U.S. patent application number 17/139501 was filed with the patent office on 2021-04-29 for anti-motion structure of column floater.
The applicant listed for this patent is Zhirong Wu. Invention is credited to Zhirong Wu.
Application Number | 20210122446 17/139501 |
Document ID | / |
Family ID | 1000005373042 |
Filed Date | 2021-04-29 |
![](/patent/app/20210122446/US20210122446A1-20210429\US20210122446A1-2021042)
United States Patent
Application |
20210122446 |
Kind Code |
A1 |
Wu; Zhirong |
April 29, 2021 |
Anti-motion Structure of Column Floater
Abstract
An anti-motion structure of a column floater, being an annular
structure surrounding the outer periphery of the bottom of a buoy
of the column floater, and an annular radial gap between the two
is, or optionally is not, set up. The anti-motion structure is
connected to a horizontal roof plate, a horizontal floor plate, an
outer annular vertical plate, and an inner annular vertical plate
to form an annular box body; and the box body is divided into a
plurality of watertight compartments; the horizontal roof plate
and/or the horizontal floor plate corresponding to each watertight
compartment are provided with damping holes capable of being opened
or closed.
Inventors: |
Wu; Zhirong; (Beijing,
CN) |
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Applicant: |
Name |
City |
State |
Country |
Type |
Wu; Zhirong |
Beijing |
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CN |
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|
Family ID: |
1000005373042 |
Appl. No.: |
17/139501 |
Filed: |
December 31, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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PCT/CN2019/093408 |
Jun 27, 2019 |
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17139501 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B63B 39/00 20130101 |
International
Class: |
B63B 39/00 20060101
B63B039/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 6, 2018 |
CN |
201810882470.3 |
Claims
1. An anti-motion structure of a column floater comprising: an
annular structure surrounding the bottom and outer periphery of the
buoy of the column float, said annular structure comprises a roof
plate, a floor plate with spacing below the roof plate, an outer
annular vertical plate and an inner annular vertical plate spaced
between the outer annular vertical plate and the buoy, and said
roof plates, floor plate, outer annular vertical plate and inner
annular vertical plate to be watertight connected with each other
to form an annular box with rectangular or trapezoidal radial
vertical cross section, and to form a total of four circles of
corner lines along the box corners, i.e., a roof outer corner line
of the box, a floor outer corner line of the box, a roof inner
corner line of the box and a floor inner corner line of the box,
wherein the centroid of each corner line of plane geometry is
located in the vertical central axis of the buoy and the said
annular box body is rotationally symmetric with the centroid, or
symmetric anteroposterior and left-right with the vertical central
axis of the buoy, and an annular radial gap is set or optionally
not set between the anti-motion structure and the buoy; wherein the
anti-motion structure is connected with the buoy by multiple radial
vertical brackets, and the box body is divided into several
watertight compartments by a plurality of radial vertical
partitions, the horizontal roof plate and/or the horizontal floor
plate corresponding to each watertight compartment are provided
with damping holes capable of being opened or closed; by opening of
the damping holes in the horizontal roof plate and the horizontal
floor plate, the compartments are filled with water introduced with
sea, or by closing of the damping holes in the horizontal roof
plate and the horizontal floor plate, a closed floating compartment
is formed, or by closing of the damping holes in the horizontal
roof plate and opening of the damping holes in the horizontal floor
plate, a closed air floating compartment is formed, so as to meet
requirements under different working conditions of the column
floater; wherein at least one of plates of the roof plate and/or
the floor plate of the anti-motion structure without the annular
radial gap shall be provided with an outer edge extending lath,
i.e., roof outer edge extending lath and floor outer edge extending
lath; and at least one of plates of the roof plate and the floor
plate of the anti-motion structure with the annular radial gap
shall be provided with an outer edge extending lath and an inner
edge extending lath separately or simultaneously, said outer edge
extending lath is the outer edge extending lath and the floor outer
edge extending lath, and said inner edge extending lath is roof
inner edge extending lath and floor inner edge extending lath;
wherein the outer edge extending lath is a plate structure, which
extends outward and/or upward and downward from the roof outer
corner line and the floor outer corner line respectively; the roof
outer edge extending lath is formed on the roof plate and the floor
outer edge extending lath is formed on the floor plate; the inner
edge extending lath is a plate structure, which extends
horizontally from the roof inner corner line and/or the floor inner
corner line of the box to the direction of the buoy; the horizontal
roof inner edge extending lath is formed on the roof plate, and the
horizontal floor inner edge extending lath is formed on the floor
plate; the inner edge extending lath shall not close the annular
radial gap.
2. The anti-motion structure of column floater according to claim 1
comprising: the anti-motion structure is a circular or regular
polygon structure, and the four box corner lines correspond to a
circular or regular polygon; or the shapes of the inner annular
vertical plate and the outer annular vertical plate of the
anti-motion are different, the inner annular vertical plate is
circular or regular polygon and the roof inner corner line and the
floor inner corner line of the box are circular or regular polygon
accordingly, and the outer annular vertical plate is oval and the
roof outer corner line and the floor outer corner line of the box
are oval accordingly, or the outer annular vertical plate is
hetero-polygon, the roof outer corner line and the floor outer
corner line of the box are closed geometric figures with parallel
straight lines on the left and right sides and circular or broken
lines on the front and rear sides, its dimensions in the left and
right directions are smaller than those in the front and rear
directions.
3. The anti-motion structure of column floater according to claim 2
comprising: the roof outer edge extending lath and the floor outer
edge extending lath are of horizontal annular structures, the edge
of the roof outer edge extending lath and the edge of the floor
outer edge extending lath forms a roof outer end edge line and a
floor outer end edge line respectively; and the plane geometric
figures of the roof outer edge line or the floor outer edge line
has the same centroid as the roof outer box corner line and the
floor outer box corner line and is rotationally symmetric to the
centroid, or symmetric to the vertical central axis of the upright
floater front-back and left-right; or, the roof outer edge
extending lath or the floor outer edge extending lath is a
protruding wall structure upward or downward respectively, and the
upper edge and the lower edge of each protruding edge extending
lath wall structure form a circle of closed upper end edge line and
a circle of closed lower end edge line respectively, which centroid
is located in the vertical central axis of buoy and the geometry of
said each end edge line is equal to or similar to the geometry of
the roof and floor corner lines of the box respectively; or the
roof outer edge extending lath or the floor outer edge extending
lath is an horizontal annular plate then folding and protruding
upward or downward to form a wall respectively, and the end edge of
the wall of the roof outer edge extending lath or of the floor
outer edge extending lath forms a circle of closed roof end edge
line or a circle of closed floor end edge line respectively, which
centroid of the plane geometry is located on the vertical central
axis of the buoy, and the plane geometry of the circle of closed
roof end edge line or the circle of closed floor end edge line is
similar to the plane geometry of the roof outer corner line of the
box or similar to the plane geometry of the floor outer corner line
of the box respectively.
4. The anti-motion structure of column floater according to claim 3
comprising: the roof outer edge extending lath or the floor outer
edge extending lath is a horizontal annular plate structure, which
is the horizontal and outward extension structure of the roof plate
or the floor plate; or the roof outer edge extending lath is an
inverted frustum-shaped wall structure with its upper dimension
larger than its lower dimension, which lower end edge line
coincides with the roof outer corner line of the box; and the floor
outer edge extending lath is a positive frustum-shaped wall
structure with its upper dimension less than its lower dimension,
which upper end edge line coincides with the floor outer corner
line of the box; or the roof outer edge extending lath or the floor
outer edge extending lath is a horizontal and outward extension
structure of the roof plate or of the floor plate with limited
extending distance, and then connected to an inverted
frustum-shaped wall structure with its upper dimension larger than
its lower dimension or to a positive frustum-shaped wall structure
with its upper dimension less than its lower dimension
respectively; at same time the dimension of the circle of closed
lower end edge line graph of the inverted frustum-shaped wall
structure is larger than that of the roof outer corner line graph
of the box, and said two graphs are similar figures with a common
centroid, and the dimension of the circle of closed upper end edge
line graph of the positive frustum-shaped wall structure is larger
than that of the floor outer corner graph of the box, and said two
graphs are similar figures with a common centroid; or the roof
outer edge extending lath or the floor outer edge extending lath is
a vertical cylindrical wall structure by folding the horizontal
roof plate upward or the horizontal floor plate downward with a
90-degree angle on the roof or floor outer corner line of the box
respectively; the lower edge line of the vertical cylindrical wall
structure of the roof outer edge extending lath coincides with the
roof outer corner line of the box, and the upper edge line of the
vertical cylindrical wall structure of the floor outer edge
extending lath coincides with the floor outer corner line of the
box; or the roof outer edge extending lath or the floor outer edge
extending lath is a horizontal and outward extension structures of
the roof plate or of the floor plate with some extending distance,
and then connected to a vertical cylindrical wall structure by
folding the extension structure upward or downward with a 90-degree
angle respectively; the dimension of the lower edge line of the
vertical cylindrical wall structure of the roof outer edge
extending lath is larger than the roof outer corner line of the
box, and the dimension of the upper edge line of the vertical
cylindrical wall structure of floor outer edge extending lath is
larger than the floor outer corner line of the box, and said two
graphs are similar figures with a common centroid.
5. The anti-motion structure of column floater according to claim 1
comprising: some damping holes are set up or optionally not set up
on the roof outer edge extending lath and/or floor outer edge
extending lath.
6. The anti-motion structure of column floater according to claim 5
comprising: for the anti-motion structure with annular radial gap,
a horizontal annular plate is arranged on at least one part of the
annular part on the outer wall of the buoy which is the same
elevation as the roof plate and/or the floor plate, thus a buoy
upper lath and/or a buoy lower lath are formed with a gap between
the buoy upper lath and the roof inner edge extending lath and/or
between the buoy lower lath and the floor inner edge extending
lath.
7. The anti-motion structure of column floater according to claim 5
comprising: at least one of the roof plate and the floor plate of
the anti-motion structure with the annular radial gap shall extend
horizontally in the direction of the buoy from the roof inner
corner line of the box and the floor inner corner line of the box
up to connecting the buoy respectively to close the annular radial
gap, and a plurality of damping holes are set up on the closing
area the gap.
8. The anti-motion structure of column floater according to claim 1
comprising: a U-shaped fairlead groove is set up horizontally and
up and down through the roof plate and the floor plate at the
position on the inner side of anti-motion structure) adjacent to
the buoy and corresponding to the space for installing fairlead,
which shall be capable of accommodating and facilitating the
maintenance of the fairlead mounted on the lower part of the outer
wall of the buoy; the structure of said each U-shaped groove is as
follows: the inner annular vertical plate corresponding to the
U-shaped groove covering area is shifted outwards, and vertical
baffles are installed on both sides of the U-shaped groove; the
plate surface of the roof plate and the floor plate covered by the
U-shaped groove are excised except that the U-shaped edge is
retained to form a U-shaped plate edge extending lath; said shifted
inner annular vertical plate, said vertical baffles on both sides
of the groove and said roof plate and floor plate been taken some
areas out are watertight connected to each other, and the water
tightness of the watertight compartments of the anti-motion
structure shall not be destroyed after the U-shaped fairlead groove
been formed.
9. The anti-motion structure of column floater according to claim 3
comprising: when both roof outer edge extending lath and floor
outer edge extending lath are horizontal annular plates, one of the
roof outer end edge line and/or the floor outer end edge line is at
least one continuous serrated line to form a serrated end edge,
and/or one of the roof inner end edge line and/or the floor inner
end edge line is at least a continuous serrated line to form a
serrated end edge; when both roof outer edge extending lath and
floor outer edge extending lath with a convex structure extending
up and down to form a closed circle roof upper end edge line and a
closed floor circle lower end edge line, at least one of the roof
upper end edge line and/or the floor lower end edge line is a
continuous serrated line to form a serrated end edge; said serrated
end edge with tooth convex and tooth concave, which have the same
or different geometric figures.
10. The anti-motion structure of column floater according to claim
9 comprising: said serrated edge on each tooth is triangular tooth,
rectangular or trapezoidal tooth, and the shape of the convex and
concave teeth of triangular teeth is triangular, the convex and
concave shapes of the rectangular teeth are rectangular, the convex
and concave shapes of the trapezoidal teeth are trapezoidal, and
the convex and concave shapes of the compound shaped teeth are
respectively a combination of triangle, rectangle or
trapezoidal.
11. The anti-motion structure of column floater according to claim
3 comprising: the roof outer edge extending lath or the floor outer
edge extending lath is a horizontal annular plate extending from
the roof plate or the floor plate respectively, and at the same
time, plus a vertical cylindrical wall structure connected upward
to the roof outer corner line of the box or downward to the floor
outer line of the box with a 90-degree angle from the horizontal
extension plate; the roof outer edge extending lath or the floor
outer edge extending lath simultaneously form a circle of roof
outer end edge line plus a circle of roof upper end edge line, or a
circle of floor outer end edge line plus a circle of floor lower
end edge line respectively.
12. The anti-motion structure of column floater according to claim
4 comprising: for the roof outer edge extending lath and floor
outer edge extending lath of anti-motion structure being horizontal
annular plates, when the roof outer edge line and the floor outer
edge line adopt serrated lines, or when the roof outer edge
extending lath and the floor outer edge extending lath are provided
with damping holes, a middle outer edge lath is arranged on the
outer annular vertical plate equidistant from the roof outer box
corner line and the floor outer box corner line, the middle outer
edge lath is a horizontal annular plate structure, and its outer
end edge is a straight and/or smooth curved edge.
13. The anti-motion structure of column floater according to claim
6 comprising: the upper gap between the roof inner edge extending
lath and the buoy upper lath and the lower gap between the floor
inner edge extending lath and the buoy lower lath should be
dislocated as far as possible; or further, adding a layer of
horizontal interspace annular plate at the midpoint between the
roof inner edge extending lath and the floor inner edge extending
lath, which is mounted on the inner annular vertical plate and
maintains a middle gap with the outer wall of the buoy, or mounted
on the outer wall of the buoy and maintains a middle gap with the
inner annular vertical plate, thus the upper gap, the lower gap and
the middle gap are dislocated with each other.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] The present application is a continuation of International
Application PCT/CN2019/093408 filed Jun. 27, 2019, which claims
benefit of priority of Chinese application CN201810882470.3 filed
on Aug. 6, 2018, both of which are incorporated herein by
reference.
FIELD OF INVENTION
[0002] The present invention relates to the technical field of
offshore engineering, and, in-particular, to an anti-motion
structure of a column floater.
BACKGROUND
[0003] Bottom damping structure or damping plate (anti-motion
structure) of a column floater (i.e., a straight cylinder type
floating platform) is an annular structure, which surrounds the
bottom and the outer periphery of the upright buoy or extended
cylinder of a column floater. For some column floaters, such as
SEVAN's cylindrical FPSO, partial fractures are arranged in the
annular anti-motion structure to form an intermittent annular
structure in order to install fairleads of mooring legs (usually 3
groups). The function of anti-motion structure is to increase added
mass of entrained water, natural period and motion damping, and
finally reduce the motion response of the platform and improve the
motion performance of the platform. Therefore, it is called
"anti-motion structure". In a word, the anti-motion structure is a
very important structural component of a column floater. According
to the structural form of the radial cross section of the annular
anti-motion structure, the anti-motion structure can be divided
into three types: the first type is represented by SEVAN's
cylindrical FPSO, its anti-motion structure is airtight box-shaped
structure with a relatively small height, which is a part of the
platform's seawater ballast compartment. The second type refers to
the U-shaped and inverted U-shaped structure of the open plate
structure proposed by the inventor. The third type refers to a
higher-height closed box structure proposed by the inventor, and
the damping holes which can be opened or closed are arranged in the
roof plate and the floor plate of the box. When the platform is in
the state of floating and wet towing, all damping holes are closed
and the anti-motion structure becomes an airtight floating
compartment, or the damping holes in the roof plate are closed and
the damping holes in the floor plate are opened to form an
air-float compartment, both of which can provide buoyancy and
stability for the platform. During in-place condition (offshore
production or survival conditions) of the platform, all damping
holes are opened and seawater is filled inside, which makes the
added mass of entrained water increase, but doesn't make the
displacement of the platform increase (see PCT/CN2017/085052). The
performance of heave motion of the column floater is the key point
that must be paid special attention to. Compare the added mass of
entrained water and viscous damping, the first type of anti-motion
structure has the worst performance, in particular, the partial
fractures of the anti-motion structure for installing fairlead
makes the structure integrity be destroyed, in addition, as the
area of horizontal projection decreases, the added mass of
entrained water of the heave motion decreases accordingly; the
second is the second type; and the optimal one is the third one.
However, the third one also falls short in terms of how to increase
viscous damping, and there is still much room for progress. After
repeated analysis and calculation and experimental research found
that a case in point where conventional cognition is hard to
explain, in order to increase the add mass of the internal
entrained water, under the condition that the outside diameter of
the anti-motion structure remains unchanged, the height of the
structure should be moderately increased, but the viscous damping
of the platform oscillation is reduced. The question is how to
increase the height of anti-motion structure moderately and
increase viscous damping at the same time? What else can be done to
increase viscous damping? Viscous damping is of great significance
to effectively reduce the motion response of a column floater under
once-in-a-century environmental conditions and improve the
platform's motion performance.
[0004] For the above reasons, based on the results of the study,
the inventor improved and optimized the above three types of
anti-motion structure, and put forward a new concept of "edge
extending lath", and with help of the edge extending lath, the
viscous damping of the platform and the add mass of the entrained
water are increased. At same time, adopting groove instead of
fracture for installing fairlead, forming a new form of anti-motion
structure, finally overcome existing shortcomings of said three
types of anti-motion structure, and further improve the motion
performance of the platform.
SUMMARY
[0005] The invention discloses an anti-motion structure of a column
floater, the anti-motion structure is an annular structure, which
surrounds the bottom and outer periphery of the upright buoy or
extended cylinder (collectively called "the buoy") of a column
floater, and an annular radial gap is set or optionally not set
between them. The structure sketch of the radial cross section of
the anti-motion structure is a rectangular or trapezoid box, which
is watertight to be connected by an horizontal roof plate, an
horizontal floor plate, an outer annular vertical plate and an
inner annular vertical plate with each other, and besides, the
annular box-typed structure is divided into a plurality of
watertight compartments by a plurality of radial vertical
partitions; At least one of the horizontal roof plate and/or the
horizontal floor plate protrudes outward from the intersection
between the horizontal roof plate and the outer annular vertical
plate (i.e., the "outer corner line of the box") to form an outer
edge extending lath. Similarly, for the anti-motion structure with
annular radial gap, an inner edge extending lath can also be
provided as an option. In order to install fairleads of mooring
legs on the lower part of the buoy of the column floater without
destroying the integrity of the anti-motion structure, a U-shaped
groove structure for installing the fairleads is arranged on the
anti-motion structure's inner side adjacent to the buoy shell, and
the groove structure shall not destroy the water tightness of the
watertight compartment.
[0006] Both physical model experiment and computer model
calculation show that in the motion process of the platform, the
inner and outer edge extending laths which are set on the
horizontal roof plate and the horizontal floor plate can change the
local flow field, intensify the turbulence and dissipate energy of
the local water body, thus significantly increasing the viscous
damping of the platform motion and increasing the add mass of the
entrained water. The groove structure is used to replace the
current intermittent fracture structure, which is beneficial to
increase the add mass of the entrained water and ensure the
integrity of the structure. Compared with the current anti-motion
structures, the viscous damping and the add mass of the entrained
water of the anti-motion structure of the present invention are
increased, so as to further improve the motion performance of the
platform.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The figures described herein are for the purposes of
interpretation only and are not intended in any way to limit the
scope of the present invention to be disclosed.
[0008] FIG. 1 is the main schematic diagram and partial sectional
view of the anti-motion structure of a column floater, showing the
basic structure of the anti-motion structure and the connection
with the buoy.
[0009] FIG. 2 is the enlarged diagram at I in FIG. 1, showing the
structure diagram of the first type of outer edge extending
lath.
[0010] FIG. 3 is a radial local section schematic diagram of the
anti-motion structure, showing the second type of outer edge
extending lath.
[0011] FIG. 4 is a radial local section schematic diagram of the
anti-motion structure, showing the third type of outer edge
extending lath.
[0012] FIG. 5 is a radial local section schematic diagram of the
anti-motion structure, showing the fourth type of outer edge
extending lath.
[0013] FIG. 6 is the radial local section schematic diagram of the
anti-motion structure, showing the fifth type of outer edge
extending lath.
[0014] FIG. 7 is a radial local section of another anti-motion
structure of the present invention and a magnified view of the same
part as that shown in FIG. 2.
DETAILED DESCRIPTION
[0015] The details of the invention can be understood more clearly
in combination with the figures and the description of the
embodiments of the present invention. However, the specific
embodiment of the present invention described herein, only for the
purpose of interpreting the present invention, cannot be construed
in any way as a limitation of the present invention.
[0016] The invention discloses an anti-motion structure of a column
floater (i.e., a straight cylinder floating platform). See FIG. 1,
the column floater 1 is floating and positioned on a water surface
2; The column floater 1 comprises a topside 11, a buoy 12 at a
water surface with an anti-motion structure 13; The buoy 12
comprises only an upright buoy or the upright buoy with extended
cylinder, the extended cylinder comprises two forms of fixed
extended cylinder and sliding extended cylinder; The anti-motion
structure 13 is an annular structure, which surrounds the bottom
and outer periphery of the buoy 12, and an annular radial gap 14 is
set or optionally not set between them. See FIGS. 2 and 3, The
anti-motion structure 13 comprises a roof plate 131, a floor plate
133 under the roof plate 131, an outer annular vertical plate 132
and an inner annular vertical plate 134 in between the outer
annular vertical plate 132 and the buoy 12, and said four plates
(131.about.134) are watertight connected with each other to form an
annular box structure with a rectangular or trapezoid radial cross
section. (FIG. 1-7 show that the structure sketch of the
anti-motion structure with rectangular typed radial crossing
section, and the trapezoidal section is not shown.) Among them, the
roof plate 131 and the floor plate 133 intersect with the outer
annular vertical plate 132 respectively to form a roof outer corner
line of the box (located on the outer edge of the roof of the box
body) and a floor outer corner line of the box (located on the
outer edge of the floor of the box body). The roof plate 131 and
the floor plate 133 intersect with the inner annular vertical plate
134 respectively to form a roof inner corner line of the box
(located on the inner edge of the roof of the box body) and a floor
inner corner line of the box (located on the inner edge of the
floor of box body), and i. e., forming four circles of closed
corner lines. The radial vertical cross section of the box body of
the anti-motion structure 13 shown in FIG. 1-7 is a rectangle, and
the vertices of the four corners of the rectangle are respectively
the points on the closed box corner line. The geometric figures of
box corner line are also different with the different structural
forms of the anti-motion structure 13. But in any case, the
geometry centroid of each corner line is located on the vertical
central axis of the buoy 12 and the anti-motion structure's box
body is rotationally symmetric with the centroid (such as a round
or regular polygon corner line), or the anti-motion structure's box
body is symmetric anteroposterior and left-right with the axis of
the rectangular coordinate system described the origin as the
centroid (i.e., the vertical central axis of the buoy 12), such as
an oval corner line or a closed geometric figure with parallel
straight lines on the left and right sides and circular or broken
line on the front and rear sides. The anti-motion structure 13 is
connected with the buoy 12 of the column floater 1 by multiple
radial vertical brackets (not shown in the attached figures). The
box body is divided into several watertight compartments by a
plurality of radial vertical partitions (not shown in the attached
figures). The horizontal roof plate 131 and/or the horizontal floor
plate 133 of each watertight compartment are provided with damping
holes that can be opened and closed. By opening or closing the
damping holes, the column floater 1 can be met the requirement
under different working conditions: When the platform is under
conditions of floating and wet towing, all the damping holes are
closed, the watertight compartment of the anti-motion structure 13
becomes a closed buoyancy module, or the damping holes of the roof
plate 131 are closed and the damping holes of floor plate 133 are
opened at same time, the interior of the compartment is filled with
air, and the watertight compartment of the anti-motion structure 13
becomes a closed gas-float compartment and buoyancy module. Both
types of buoyancy module can provide buoyancy and stability for
floating and wet towing of the platform. During in-place condition
of the platform, the damping holes are opened (the best option is
to open all damping holes) and the water from the sea is filled
inside the anti-motion structure 13, which makes the added mass of
inside entrained water increase, but doesn't make the displacement
of the platform increase.
[0017] The fundamental difference between the present invention and
PCT/CN2017/085052 is: at least one plate of roof plate 131 and
floor plate 133 of the anti-motion structure 13 without annular
radial gap 14 shall be provided with an outer edge extending lath
respectively; The outer edge extending laths are roof edge
extending lath 135 and floor edge extending lath 136. Refer to FIG.
1-7, showing the anti-motion structure 13 with annular radial gap
14, an outer edge extending lath and/or an inner edge extending
lath are set separately or simultaneously on at least one plate of
the roof plate 131 and/or the floor plate 133 of the anti-motion
structure 13. The outer edge extending laths are roof outer edge
extending lath 135 and floor outer edge extending lath 136, while
the inner edge extending laths are roof inner edge extending lath
and floor inner edge extending lath. The outer edge extending lath
is a plate structure, which extends outward and/or upward and/or
downward from the roof outer corner line and the floor outer corner
line respectively. The roof outer edge extending lath 135 is formed
on the roof plate 131 and the floor outer edge extending lath 136
is formed on the floor plate 133. The inner edge extending lath is
a plate structure, which extends horizontally from the roof inner
corner and/or the floor inner corner of the box to the direction of
the buoy 12. The horizontal roof inner edge extending lath is
formed on the roof plate 131, and the horizontal floor inner edge
extending lath is formed on the floor plate 133. The inner edge
extending lath shall not close the annular radial gap 14 (See FIG.
7).
[0018] As a practical embodiment, the anti-motion structure 13 is a
circular or a regular polygon structure, and the four box corner
lines correspond to a circular or a regular polygon. As another
practicable embodiment, the shape of the inner wall (the inner
annular vertical plate 134) and the outer wall (the outer annular
vertical plate 132) of the annular anti-motion structure of the
present invention is different. For example, the inner wall is a
circular of ring plate or positive multilateral ring plate, and the
roof inner corner line of the box and the floor inner corner line
of the box are corresponding to a circular or regular polygon, and
the outer wall is oval-shaped, and the roof outer corner line and
the floor outer corner line of the box is an oval; or the outer
wall is hetero-polygons-shaped, the roof outer corner lines and the
floor outer corner line of the box is a closed geometric figures
formed by parallel straight lines on the left and right sides and
circular or broken lines on the front and rear sides, the
dimensions in the left and right directions are smaller than those
in the front and rear directions. Its advantage is that the
requirements of width of drydock for platform construction of can
be reduced.
[0019] Further, the roof outer edge extending lath 135 and the
floor outer edge extending lath 136 are of annular plate
structures. The end edge of roof outer edge extending lath 135 and
the end edge of the floor outer edge extending lath 136 form a roof
outer end edge line and a floor outer end edge line respectively.
The geometric figures of said two end edge lines have the same
centroid as the roof outer corner line and the floor outer corner
line of the box, which is rotationally symmetric with the centroid
or symmetric with the vertical central axis of the buoy 12 in
direction of anteroposterior/left-right. Or, the roof outer edge
extending lath 135 and the floor outer edge extending lath 136 are
protruding to form a wall structure upward and downward
respectively, and the upper edge and lower edge of the protruding
edge extending lath wall structure form a circle of closed upper
end edge line and a circle of closed lower end edge line
respectively. The centroid of the geometry of said each end edge
line is located in the vertical central axis of buoy 12 and equal
to or similar to the geometry of the roof and floor corner lines of
the box respectively; or the roof outer edge extending lath 135 and
the floor outer edge extending lath 136 is an horizontal annular
plate then folding and protruding upward or downward to form a wall
structure respectively, and the end edge of the wall of the roof
outer edge extending lath 135/the floor outer edge extending lath
136 forms a circle of closed roof/floor end edge line respectively.
The centroid of the plane geometry of the circle of closed
roof/floor end edge line is located in the vertical central axis of
the buoy 12, which is similar to the plane geometry of the roof
outer corner line of the box/the floor outer corner line of the
box. Alternatively, the roof outer edge extending lath 135/the
floor outer edge extending lath 136 consists of a horizontal
annular plate structure plus a vertical ring wall structure
protruding upward/downward respectively; and in such case, the roof
outer edge extending lath 135 forms a circles of roof outer end
edge line plus a circle of roof upper end edge line, and the floor
outer edge extending lath 136 forms a circles of floor outer end
edge line plus a circle of floor lower end edge line, i.e., both of
the roof outer edge extending lath 135 and the floor outer edge
extending lath 136 have two circles of end edge lines.
[0020] Further, roof outer edge extending lath 135 and floor outer
edge extending lath 136 are single-layer plate structures (see
FIGS. 1-7). For the convenience of description and understanding,
the plate thickness of the edge extending lath structure is very
small, and the plate thickness is ignored in the following
description of the invention and regarded as "paper". Therefore, as
the edge extending lath with a convex structure extending up and
down (see FIG. 3.about.6), said convex structure of the roof outer
edge extending lath 135 and the floor outer edge extending lath 136
will form an upright frustum cone wall or an upright cylindrical
wall (see FIG. 3 and FIG. 5), or form a horizontal annular plate
structure then folding and protruding upward or downward being a
convex structure (see FIG. 4 and FIG. 6), said convex structure
forms a circle of closed upper end edge line and a circle of closed
lower end edge line, which centroid of the geometry is located in
the vertical central axis of the buoy 12 and which geometry is
equal to or similar to the geometry of the roof and floor corner
lines of the box respectively. When the outer edge extending laths
are as shown as FIGS. 1/2/7 being horizontal extension structures
of the roof plate 131 and/or the floor plate 133, both of the roof
outer edge extending lath 135 and the floor outer edge extending
lath 136 are horizontal annular plates and each plate with only one
closed circle outer end edge line (the inner edge line is merged
with the outer box corner line).
[0021] Optionally, multiple damping holes can be set or not be set
on the roof outer edge extending lath 135 and the floor outer edge
extending lath 136.
[0022] The outer edge extending lath (i.e., the roof outer edge
extending lath 135 and/or the floor outer edge extending lath 136)
comprises six structural forms.
[0023] (1) The roof outer edge extending lath 135 or the floor
outer edge extending lath 136, as horizontal annular plate
structures, are the horizontal extension structures of the roof
plate 131 or the floor plate 133 respectively, and the geometries
of their outer end edge lines (i. e., the outer end edge line of
the roof outer edge extending lath 135 and the outer edge line of
the floor outer edge extending lath 136) have the same centroid as
the geometries of the roof corner line of the box and the floor
corner line of the box, and are rotationally symmetrical with the
centroid, or anteroposterior and left-right symmetrical with the
axes of the Cartesian coordinate system with the centroid as the
origin, as shown in FIGS. 1, 2 and 7.
[0024] (2) The roof outer edge extending lath 135 is an inverted
frustum-shaped wall structure with its upper dimension larger than
its lower dimension, which lower end edge line coincides with the
roof outer corner line of the box; and the floor outer edge
extending lath 136 is a positive frustum-shaped wall structure with
its upper dimension less than its lower dimension, which upper end
edge line coincides with the floor outer corner line of the box,
see FIG. 3.
[0025] (3) The roof outer edge extending lath 135 or the floor
outer edge extending lath 136 is a horizontal annular plate as the
extension structure of the roof plate 131 or the floor plate 133
(the extension distance is smaller), and then folded upward to form
an inverted frustum-shaped wall structure with its upper dimension
larger than its lower dimension or downward to form a positive
frustum-shaped wall structure with its upper dimension less than
its lower dimension respectively. The dimension of the lower edge
line graph of the inverted frustum-shaped wall structure is larger
than that of the roof outer corner line graph of the box, and said
two graphs are similar figures with a common centroid; the
dimension of the upper edge line graph of the positive
frustum-shaped wall structure is larger than that of the floor
outer corner graph of the box, and said two graphs are similar
figures with a common centroid, see FIG. 4.
[0026] (4) The roof outer edge extending lath 135 is a vertical
cylindrical wall structure by folding the horizontal roof plate 131
upward with a 90-degree angle on the roof outer corner line of the
box, and the floor outer edge extending lath 136 is a vertical
cylindrical wall structure by folding the horizontal floor plate
133 downward with a 90-degree angle on the floor outer corner line
of the box; the lower edge line of the vertical cylindrical wall
structure of the roof outer edge extending lath 135 coincides with
the roof outer corner line of the box, and the upper edge line of
the vertical cylindrical wall structure of the floor outer edge
extending lath 136 coincides with the floor outer corner line of
the box, see FIG. 5.
[0027] (5) The roof outer edge extending lath 135 or the floor
outer edge extending lath 136 is a horizontal annular plate as the
extension plate of the roof plate 131 or the floor plate 133 (the
extension distance is smaller), and then connected with a vertical
cylindrical wall structure by folding the horizontal extended plate
upward or downward with a 90-degree angle respectively. The
dimension of the lower edge line graph of the vertical cylindrical
wall structure of the roof outer edge extending lath 135 is larger
than that of the roof outer corner line graph of the box, and said
two graphs are similar figures with a common centroid. The
dimension of the upper edge line graph of the vertical cylindrical
wall structure of the floor edge extending lath 136 is larger than
that of the floor outer corner graph of the box, and said two
graphs are similar figures with a common centroid, see FIG. 6.
[0028] (6) A combination of the above-mentioned two structural
forms (1) and (4), the roof outer edge extending lath 135 or the
floor outer edge extending lath 136 is a horizontal extension plate
extending from the roof plate 131 or the floor plate 133, and at
the same time, plus a vertical cylindrical wall structure connected
upward to the roof outer corner line of the box or downward to the
floor outer line of the box with a 90-degree angle from the
horizontal extension plate; thus the roof outer edge extending lath
135 or the floor outer edge extending lath 136 both has two circles
of end edge lines, i.e., a circle of roof outer end edge line plus
a circle of roof upper end edge line, and a circle of floor outer
end edge line plus a circle of floor lower end edge line
respectively (not shown in the figures).
[0029] In order to understand the convex edge extending lath
structure more clearly, taking the doughnut-shaped anti-motion
structure with said third form of edge extending lath structure
(the radial cross section is rectangular) as an example to give
description: Under the above conditions, the four corner lines of
the box of the anti-motion structure are all round, and the center
of the four circles are located in the vertical central axis of
buoy 12, the roof outer edge extending lath 135 or the floor outer
edge extending lath 136 is formed by a horizontal extension plate
of the roof plate 131 or the floor plate 133 firstly, and then
folding the extension plate upward or downward as an inverted
circular truncated cone with its upper diameter larger than its
lower diameter or a positive circular truncated cone with its upper
diameter less than its lower diameter respectively, and the lower
diameter of the inverted circular truncated cone is larger than
diameter of the circle of the roof outer corner line with a common
circle center and the upper diameter of the positive circular
truncated cone is larger than diameter of the circle of the floor
outer corner line with a common circle center.
[0030] Although FIG. 1.about.6 shows that the roof outer edge
extending lath 135 and the floor outer edge extending lath 136
adopt a combination of the same structural form, the roof outer
edge extending lath 135 and the floor outer edge extending lath 136
can adopt a different combination according to different demands.
For example, the roof outer edge extending lath 135 adopts the
second form of structure (shown in FIG. 3) and the floor outer edge
extending lath 136 adopts the first form of structure (shown in
FIG. 2), etc. The protruding size of the edge extending lath (the
roof outer edge extending lath 135 and the floor outer edge
extending lath 136) is smaller compared to the size of anti-motion
structure 13. The specific size of the edge extending lath of plate
structure, whether damping holes setting up on the edge plate or
not, and the number and diameter of the damping holes should be
determined and optimized by experiment and calculation.
[0031] For the anti-motion structure 13 with annular radial gap 14,
as an optimized embodiment of the present invention, a horizontal
annular plate is arranged on at least one annular part on the outer
wall of buoy 12 which is the same as the elevation of the roof
plate 131 and/or the floor plate 133, thus a buoy upper lath 121
and/or a buoy lower lath 122 (see FIG. 7) are formed with a gap
between the buoy upper lath 121 and the roof inner edge extending
lath and/or with a gap between the buoy lower lath 122 and the
floor inner edge extending lath respectively to further increase
the damping of heave motion. Another embodiment to increase the
damping of the heave motion is presented below, for the anti-motion
structure 13 with annular radial gap 14, at least one plate of the
roof plate 131 and the floor plate 133 shall extend horizontally in
the direction of buoy 12 from the roof inner corner line of the box
and/or from the floor inner corner line of the box up to connecting
the buoy 12 respectively to close the annular radial gap 14, and a
plurality of damping holes are set up on the closing area of the
gap, usually evenly distributed (not shown in the figures). In
order to further increase damping, as an optimal embodiment, the
upper gap between the roof inner edge extending lath and the buoy
upper lath 121 and the lower gap between the floor inner edge
extending lath and the buoy lower lath 122 should be dislocated as
far as possible. For example, the upper gap is closer to the buoy
12 and the lower gap is closer to the inner annular vertical plate
134. Or further, adding a layer of horizontal interspace annular
plate at the midpoint between the roof inner edge extending lath
and the floor inner edge extending lath, which is mounted on the
inner annular vertical plate 134 or on the outer wall of the buoy
12 and maintains a gap with the outer wall of the buoy 12 or with
the inner annular vertical plate 134 (both called "middle gap")
respectively, thus making the upper gap, lower gap and middle gap
dislocation of each other. The gap dislocation, especially the
horizontal interspace annular plate can not only increase the
viscous damping, but also lessen the mass reduction of the
entrained water due to the gap between the anti-motion structure 13
and the buoy 12.
[0032] As a further optimal embodiment, said outer end edge line
(the roof outer end edge line or the floor outer end edge line) can
adopt a serrated line to replace a flat straight line or smooth arc
line, that is, a serrated end edge with tooth convex and tooth
concave to replace the straight or smooth curved end edge, and the
tooth convex and the tooth concave have the same or different
geometric figures. That is to say, when both roof outer edge
extending lath 135 and floor outer edge extending lath 136 are
horizontal annular plates, one of the roof outer end edge line
and/or the floor outer end edge line is at least one continuous
serrated line, and/or one of the roof inner end edge line and the
floor inner end edge line is at least a continuous serrated line.
The serrated edge on each tooth is usually described as a regular
geometric figure, such as triangular tooth, rectangular or
trapezoidal tooth; and the convex and concave shapes of triangular
teeth are triangular, the convex and concave shapes of the
rectangular teeth are rectangular, or the convex and concave shapes
of the trapezoidal teeth are trapezoidal, and the convex and
concave shapes of the s are a combination of triangle, rectangular
and/or trapezoidal; Or the serrated edge on each tooth is an
irregular geometric figure, of which the convex and concave shapes
of the teeth are other figures different from triangle, rectangle
or trapezoid. For example, for the roof outer edge extending lath
135 and the floor outer edge extending lath 136 with multiple
damping holes, a notch from the end edge of the edge extending lath
to each damping hole is set up to form a convex and concave of
tooth.
[0033] As another further optimal embodiment, said roof upper end
edge line or said floor lower end edge line can adopt a serrated
line to replace a flat straight line or smooth arc line, that is, a
serrated end edge with tooth convex and tooth concave to replace
the straight or smooth curved end edge, and the tooth convex and
the tooth concave have the same or different geometric figures.
That is to say, when the roof outer edge extending lath 135 or the
floor outer edge extending lath 136 extending up or down to form a
closed circle roof upper end edge line or a closed floor circle
lower end edge line, one of the roof upper end edge line and/or the
floor lower end edge line is at least a continuous serrated line.
The serrated edge on each tooth is usually described as a regular
geometric figure, such as triangular tooth, rectangular or
trapezoidal tooth; and the convex and concave shapes of the
triangular teeth are triangular, the convex and concave shapes of
the rectangular teeth are rectangular, or the convex and concave
shapes of the trapezoidal teeth are trapezoidal, and the convex and
concave shapes of the compound teeth are a combination of triangle,
rectangular and/or trapezoidal; Or the serrated edge on each tooth
is an irregular geometric figure, of which the convex and concave
shapes of the teeth are other figures different from triangle,
rectangle or trapezoid. For example, for the roof outer edge
extending lath 135 and the floor outer edge extending lath 136 with
multiple damping holes, a notch from the end edge of the edge
extending lath to each damping hole is set up to form a convex and
concave of tooth.
[0034] Compared with a straight or smooth curved end edge, the edge
extending lath with an end edge line shaped the convex and concave
of teeth will further increase the viscous damping of the platform
motion.
[0035] As an optimized embodiment, for the roof outer edge
extending lath 135 and/or the floor outer edge extending lath 136
of the anti-motion structure being horizontal annular plate, when
the roof outer end edge line and the floor outer end edge line
adopt serrated lines, or when the roof outer edge extending lath
135 and floor outer edge extending lath 136 are set up damping
holes, a layer of horizontal interspace annular plate at the
midpoint between the roof outer edge extending lath and the floor
outer edge extending lath, namely middle outer edge extending lath,
is mounted on the outer annular vertical plate 132, and the end
edge of the middle outer edge extending lath is a straight and/or
smooth curved edge line. The function of the middle outer edge
extending lath is to reduce the loss of add mass of the entrained
water of heave motion due to the serrated edges and/or damping
holes of the roof outer edge extending lath 135 and floor outer
edge extending lath 136.
[0036] In order to install fairleads of mooring legs at the lower
part of the outer wall of the buoy 12 without destroying the
integrity of the anti-motion structure and to increase the add mass
of the entrained water, at the position on the inner side of
anti-motion structure 13 adjacent to the buoy 12 and corresponding
to the space for installing fairlead, a U-shaped fairlead groove is
set up horizontally and up and down through the roof plate and the
floor plate (not shown in the figures). The structure of said each
U-shaped groove is as follows: the inner annular vertical plate 134
corresponding to the U-shaped groove covering area is shifted
outwards (in the horizontal direction away from the buoy 12), and
vertical baffles are installed on both sides of the U-shaped
groove; the plate surface of the roof plate 131 and the floor plate
133 covered by the U-shaped groove are excised except that the
U-shaped edge is retained to form a U-shaped plate edge extending
lath. A total of 5 pieces of plates, i.e., said shifted inner
annular vertical plate, said vertical baffles on both sides of the
groove and said roof plate 131 and floor plate 133 taken some areas
out, are watertight connected with each other. In other words, the
water tightness of the watertight compartments of the anti-motion
structure shall not be destroyed after the U-shaped fairlead groove
been formed. The so-called U-shaped plate edge extending lath
refers to the U-shaped edges of the horizontal roof plate 131 and
the floor plate 133 protruding from the shifted part of the inner
annular vertical plate and the vertical baffles on both sides of
the groove. The U-shaped plate edge extending lath is good for
viscous damping. The space of the groove must be capable of
accommodating the fairlead mounted below the buoy 12 and ensuring
necessary maintenance requirements. As a practical embodiment, the
fairlead groove of the anti-motion structure 13 was broken as a
fracture at the initial stage of construction, and after the
fairlead guide groove been installed to the buoy 12, a water-tight
box structure are installed to close the fracture to form a
complete U-shaped fairlead groove.
[0037] The present invention overcomes the shortcomings of the
current anti-motion structure of column floater, not only increases
the add mass of the entrained water, but also increases the damping
of motions, especially the damping of heave motion, at the same
time ensures the integrity of anti-motion structure, and finally
greatly improves the motion performance of the column floater.
* * * * *