What is claimed and desired to be secured by Letters Patent is as follows:
1. A semi-submersible vessel adapted to resist heave motion, said semi-submersible vessel comprising:
a plurality of support columns, each column of said plurality of support columns having an upper end and a lower end;
a deck interconnected between said plurality of support columns at locations proximate said upper ends of each of said columns of said plurality of support columns;
a ring-pontoon connected to said plurality of support columns at locations proximate said lower ends of each of said columns of said plurality of support columns;
each of said plurality of support columns having a longitudinal axis inclined upwardly and inwardly from said ring-pontoon to said deck.
2. The semi-submersible vessel as recited in claim 1 wherein said longitudinal axis of each of said plurality of support columns is oriented substantially radially from a center point of said vessel.
3. The semi-submersible vessel as recited in claim 2 wherein an angle of incline of said longitudinal axis of each of said plurality of support columns is at least five degrees from vertical.
4. The semi-submersible vessel as recited in claim 2 wherein said ring-pontoon is substantially rectangular-shaped.
5. The semi-submersible vessel as recited in claim 2 wherein said ring-pontoon is substantially square-shaped having corner pontoon portions connected by elongate pontoon portions, and said square-shaped pontoon having a centerline intersecting center points of vertically taken cross-sections of said square-shaped pontoon.
6. The semi-submersible vessel as recited in claim 5 wherein each of said lower ends of said columns of said plurality of columns is substantially connected at a corner pontoon portion of said square-shaped ring-pontoon.
7. The semi-submersible vessel as recited in claim 6 wherein said deck is positioned substantially inboard of said centerline of said ring-pontoon.
8. The semi-submersible vessel as recited in claim 6 wherein said elongate pontoon portions comprise four box-shaped structures, each of said box-shaped structures having a substantially four-sided vertically taken cross-sectional configuration.
9. The semi-submersible vessel as recited in claim 6 wherein a center-point of said lower end of each of said columns of said plurality of columns is positioned inboard of said centerline of said ring-pontoon.
10. The semi-submersible vessel as recited in claim 9, further comprising:
a substantially triangularly-shaped tank having a height substantially equal to a height of said ring-pontoon, said substantially triangularly-shaped tank positioned at a location inboard of a corner pontoon portion and of a said lower end of a column connected to said ring-pontoon at said corner pontoon portion.
11. The semi-submersible vessel as recited in claim 9, further comprising:
each of said support columns being subdivided into four quadrants by cruciform bulkheads, each of said bulkheads being oriented at substantially the same inclination as said longitudinal axis of said support column; and
each of said bulkheads being arranged as extensions of inward sides of said ring-pontoon.
12. The semi-submersible vessel as recited in claim 9, further comprising:
each of said support columns being subdivided into four quadrants by cruciform bulkheads, each of said bulkheads being oriented at substantially the same inclination as said longitudinal axis of said support column;
each of said bulkheads being arranged as extensions of longitudinally oriented bulkheads contained within said ring-pontoon; and
said longitudinally oriented bulkheads dividing said pontoon box-shaped structures into at least two compartments.
13. The semi-submersible vessel as recited in claim 9, further comprising:
an external periphery of said ring-pontoon being substantially octagonally shaped.
14. The semi-submersible vessel as recited in claim 9, further comprising:
an internal periphery of said ring-pontoon being substantially octagonally shaped.
15. The semi-submersible vessel as recited in claim 9, further comprising:
an external surface of a corner pontoon portion being substantially rounded and forming an extension of a lower end of a respective column connected at said corner pontoon portion.
16. The semi-submersible vessel as recited in claim 9, wherein said deck is configured as a box-shaped structure.
17. The semi-submersible vessel as recited in claim 9, wherein said semi-submersible vessel is adapted for accommodating the production of hydrocarbons from at least one sub-sea well-head that is connected to said semi-submersible vessel by at least one substantially rigid pipe laying along the sea floor and extending upwards in a catenary to said semi-submersible vessel.
18. The semi-submersible vessel as recited in claim 9, wherein said semi-submersible vessel is adapted for accommodating the production of hydrocarbons through a substantially vertical rigid riser terminating at a well-head positioned proximate said deck and which in turn is connected to production equipment by a jumper-hose.
19. A method for providing a semi-submersible vessel adapted to resist heave motion, said method comprising:
providing:
a plurality of support columns, each column of said plurality of support columns having an upper end and a lower end;
a deck interconnected between said plurality of support columns at locations proximate said upper ends of each of said columns of said plurality of support columns; and
a ring-pontoon connected to said plurality of support columns at locations proximate said lower ends of each of said columns of said plurality of support columns;
locating a predominance of a buoyancy capacity of said ring-pontoon proximate said lower ends of said columns of said plurality of support columns; and
inclining each of said plurality of support columns upwardly and inwardly from said ring-pontoon to said deck.
20. The method as recited in claim 19, further comprising:
orienting a longitudinal axis of each of said plurality of support columns substantially radially from a center point of said vessel.
21. The method as recited in claim 19, further comprising:
configuring said ring-pontoon into a substantially rectangular shape.
22. A semi-submersible vessel adapted to resist heave motion, said semi-submersible vessel comprising:
a plurality of support columns, each column of said plurality of support columns having an upper end and a lower end;
a deck interconnected between said plurality of support columns at locations proximate said upper ends of each of said columns of said plurality of support columns;
a ring-pontoon connected to said plurality of support columns at locations proximate said lower ends of each of said columns of said plurality of support columns;
at least four of said plurality of support columns having a longitudinal axis inclined upwardly and inwardly from said ring-pontoon to said deck and said longitudinal axis being oriented substantially radially from a center point of said vessel.
23. A semi-submersible comprising:
a superstructure deck;
a ring pontoon having four box-structures having a substantially four-sided cross-section and formed into a symmetrical square ring;
four columns inclined inwards toward the upper end with an angle of inclination of at least five degrees from vertical; and
a longitudinal axis of said pontoon box-structures being located outside of lower end center-points of said columns.
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. A balancer device for a parallel twin cylinder internal combustion engine in which a common crankshaft is provided with a first crankpin and a second crankpin at a predetermined phase angle, and a cylinder block is formed with a first cylinder corresponding to the first crankpin and a second cylinder corresponding to the second crankpin,
the balancer device for the parallel twin cylinder internal combustion engine being configured to reduce first cylinder vibratory force and second cylinder vibratory force which are generated when the crankshaft is rotated, in the parallel twin cylinder internal combustion engine,
the first cylinder vibratory force generating force directed outward in a radial direction of the crankshaft while performing inverse rotation with the same period as the crankshaft based on a position where a first piston stored in the first cylinder is at a top dead center,
the second cylinder vibratory force generating force directed outward in the radial direction of the crankshaft while performing the inverse rotation with the same period as the crankshaft based on a position where a second piston stored in the second cylinder is at the top dead center,
wherein when viewed in an axial direction of the crankshaft, a straight line for bisecting an angle formed between the first cylinder vibratory force and the second cylinder vibratory force is defined as an angle bisector,
force with the first cylinder vibratory force and the second cylinder vibratory force resolved in a direction parallel to the angle bisector is defined as an inertial force component,
force with the first cylinder vibratory force and the second cylinder vibratory force resolved in a direction parallel to a plane perpendicular to the angle bisector is defined as a couple component,
an inertial force balancer is provided for generating force facing the inertial force component, and wherein
a couple balancer is provided for generating force facing the couple component.
2. The balancer device for a parallel twin cylinder internal combustion engine according to claim 1,
wherein the inertial force balancer comprises the first inertial force balancer and the second inertial force balancer which have the equal amount of unbalance,
the crankshaft is configured along a width direction of the parallel twin cylinder internal combustion engine,
in a planar view, the first inertial force balancer and the second inertial force balancer are configured symmetrically with a bisection point positioned around the center of the crankshaft as the center, on a plane that bisects a segment for connecting the center of the first cylinder to the center of the second cylinder and that is perpendicular to the segment, and
the couple balancer is configured in such a manner that the first couple balancer and the second couple balancer are configured coaxially with each other, and also are symmetrical at 180 degrees about the shaft.
3. The balancer device for a parallel twin cylinder internal combustion engine according to claim 2, wherein at least any one of the first inertial force balancer, the second inertial force balancer, the first couple balancer and the second couple balancer is configured outside of a crankcase.
4. The balancer device for a parallel twin cylinder internal combustion engine according to claim 3,
wherein at least one of the first inertial force balancer and the second inertial force balancer is configured outside of the crankcase, and
a drive shaft of at least one of the first inertial force balancer and the second inertial force balancer that are configured outside is supported by a side surface of the crankcase and a crankcase cover for covering the side surface of the crankcase.
5. The balancer device for a parallel twin cylinder internal combustion engine according to claim 2,
wherein a combined balancer is composed by combining one of the first inertial force balancer and the second inertial force balancer with one of the first couple balancer and the second couple balancer, and
in the planar view, the other of the first inertial force balancer and the second inertial force balancer, and the combined balancer are configured symmetrically with the bisection point positioned around the center of the crankshaft as the center, on the plane that bisects the segment for connecting the center of the first cylinder to the center of the second cylinder and that is perpendicular to the segment.
6. The balancer device for a parallel twin cylinder internal combustion engine according to claim 5, wherein the other of the first couple balancer and the second couple balancer, and the combined balancer are configured coaxially with each other.
7. The balancer device for a parallel twin cylinder internal combustion engine according to claim 5, wherein after an axial position of one of the first couple balancer and the second couple balancer is preliminarily determined, one of the first inertial force balancer and the second inertial force balancer is combined with one of the first couple balancer and the second couple balancer, and a phase of the combined balancer with respect to the other of the first couple balancer and the second couple balancer is set.
8. The balancer device for a parallel twin cylinder internal combustion engine according to claim 5, wherein the combined balancer, and at least one of the other of the first inertial force balancer and the second inertial force balancer and the other of the first couple balancer and the second couple balancer are configured outside of the crankcase.
9. The balancer device for a parallel twin cylinder internal combustion engine according to claim 8,
wherein the other of the first inertial force balancer and the second inertial force balancer is configured outside of the crankcase, and
the drive shaft of the other of the first inertial force balancer and the second inertial force balancer is supported by the side surface of the crankcase and the crankcase cover for covering the side surface of the crankcase.
10. The balancer device for a parallel twin cylinder internal combustion engine according to claim 8,
wherein the combined balancer, and the other of the first couple balancer and the second couple balancer are configured outside of the crankcase, the combined balancer, and the other of the first couple balancer and the second couple balancer being configured coaxially with each other, and
the combined balancer, and one of the other of the first couple balancer and the second couple balancer are formed integrally with a drive shaft thereof, the other thereof being separately fixed to the drive shaft by a fastening member.
11. The balancer device for a parallel twin cylinder internal combustion engine according to claim 5,
wherein the crankcase has a vertically divided structure,
the drive shaft of the other of the first inertial force balancer and the second inertial force balancer is arranged in an upper half body of the crankcase, and
the drive shaft of the combined balancer and the other of the first couple balancer and the second couple balancer is configured in a lower half body of the crankcase.
12. The balancer device for a parallel twin cylinder internal combustion engine according to claim 5,
wherein the drive shaft of the other of the first inertial force balancer and the second inertial force balancer is configured behind the crankshaft, and
the drive shaft of the combined balancer and the other of the first couple balancer and the second couple balancer is configured in front of the crankshaft.