U.S. patent application number 14/923770 was filed with the patent office on 2017-04-27 for disconnectable tower yoke assembly and method of using same.
This patent application is currently assigned to SOFEC, INC.. The applicant listed for this patent is SOFEC, Inc.. Invention is credited to Stephen P. Lindblade.
Application Number | 20170113762 14/923770 |
Document ID | / |
Family ID | 58561798 |
Filed Date | 2017-04-27 |
United States Patent
Application |
20170113762 |
Kind Code |
A1 |
Lindblade; Stephen P. |
April 27, 2017 |
DISCONNECTABLE TOWER YOKE ASSEMBLY AND METHOD OF USING SAME
Abstract
A disconnectable rigid mooring system for attaching a ship to a
tower structure includes a yoke releasably connected to a yoke
head. The yoke head is pivotally attached to the tower structure
and the yoke is arranged and designed to attach to the ship. The
yoke and the yoke head each have a mating connector portion
arranged and designed to connect the yoke to the yoke head. When
the connector portions are engaged and locked, the yoke is securely
attached to the yoke head, allowing a rigid interconnection between
the ship and the tower structure. During normal operations and in
normal sea states, the yoke remains connected to the yoke head
pivotally attached to the tower structure. In the event of
predicted abnormally high sea states, the yoke may be disconnected
from the yoke head by the ship and be secured to the ship and
removed prior to the abnormally high sea state event. The yoke and
yoke head are provided with alignment guides and mechanisms which
permit the yoke and yoke head to be properly aligned during the
connect and disconnect procedures.
Inventors: |
Lindblade; Stephen P.;
(Waller, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SOFEC, Inc. |
Houston |
TX |
US |
|
|
Assignee: |
SOFEC, INC.
Houston
TX
|
Family ID: |
58561798 |
Appl. No.: |
14/923770 |
Filed: |
October 27, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B63B 2021/002 20130101;
B63B 21/507 20130101; B63B 21/00 20130101 |
International
Class: |
B63B 21/00 20060101
B63B021/00 |
Claims
1. A disconnectable tower yoke assembly, the tower yoke assembly
for connecting a floating vessel to a tower structure in a body of
water, comprising: a yoke head having a first portion connected to
the tower structure, a second portion connected to the first
portion, and a head connector portion; a yoke having a yoke coupler
arranged and designed to connect to and disconnect from the yoke
head, the yoke including a ballast tank distal of the yoke coupler,
and the yoke coupler including a coupler connector portion, wherein
the head connector portion and coupler connector portion are
arranged and designed to matingly engage one another; one of the
head and coupler connector portions in communication with at least
one actuator, the at least one actuator arranged and designed to
secure the head and coupler connector portions in mating engagement
and arranged and designed to allow the head and coupler connector
portions to disengage from one another.
2. The disconnectable tower yoke assembly of claim 1, wherein the
at least one actuator is in hydraulic communication with one of the
head and coupler connector portions.
3. The disconnectable tower yoke assembly of claim 1, wherein the
at least one actuator is in communication with the head connector
portion.
4. The disconnectable tower yoke assembly of claim 1, wherein the
second portion of the yoke head comprises the at least one actuator
and a head conical section, wherein the yoke coupler comprises a
yoke conical section, and wherein the head conical section is
arranged and designed to cooperate and interface with the yoke
conical section by providing guidance during connection of the yoke
to the yoke head.
5. The disconnectable tower yoke assembly of claim 4, wherein the
head conical section has a conical surface and the yoke conical
section has a conical surface, and the head conical surface and the
yoke conical surface are arranged and designed to be completely
engaged when the head conical section is fully interfaced with the
yoke conical section.
6. The disconnectable tower yoke assembly of claim 5, wherein the
head connector portion and coupler connector portion are arranged
and designed to matingly engage one another with the head conical
surface and yoke conical surface completely engaged.
7. The disconnectable tower yoke assembly of claim 1, wherein the
yoke head second portion is connected to the yoke head first
portion such that the yoke head second portion is allowed to
partially rotate relative to the yoke head first portion.
8. The disconnectable tower yoke assembly of claim 7, wherein the
yoke head first portion is connected to the tower structure such
that it can vertically pivot about a horizontal axis.
9. A disconnectable tower yoke assembly, the tower yoke assembly
for connecting a floating vessel to a tower structure in a body of
water, the tower structure having a turntable for rotation about a
vertical axis, the disconnectable tower yoke assembly comprising: a
yoke head connected to the turntable in a manner permitting the
yoke head to vertically pivot about a horizontal axis, the yoke
head including a head connector element and a head conical section;
a yoke having a pair of spaced legs, one end of each leg is
attached to a yoke coupler, the yoke coupler including a coupler
connector element and a coupler conical section; the head and
coupler connector elements being engageable to provide a rigid
interconnection therebetween; an actuator arranged and designed to
secure engagement of the head connector element with the coupler
connector element; a cable having a first end attached to an
interior portion of the yoke head with the cable extending through
the head and coupler conical sections and through the head and
coupler connector elements, the cable providing initial guidance of
the yoke for connection with the yoke head; the head conical
section is arranged and designed to cooperate and interface with
the coupler conical section by providing guidance during connection
of the yoke to the yoke head.
10. The disconnectable tower yoke assembly of claim 9, wherein the
head conical section has a conical surface and the coupler conical
section has a conical surface, and the head conical surface and the
coupler conical surface are arranged and designed to be completely
engaged when the head conical section is fully interfaced with the
coupler conical section.
11. The disconnectable tower yoke assembly of claim 10, wherein the
head and coupler connector elements are arranged and designed to
matingly engage one another with the head conical surface and
coupler conical surface completely engaged.
12. The disconnectable tower yoke assembly of claim 9, further
comprising a second actuator arranged and designed to be attached
to the yoke head to provide a desired angular orientation of the
yoke head during connection of the yoke to the yoke head.
13. The disconnectable tower yoke assembly of claim 9, further
comprising a second actuator arranged and designed to be attached
to the yoke head to provide a desired angular orientation of the
yoke head during disconnection of the yoke from the yoke head.
14. The disconnectable tower yoke assembly of claim 13, wherein the
second actuator is a hydraulic cylinder having one end attached to
the yoke head and a second end attached to the turntable.
15. (canceled)
16. A method for a floating vessel to disconnect a mooring yoke
from a yoke head attached to a tower structure, the vessel provided
with a motion compensated winch assembly and a yoke support
structure supporting one end of the yoke, the steps comprising:
attaching a winch line from the motion compensated winch assembly
to a coupler end of the yoke connected to the yoke head;
disengaging a head connector element of the yoke head from a
coupler connector element of the yoke; maintaining desired angular
orientation of the yoke head upon the head and coupler connector
elements disengaging; and supporting the yoke by the motion
compensated winch assembly and the yoke support structure of the
vessel as the yoke disconnects from the yoke head.
17. The method of claim 16, further comprising the step of:
separating an inner surface of a yoke coupler from contacting
engagement with an outer surface of the yoke head.
18. The method of claim 16, further comprising the step of: moving
the yoke in a substantially axial direction away from the yoke
head.
19. A disconnectable tower yoke assembly, the tower yoke assembly
for connecting a floating vessel to a tower structure in a body of
water, the tower structure having a turntable for rotation about a
vertical axis, the disconnectable tower yoke assembly comprising: a
yoke head connected to the turntable in a manner permitting the
yoke head to vertically pivot about a horizontal axis, the yoke
head including a head connector element and a head conical section;
a yoke having a pair of spaced legs, one end of each leg is
attached to a yoke coupler arranged and designed to connect to and
disconnect from the yoke head, the yoke coupler including a coupler
connector element and a coupler conical section; wherein the head
connector element and the coupler connector element being
engageable to provide a rigid interconnection therebetween; an
actuator positioned within the head conical section and arranged
and designed to secure engagement of the head connector element
with the coupler connector element; the head conical section is
arranged and designed to cooperate and interface with the coupler
conical section by providing guidance during connection of the yoke
coupler to the yoke head.
20. The disconnectable tower yoke assembly of claim 19, wherein the
head connector element is positioned within the head conical
section.
21. The disconnectable tower yoke assembly of claim 20, wherein the
coupler connector element includes a mating hub positioned within
the coupler conical section.
22. The disconnectable tower yoke assembly of claim 19, wherein the
head conical section has a conical surface and the coupler conical
section has a conical surface, and the head conical surface and the
coupler conical surface are arranged and designed to be completely
engaged when the head conical section is fully interfaced with the
coupler conical section.
23. The disconnectable tower yoke assembly of claim 22, wherein the
head and coupler connector elements are arranged and designed to
matingly engage one another with the head conical surface and
coupler conical surface completely engaged.
24. The disconnectable tower yoke assembly of claim 19, further
comprising a second actuator arranged and designed to be attached
to the yoke head to provide a desired angular orientation of the
yoke head during connection of the yoke to the yoke head.
25. The disconnectable tower yoke assembly of claim 19, further
comprising a second actuator arranged and designed to be attached
to the yoke head to provide a desired angular orientation of the
yoke head during disconnection of the yoke from the yoke head.
26. The disconnectable tower yoke assembly of claim 24, wherein the
second actuator is a hydraulic cylinder having one end attached to
the yoke head and a second end attached to the turntable.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to a rigid mooring
system for use in attaching a floating vessel or ship to a tower
structure attached to the sea floor. More particularly, the
invention relates to a tower mooring system comprising a rigid
tower yoke assembly having a yoke releasably attached to a yoke
head via a connector allowing removal of the yoke by the ship in
the event of predicted abnormally high sea states.
[0003] 2. Description of the Related Art
[0004] Typical tower yoke mooring systems are permanent mooring
systems where the floating vessel cannot leave for a storm. The
typical tower yoke, single point mooring system includes a "soft
yoke" for mooring a floating vessel directly to a fixed tower. A
turntable is fastened to the tower, typically with a roller
bearing, to allow the floating vessel to freely weathervane about
the fixed tower. A yoke is connected to the turntable with pitch
and roll joints to allow the vessel to pitch and roll. The yoke
includes a large ballast tank adapted to be filled with water to
provide the necessary restoring force to minimize vessel motions.
Two mooring links suspend the ballast tank from a support structure
mounted on the floating vessel.
[0005] Product, such as oil or gas for example, is transferred from
the tower across swivels located on the turntable and through hoses
from the turntable to the vessel. The tower includes deck space for
a manifold and other equipment. Access to the tower can be made via
walkways from the vessel and on the yoke.
[0006] However, some tower yoke mooring system applications in
shallow water are needed in areas potentially subjected to large
storms or extreme sea states such as hurricanes or typhoons, during
which the floating vessel will leave the area. For purposes of
safety and to survive the extreme sea states it is desirable that
the tower yoke be disconnectable from the tower structure.
SUMMARY OF THE INVENTION
[0007] The present invention includes a disconnectable tower yoke
for a large storm environment. The disconnectable tower yoke allows
the yoke to be removed from the tower structure and remain with the
floating vessel when disconnecting for a large storm. In a
preferred embodiment, the disconnection takes place at a yoke head
with a hydraulic connector. The yoke head includes a trunnion for
pivotal movement relative to the tower structure. Preferably, a
conical interface at the yoke to yoke head connection allows for
alignment and connection of the yoke to the yoke head. A pull-in
line attached to the yoke head trunnion housing serves as a guide
for the yoke and yoke head during vessel pull-in and
connection.
[0008] The preferred embodiment of the present invention further
includes a frame, attached to the mooring support structure of the
vessel, containing a motion compensated winch that allows for the
yoke to be supported by the vessel and allows for reconnection of
the yoke to the yoke head. Hoses and flow lines are disconnected at
the tower structure and transferred to the vessel prior to
disconnection.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0009] The various aspects and advantages of the preferred
embodiment of the present invention will become apparent to those
skilled in the art upon an understanding of the following detailed
description of the invention, read in light of the accompanying
drawings which are made a part of this specification and in
which:
[0010] FIG. 1 is an elevation view showing a floating vessel or
ship moored to a tower via a tower yoke;
[0011] FIG. 2 is a plan view of the yoke;
[0012] FIG. 3 is an elevation view showing a connection between a
turntable and a yoke head;
[0013] FIG. 4 is an elevation view showing a preferred embodiment
of the invention in which the yoke and yoke head are in a
disconnected condition;
[0014] FIG. 5 is a cross-sectional view of the preferred embodiment
showing the yoke and yoke head in a disconnected condition; and
[0015] FIG. 6 is a cross-sectional view showing the yoke and the
yoke head in a connected condition, with the hydraulic connector
engaged in the upper half of the figure and disengaged in the lower
half of the figure.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] The preferred embodiment of the present invention will now
be discussed with reference to the drawings. FIG. 1 shows a tower
10 including a jacket structure 12 fixedly attached to the sea
floor F, typically via piling. The tower 10 also includes a
plurality of decks 14 mounted on the jacket structure 12 at various
elevations above the water level L, typically mean water level, and
a vertical support column 16. It is understood by those of skill in
the art that the decks 14 are arranged and designed to support
various equipment, including manifolds, etc. A turntable 18 is
fastened to the support column 16, with a turntable bearing 28
(FIG. 5), preferably a roller bearing, to allow a floating vessel V
moored to the tower 10 to freely weathervane about the tower 10.
Preferably, one or more decks, including a hose deck 19, are
located above the turntable 18 and rotate with the turntable
18.
[0017] The floating vessel V is moored to the tower 10 via a yoke
24. FIG. 2 shows a plan view of a yoke 24. Typically, the yoke 24
is formed primarily from tubular members. As shown in FIG. 2, the
yoke 24 is generally triangular in shape when viewed in plan view.
The yoke 24 includes a large ballast tank 26 adapted to be filled
with water or other ballast to provide the necessary restoring
force to minimize motions of the vessel V when connected to the
tower 10. The yoke 24 includes a pair of legs 25 angled towards
each other. Each leg 25 has one end connected to the ballast tank
26 and a second end connected to a yoke coupler 30. In the
preferred embodiment, the yoke 24 is arranged and designed to be
connected to and disconnected from a yoke head 20 while on
location. Preferably, the yoke coupler 30 is a conical section for
alignment and connection with the yoke head 20 as best shown in
FIG. 4.
[0018] In the preferred embodiment, the yoke head 20 is mounted to
the turntable 18 via a pair of trunnions 23 for pivotal movement
relative to the turntable 18 as shown in FIGS. 3-5. Referring to
FIG. 5, the pair of trunnions 23 extend outwardly from a trunnion
housing 22. A pull-in line 38 attached to the trunnion housing 22
of the yoke head 20 serves as a guide for the yoke 24 and yoke head
20 during vessel V pull-in and connection.
[0019] As shown in FIG. 5, a yoke head conical section 32 is
connected to the trunnion housing 22, preferably via a roll bearing
40. The yoke head roll bearing 40 allows the head conical section
32 to rotate relative to the trunnion housing 22.
[0020] In the preferred embodiment the yoke head conical section 32
is arranged and designed to cooperate and interface with the yoke
conical section 30. This interface includes two conical machined
surfaces: an inner surface 34 on the yoke conical section 30
(female) and an outer surface 36 on the head conical section 32
(male) as shown in FIG. 5. The conical sections 30 and 32 at the
ends of the yoke 24 and the yoke head 20, respectively, allow for
guidance during connection and allow for load transfer from the
yoke 24 to the yoke head 20.
[0021] In the preferred embodiment as shown in FIG. 5, a hydraulic
connector 50 is positioned inside of the yoke head conical section
32 and is actuated from the tower side by accumulators and
telemetry controlled valves. Accumulators and telemetry controlled
valves are well known to those skilled in the art. The hydraulic
connector 50 has a stationary housing 52 mounted within the head
conical section 32. The stationary housing 52 is preferably a
substantially cylindrical housing having a bore 54 therethrough.
The stationary housing 52 includes an outwardly facing shoulder 56
and one or more line guides 58 within the bore 54. The pull-in line
38 extends through the bore 54 and between the one or more line
guides 58. The hydraulic connector 50 also includes a movable
sleeve 60 extending around the outwardly facing shoulder 56. The
movable sleeve 60 includes an inwardly directed flange 62 at one
end and a band 64 at an opposite end. The band 64 contacts one or a
plurality of pivot fingers 66. One or more actuators 68, preferably
hydraulic cylinders, are positioned between and connected to the
outwardly facing shoulder 56 of the stationary housing 52 and the
inwardly directed flange 62 of the movable sleeve 60. Preferably,
when more than one actuator 68 is used, all of the actuators are
controlled by a singular control to provide simultaneous operation
and movement of the movable sleeve 60.
[0022] A mating hub 70 of the hydraulic connector 50 is mounted
within the yoke conical section 30 by means of an adapter 72.
Preferably, the mating hub 70 and the adapter 72 are annular
members having a common bore 74 extending therethough. Preferably,
one or more line guides 58 are mounted within the common bore 74.
The pull-in line 38 extends through the common bore 74 and between
the one or more line guides 58.
[0023] FIG. 5 shows the yoke 24 and the yoke head 20 in a
disconnected condition and FIG. 6 shows the yoke 24 and the yoke
head 20 in a connected condition, with the hydraulic connector 50
engaged in the upper half of the figure and disengaged in the lower
half of the figure for exemplary purposes. When the hydraulic
connector 50 is engaged, it provides a preload to the conical
structural interfaces 34 and 36. With reference to FIG. 5 and the
lower half of FIG. 6, the rod of the actuator 68 is extended such
that the band 64 of the movable sleeve 60 allows the pivot fingers
66 to pivot outwardly. Upon engagement of the end of the stationary
housing 52 with the end of the mating hub 70 and the engagement of
the conical structural interfaces 34 and 36, the actuators 68 are
actuated to move the movable sleeve 60 in the direction of the
mating hub 70 until the pivot fingers 66 are forcibly inserted into
the mating hub recess 76 as shown in the upper half of FIG. 6. With
the pivot fingers 66 forcibly inserted in the mating hub recess 76,
the yoke 24 is securely connected to the yoke head 20. Preferably,
secondary mechanical locks (not shown) in line with the actuators
68 keep the connector locked without the need of hydraulic
pressure. Secondary mechanical locks may be interference sleeve
locks such as the Bear-Loc.TM. locking device, manufactured by
Wellman Dynamics Machining and Assembly Inc. of York, Pa.
[0024] Referring to FIG. 1, the floating vessel V is equipped with
a support structure 100 preferably including a pair of mooring
links 102. The mooring links 102 are connected to the support
structure via upper U-joints 118. Lower U-joints 120 connect the
mooring links 102 to the ballast tank 26 of the yoke 24. The
support structure 100 with the pair of mooring links 102 are
arranged and designed to suspend the ballast tank 26 of the yoke
24. A motion compensated winch or lifting device 110 is mounted on
a cantilevered section 104 of the mooring support structure 100.
The motion compensated winch 110 may be located elsewhere on the
mooring support structure 100 or vessel V and the line 112 reeved
through sheaves located on the mooring support structure 100 and
cantilevered structure 104. The motion compensated winch 110 is
arranged and designed to support the yoke 24 during disconnection
and reconnection. A mooring connection winch 106 on the vessel V is
arranged and designed to pull the vessel V to the tower 10 and
provide guidance for the structural connection of the yoke 24 to
the yoke head 20. Preferably, the rope or cable 108 of the mooring
connection winch 106 is connected to the pull-in line 38 attached
to the trunnion housing 22 of the yoke head 20.
[0025] Still referring to FIG. 1, during normal operations with the
vessel V moored to the tower 10, one or more hoses or flow lines
114 and cables 116 from the vessel V to the tower 10 are typically
connected for process flow. The link arms 102 are connected to the
ballast tank 26 of the yoke 24 and support the ballast tank 26
above the water level L. In the event of excessive environmental
conditions anticipated at the tower location, the following
procedures are permitted as a result of the preferred embodiment of
the present invention.
[0026] Initially, the hoses or flow lines 114 and cables 116 are
disconnected at the tower interface and retrieved to the vessel V
and stored for transportation. An alternative configuration allows
the hoses 114 and cables 116 to be disconnected at the vessel V and
stored on the hose deck 19 of the tower 10. Referring to FIG. 1, a
winch line 112 of the motion compensated winch 110 is attached to
the yoke 24 to suspend the yoke coupler 30 end of the yoke 24 after
disconnection from the yoke head 20. A cylinder 42, preferably a
hydraulic cylinder (FIG. 4), attached to the trunnion housing 22 of
the yoke head 20 and to the tower turntable 18 orients the yoke
head 20 in a near horizontal orientation (or at the proper angle)
during disconnection of the yoke 24, while the yoke 24 is
disconnected and during reconnection of the yoke 24. The hydraulic
cylinders 68 of the hydraulic connector 50 inside the yoke head 20
are actuated to move the movable sleeve 60 from the position shown
in the upper half of FIG. 6 to the position shown in the lower half
of FIG. 6, allowing the yoke 24 to disconnect from the tower
structure 10 at the yoke head 20 while being supported by the
motion compensated winch 110 and the mooring links 102 of the
vessel support structure 100. The yoke 24 is stored and pulled
against fenders of the vessel V and the yoke coupler end 30 is
fastened to the cantilevered structure 104 for sailing of the
vessel V.
[0027] During reconnection of the yoke 24 to the yoke head 20, the
motion compensated winch 110 is attached to the yoke 24 to suspend
the yoke coupler 30 end of the yoke 24. The pull-in line 38
attached to the inside of the trunnion housing 22 is retrieved, and
the pull-in line 38 or winch cable 108 of the mooring connection
winch 106 is inserted through the mating hub 70 of the yoke 24. The
pull-in line 38 is connected to the winch cable 108 of the mooring
connection winch 106. The vessel V is pulled towards the tower 10
for connection. The pull-in line 38 extends through the plurality
of line guides 58 inside the connector 50 and mating hub 70,
providing for initial guidance of the yoke head 20 and yoke 24 for
connection. Final guidance is obtained by the mating conical
surfaces 34 and 36 of the yoke 24 and yoke head 20, respectively,
in addition to the connector 50 and hub 70 interface. The trunnion
cylinder 42 supports the yoke head 20 for alignment and
reconnection. The mooring links 102 and the yoke lifting device 110
support the yoke 24 for alignment and reconnection. Once the mating
conical surfaces 34 and 36 are completely engaged, the hydraulic
cylinders 68 are actuated to structurally connect the connector 50
to the mating hub 70. The vessel is now moored. The trunnion
cylinder 42 is then disengaged from the yoke head 20 and the yoke
lifting device 110 is disengaged from the yoke 24. Preferably, the
winch cable 108 of the mooring connection winch 106 is also
disconnected from the pull-in line 38 in preparation for the next
yoke disconnection.
[0028] Preferably, the disconnection takes place at the yoke head
20 which allows the yoke 24 to be transported with the vessel V.
This leaves the tower 10 and the yoke head 20 attached to the tower
10 to survive the large storm. The hydraulic connector 50 is placed
at the yoke/yoke head disconnection interface to allow for quick
disconnection under load. Preferably, the yoke disconnection
interface is located as close to the yoke head roll bearing 40 as
possible. The yoke 24 is suspended by a motion compensated winch
110 and attached to the vessel V for evasion of the storm.
[0029] While preferred embodiments of the present invention have
been illustrated in detail, it is apparent that modifications and
adaptations of the preferred embodiment will occur to those skilled
in the art. However, it is to be expressly understood that such
modifications and adaptations are within the spirit and scope of
the present invention as set forth in the following claims.
* * * * *