The present invention relates to a method and a system for submerging a hydraulic turbine engine down to a seabed.
Among clean natural energy sources, a currently underexploited energy source corresponds to water currents naturally present around the world: open sea currents, tidal currents, strait and estuary currents, stream or river currents.
Installation methods and systems are a key point for the industrial success of hydraulic turbine engines. They must first enable to safely install hydraulic turbine engines on sites that may reach great depths (down to 200 meters). Second, limiting the machine installation cost is essential. Now, in many currently-used systems, this cost may largely exceed machine manufacturing costs.
Thus, it has been provided to use permanent floating platforms, drilled or anchored, originating from off-shore oil drilling.
It has also been provided to attach the turbines to piles. The drilling or piling operations necessary to install the piles are hazardous and technically long, difficult, and expensive since they are the transposition of complex operations used for offshore oil drilling. Further, the ground of the site where a pile is to be installed (sands, clays) must have good geomechanical features, especially for the drilling.
Gravity-type solutions where the water turbine is attached to a heavy body, for example, a strengthened concrete block or plate, which is placed on the sea or river bed, have also been provided. The ground of the location where these bodies are deposited (sands, clays) must be modified before the installation to make it possible. Further, such foundations are heavy and bulky. Their installation requires extremely powerful cranes, which are embarked on support vessels. Lastly, operations are risky on high seas if the vessel does not itself have considerable dimensions to remain steady in the swell during transshipment operations. Subsea Inspection, Maintenance, and Repair (IMR) support vessels designed for offshore oil drilling are thus considered: MAERSK's “Subsea Support/Cable Laying Vessels”, JUMBO's “Heavy Lift Cargos”, DOCKWISE's “Open Deck Heavy Transport Carrier”. IMR vessels, which are generally provided with a dynamic positioning technology, equipped with cranes sometimes integrating swell compensation systems, and capable of handling loads of 100 tons down to 3,000 meters deep, also have a very large deck surface area. Such vessels further provide all lift and logistic support capacities. But they have a low availability and bring about very high operating costs (handling, transport).
Patent applications WO2008125285 and WO2008125286, provide using a specific self-propelled or towed multihulled floating platform (a catamaran, or possibly a trimaran), having at its center a portal of sufficient dimensions to let through a large axial flow turbine. The turbine base structure is secured under the platform. The installation comprises several steps: a pre-installation of the turbine+base assembly on the vessel, the vessel being alongside the quay of the port of departure, and a laying down of the above assembly on the sea or river bed, while the vessel is above the selected installation site, by means of pull lines (cables, ropes, chains moved by winches secured on the vessel). Thus solution has several disadvantages:
An object of an embodiment of the present invention is to provide a method and a system for submerging a hydraulic turbine engine down to a sea or river bed, which enables to obtain a reasonable installation cost as compared with the actual machine manufacturing cost.
An object of an embodiment of the present invention is to provide a fast and safe installation, which does not require the presence of divers or of large crafts.
An object of an embodiment of the present invention is to provide an installation which can use current non-specific vessels.
An object of an embodiment of the present invention is to provide an installation which enables to install hydraulic turbine engines on sites as deep as 200 meters.
Generally, to achieve all or part of these and other objects, the present invention provides selecting as a turbine engine a cross-flow turbine engine of elongated shape. It will be shown that such cross-flow turbine engines are particularly well adapted to a simple assembly and submersion mode requiring no specific vessel.
More specifically, an embodiment of the present invention provides a method for submerging a hydraulic turbine engine, comprising the steps of:
According to an embodiment of the present invention, said assembly comprises a base structure solidly attached to the lower end of the turbine engine.
According to an embodiment of the present invention, during the step where the carriage is placed upright, the turbine engine is attached to the carriage by removable fasteners.
According to an embodiment of the present invention, the base structure comprises extendable arms, and the method further comprises, once the turbine engine has been lowered all the way down to the bottom, the steps of:
An embodiment of the present invention provides a system for submerging a hydraulic turbine engine comprising:
According to an embodiment of the present invention, said assembly comprises a base structure solidly attached to the lower end of the turbine engine.
According to an embodiment of the present invention, the ship is provided with a dynamic positioning system, and transmit means are connected to the bottom of the turbine engine or to the base structure.
According to an embodiment of the present invention, the base structure comprises a base plate having extendable arms solidly attached thereto, each arm being associated with one or several jacks to extend and be set, the turbine engine being linked to the ship during its positioning by electric cables capable of driving the various jacks.
According to an embodiment of the present invention, the pull line is connected to the top of a structure for holding the turbine engine.
According to an embodiment of the present invention, the pull line is connected to the turbine engine via electromagnets.
According to an embodiment of the present invention, the base structure comprises a base plate on which is assembled a plate pivoting around a vertical axis, the turbine engine being linked to the pivoting plate.
The foregoing and other objects, features, and advantages of the present invention will be discussed in detail in the following non-limiting description of specific embodiments in connection with the accompanying drawings:
For clarity, the same elements have been designated with the same reference numerals in the different drawings.
In the following, it will be spoken of top and bottom, or of upper and lower ends of a turbine engine, referring to the position that the turbine engine must have once installed, and this denomination will be kept even if the turbine engine is in horizontal position.
This turbine engine, of the type described in French patent No. 04/50209 (B6412—Patent 1), is associated with a holding structure of the type described in French patent application No. 05/50420 (B6869—Patent 2) and is provided with a base of the type described in undisclosed French patent application No. 08/55593 (B9030—Patent 4).
This turbine engine comprises three V-shaped wings 1, 2, and 3 attached to a same axis 5 which drives a generator 7. The assembly of the turbines and of the generator is surrounded with a holding structure comprising posts 10 connected by hoops 11 which support bearings maintaining axis 5 between two turbine engines. Preferably, the different elements of holding structure 10, 11 are solidly associated together and with a base 20 to be liftable in one block from the top, moving along the turbine engine and base 20. Base 20 comprises a base plate 21 having holding structure 10, 11 assembled thereon and having four extendable arms 22, 23, 24, 25 shown in folded position attached thereto. Substantially at the center of base plate 21, the lower end is attached to an anchoring system, for example a mooring 27, and each of arms 22 to 25 also supports a foundation system, for example, a mooring 26. Each of the arms is foldable at the level of a joint 28 to take, in the installed state, the position illustrated in
The twin columns are assembled within a holding structure 34 comprising portions 35 forming a fairing, so that the structure automatically orients in the flow direction, given that the assembly of the two columns and of the fairing is connected to a plate 36 assembled to axially rotate on base plate 21.
The turbine engine structures illustrated in
A way to install or submerge a turbine engine will now be described in relation with
The ship deck is equipped with a winch 45 having its pull line 46 attached to the high portion of the turbine engine. Pull line 46 is also shown in
According to an important advantage of the present invention, the installation of the turbine engine on the carriage may be performed while the carriage is on shore, for example, in a shed provided with a bridge crane. Then only is the carriage supporting the turbine engine brought onto the ship deck. Although this has not been shown, it should be clear that various means for securing and protecting the carriage and the turbine engine on the ship deck may be provided.
As illustrated in
The beginning of the descent of the turbine engine is illustrated in
At the step illustrated in
At the step illustrated in
Ship 44 is provided with a dynamic positioning system, for example, of GPS type, currently equipping many offshore support vessels, to make sure that turbine engine 40 is well positioned above target 50 and the rest during its descent. Such computer-controlled dynamic positioning systems enable to maintain the ship position by using the helixes and bow thrusters of the ship. Various embarked sensors are used to provide the computer with data relative to the ship position and to the direction of the environmental forces affecting this position. Such systems are currently sufficiently accurate to enable to also consider, if the turbine engine is desired to be pulled back up, to run down a pull line and to position it properly to catch a hooking system such as a ring arranged at the top of the turbine engine.
According to a significant advantage, given that the method and the system according to the present invention apply to cross-flow turbine engines, the rotational position with respect to a vertical axis is of no importance, be it in the case of a single-column turbine engine or in the case of a twin-column turbine engine provided with a swiveling fairing and pivotally assembled around a vertical axis.
According to an advantage of the present invention, the use of cranes and other lifting elements on the ship is avoided. Only a winch of adapted power, possibly associated with various gear systems, is used.
Specific embodiments of the submerging system and of turbine engines selected for such an installation have been described previously. Of course, the present invention is likely to have many alterations and modifications which will occur to those skilled in the art, some being mentioned hereafter.
Although a ship capable of submerging one turbine engine at a time has been described, larger ships, capable of storing several turbine engines and of successively submerging them may be selected, although this is not preferred. The submerging may also be provided to be performed from any side of the ship instead of from the ship stern, by satisfactorily solving balance and heel issues.
Although a carriage provided with wheels has been described, it should be noted that, although this is preferred for the transfer of the carriage from a shed to the ship, this carriage may also be provided with other means of cooperation with the ship once it is mounted thereon, for example, rails or slide bars.
Further, bases solidly attached to moorings (of gravity type) have been illustrated previously. Suction anchors may also be provided. Suction anchors are hollow, and have a cylindrical or trihedral shape. They are driven into the ground by pumping of the water inside of them. Such anchors may have a height ranging from up to 10 to 25 m with a diameter ranging from 3 to 7 m. The ground of the site where they must be installed (sands, clays) must have specific geomechanical features. A pneumatic line connected to a pump on the ship must then be added to the pull line and to the electric cables used to install the turbine engine. It may also be provided for the support base plate of the turbine engine to be an anchored base plate.
A preferred embodiment where an elongated turbine engine is associated with a base system to which it is solidly attached during the installation has been described. Elongated turbine engines integrating no base structure, and designed to be able to attach to a foundation system previously installed on the sea or river bed, may also be provided.
Number | Date | Country | Kind |
---|---|---|---|
0951595 | Mar 2009 | FR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/FR2010/050436 | 3/12/2010 | WO | 00 | 11/21/2011 |