Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
11~037S
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~ he invention relates to a r~ova~le connecting conduit between
a maoring buoy for fluid transfer and a submerged pipeline, the
r~oring bucy being provided with rneans for m~oriny thereto~a ship
which is to be loaded or unloaded. A mcoring buoy of this type is
descri~ed, for ex~unple, in British patent specification I~Jo. 977,451.
For this purpose rnovable connecting conduits are known which
are entirely Duilt up of hoses. ~en a high specific gravity fluid,
for exam~le a liquid/solid slurry, is ~assed through such a r,~vable
connecting conduit entirely built up of hoses, the connecting
conduit will easily be able to sag. Owing to the sagging stresses
may occur which may give rise to crack f~rmation and even rupture
of the conduit. Another drawback of a movable connecting conduit
entirely made up of hoses is the relatively short lifetime of the
hoses. .~reover, the hoses are subject ~o substantial wear cwing to
the continuous r~ovements of the rnaoring ~uoy in relation to the
sukmerged pipeline, as a result of which warn hoses rlust often be
replaced. Owing to the high price of th~ hoses tneir replacement
means an economic disadvantage. ~reover, owing to the rapid wear
of the hoses the r,~oring buoy often cannot be used.
Another kn~wn movable connecting cond~it between a r~ooring
buoy and a sukmerged pipeline consists of a series of rigid pipes
which are r~3vably intercormected. Connecting conduits of this type
are, for example, known fram British patent specification ~o.
1374392.
A drawback of a connecting conduit of thL last-mentioned type
is that the rigid pipe(s) located closest to the mooring buoy can
easily be damaged when a ship red to the b~ay bumps against the
rigid pipe(s).
m e risk of a rigid pipe being damaged by a ship will be
greater according as larger ships provided with a bulbous bow are
r.~ored to the buoy.
The object of the invention is to remove the aforementianed
drawbacks, which are inherent in the known rn~vable cor)necting
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conduit, by providing a movable connecting conduit which is
characterized in that, seen from the mooring buoy in the direction
of the pipeline, the connecting conduit is built up of at least one
hose and at least one rigid pipe, which rigid pipe is movably
connected to the pipeline, while at least one flexible tension
member, which is under tensile stress, extends between the mooring
buoy and the rigid pipe end located near the hose.
With this proposed movable connecting conduit the chance that
a ship will cause damage is small, since the hose part of the
conduit has a high degree of flexibility and in the event of a
collision it can th refore readily bend away without permanent
deformation.
Owing to the presence of said flexible tension member it is
prevented that the hose part is subjected to excessire tensile
stress. In the event of a collision this flexible tension member
can also readily bend away without incurring damage. Moreover, the
hose according to the invention is stretched as much as possible
and under any conditions it is subject to only a slight degree of
bending. This is an advantage compared with a connecting conduit
entirely built up of hoses, in which case the hoses, for example in
the event of strong currents or wave action or high specific gravi-
ties of the fluids to be transported through the hoses, are highly
subject to bending and will therefore soon be worn out. As may
appear from the foregoing, the lifetime of the hose part of the
connecting conduit according to the invention is prolonged con-
siderably, owing to which a more economic use can be made of the
mooring buoy.
The invention will now be further discussed with reference to
an embodiment of the invention, as shown in the drawings, wherein:
Fig. 1 is a side-view of a movable connecting conduit accor-
ding to the invention, and
Fig. 2 is a front view of part of the movable connecting
conduit seen in the direction II according to Fig. 1.
Fig. 1 shows the submerged part of a single buoy mooring or
mooring buoy 1 for fluid transfer which is connected to the
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bottom 2 of a body of water 3 by means of anchor chains (not shown
in the drawings). The mooring buoy 1 is further provided with
conventional means (not shown in the drawings) for mooring a ship
to the buoy. A fixed pipeline 4 for thé supply and discharge of
fluid is located near the bottom 2.
A movable connecting conduit is located between the mooring
buoy 1 and the pipeline 4, which connecting conduit is formed by a
hose 5 and a rigid pipe 6, which pipe is provided with reinforcing
elements 7 and is connected to the pipeline 4 by means of a univer-
sal joint 8.
The universal joint 8 has a rotary shaft 9 normal to the planeof the drawing and a rotary shaft 10 located in the plane of the
drawing. At the universal joint 8 the pipeline 4 and the rigid pipe
6 are interconnected by means of a hose piece 11, in order to
create a flexible fluid connection between the pipeline 4 and the
rigid pipe 6.
The hose 5 is built up of a number of hose parts 12 which are
interconnected by means of flanged connections 13. The ends of the
hose 5 are connected by means of flanged connections 14 and 15,
respectively, to the rigid pipe 6 and a pipe 16 which forms part of
the moor;.ng buoy 1.
Furthermore, two flexible tensile members in the form of
chains 17 and 18 which are subject to tensile stress, extend
between the mooring buoy 1 and the rigid pipe 6, which chains are
connected to the rigid pipe 6 and the mooring buoy 1 by means of
universal joints 19 and 20 respectively. The universal joints 19
and 20 are provided with a rotary shaft 21 and 22 respectively,
normal to the plane of the drawing, and a rotary shaft 23 and 24
respectively, located in the plane of the drawing. Between the
universal joint 20 and the mooring buoy 1 there is a rotatable
coupling 25 allowing rotation around a vertical axis.
The universal joints 8, 19 and 20, together with the rotatable
coupling 25, allow displacements of the mooring buoy 1 in relation
to the pipeline 4, so that the occurrence of torsional stresses in
the hose 5 and the rigid pipe 6 is prevented.
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In order to prevent the hose 5 being damaged by the chains 17
and 18, the hose 5 is provided with removable collars 27 made, for
example, of rubber.
In order to maintain the chains 17 and 18 under tensile
stress also in heavy wheather, when the mooring buoy 1 is subject
to large displacements in relation to the pipeline 4, the rigid
pipe 6 is provided with a weight 28. Preferably each of the chains
17 and 18 is provided with a device 29 to enable the length of the
chains 17 and 18 to be adjusted. To measure the tensile stresses
in the chains 17 and 18 an electronic measuring device (not shown
on drawing) may, if desired, be used.
Furthermore the chains 17 and 18 may be provided with a shock
absorber (not shown in the drawings) in order to prevent the
occurrence of too heavy shocks. Such a shock absorber is in
particular desirable in regions where wide tidal ranges and very
poor weather conditions may occur.
When a ship moored to the mooring buoy 1 bumps against the
hose 5 and the chains 17 and 18, for example owing to the wave
movements, the combination of hose and chains will, as a result of
its flexibility, bend away and therefore incur no damage from the
collision.
Since the chains 17 and 18 invariably absorb the weight of
the rigid pipe 6, the hose 5 can be replaced in a rapid and simple
manner.
It should be noted that instead of the chains 17 and 18
shown, another suitable flexible tension member, for example a
cable, can be used.
It is further remarked that the invention is not limited to
the combination of one hose and two chains or other flexible
3o tension members. For example, a combination of two hoses and one
tension member or combinations of several hoses and several
tension members is/are also possible.
Instead of the weight 28, it is also possible to use other
forms of ballast to maintain the tension members under tensile
stress. In this connection reference is made, for example, to
ballast tanks which are connected to the rigid pipe 6.
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Finally, it is noted that the universal joints 8, 19 and 20,
together with the rotatable coupling 25, can be replaced by other
special couplings, for example ball joints.
