U.S. patent application number 14/841312 was filed with the patent office on 2016-03-03 for in or relating to crawlers.
The applicant listed for this patent is REECE INNOVATION CENTRE LIMITED. Invention is credited to Ross James LAMONBY, Neil William STUTCHBURY.
Application Number | 20160059939 14/841312 |
Document ID | / |
Family ID | 51752347 |
Filed Date | 2016-03-03 |
United States Patent
Application |
20160059939 |
Kind Code |
A1 |
LAMONBY; Ross James ; et
al. |
March 3, 2016 |
IN OR RELATING TO CRAWLERS
Abstract
A dual-mode crawler unit for traversing a generally tubular
target, the unit comprising means for effecting a hand-over-hand
action along the target and also means for effecting a driven
action along the target, the unit comprising two or more traversing
units, the units being directly connected to each other by one or
more linear actuators.
Inventors: |
LAMONBY; Ross James;
(Northumberland, GB) ; STUTCHBURY; Neil William;
(Tyne-and-Wear, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
REECE INNOVATION CENTRE LIMITED |
Newcastle-Upon-Tyne |
|
GB |
|
|
Family ID: |
51752347 |
Appl. No.: |
14/841312 |
Filed: |
August 31, 2015 |
Current U.S.
Class: |
114/337 |
Current CPC
Class: |
E21B 23/001 20200501;
E21B 41/00 20130101; G01V 13/00 20130101; E21B 17/012 20130101;
E21B 17/015 20130101; B08B 9/023 20130101; E21B 41/04 20130101;
G01N 21/952 20130101; G01M 3/005 20130101; G01M 3/00 20130101; E02B
17/0034 20130101; G01N 29/00 20130101 |
International
Class: |
B63B 35/00 20060101
B63B035/00; B63H 19/00 20060101 B63H019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 29, 2014 |
GB |
1415334.0 |
Claims
1) A dual-mode crawler unit for traversing a generally tubular
target, the unit comprising two or more traversing modules which
can effect a hand-over-hand action along the target and also a
driven action along the target, the units being connected to each
other by one or more linear actuators.
2) A unit as claimed in any claim 1, in which the modules comprise
drive means selected from: rollers, tracks, wheels, thrusters,
rolling support means, bristle drive or the like for effecting a
driven action along the target.
3) A unit as claimed in claim 1, in which the modules comprise
clamps for effecting a hand-over-hand action.
4) A unit as claimed in claim 3, in which the clamps are capable of
moving toward and away from each other along the target.
5) A unit as claimed in claim 1, in which there are two sets of
driven rollers, tracks or wheels separated by a linear actuator,
and in which each set of driven rollers or tracks is capable of
supporting and propelling the unit/tool along the target without
the other being in contact with the target.
6) A unit as claimed in claim 1, comprising a roller, track or
wheel capable of rotating the unit about the tubular target.
7) A unit or tool as claimed in claim 2, in which the drive means
are movable between a retracted position and an engaged
position.
8) A unit as claimed in claim 1, including thrusters for traversing
the target and/or for keeping the unit concentric with the target
during movement.
9) A unit as claimed in claim 1, including sensors for keeping the
unit concentric with the target.
10) A unit as claimed in claim 1, including capability to adjust
clockwise or anticlockwise rotation bias.
11) A unit as claimed in claim 1, which incorporates a sensor for
giving its rotational position, either absolute, or relative to a
datum.
12) A unit as claimed in claim 1, where a control system is used to
automatically adjust clockwise or anticlockwise bias to maintain a
desired rotational position or path on the target.
13) A unit as claimed in claim 1, where the modules include clamps
for effecting hand-over-hand action comprise clamps and the clamps
include a set of overlapping fingers forming an aperture, which
retain the target when the clamps are opened, and centralize the
target as the clamps are closed.
14) A unit as claimed in claim 1, including an on-board
electrically driven HPU.
15) A unit as claimed in claim 1, including a module for cleaning
the target.
16) A unit or tool as claimed in claim 15, in which the module
cleans the target by scraping and/or rotating brushes and/or water
jetting.
17) A unit or tool as claimed in claim 1, including a sensor or
inspection module.
18) A unit as claimed in claim 1, including a set of subsea
thrusters to enable the unit to swim, so to position itself around
the target when in water.
19) A subsea bi-directional crawler unit for traversing a generally
tubular target, in which the unit includes capability to monitor
and correct rotational position, the unit comprising a sensor for
providing absolute or relative rotation to a target and the ability
to actively rotate the unit.
20) A crawler unit comprising a frame with a generally central
roller set, a pair of lateral roller sets being provided on or by
each side of the frame and being movable from an open position in
which the frame can be positioned on a tubular target with the
central roller set engaged, and a closed position in which the
lateral roller sets are closed around the target and engage
thereon.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to crawlers,
climbers and the like for traversing a generally tubular target
such as an umbilical, riser or pipe.
BACKGROUND
[0002] There are already in existence umbilical, riser or pipe
climbers, which use either a hand-over-hand climbing operation, or
a set of driven rollers to propel itself along the length of the
umbilical, riser or pipe.
[0003] Hand-over-hand movement is done by extending an open clamp
in the direction of travel, while a trailing clamp remains clamped
to the umbilical, riser or pipe. Once extended the leading clamp is
closed onto the umbilical, riser or pipe to grip it, before opening
the trailing clamp and retracting it towards the previously
extended leading clamp. This method of propelling the unit, while
versatile, can be a slow stop-start action.
[0004] Using a set of driven wheels or tracks clamped onto the
umbilical, riser or tube for traction gives a smoother, faster, and
continues way of propelling the climber unit. The problem with
using only driven tracks or rollers for propulsion is that it does
not lend itself to allowing the crawler unit to pass items (such a
strakes or buoyancy) or anything that deviates too much from a
continuous uniform diameter.
[0005] According to an aspect of the present invention there is
provided a dual-mode crawler unit for traversing a generally
tubular target, the unit comprising means for effecting a
hand-over-hand action along the target and also means for effecting
a driven action along the target, the unit comprising two or more
traversing units, the units being directly connected by one or more
linear actuators.
[0006] In some embodiments two traversing units are provided and
are connected to each by one or more linear actuators. In
embodiments with more than two traversing units, they are connected
to each other by respective linear actuator/s.
[0007] The linear actuator may comprise a non-jointed actuator
(linear actuation is achieved with no rotation).
[0008] The traversing action may be of the "push me pull you"
type.
[0009] The target may be a riser or umbilical.
[0010] Conduits to transfer materials from the seafloor to
production and drilling facilities atop the water's surface, as
well as from the facility to the seafloor, subsea risers are a type
of pipeline developed for this type of vertical transportation.
Whether serving as production or import/export vehicles, risers are
the connection between the subsea (oil) field developments and
production and drilling facilities. Similar to pipelines or
flowlines, risers transport produced hydrocarbons, as well as
production materials, such as injection fluids, control fluids and
gas lift. Usually insulated to withstand seafloor temperatures,
risers can be either rigid or flexible.
[0011] Umbilicals play an important role in offshore and subsea oil
and gas developments. They provide the connection between the host
facility through which control is exercised, power transmitted and
utilities such as injection chemicals delivered to subsea wells.
Current trends in the market--the growing number of satellite
developments from mature fields, the advance of exploration and
production into ever deeper waters and the increasing length of
step-outs--indicate that in coming years umbilicals will play an
even more important role in offshore oil and gas production.
[0012] Umbilicals are long flexible constructions made up of tubes,
cables, armouring, fillers and wrapping contained with a protective
sheath. The most common form of umbilical often contains electric
cables for transmitting control and power signals, and high-,
medium- or low-pressure tubes for carrying hydraulic liquids to
control valves and chemicals for injection into the well or
pipeline. It is therefore known as an electro-hydraulic umbilical.
There may be additional elements--for example, fibre-optic cables
for monitoring purposes are increasingly being incorporated.
[0013] A further aspect provides a subsea bi-directional tool for
traversing a generally tubular target, in which the tool includes
means for monitoring and correcting rotational position, comprising
a sensor for providing absolute or relative rotation to a target
and means for actively rotating the unit.
[0014] According to a further aspect of the present invention there
is provided a dual-mode crawler/climber unit for traversing a
generally tubular target, the unit comprising means for effecting a
hand-over-hand action along the target and also means for effecting
a driven action along the target.
[0015] The present invention also provides a subsea bi-directional
tool for traversing a generally tubular target, the unit comprising
means for effecting a hand-over-hand action along the target and
also means for effecting a driven action along the target.
[0016] The tubular target may be, for example, an umbilical, riser
or pipe.
[0017] In units or tools provided by the present invention the
means for effecting a driven action may be incorporated into the
means for effecting a hand-over-hand action.
[0018] The means for effecting a driven action may comprise
rollers, tracks, wheels, bristle drive or the like.
[0019] The means for effecting a hand-over-hand action may comprise
two or more clamps.
[0020] The clamps may be capable of moving toward and away from
each other along the target.
[0021] There may be two sets of driven rollers, tracks or wheels
separated by a linear actuator, and in which each set of driven
rollers or tracks is capable of supporting and propelling the
unit/tool along the target without the other being in contact with
the target.
[0022] There may be a set of driven rollers, tracks or wheels
capable of supporting and propelling the crawler along the
umbilical, riser or tube, separated by a linear actuator from a set
of rollers capable of rotating the crawler about the umbilical,
riser or tube axis.
[0023] There may be a set of driven rollers or tracks separated
from a clamp by a linear actuator.
[0024] The means for effecting a driven action and/or the means for
effecting a hand-over-hand action may be retractable.
[0025] The means for effecting a driven action and/or the means for
effecting a hand-over-hand action may be retractable.
[0026] The means for effecting a drive action may be movable
between a retracted position and an engaged position. For example,
in a system with two or more positions of driving engagement it may
be possible to lock a set (for example a set of wheels) to prevent
rotation whilst a hand-over-hand action is being effected (for
example while an upstream/downstream clamp is released).
[0027] Units or tools may include thrusters for traversing the
target and/or for keeping the unit/tool concentric with the target
during movement.
[0028] Units or tools may include sensors for keeping the unit/tool
concentric with the target.
[0029] The unit or tool may include the capability to adjust
clockwise or anticlockwise rotation bias. For example, it may
include the capability to adjust the trim of a roller, track or
wheel in contact with the target to cause the unit/tool to rotate
about the target.
[0030] Units or tools may incorporate a sensor for giving its
rotational position, either absolute, or relative to a datum.
[0031] A control system may be used to automatically adjust
clockwise or anticlockwise bias to maintain a desired rotational
position or path on the target.
[0032] The control system may be a programmable logic controller
(PLC).
[0033] The means for effecting hand-over-hand action may comprise
clamps and the clamps may include a set of overlapping fingers
forming an aperture which retain the target when the clamps are
opened, and centralise the target as the clamps are closed.
[0034] Units or tools may include an on-board electrically driven
HPU. Electrical power may be provided via an umbilical or cable
from a power supply remote to the unit/tool.
[0035] The on-board HPU may be used to supply hydraulic fluid to
motors and/or cylinders and/or additional on-board systems.
[0036] The unit or tool may include a module for cleaning the
target. The module may clean the target, for example, by scraping
and/or rotating brushes and/or water jetting.
[0037] The unit or tool may include a sensor or inspection
module.
[0038] In embodiments with cleaning and sensor modules the sensor
module may be positioned "after" (i.e. downstream) the cleaning
module.
[0039] The unit or tool may include a set of subsea thrusters to
enable the crawler unit/tool to swim, so to position itself around
the target when in water.
[0040] The position of centre of gravity and centre of buoyancy of
the unit/tool may be in or near to the same position.
[0041] The present invention also provides a method of traversing a
tubular target as described herein.
[0042] In some aspects and embodiments the invention is the use of
at least a single set of driven rollers or tracks alongside a
crawling type method of propulsion. By combing these two methods of
propulsion the crawling unit is able to propel itself along an
umbilical, riser or pipe in a continues manner at reasonable speed,
while still being able to crawl along sections where it is not
possible to use driven wheels or tracks, such as when clearing an
object such as a strake or buoyancy.
[0043] The unit may also be able to `step over` obstacles in some
embodiments, by retracting its driven rollers or tracks approaching
an obstacle, and using an additional trailing set of driven rollers
or tracks to move the leading retracted set over the obstacle.
[0044] This method of stepping over an obstacle may be further
enhanced with the individual sets of rollers capable of extending
away, and retracting back toward each other, as by moving further
apart allows the crawler unit to `step over` a larger gap.
[0045] Once the leading set of rollers or tracks has moved beyond
an obstacle, they re-clamp to the umbilical, riser or pipe, and the
trailing set are retracted.
[0046] The leading set of driven rollers or tracks is then used to
move the trailing retracted set over the obstacle, so moving the
entire unit beyond the obstacle.
[0047] Another aspect of the present invention relates to the
monitoring and correction of the crawling unit rotational position.
As the unit moves along the umbilical, riser, or tube it may
undergo multiple revolutions, hampering the management of the
connecting power and control umbilical, as it could be being
wrapped around the umbilical, riser, or tube the unit it is
traversing.
[0048] The invention is to use a sensor, such as a magnetometer or
gyroscopic compass, to give the absolute or relative rotation to
the umbilical, riser, or tube. By knowing the number of rotations,
and in which direction, the crawler unit has gone through, the unit
can be actively rotated to reduce or remove the number times which
the power umbilical has been wound around the umbilical, riser, or
tube.
[0049] One embodiment of this could simply involve adjusting a
clockwise/anticlockwise bias, which could be done by adjusting the
angle of a contacting passive or driven roller. Either an operator
could manually adjust this as the unit traverses, or it could be
used in conjunction with a control system to continually adjust the
bias to prevent the crawler unit going through any rotation.
[0050] Rather than introduce a clockwise or anticlockwise bias as
the unit transverses along the umbilical, riser or tube, the unit
could be stopped, and then rotated about the axis of the umbilical,
riser or tube using a set of rollers.
[0051] These rollers could either be fixed, with sole purpose of
rotating the crawler unit about the umbilical, riser, or tube axis,
or they could be the same rollers used for traversing rotated
through or near to 90 degrees (pivoted about axis perpendicular to
umbilical, riser or tube axis).
[0052] Another innovation is the incorporation of a set of
overlapping fingers forming an aperture, which are required to both
position the umbilical, riser or tube as the clamping mechanism is
closed, and to fully encompass the umbilical, riser or tube when
the clamps are open.
[0053] The detail of these fingers is better described in the
following embodiments; however, the fundamental invention is the
incorporation of a method or mechanism to centralise the umbilical,
riser or tube within the clamping elements.
[0054] The crawler unit is intended to deliver either cleaning
tools, Inspection equipment, or both. However, the crawler unit
described in the preferred embodiment could well be used to move
other modular subsea equipment packages along an umbilical, riser
or tube.
[0055] In some embodiments the present invention relates to a riser
cleaning and inspection robot.
[0056] In some embodiments the present invention relates to a riser
and umbilical crawler. The purpose of the may be to remove marine
fouling, and to position a flexible inspection tool along an
umbilical or riser. The crawler unit may be capable of both foul
removal and inspection tool deployment.
[0057] The crawler may, for example, be a subsea vehicle.
[0058] A further aspect provides a crawler unit comprising a frame
with a generally central roller set, a pair of lateral roller sets
being provided on or by opposite sides of the frame and being
movable from an open position in which the frame can be positioned
on a tubular target with the central roller set engaged, and a
closed position in which the lateral roller sets are closed around
the target and engage thereon.
[0059] The central and/or lateral roller sets may comprise one or
more rollers. In some embodiments the rollers are concave.
[0060] In some embodiments all rollers are driven. In other
embodiments some rollers are passive. For example the central
roller set (including one or more rollers) may be passive and the
or one of the rollers on either or both of the arms may be driven,
for example by a direct drive hydraulic motor.
[0061] In some embodiments front and rear arm pairs are provided at
or towards either end of the frame and close around the target. The
lateral roller sets may be positioned between the front and rear
arms.
[0062] Different aspects of the present invention may be used
separately or together.
[0063] Further particular and preferred aspects of the present
invention are set out in the accompanying independent and dependent
claims. Features of the independent and dependent claims may be
combined with the features of the other independent and dependent
claims as appropriate, and in combination other than those
explicitly set out in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0064] FIG. 1 is a perspective view of a crawler unit formed
according to an embodiment of the present invention;
[0065] FIG. 2 shows end views of the unit of FIG. 1 with: i) a
clamp closed and guides closed; ii) a clamp closed and guides
closed for a smaller diameter target; and iii) a clamp closed and
guides open;
[0066] FIG. 3 is a magnified view showing different positions of
clamping and centralising units;
[0067] FIG. 4 shows the unit of FIG. 1 in use, driving along a
tubular target until it meets an obstruction;
[0068] FIG. 5 shows the unit of FIG. 4 rotated to align a gap with
a mooring line;
[0069] FIG. 6 shows the crawling unit front module extending in a
direction of travel towards the obstruction;
[0070] FIG. 7 shows the rear module being retracted towards the
front module;
[0071] FIG. 8 shows the front module again being extended so as to
pass over the obstruction;
[0072] FIG. 9 shows the unit following repeated cycles of front
module extension/rear module retraction hand-over-hand propulsion
process;
[0073] FIG. 10 shows a bidirectional tool formed according to a
further embodiment;
[0074] FIG. 11 shows an end view of the tool of FIG. 10;
[0075] FIG. 12 shows the tool in an open position whilst being
affixed to a tubular structure.
[0076] FIG. 13 illustrates a centraliser finger closing sequence
for the tool;
[0077] FIG. 14 shows the tool of FIG. 10 in a swimming mode;
[0078] FIGS. 15 to 18 illustrate the tool stepping over an
obstacle;
[0079] FIGS. 19 to 24 illustrate the tool negotiating multiple
objects;
[0080] FIG. 25 shows a crawling module of a unit formed according
to a further embodiment;
[0081] FIG. 26 shows the module of FIG. 25 together with a cleaning
module;
[0082] FIG. 27A shows the unit open and positioned around a 14 inch
diameter umbilical;
[0083] FIG. 27B shows the unit closed around the umbilical;
[0084] FIG. 27C shows the unit closed around an 8 inch
umbilical;
[0085] FIG. 28 illustrates the tool being positioned amongst
tightly packed umbilicals;
[0086] FIG. 29 shows the unit with an inspection tool attached;
[0087] FIG. 30 shows a possible system architecture for operating
the unit;
[0088] FIG. 31 shows the unit attached to an umbilical; and
[0089] FIG. 32 in an end view showing the unit of FIG. 21 attached
around an umbilical.
DETAILED DESCRIPTION
[0090] The present invention will now be more particularly
described, by way of example, with reference to the accompanying
drawings.
[0091] An embodiment is shown in FIG. 1. The crawler unit comprises
of multiple, but preferably two, modules mechanically connected by
hydraulic cylinders. Each module has a clamp unit, with at least a
single one of these module clamp units comprising a set of driven
rollers or tracks capable of propelling the unit along the axis of
the umbilical, riser, or tube.
[0092] The front module has three clamping units, although could be
in excess of this, which incorporate at least a single driven set
of rollers or tracks. Each clamping unit has a pair of rollers
which are sufficiently spaced to give moment support from the
umbilical, riser or pipe (600 mm separation shown on the embodiment
in FIG. 2). A degree of moment support on the module is required,
as it is intended that the module can support/hold the crawler unit
onto the umbilical, riser, or pipe without the rear or any other
additional modules providing additional support. The moment support
helps keep both modules concentric with the umbilical, riser or
pipe while the other is open.
[0093] When clamped onto the umbilical, riser or pipe the crawler
unit can be driven along using the driven rollers. In embodiment
shown all 3 roller set are driven, with each pair mechanically
linked (by chain, shaft, or belt). The rollers themselves can have
a concave surface to suite a range of diameters, which could be
changed out to suit, which both helps to reduce contact pressure
and holds umbilical, riser or tube more securely.
[0094] The clamping units of each module can open up to clear an
item of larger diameter than the umbilical, riser or tube, such as
strakes or buoyancy. FIG. 3 shows various positions of the clamping
and centralising units for each module.
[0095] The centralising units (or guides) are required to keep the
umbilical, riser, or pipeline concentric with the module as the
clamping units close around, and without them the umbilical, riser,
or tube risks being missed by the clamping wheels.
[0096] When the crawler unit is only supported by a single module,
although a degree of moment support is provided, it is likely that
the umbilical, riser, or pipe, although remaining contained by the
centralising fingers of the module, would not be concentric prior
to closing of its clamping units. In addition it aids in initial
attachment by self-centralising when the crawler unit is first
placed around the umbilical, riser or tube. A segment of the
centralising units is able to open up, to both allow initial
placement on the umbilical, riser or pipe, and to allow the unit to
pass mooring cables, the detail of which shall be described further
on in an operational sequence.
[0097] The centralising fingers of the preferred embodiment are
part of the module clamping units, and so do not require additional
actuation, although alternative embodiments could use a
centralising system which is separate from the clamping mechanism.
The fingers are mounted to a parallel link which is always parallel
to the umbilical, riser or pipe as shown in FIG. 2, with the
clamping wheels a set distance closer to the umbilical, riser or
tube, so giving same amount of clearance between finger and
umbilical, riser or tube regardless of diameter closed around. The
centralising fingers themselves have an overlapping arrangement to
form an aperture surrounding the umbilical, riser or tube.
[0098] The set of centralising fingers shown on the preferred
embodiment are intended to be used for the full crawler unit
diameter range; however, these are capable of being swapped out for
a set suiting a specific diameter, or for alternative designs such
as a set incorporating roller elements.
[0099] The rear module is used to provide a second clamp for
hand-over-hand prolusion, for rotation about the umbilical, riser
or tube axis, and as a light contact support while traversing along
the umbilical, riser or tube using the driven rollers. The rear
module driven clamping rollers are orientated to rotate the crawler
unit about the umbilical, riser or tube axis. The non-driven caster
rollers of each clamping mechanism are supported by a spring stack.
When first closed, there is a gap between the rotational drive
wheel and surface of umbilical, riser or tube, with only the caster
wheel in contact, acting as a light support for keeping the rear
module concentric with the umbilical, riser, or tube.
[0100] When rotation is required, the clamp mechanism is further
closed, compressing the caster spring stack until the rotational
drive wheel is clamped onto the umbilical, riser, or tube. The
caster axis runs through the centre of the caster wheel, and will
rotate though 90 degree as the crawler unit is first rotated. With
rotational motors in hold, the rear module acts a moment supporting
clamp for hand-over-hand propulsion.
[0101] The preferred embodiment of the crawler unit uses an
on-board accumulator, or multiple with various pressure ranges, to
supply a constant push force to a number of the clamp cylinders. Of
the three clamp cylinders on a module, two of them are used to
supply a constant push force (Supplied from accumulator), while the
other is used to control the position, used to keep the umbilical,
riser or tube central within the module. At least a single clamp
arm (which would be one used to control position) would have
positional feed back to the PLC from a sensor such as a liner
transducer.
[0102] The preferred embodiment of the crawler unit uses an
on-board HPU in conjunction with hydraulic motors and cylinders for
reliability, and to enable power to be supplied electrically to
simplify the umbilical, rather than having to supply hydraulic
power via hoses. Supplying hydraulic power via an umbilical could
however be an embodiment of the crawler unit, and may even be
preferred when only short umbilical lengths are required, as it
removes need for a sub-sea or marinised HPU. An on-board power
supply such as a battery could also be used to remove the need to
supply power through an umbilical.
[0103] The preferred embodiment for controlling the crawler unit is
by use of an on-board PLC, with communication with a surface user
control console. The PLC shall use inputs from both on-board
sensors and surface control console inputs to control hydraulic
manifolds and other on-board systems. Communication between the PLC
and any other on-board systems such as cameras or a
sensor/inspection module being carried by the crawler unit, shall
preferably be done via a fibre optic core within a combined power
and control umbilical.
[0104] The embodiment could also have incorporated a set of subsea
thrusters to enable the crawler unit to position itself onto the
umbilical, riser or tube without the need for diver or ROV
intervention. The crawler unit would be first deployed into the
water, and would then swim to, and orientate itself with, the
umbilical, riser or tube. Further to this, the embodiment could
also feature adjustable ballast, which would allow the unit to
adjust the amount, and position of its centre of buoyancy. This
could be used to help maintain a desired crawler unit orientation
when submerged.
Operational Sequence
[0105] 1) The front module rollers are used to propel the crawler
unit along the umbilical, riser, or tube until reaching an item
such as a clamp on buoyancy or strake, or simply a section of
umbilical, riser, or tube which the rollers cannot be driven over,
as shown in FIG. 4. The rear module caster rollers are lightly
clamped onto the surface of the umbilical, riser, or tube to
support the rear of the climber unit. [0106] 2) The rear module
clamping units are fully closed, with caster roller spring stack
compressed, and rotational rollers clamped onto umbilical, riser or
tube. The front module clamp rollers, including the centralising
fingers, are then fully opened to allow passage of an item. [0107]
At this point the crawling unit would be rotated to align gap with
the mooring rope if required. Note also that should an item or
object extend outside the maximum module aperture diameter, such as
a buoyancy mooring line, then the centralising fingers will also
need to be opened as shown in FIG. 5. [0108] 3) The walking
cylinders are extended to move front module in direction of travel,
positioning front module rollers over or beyond item being passed.
The front module rollers are then clamped onto the surface of the
item, umbilical, riser or tube as shown in FIG. 6. The front module
rollers being driven are normally in hold, so preventing crawler
unit from freely traversing. [0109] 4) The rear module clamps are
partially released, removing the rotational rollers from the
surface of the umbilical, riser, or tube, but keeping the caster
rollers in contact to give support to the rear module. The walking
cylinders are then retracted, moving the rear module either nearer,
over or beyond the item as shown in FIG. 7. Note that when the rear
module is being taken past an item the rear clamps would need to be
fully opened rather than serving as a support. In instances of the
rear or front clamp being fully opened, then the other clamp would
be providing moment support to try and keep the modules concentric
to the umbilical, riser or tube. Should the umbilical, riser or
tube lose concentricity with either module, the centralising
fingers will return the module to being concentric as the clamps
are closed. [0110] 5) The rear module clamping units are again
fully closed as they were in step 2, and the hand-over-hand
propulsion process is repeated until the item is fully cleared, as
shown in FIG. 8. [0111] 6) Once fully clear of the item or
obstacle, and front module driven roller engaged onto a section of
umbilical, riser or tube which can be driven across, the rear
module caster rollers are positioned to provide a light support,
with rotational rollers clear from surface of umbilical, riser or
tube, as shown in FIG. 9.
[0112] A further embodiment of the present invention relates to a
subsea, bi-directional tool that is able to clean and inspect the
outside diameter of risers, umbilical's, flowlines, pipelines,
mooring lines, ropes, cables and subsea conduit structures.
Further, the tool could be used as a cargo lift to transport
equipment to the ocean floor or from the ocean floor to the
surface.
[0113] The tool is controlled and operated by a topside operative
via a power and/or control umbilical.
[0114] The tool may carry a hydraulic power unit (HPU) or it may be
remotely located.
[0115] The tool has the ability to rapidly traverse structures by
using drive wheels, rollers or tracks.
[0116] The tool has the ability to step over obstacles, for
example, anti-VIV strakes, mooring rope clamps, pipe flanges or
buoyancy modules, by combining the actions of its driven wheels,
its ability to lock the rotational aspect of its driven wheels, the
ability to withdraw its driven wheels from the structure, and by
extending or retracting its linear stepping actuators.
[0117] The tool can swim and attach itself to subsea conduits.
[0118] The tool can swim along and rotate about the axis of subsea
conduits by retracting all wheels and using thrusters in
combination with proximity sensors to remain concentric to the
structure being traversed. (Note: the thrusters and sensors
mentioned are not shown in the following figures).
[0119] The tool is also able to rotationally trim itself through
the use of front and rear steering.
[0120] The tool in FIG. 10 comprises front and rear modules. The
modules are interconnected by three double acting hydraulic
stepping actuators--actuators are used to step/span over obstacles.
Each module is made up of two distinct hinged halves--in the style
of a clamshell--this enables the tool to open and close around the
umbilical or conduit. The halves of each module are moved towards
and away from one another by one or more double acting hydraulic
actuators. When the two halves are closed a gap remains, this
allows the tool to pass mooring ropes without detaching its drive
mechanism or itself from the structure it is traversing.
[0121] The front and rear modules of the tool each have six wheels,
split into three groups of two wheels, each group being arranged at
120.degree. radial intervals. In this embodiment, the tyres on the
wheels are formed with a concave radii to suit the outside diameter
profile of the structure being traversed. The double, in-line wheel
arrangement at each end of the tool is designed to give moment
support when the wheels at one end of the tool are fully withdrawn,
for example, when stepping over an obstacle. The wheel arrangement
of the tool in this preferred embodiment, as shown in FIG. 1, can
accommodate nominal structure diameters between 4'' OD and 24'' OD.
Note: the clearance bore (I.D.) of the tool is 800 mm (31.5'') and
the basic design principles of the tool can be scaled.
[0122] FIG. 11 shows an end view of the tool. Here, the tool is
shown attached to a 12'' OD riser--the gap for passing a mooring
rope or other slender off-take is clearly shown, as are the two
halves of the clamshell arrangement--halves A and B. The double
acting clamshell hydraulic actuator(s) is used to open and close
the clamshell. A steering gear and actuator mechanism are provided
on each of the two modules, with the steering gear allowing a
limited amount of rotational trim to be applied as the tool
traverses--thus, irrespective of the direction of travel of the
tool, full rotational tool trim can be maintained--in all respects,
the tool is fully bi-directional.
Tool Operation
[0123] The tool can be attached onto the structure to be cleaned or
inspected in a number of ways. It can be manually attached by
either divers at or near the surface or subsea, it can be loaded at
or above the splash zone/surface by operatives in a tender, or the
tool can also swim under its own power to the structure.
[0124] To attach, all wheel carriers are fully retracted to ensure
the maximum tool clearance bore available, and the clamshell is
opened. FIG. 12 shows both modules fully open and all wheel
carriers fully retracted. (Note: In FIG. 12 a set of wheels on each
module has been omitted for clarity).
[0125] The tool maneuvers to encircle the structure and the
clamshell closes. Tool centralising occurs in one of two ways: by
centralising fingers (shown in FIG. 13), two of which are connected
to each wheel carrier, each wheel carrier covering a 120.degree.
segment--three segments per module covering 360.degree.. FIG. 13
shows the wheel carriers closing, that is, extending towards the
structure they will clamp on to--the centralising fingers move
simultaneously. The fingers are designed to overlap and clear one
another, thus they are able to close down to less than 4'' OD.
Another method of centralising the tool is the use of proximity
sensors arranged around the perimeter of the tool.
[0126] As the wheel carriers begin to move towards the structure
(which move at the same rate, and are at the same extension), the
position of the umbilical or conduit from each wheel carrier is
measured, which also allows the control system to operate thrusters
to keep the umbilical or conduit concentric as the wheel carriers
close on it.
[0127] FIG. 10 shows the tool correctly loaded onto the structure.
The tool can now undertake its intended operation, whether that be
cleaning, inspection or transportation (Note: for clarity, no
cleaning tools, inspection tools, transportation securing devices,
centralising fingers, umbilical or HPU are shown in FIG. 10).
[0128] The tool is driven along the structure, steering and
correcting its rotational attitude via operator input or by a
control system making constant adjustment to the trim, with a
sensor such as a gyrocompass used to measure relative rotational
position. Where an obstacle is observed approaching, the steering
gear on the tool is used to align the mooring rope gap. The
diameter of an approaching rope can be measured to ensure safe
passage through the mooring rope gap. Through appropriate sensing
and detection, should the tool or operator determine that it is not
possible to safely pass due to obstacle size or geometry, then the
tool can revert to swimming mode.
[0129] In swimming mode the tool will retract all of its wheels.
FIG. 14 shows the tool in this orientation, the tool can use
thrusters to move over/past the obstacle as long as the tool ID
provides sufficient clearance.
[0130] As the tool traverses the structure, the steering gear has
the ability to induce continuous corrections to the rotational
attitude of the tool--this prevents the tool winding its umbilical
around the structure and subsequently stalling. However, it may be
desirable to impose deliberate tool rotation to pre-wind the
umbilical around the structure--this may be useful where, for
example, the tool is required to traverse anti-VIV devices that
contains helical strakes or fins. The pre-wind would be imposed in
a direction opposite to that of the strake helix, such that, the
two should cancel out one another, post obstacle traversal.
Further, half the required pre-winding could be imposed before the
obstacle and half removed post obstacle. Finally, full helical
correction could be made after the traversal of the obstacle.
Should umbilical winding be so large as to stop the tool
traversing, or there is insufficient rotation rate from trim to
unwind, then the tool can release all of its wheels and rotate
itself around the structure using thrusters to unwind it.
[0131] It is intended that the tool's centre of buoyancy will be in
the same position as its centre of gravity, so that there is little
or no moment applied to the umbilical, riser or tube when clamped
using a single module. If this was not the case then the
self-weight and buoyancy forces could act to rotate the tool. This
reduces the forces the wheel carrier actuator shafts and bodies are
exposed to.
[0132] Where the tool meets an obstacle it has the ability to step
over it. However, the tool does not necessarily need to use its
stepping actuators (FIG. 10) for this task, as demonstrated in
FIGS. 15 to 18. [0133] The tool drives up to an obstacle, retracts
the wheel carriers of the module nearest the obstacle (leading),
whilst still being supported by the wheel carriers located on the
other module (trailing). [0134] The remaining set of wheels still
in contact with the structure (trailing) drive the retracted wheels
(leading) over the obstacle (Shown in FIG. 16). [0135] The leading
module re-clamps against the structure having cleared the obstacle,
and the trailing module wheels are opened (Shown in FIG. 17).
[0136] The leading module wheels move the trailing wheels clear of
the obstacle and are re-clamped against the structure. The tool can
now continue on its way (Shown in FIG. 18).
[0137] FIGS. 15 to 18 show the tool passing a buoyancy attachment
type obstacle.
[0138] The extending actuators are included in the design to allow
the tool to step over complex geometry, for example, where multiple
obstacles occur in close proximity to one another FIGS. 19 to 24.
Further, the tool also has the ability to withdraw front and rear
wheel carriers/systems completely, and simply swim over an obstacle
while remaining concentric with the umbilical, riser or tube it is
traversing.
[0139] The general arrangement of a riser and umbilical crawler
used for delivering flexible inspection tools formed according to
an alternative aspect is shown in FIG. 25.
[0140] The basic crawler unit is not able to pass over objects such
as strakes or buoyancy, however would cope with limited diameter
and ovality changes. The unit is hydraulically driven, and uses
cylinders backed by a hydraulic accumulator to apply a constant
clamp force to the umbilical. The umbilical is contacted by
conforming polyurethane concave rollers, two of which are driven,
to reduce contact pressure.
[0141] The unit shown in FIGS. 25 and 26 can accommodate an
umbilical diameter range from 14'' to 8'', however a change out of
the rollers (either to a larger or smaller diameter) would allow
the crawler to be used with a different riser or umbilical diameter
range.
[0142] FIG. 27A shows the crawler unit open and positioned around a
14 inch diameter umbilical. FIG. 27B shows the unit closed around
the umbilical. FIG. 27C shows the unit closed around an 8 inch
umbilical.
[0143] Before being placed around a riser or umbilical, the central
roller set is positioned to suit the intended diameter, which is
done by removing a couple of pins, positioning the central roller
set, and re-pinning to the crawler frame.
[0144] The crawler unit may allow inspection and cleaning tools to
be deployed to positions where space limitations prohibit an ROV,
such as within a tightly packed group of risers or umbilicals as
shown in FIG. 28. Crawler unit could be attached directly to
closely packed riser, or further along Riser/Umbilical were spacing
has sufficiently increased to allow attachment by an ROV.
[0145] While designed to suit a range of diameters, the prototype
Crawler unit may not be suited to diameters smaller than 8'', with
Risers or Umbilical's of smaller diameter potentially requiring an
alternative unit. DNV recommended practice (DNV-RP-F203) is for
Risers to have a minimum spacing of 2.times.OD between outers
surfaces, as shown in FIG. 28 for a 14'' diameter. In some
embodiments the crawler can be positioned between 14'' Risers, it
takes a spacing of at least 3.times.OD for the Crawler to be
positioned within a collection of 8'' Risers. While 2.times.OD is
given as the minimum spacing, this is usually greater for smaller
diameter Risers, as spacing is dictated by that of their hang off
collars. The crawler unit requires a minimum spacing of 600 mm
between outside faces to pass between a collection of risers or
umbilicals.
[0146] While the crawler unit may have limited access to tightly
packed small diameter (<8'') Risers as indicated in FIG. 28, it
would be better suited to deployment of inspection and cleaning
tools than a free flying ROV, which have far greater access
limitations within a group of tightly packed risers or umbilical's
(the body of ROV+inspection tool would sit within a much larger
space envelope than that highlighted by red circle in FIG. 28).
[0147] The crawler unit may be configured to have some/all of the
following features: [0148] 100 m depth rating. [0149] Hydraulic
actuation and drive motors. [0150] Positive buoyancy. [0151]
Weight--.about.130 kg. [0152] Height--700 mm. (1600 mm including
buoyancy & brushes) [0153] Optional cameras, lighting, and
sensors. [0154] PC controlled via optical Ethernet connection.
[0155] Flexible inspection tool/net in air load--+75 kg.
[0156] The crawler unit could be attached to the riser or umbilical
in a number of ways. The crawler unit could be deployed by first
lowering it into the water using either an existing crane or a
dedicated over boarding system such as an A-frame. The crawler unit
sits upright when in water, with its centre of buoyancy located
both centrally and above its centre of gravity. Once in the water
the unit would be maneuvered around the riser or umbilical by
either divers, an ROV (although one of the key advantages of the
Crawler is to negate the use of free flying work class ROV's), or
possibly even by its own thrusters (Self swim). The crawler unit
could either be closed around the riser by divers using local
control for safety, or remotely from the controlling PC.
Environmental conditions may be too severe to allow the crawler
unit to be attached at the water surface, with risk to personnel or
ROV being `slammed` against riser, umbilical, FPSO or Jacket
structure. The crawler unit could be deployed onto the riser or
umbilical by an ROV below the surface of the water, in a similar
manner to how a number of inspection tools are currently deployed,
and could be recovered directly using a lift line rather than
additional ROV manipulation.
[0157] The crawler unit could also be made negatively (or at least
near neutrally) buoyant, which would allow divers to attach the
crawler below the surface of the water rather than use an ROV. The
crawler unit could also be directly deployed onto the riser or
umbilical from above the water.
[0158] Assuming the crawler has been lowered into the water from
the deck of an FPSO or Jacket, the line used to deploy the unit
could be kept attached for retrieval, or as a fall restrictor if
being operated above the waterline.
[0159] The control valves could be arranged to suit how the crawler
is to be deployed. If for example the unit was to traverse below
the surface of the water, then the clamps could be made to open
following loss in power or communication, allowing the crawler to
freely float to the surface. This would not be suitable if the
crawler was being driven up from the water line, where the unit
would remain clamped with rollers locked following loss in power or
communication. A normal `release` state in this situation would
only be acceptable if the crawler had a safety or lift line (fall
restrictor) from above. It could be possible that following a power
or communication failure that the rollers remain clamped, but the
motors are throttled, which would give the crawler a steady decent
if above water, or allow it to float to the surface if below
it.
[0160] Following a failed subsea surface retrieval, an ROV or Diver
could be used to operate a manual valve to release and open the
rollers, allowing the crawler to freely float or be lifted to the
surface.
[0161] It may be possible to integrate an existing inspection tool
of choice into the crawler.
[0162] Inspection tools may be attached to the upper side of the
crawler, with cleaning equipment located on the underside, so
inspection elements do not have to work through thickness of
accumulated marine fouling. An inspection tool attached to the
crawler is shown in FIG. 29.
[0163] A sensor package could be a simple fixed attachment suited
to a particular riser or umbilical diameter
[0164] The sensor mounting could be slightly loaded against the
umbilical so that it is always a set distance from the surface
[0165] It may be of benefit to have ability to rotate the sensor
about the axis of the riser or umbilical, and if so the inspection
tool mounting could enable limited rotation of the tool (/+60
degree, or a full+/-180 mounting could be investigated).
[0166] The inspection tool may be connected to the crawler unit
subsea electronics pod, which provides it with an Ethernet
connection to a surface PC.
[0167] The riser and umbilical crawler subsea electrical pod may
contain the units controller (for example a PLC), which is used to
drive valves on the hydraulic manifold, as well as connect to
additional I/O such as auxiliary systems and sensors. Although
partially dependent on umbilical crawler depth requirement, it is
likely that the electronics pod will be oil filled and pressure
compensated.
[0168] The on-board control unit may be connected to a surface PC,
with the surface PC used as an input to the on-board control unit.
The surface PC would be connected to the control unit through a
fibre via an Ethernet to Fibre convertor. On-board subsea IP
cameras could also be used to relay video to the surface PC if
required, allowing the operator to perform visual inspection, and
to monitor the crawler unit as it moves and/or cleans along the
Riser or Umbilical.
[0169] Sensor and tool packages carried by the crawler may be
connected to the subsea electronics pod, with data relayed to a
surface PC via same fibre optic data line used for control and any
IP cameras.
[0170] FIG. 30 shows proposed system overview.
[0171] The same PC used to read and record data from the inspection
tool could also be used to control the crawler, with interface
software provided.
[0172] Additional analogue or digital I/O which could be connected
to the on-board control unit could include: [0173] Pressure
sensors. [0174] Rotatory encoder; for measuring speed and distance
travelled along the Riser or Umbilical. [0175] Linear transducer;
for giving cylinder positions. [0176] Leak detection; if not oil
filled. [0177] Oil compensator position or min level warning.
[0178] In one embodiment the following are used: [0179] 4.times.
Pressure transducers; for accumulator (.times.2), return, and
supply pressure. [0180] 1.times. Rotatory encoder; for measuring
speed and distance traveled along the umbilical.
[0181] In some embodiments the crawler requires hydraulic power to
drive motors and cylinders, which will be supplied from a remote
surface HPU (other embodiments may have on-board HPU). As some
units are only required to travel to relatively shallow depths of
between 50-100 m, and as it has a low power requirement, then it
would be feasible to supply hydraulic power via a neutrally buoyant
hose, such as those used to drive diver operated equipment.
[0182] In addition to hydraulic power, the crawler may be supplied
with a 28 VDC electrical supply and fibre control core. It is
envisaged that any tool or sensor package to be carried would be
supplied via common electrical cores supplying the crawler unit,
with the tool or sensor package being connected to the unit's
subsea electrical pod.
[0183] Rather than using an expensive bespoke umbilical, the
prototype unit will use a collection of individual cores to make up
its umbilical. The cores may be kept together in a spiral cable
wrap or similar cable management/tidy cover.
[0184] The fibres and electrical cores may terminate into small
housings onto dry-mate connectors, and hydraulic lines would
terminate with quick-connects, allowing the umbilical to be quickly
detached (or replaced) from the crawler unit. The quick connects
may connect directly to the control manifold, while the electrical
and fibre dry-mate connectors would connect to the electronics
pod.
[0185] In many cases, before inspection by various sensor packages,
the riser or umbilical must be relatively free of marine fouling,
Embodiments of the present invention may comprise a riser and
umbilical cleaning module which can be carried by/integrated into
the crawler unit.
[0186] For example, the brush cleaning attachments shown in FIGS.
31 and 32 would allow for 360.degree. continual cleaning, allowing
the crawler to progress at a constant speed along the umbilical.
Cleaning is done using three hydraulically driven brush heads
pressed against the surface of the umbilical. The cleaning brushes
would be suited to a particular diameter, or at best a limited
diameter range, so would need to be changed out to suit diameter to
be cleaned. A scrapper could possibly be attached ahead of the
brushes, just off the surface of the umbilical, to remove the bulk
of any dense marine fouling.
[0187] In this embodiment the brush heads are generally cylindrical
but taper inwards from each side towards their centre so that they
fit onto a generally cylindrical target.
[0188] Allowing the deployment of inspection and cleaning tools
above, below, and within the splash zone. It would require a
combination of ROV's or divers, and personnel hanging from ropes to
deploy to same locations. The unit could be attached at any point
along the riser or umbilical, and traverse to position above,
below, or within splash zone.
[0189] While ROV's or divers may be capable of deploying inspection
or cleaning tools at a distance below the water line, surface waves
may make it difficult or impossible to position and hold a tool at
or near its surface. The crawler unit could be attached either
above or below the water line if surface attachment is not
possible, while being able to move into and hold itself within the
splash zone. This would remove need for divers or expensive ROV's
to operate near the surface where environmental conditions may be
too severe (risk to personnel or equipment being `slammed` into
Riser, Umbilical, FPSO, or Jacket structure).
[0190] The crawler unit may use the riser/umbilical to attach and
position itself, giving greater positioning and attachment security
than a free flying ROV, and so allowing a larger environmental
operating window.
[0191] The crawler unit may combine riser/umbilical cleaning (often
required before inspection) and inspection into a single tool
deployment and operation. Many present systems have to use an ROV
with a cleaning tool before redeploying with an inspection tool.
The present invention removes the need to tie up high value work
class ROV's and their pilots, at most being required for initial
attachment and removal, or possibly not at all if attached by
personnel or self-swim ability.
[0192] Although illustrative embodiments of the invention have been
disclosed in detail herein, with reference to the accompanying
drawings, it is understood that the invention is not limited to the
precise embodiment shown and that various changes and modifications
can be affected therein by one skilled in the art without departing
from the scope of the invention as defined by the appended claims
and their equivalents.
* * * * *