1. An offshore floating production, storage and off-loading vessel structure for use in producing, storing and transporting oil andor liquefied gas, comprising:
a hull having a top wall defining a deck, a bottom wall, and a generally cylindrical exterior side wall configuration surrounding a central moon pool, said side wall having a lower portion extending upwardly from said bottom wall and an upper portion extending angularly inward and upward therefrom terminating adjacent to a bottom of said deck;
ballast compartments and storage compartments contained in said hull;
an adjustable ballasting system for ballasting and deballasting selected said ballast compartments and storage compartments to induce heave, roll, pitch and surge motions of said vessel to dynamically position and maneuver said vessel and carry out moving operations; and
said moon pool having a double tapered conical interior configuration with respect to a vertical axis for entrainment of water to selectively provide added hydrodynamic virtual mass to increase the natural period of the roll and heave modes, reduce dynamic amplification and resonance due to waves and vessel motion, and facilitate maneuvering the vessel.
2. The offshore floating structure according to claim 1, wherein
said moon pool creates water flow and fills with water in the central core to reduce the effective water plane area sufficient to increase the heave natural period of said vessel without significantly reducing the overall moment of inertia of the remaining water plane area of said moon pool, and retain stability of said vessel.
3. The offshore floating structure according to claim 1, further comprising:
a central casing having a top end secured to said hull top wall in fluid tight relation and extending vertically downwardly therefrom through the center of said moon pool terminating in a bottom end adjacent to a lower end of said moon pool, said central casing defining an annulus between the casing exterior and said moon pool interior; and
support means in a lower end of said moon pool adjoined to said central casing lower end for receiving and supporting an upper end of a buoyant turret buoy;
a buoyant turret buoy having an upper portion and a lower portion which rotate with respect to one another, said upper portion releasably engaged with said support means and said lower portion disposed beneath said hull bottom wall;
said turret buoy lower portion having at least one riser connection for connecting a first end of at least one flexible riser having a second end which extends from a seabed hydrocarbon supply location; and
at least one second riser section extending vertically upward through said central casing from said turret buoy to said deck coupled at a lower end with said turret buoy in fluid communication with said first end of said flexible riser to form a fluid flow path from said seabed hydrocarbon supply to equipment on said deck.
4. The offshore floating structure according to claim 3, wherein
said buoyant turret buoy upper portion is selectively disengaged from said support means when said vessel is subjected to harsh environments and winter or summer storms to allow relocation of said vessel andor stationary mooring of said vessel with conventional mooring devices.
5. The offshore floating structure according to claim 3, wherein
said support means in said lower end of said moon pool is configured to prevent water from flowing around said turret buoy upper portion and into the annulus between the exterior of said central casing and interior of said moon pool;
said hull has channels or tunnels extending angularly downward and outward from the interior of said moon pool to the exterior of said hull to allow water to enter into the annulus between the exterior of said central casing and interior of said moon pool; and
mooring lines extending from winches on the deck, through the deck, and the interior of said moon pool and outwardly through said channels or tunnels supported by fairlead sheaves at each end of said channels or tunnels.
6. The offshore floating structure according to claim 1, further comprising:
a central casing having a top end secured to said hull top wall in fluid tight relation and extending vertically downwardly therefrom through the center of said moon pool terminating in a bottom end adjacent to a lower end of said moon pool, said central casing defining an annulus between the casing exterior and said moon pool interior; and
support means in a lower end of said moon pool adjoined to said central casing lower end having openings therethrough to allow water entry into said annulus around said casing exterior.
7. The offshore floating structure according to claim 1, further comprising:
virtual mass trap and fluid damping means associated with a lower portion of said hull for entrapping water to provide additional hydrodynamic virtual mass to minimize heave response, increase the natural period of roll and heave modes, reduce dynamic amplification and resonance due to waves and vessel motion, and facilitate maneuvering the vessel.
8. The offshore floating structure according to claim 7, wherein
said virtual mass trap and fluid damping means comprises one or more plate-like members extending horizontally outward from a lower portion of said exterior side wall of said hull.
9. The offshore floating structure according to claim 7, wherein
said virtual mass trap and fluid damping means comprises one or more upper plate-like members extending horizontally outward from a lower portion of said exterior side wall of said hull; and
one or more horizontal outwardly extending lower plate-like members disposed a distance below said one or more upper plate-like members and below said hull bottom wall to provide a space for entrapping water therebetween to provide additional hydrodynamic virtual mass and fluid damping to minimize heave, roll and pitch response, increase the natural period of roll, pitch and heave modes, reduce dynamic amplification and resonance due to waves and vessel motion, and facilitate stabilizing and maneuvering the vessel.
10. The offshore floating structure according to claim 1, wherein
said moon pool is a double tapered conical configuration having a lower portion of a first transverse dimension extending vertically upward from said hull bottom wall to a first elevation, an intermediate portion diverging angularly upward and outward therefrom to a second greater transverse dimension at a second elevation, and an upper vertical portion of said greater transverse dimension continuing vertically upward therefrom to a third elevation; and
said first transverse dimension of said lower portion is of a size and height sufficient to provide larger said ballast compartments and storage compartments at a lower portion of said hull, provide a reduced water plane area in said moon pool at an elevation near to the still water level, and to lower the overall center of gravity of said vessel to the lower portion of said hull and thereby increase stability of said vessel.
11. The offshore floating structure according to claim 10, wherein
the center of gravity of said hull is raised or lowered relative to the center of buoyancy of said hull depending upon the weight of said ballast compartments and the weight of said storage compartments, and
stability of the vessel is achieved when the center of gravity is either above or below the center of buoyancy.
12. The offshore floating structure according to claim 10, further comprising:
damping means on the interior of said moon pool for reducing resonance of water in said moon pool due to waves and vessel motion.
13. The offshore floating structure according to claim 12, wherein
said damping means on the interior of said moon pool comprises a plurality of inwardly facing vertically spaced baffle plates on the interior of said moon pool.
14. The offshore floating structure according to claim 3, further comprising:
a series of mooring lines connected between said turret buoy lower portion and the sea floor such that said floating structure can rotate and weathervane about said turret buoy in response to environmental forces of waves, wind, current, and heave, roll, pitch and surge motions.
15. The offshore floating structure according to claim 3, further comprising:
a series of mooring lines connected between said hull and the sea floor so as to provided resistance of said floating structure to pitch and roll motions in response to environmental forces of waves, wind, and current.
16. The offshore floating structure according to claim 1, further comprising:
a telescoping vertically adjustable ballast keel tank adjoined to said hull structure so as to be movable between a retracted position closely adjacent to said bottom wall of said hull and an extended position disposed a distance therebelow; and
in said extended position, water is entrapped in the space between said hull bottom wall and said keel tank to provide additional hydrodynamic virtual mass to minimize heave response, increase the natural period of roll and heave modes, reduce dynamic amplification and resonance due to waves and vessel motion, and facilitate maneuvering the vessel.
17. The offshore floating structure according to claim 1, further comprising:
a telescoping vertically adjustable ballast keel tank adjoined to said hull structure so as to be movable between a retracted position closely adjacent to said bottom wall of said hull and an extended position disposed a distance therebelow; and
in said extended position, the mass of the ballast in said keel tank and the distance between said hull bottom wall and said keel tank is optionally adjusted to position the center of gravity of said hull below the center of buoyancy to achieve stability of the vessel.
18. The offshore floating structure according to claim 1, wherein
said hull has a height from said bottom wall to said deck that is less than the largest diameter and less than the smallest diameter of said exterior side wall configuration.
19. An offshore floating production, storage and off-loading vessel structure for use in producing, storing and transporting oil andor liquefied gas, comprising:
a hull having a top wall defining a deck, a bottom wall, and a generally cylindrical exterior side wall configuration, said side wall having a lower portion extending upwardly from said bottom wall and an upper portion extending angularly inward and upward therefrom terminating adjacent to a bottom of said deck;
ballast compartments and storage compartments contained in said hull; and
an adjustable ballasting system for ballasting and deballasting selected said ballast compartments and storage compartments to induce heave, roll, pitch and surge motions of said vessel to dynamically position and maneuver said vessel and carry out moving operations.
20. The offshore floating structure according to claim 19, further comprising:
a central moon pool extending from said deck to said bottom wall having an interior configuration for entrainment of water to selectively provide added hydrodynamic virtual mass to increase the natural period of the roll and heave modes, reduce dynamic amplification and resonance due to waves and vessel motion, and facilitate maneuvering the vessel.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An arrangement for the generation of extreme ultraviolet radiation by means of an electrically operated gas discharge, comprising:
a discharge chamber which has a discharge area for a gas discharge for forming a radiation-emitting plasma;
a first disk-shaped electrode and a second disk-shaped electrode;
at least one of said electrodes being rotatably mounted and having an edge area to be coated by a molten metal;
an energy beam source for supplying a pre-ionization beam; and
a discharge circuit connected to the electrodes for generating high-voltage pulses;
the edge area to be coated having at least one receiving area, which extends in a closed circumferential manner along the electrode edge on the electrode surface and which is formed so as to be wetting for the molten metal; and
a coating nozzle for regenerative application of the molten metal having a shutoff valve connected to a valve regulating device being directed to said receiving area.
2. The arrangement according to claim 1, wherein the valve regulating device is connected to a temperature measuring device for measuring the surface temperature of the electrodes.
3. The arrangement according to claim 2, wherein the disk-shaped electrodes are outfitted with a permanently operating cooling device.
4. The arrangement according to claim 3, wherein a coolant to be used has an operating temperature below the melting temperature of a material provided for the molten metal.
5. The arrangement according to claim 4, wherein the cooling device is provided with means for regulating temperature.
6. The arrangement according to claim 5, wherein the disk-shaped electrodes are traversed by cooling channels through which a liquid flows.
7. The arrangement according to claim 1, wherein the coating nozzle is directed to the electrode surface in an electrode region which is located opposite the discharge area and which is provided for applying the molten metal.
8. The arrangement according to claim 7, wherein the electrodes are constructed as circular disks, are rigidly connected to one another at a mutual distance and are supported so as to be rotatable around a common axis of rotation which coincides with their center axes of symmetry, wherein each of the electrodes contains, on electrode surfaces facing one another, the at least one receiving area which is formed so as to be wetting for the molten metal and to which a coating nozzle is directed.
9. The arrangement according to claim 8, wherein a disk-shaped insulating body which penetrates into the intermediate space between the two electrodes to prevent electrical short-circuiting is provided in the electrode area to which the molten metal is to be applied.
10. The arrangement according to claim 9, wherein the coating nozzles which are directed to the electrode surfaces of the two electrodes are guided through the disk-shaped insulating body from opposite sides.
11. The arrangement according to claim 1, wherein the coating nozzle comprises two microstructured plates which lie one on top of the other, wherein a portion of a first plate is perforated by a hole structure, the second plate being outfitted with a membrane which lies opposite to the hole structure and which is flexible toward the hole structure, which membrane has a closure element for the hole structure which can be pressed against the hole structure by actuating means acting at the flexible membrane, and wherein the two plates enclose a channel into which the hole structure opens and which is guided out of the first plate as a nozzle outlet.
12. The arrangement according to claim 11, wherein the hole structure has hole diameters that are smaller than the diameter of the nozzle outlet.
13. The arrangement according to claim 12, wherein the coating nozzle is constructed so as to be heatable by a current-carrying resistor which is arranged on the surface of at least one of the plates.
14. The arrangement according to claim 1, wherein the electrodes are in electrical contact with contact elements which are oriented coaxial to the axis of rotation and which are immersed in ring-shaped, electrically separated molten metal baths which are electrically separated from one another and which communicate with a discharge circuit of the high-voltage supply.
15. The arrangement according to claim 1, wherein the electric contacting of the electrodes is carried out by means of the coating nozzle and a liquid jet dispensed by the coating nozzle.
16. The arrangement according to claim 1, wherein copper, chromium, nickel or gold are provided as wetting agent for the receiving area.
17. The arrangement according to claim 16, wherein at least a portion of the electrode surface adjoining the receiving area is constructed so as to be non-wetting for the molten metal.
18. The arrangement according to claim 17, wherein the portion of the electrode surface adjoining the receiving area comprises PTFE, stainless steel, glass, or ceramic.
19. The arrangement according to claim 1, wherein an injection device is directed to the discharge area and supplies a series of individual volumes of an emitter material, which is used to generate radiation, at a repetition frequency corresponding to the frequency of the gas discharge and by limiting the amount of the individual volumes so that the emitter material which is injected into the discharge area at a distance from the electrodes is entirely in the gaseous phase after the discharge.
20. The arrangement according to claim 19, wherein the pre-ionization beam supplied by the energy beam source is directed synchronous to the frequency of the gas discharge to a location for plasma generation in the discharge area at a distance from the electrodes at which the individual volumes arrive and are successively ionized by the pre-ionization beam.
21. The arrangement according to claim 1, wherein the regeneratively applied molten metal is emitter material serving for the generation of radiation and the pre-ionization beam supplied by the energy beam source is directed to the emitter material synchronous to the frequency of the gas discharge in the discharge area.
22. The arrangement according to claim 21, wherein the pre-ionization beam is simultaneously directed to the regeneratively applied emitter material of the first electrode (1) and second electrode.
23. The arrangement according to claim 1, wherein xenon, tin, tin alloys, tin solutions, or lithium are provided as emitter material.
24. A method for generating extreme ultraviolet radiation by an electrically operated gas discharge for forming a radiation-emitting plasma from pre-ionized emitter material comprising the steps of:
coating at least one rotatably mounted disk-shaped electrode of a pair of electrodes provided for the gas discharge in the edge area with a molten metal in a regenerating manner; and
controlling the regenerative coating of the edge area during the rotation depending on the electrode surface temperature.
25. The method according to claim 24, wherein the coating is interrupted when the temperature drops below a limit temperature lying above the melting temperature of a material provided for the molten metal and is continued when the temperature rises above the limit temperature.
26. The method according to claim 25, wherein the electrodes are cooled during coating by a coolant which has an operating temperature below the melting temperature of the material provided for the molten metal.
27. The method according to claim 26, wherein the cooling is regulated.