-01), Meuth
patent: 5908049 (1999-06-01), Williams et al.
patent: 5913337 (1999-06-01), Williams et al.
patent: 5921285 (1999-07-01), Quigley et al.
patent: 5933945 (1999-08-01), Thomeer et al.
patent: 5944099 (1999-08-01), Sas-Jaworsky
patent: 5988702 (1999-11-01), Sas-Jaworsky
patent: 6044038 (2000-03-01), Allensworth
patent: 6239363 (2001-05-01), Wooters
patent: 6355879 (2002-03-01), Bertini et al.
Dunlop Coflexip Umbilicals Ltd.;DUCO Brochure Ltd.; pp. 1-26; 1991.
Kvaerner Enery a.s;Kvaerner Umbilicals Product Brochure; pp. 1-20; Mar. 1993.
Coflexip Stena Offshore;Pipe and Umbilical Brochure; pp. 1-20; 1996.
Alcatel;Total offshore cable systems brochure; pp. 1-34; Aug. 1998.
Duco Umbilical Systems;Duco Umbilical SystemsBrochure; all; Apr. 1999.
Honeycutt Timothy M.
Reichard Dean A.
Walkenhorst W. David
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