Note: Descriptions are shown in the official language in which they were submitted.
~L~9~
The invention relates to an anchor for attaehing
or connecting device having a buoyancy resulting in an
upwardly directed force eomponent being exerted on the anchor,
which force is applied to a part which is maintained in
position by means of underpressure.
Such an anchor is known from the U.S. patent No.
4,029,039. In this known device, functioning with under-
pressure, the anchor in fact consists of one single body to
which the upwardly directed force is applied, which body has
at the underside a cavity which is closed by the bottom after
positioning the anchor on the bottom. In said cavity an
underpressure can be created to hold the body more strongly
to the bottom than by its own weight alone. There are many
other publieations describing these so-called suction anchors,
however they all are based on the principle that the anchor
body is drawn onto the bottom by means of the underpressure.
Therefore all suction anchors have the disadvan-
tage that their operation is dependent on the quality of a
fluid tight seal between the bottom and the cavity in the
anchor body in which the underpressure should be created.
The bottom is however in many cases porous, so that the
influence of the underpressure is impaired by penetrating
water. Therefore in these prior art suetion anehors, whieh
should be kept in position during a rQlatively long period,
the weight cf the anehor plays always a dominating role.
In emergency situations howeverr for instance when a floating
island eonstruetion or a mooring system is threatened by an
ieeberg and therefore should be removed immediately, time
eonsuming problems are eneountered when ~oosening the anchor
and similar problems are of course eneountered when the
original anehoring situa-tion is to be restored.
An object of the invention is now to provide in
a very simple way a solution for this problem.
Aeeording to the invention there is provided in
an anehor for eonneeting or attaehing a buoyant deviee,
said anehor eomprising a first body which is anchored on
the oeean floor, and a second body whieh is eonnected to
:
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the buoyant device, said first and second bodies cooperating
with each other such that between said bodies a sealed space
is formed within which a pressure can be created which is
lower than the water pressure outside said bodies; the
improvement in which said first body has a vertical guide
element for the second body, the guide element being a
cylinder open at the top and closed at the bot-tom and the
second body being a cylinder which by means of a circum-
ferentially extending sealing ridge is guided and sealed
within the first-mentioned cylinder.
According to the invention therefore the anchor is divided
into two parts, one of which permanently rests on the sea bottom
or is attached to the sea bottom, for instance by poles driven
into the ground, whereas the other part is guided on said first
part and can be coupled therewith under the influence of the
underpressure. The result thereof is that not only the under-
pressure coupling has a permanent character, but also tha-t de-
coupling is very simple and the part of the anchor to be elevated
has a manageable weight. Now a mooring system can comprise a
column having buoyancy capacity in the upper end thereof and a
thereto connected tanker~ which column for instance has a
universal joint connection to the anchor and by removing the
underpressure the whole system can be sailed away immediately.
In general fluid conduits are running along such a column or
through such a column, which conduits may comprise automatic
coupling elements near the universal anchor joint closing the
conduits automatically when the connection is broken and auto-
matically opening said conduits when the connection is restored.
It is very easy to restore the anchoring position by sailing
backwards and bringing the lower end of the column into the
correct position above the fixed anchor part for instance
using underwater cameras and lowering the column until the
guiding elements cooperate, after which the coupling is restored
again by generating the underpressure.
Eventually it is possible to activate a normal locking device
after the coupling is realized by means of the underpressure,
whereafter the underpressure can be released. Such a normal
locking device is however less suitable for quick coupling, even
i~ it is remote controlled, because the upward force acting
on the anchor is also applied to the locking device eventually
preventing the decoupling thereof. The forces applied to said
locking devices can be reduced to zero if the underpressure is
generated again and thereafter said locking device can be de-
coupled.
According to the invention the base body may have a space
which is open at the upper side in which space the second body is
"~ axially moveably guided and sealed off against the first body.
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Said space can ~or instance be a cylindrical space into
which the second body can move in the same way as a piston,
which second body is coupled to an anchor line or other
anchoring means. Said upwardly open cylindrical space has
a double function, namely a guiding function and a coupling
function in cooperation with the underpressure.
It is also conceivable to use separate guiding means for
instance in the form of upwardly extending guiding pins on the
first body. The second body is thereby sealed against the
first body by means of a sealing ridge between the guiding
elements such that an underpressure chamber is created between
the first and second body. That implies essentially that the
first body has a smooth upper surface between the guiding pins
and the seco~d body has a smooth lower surface b~tween which
smooth surfaces a ring shaped sealing ridge is positioned
connected to the one or the other body. As soon as the sealing
is effected because the sealing ridge is clamped between both
bodies, i is possible to obtain the coupling by generating
the underpressure. This type of coupling has the advantage that
the second body can be embodied as a suction cup, the sucking~
force of which is applied to the first body.
A very simple embodiment is according to the invention
obtained when the second body comprises a closed hollow space
which is connected through some kind of valve means to the space
bounded by both bodies. ~aid hollow space can, as long as it
is above the water level, be filled with air under atmospheric
pressure and thereafter be closed. If the second body is now
submerged and moved in the direction of the first body such,
that the space bounded between both bodies is created, then
said space will be filled with water. If the val~e means
between the air filled hollow space and said water containing
space between both bodies is opened, then immediately water will
flow into said air filled space, because the air pressure is
significantly lower than the water pressure at the same depth.
In this way the connection between both bodies is established
automatically without the necessity to supply additional energy.
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The invention will now be explained in more detail with
reference to the drawings.
Fig. 1 illustrates schematically a possible embodiment
of the anchor according to the invention.
Fig. 2 illustrates schematically anobher embodiment.
Fig. 3 illustrates a third embodiment and
Fig. 4 illustrates a fourth embodiment.
Fig. 5 illustrates a fifth embodiment.
The anchor illustrated in Fig. 1 comprises a body 1
positioned to the sea bot-tom 2 and maintained in that position
by means of the piles 3 having the larger heads 4.
Said body 1 has a cylindrical caslng 5 into which the
second body 6 i5 inserted, which second body is embodied as a
cylindrical body having a sealing ridge 7 and a guiding or a
sealing ridge 8.
Said body 6 is through a universal joint 9 coupled to a
column 10, of which the upper endcomprises a buoyant body 11,
such that the column tries to maintain a vertical position.
Said buoyant body may also be positioned below the water level~
The reference number 12 indicates a pump on the second body 6
by means of which through the channel 13 water can be pumped out
of the space 14, creating an underpressure in said space and
establishing the coupling between the parts 1 and 6. It will be
clear that when the underpressure is relieved, which is very
~5 easily done by means of opening a remotely controlled valve,
the second body 6 with the thereto connected column 10 and
further means or systems connected to said column can be sailed
away immediately. It is very easy to reestablish the
connection thereafter.
Because in general conduits will run through or along the
column 10, connected to conduits which are positioned on the
sea bottom, it is preferred that at greater depth the coupling and
decoupling of said conduits is carried ou-t automatically. That
can be realized in a very simple way using prior art means. In
the figures schematically one conduit 15 is indicated bridging
" the universal joint 9 by means of the flexible tube 16 and
connected through the coupling 17 to a conduit 18 alongside the
5g~
casing 5, which conduit 18 is connected to the
conduit 20. The coupling 17 can be embodied as an
automatic remotely controlled automatic coupling.
The reference number 21 indicates a stop element.
The anchor in the embodiment illustrated in
Fig. 2 comprises also a first body 22, resting on
the sea bottom or connected there-to by means (not
shown in detail) and comprising a cylindrical par-t
23 for receiving the second body 24 which is through
the universal joint 25 coupled to the column 26 the
upper end of which is connected to the coupling arm
27 of the tanker 28. Said arm 27 is influenced by the
buoyant body 29. The sealing elements are schematically
indicated by 30 and the pump is indicated by 31.
In this embodiment the first body 22 comprises a
mlmber of upwardly directed guiding pins or columns 32,
cooperating with sidewardly extending guiding means 33
of the second body 24. In this embodiment the guiding
function and coupling function are therefore separated.
The embodiment of Fig. 3 is very similar to the
embodiment of Fig. 2 with the exception that the first
body ~2 comprises a section 34 of a locking device attached
to the wall of the cylindrical part 23, which element
cooperates with the, part 35 of the locking device attached
to the second body 24~
In this embodiment an anchor line 36 is illustrated
instead of a column 26.
In the embodiment of Fig. 4 the first body 37
comprises guiding pins 38 and the second body 39 is
essentially embodied as a plate having guiding passages
40 for the pins 38. Said plate 39 carries a ring
shaped sealing ridge 41. As soon as said ridge is
positioned ~ tne uppe,r surface 42 of the first body 37a
space of relatively small volume is created from which
by~means of the pump 43 water can be removed resulting
in an underpressure in said space.
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It will be clear that instead o~ cylindrical
underpressure chambers also underpressure chambers
of other shapes are conceivable. Furthermore it
will be clear that any type of anchoring means can
be connected to the detachable second body. The
guiding means will in general have a vertical axis,
however it is also conceivable that the central axis
is not exactly vertical.
The embodiment of Fig. 5 corresponds in essense
with the embodiments illustrated in Figs, 1 and 2.
In this embodiment the base element, maintained
on the sea bottom is indica-ted by 50 and on said
base the upwardly open wall section 51 is installed
into which the second body 52 is inserted and sealed
by means of the sealing ring 53. The second body is
positioned at the lower end of an upwardly directed
column 54.
The second body 52 comprises a closed box having
a hollow space 55. Said box comprises at the under
side a valve 56 and a tube 57 runs through said space
55 to a valve 58 at the upper side.
The space 55 can be filled with air under atmospheric
pressure. If the body 52 is inserted into the body 51 then
by opening the valve 56 water will enter from the space 59
between both bodies 51 and 52 into the inner space 55 with
the result that the coupling is established.
For decoupling it is only necessary to open the valve
58 so that the pressure in the space between -the bodies 51
and 52 is brought back to the value it had before so that
the body 52 can be removed upwardly out of the body 51.
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