Arctic multi-angle conical structure
First Claim
1. An offshore structure for use in a body of water that contains ice masses, comprisinga lower portion having a first circumferential wall substantially in the shape of a first truncated cone so that the wall of said lower portion is inclined at an angle to the horizontal, said first circumferential wall providing a ramp-like surface means for receiving ice masses moving relative to and in contact with said structure so as to elevate said ice above its natural level to cause said ice to fail in flexure adjacent said structure;
- means for affixing said lower portion to the bottom of a body of water; and
an upper portion coaxially positionable above said lower portion, said upper portion having a second circumferential wall substantially in the shape of a second truncated cone so that the wall of said upper portion is inclined at an angle to the horizontal, said second circumferential wall providing a ramp-like surface means for receiving ice masses moving relative to and in contact with said structure so as to elevate said ice above its natural level to cause said ice to fail in flexure adjacent said structure, the angle of inclination from the horizontal of the wall of said upper portion being greater than the angle of inclination from the horizontal of the wall of said lower portion and the cross-sectional diameter of the wall of said upper portion being no greater than the cross-sectional diameter at the top of the wall of said lower portion.
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Accused Products
Abstract
An offshore structure which is able to withstand the ice forces imposed thereon by impinging ice sheets and other larger masses of ice wherein the structure has an upper conical portion coaxially positioned relative to a lower conical portion. The walls forming both the upper and lower portions are inclined at an angle to the horizontal to receive ice masses moving into contact with the structure. The angle of inclination from the horizontal of the upper portion is greater than the angle of inclination of the lower portion, and the cross-sectional diameter of the upper conical portion is no greater than that at the top of the lower conical portion.
26 Citations
32 Claims
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1. An offshore structure for use in a body of water that contains ice masses, comprising
a lower portion having a first circumferential wall substantially in the shape of a first truncated cone so that the wall of said lower portion is inclined at an angle to the horizontal, said first circumferential wall providing a ramp-like surface means for receiving ice masses moving relative to and in contact with said structure so as to elevate said ice above its natural level to cause said ice to fail in flexure adjacent said structure; -
means for affixing said lower portion to the bottom of a body of water; and an upper portion coaxially positionable above said lower portion, said upper portion having a second circumferential wall substantially in the shape of a second truncated cone so that the wall of said upper portion is inclined at an angle to the horizontal, said second circumferential wall providing a ramp-like surface means for receiving ice masses moving relative to and in contact with said structure so as to elevate said ice above its natural level to cause said ice to fail in flexure adjacent said structure, the angle of inclination from the horizontal of the wall of said upper portion being greater than the angle of inclination from the horizontal of the wall of said lower portion and the cross-sectional diameter of the wall of said upper portion being no greater than the cross-sectional diameter at the top of the wall of said lower portion.
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2. A marine structure for use in a body of water that contains ice masses, comprising
a base portion; -
means for affixing said base portion to the bottom of a body of water; a lower portion coaxially positionable on top of said base portion for joining thereto, said lower portion forming a first circumferential wall substantially in the shape of a first truncated cone so that the wall of said lower portion is inclined at an angle to the horizontal, said first circumferential wall providing a ramp-like surface means for receiving ice masses moving relative to and in contact with said structure so as to elevate said ice above its natural level to cause said ice to fail in flexure adjacent said structure; and an upper portion coaxially positionable on top of said lower portion for joining thereto, said upper portion forming a second circumferential wall substantially in the shape of a second truncated cone so that the wall of said upper portion is inclined at an angle to the horizontal, said second circumferential wall providing a ramp-like surface means for receiving ice masses moving relative to and in contact with said structure so as to elevate said ice above its natural level to cause said ice to fail in flexure adjacent said structure, the angle of inclination from the horizontal of the wall of said upper portion being greater than the angle of inclination of the wall of said lower portion and the cross-sectional diameter of the wall of said upper portion being no greater than the cross-sectional diameter at the top of the wall of said lower portion. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An offshore structure for use in a body of water which becomes frozen through natural conditions, comprising:
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a supporting base portion positioned in a body of water; a means for securing said base portion to the underwater bottom; a lower portion directly joined to and rigidly supported on said base portion, said lower portion forming a first peripheral wall which converges upwardly and inwardly of said base portion, said first peripheral wall providing means for receiving and supporting an edge portion of a sheet of ice or other larger mass of ice which moves in contact with said lower portion so as to elevate said ice above its natural level an amount to cause said ice to fracture continuously adjacent said offshore structure; and an upper portion directly joined to and rigidly supported on said lower portion, said upper portion forming a second peripheral wall which converges upwardly and inwardly of said lower portion to, said second peripheral wall providing means for receiving and supporting an edge portion of a sheet of ice or other ice mass which moves into contact with said upper portion so as to elevate said ice above its natural level an amount to cause said ice to fracture continuously adjacent said offshore structure, said second peripheral wall having a base diameter no greater than that of the top diameter of said first peripheral wall and said second peripheral wall converging upwardly and inwardly at a greater slope than said first peripheral wall. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. An offshore structure for use in arctic waters comprising:
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a base section constructed to be installed in a relatively fixed position in a body of water; a lower truncated cone section in vertical abutting relationship with said base section, said lower section providing means for receiving and supporting an edge portion of an ice mass which moves into contact with said lower section so as to elevate said ice above its natural level an amount to cause said ice to fracture continuously adjacent said structure; an upper truncated cone section of a steeper angle and of no greater cross-sectional diameter than said lower section and in vertical abutting relationship with said lower section, said upper section providing means for receiving and supporting an edge portion of an ice mass which moves into contact with said lower section so as to elevate said ice above its natural level an amount to cause said ice to fracture continuously adjacent said structure; a cylindrical throat section in vertical abutting relationship with said upper truncated cone section; an inverted truncated cone section in vertical abutting relationship with said throat section; and a work platform positioned on said inverted truncated cone section.
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21. An offshore structure to be located in a body of water that contains ice masses, comprising:
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a base portion; means for securing said base portion to the bottom of a body of water; a lower portion coaxially positionable on top of said base portion, said lower portion forming a first circumferential wall substantially in the shape of a first truncated cone so that the wall of said lower portion is inclined to the bottom of the body of water at an angle of between approximately 15° and
25°
from the horizontal, said first circumferential wall providing a first ramp-like surface means for receiving ice masses moving relative to and in contact with said structure; andan upper portion coaxially positionable on top of said lower portion, said upper portion forming a second circumferential wall substantially in the shape of a second truncated cone so that the wall of said upper portion is inclined to the bottom of the body of water at an angle of between approximately 26° and
70°
from the horizontal, said second circumferential wall providing a second ramp-like surface means for receiving ice masses moving relative to and in contact with said structure, the cross-sectional diameter of the wall of said upper portion being no greater than the cross-sectional diameter at the top of the wall of said lower portion so that the wall of said upper portion and the wall of said lower portion form a continuous ramp-like surface; anda cylindrical throat portion supported on said upper portion. - View Dependent Claims (22, 23)
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24. A method of reducing the ice forces imposed on an offshore structure which contains ice masses, comprising:
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constructing an offshore structure with a lower portion having a first circumferential wall substantially in the shape of a first truncated cone so that the wall of said lower portion is inclined at an angle to the horizontal, said first circumferential wall providing a ramp-like surface means for receiving ice masses moving relative to and in contact with said structure; and positioning an upper portion of said structure coaxially on top of said lower portion, said upper portion having a second circumferential wall substantially in the shape of a second truncated cone so that the wall of said upper portion is inclined at an angle to the horizontal, said second circumferential wall providing a ramp-like surface means for receiving ice masses moving relative to and in contact with said structure, the angle of inclination from the horizontal of the wall of said upper portion being greater than the angle of inclination from the horizontal of the wall of said lower portion and the cross-sectional diameter of the wall of said upper portion being no greater than the cross-sectional diameter at the top of the wall of said lower portion.
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25. A method of reducing the ice forces imposed on an offshore structure which contains ice masses, comprising:
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constructing an offshore structure with a base portion so that said base portion may be affixed to the bottom of a body of water; positioning a lower portion of said structure coaxially on top of said base portion, said lower portion having a first circumferential wall substantially in the shape of a first truncated cone so that the wall of said lower portion is inclined at an angle to the horizontal, said first circumferential wall providing a ramp-like surface means for receiving ice masses moving relative to and in contact with said structure; joining said lower portion to said base portion; positioning an upper portion of said structure coaxially on top of said lower portion, said upper portion having a second circumferential wall substantially in the shape of a second truncated cone so that the wall of said upper portion is inclined at an angle to the horizontal, said second circumferential wall providing a ramp-like surface means for receiving ice masses moving relative to and in contact with said structure, the angle of inclination from the horizontal of the wall of said upper portion being greater than the angle of inclination from the horizontal of the wall of said lower portion and the cross-sectional diameter of the wall of said upper portion being no greater than the cross-sectional diameter at the top of the wall of said lower portion; and joining said upper portion to said lower portion. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32)
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Specification