Patent Description:
A first known solution is a transfer system comprising at least one flexible pipe. However, this type of transfer system has a very limited range of movement. More particularly, this transfer arm comprises flexible pipes. However, flexible pipes must not be bent beyond a certain limit in order not to be damaged. Furthermore, the rate of flow is limited by high losses in pressure from the flexible pipes, in particular on the vapor return line in which the pressure losses must be minimal.

A second solution is described in patent application <CIT>. However, the transfer arm, described in that document, has a limited range of movement. Furthermore, the sections of rigid pipe employed in the cited application require to be supported in the zone between the two ships.

This solution is also very constraining, in particular because it requires the use of a crane throughout the time of transfer of a cryogenic product between for example an LNGC and an FSRU.

The present invention is directed to providing a system for the transfer of cryogenic product from a first floating structure for storage and transport of cryogenic product to a second fixed or floating structure for storing cryogenic product placed side by side and not having the drawbacks mentioned above and furthermore leading to other advantages.

To that end, according to a first aspect the present invention concerns a floating structure for storage and transport of cryogenic product, as defined in claim <NUM>.

Such a solution has numerous advantages and in particular those of fast implementation and avoids the permanent use of a hoisting device dedicated to the transfer of fluid.

According to other possible features, taken in isolation or in combination one with another:.

According to a second aspect the present invention concerns a method of fluidically connecting a system for transferring cryogenic product, as defined in claim <NUM>.

Still other particularities and advantages of the invention will appear in the following description of non-limiting examples, made with reference to the accompanying drawings, in which:.

<FIG> represents a diagrammatic side view of a short-chain transfer system for the transfer of cryogenic product from a first floating structure <NUM> for storage of cryogenic product (here a LNGC) to a second fixed or floating structure <NUM> for storing cryogenic product (here an FSRU), comprising a transfer pipe formed from rigid sections of pipe configured for transporting the cryogenic product between an extension pipe <NUM> linked to the first structure <NUM> and an extension pipe <NUM> linked to the second structure <NUM>, the sections of pipe being fluidically connected each to the next by connection means <NUM> to <NUM> able to transport the cryogenic product.

A extension pipe <NUM> is linked at one of its ends to the second structure by a collecting device <NUM> and at its other end to a section of transfer pipe by two bolted couplings <NUM>.

A bent portion <NUM> is linked by a cryogenic swivel joint <NUM> to a transfer pipe tip <NUM>' bearing the linking coupling to a coupling of the extension pipe <NUM> (cf. the pair of couplings <NUM> in <FIG>).

The cryogenic joint <NUM> has its horizontal main axis in the plane of the drawing paper. Thus, this structure enables rotation of the transfer system in a vertical plane.

The bent portion <NUM> is linked to the rest of the transfer system by an ERS <NUM>, which latter will be described later.

The ERS comprises in particular a lower part <NUM> linked to a section of pipe of half-circular general shape.

The half-circle section of pipe comprises two bent sections abutted so as to form a half-circle. The upper part of the half-circle section of pipe is linked to the lower part <NUM> of the ERS by a cryogenic swivel joint <NUM> and at its other end by a cryogenic swivel joint <NUM> to a bent section of pipe <NUM>.

The cryogenic swivel joint <NUM> has its vertical main axis in the plane of the drawing paper and enables a rotation around the main axis of the ERS <NUM>.

The cryogenic swivel joint <NUM> has its horizontal main axis in a plane perpendicular to the drawing paper and enables a movement in the plane of the drawing paper.

Thus, the specific arrangement of the three cryogenic swivel joints <NUM> to <NUM> makes it possible to obtain movements in three dimensions of the system for transfer between two structures.

Next there are represented four bent sections of pipe <NUM> to <NUM> linked to each other by a cryogenic swivel joint <NUM> to <NUM>.

In other words, the bent section of pipe <NUM> is linked to the bent section of pipe <NUM> by a cryogenic swivel joint <NUM> of which the horizontal main axis is perpendicular to the plane of the drawing paper.

The bent section of pipe <NUM> is linked to the bent section of pipe <NUM> by a cryogenic swivel joint <NUM> of which the horizontal main axis is also perpendicular to the plane of the drawing paper.

The bent section of pipe <NUM> is linked to the extension pipe <NUM> by three abutted bent sections immobile relative to each other.

In other words, the bent section of pipe <NUM> is linked to the bent section of pipe <NUM> via a section comprising three bent sections abutted so as to form a half-circle terminated by a section bent at <NUM>° to its upper part. The lower part of the half-circle section is linked to the bent section of pipe <NUM> by a cryogenic swivel joint <NUM>. The upper part of the section is immobile relative to the bent section of pipe <NUM>.

The upper part of the bent section of pipe <NUM> is linked to the extension pipe <NUM> via a cryogenic swivel joint <NUM>, a bent portion, a second cryogenic swivel joint <NUM> and a coupling tip forming with the coupling of the extension pipe <NUM> a pair of couplings <NUM>.

The cryogenic swivel joint <NUM> has its vertical main axis in the plane of the drawing paper and enables a rotation around the main axis of the bent section of pipe <NUM>.

The cryogenic joint <NUM> has its horizontal main axis in the plane of the drawing paper. Thus, this structure enables rotation of the transfer arm in a vertical plane.

Furthermore, the short chain part <NUM> of the transfer pipe is constituted here by the sections of pipe <NUM> to <NUM> linked each to the next and to the rest of the structure by cryogenic swivel joints <NUM> to <NUM>. The number of such sections of pipe may in practice be reduced to three or be greater than four.

At the location of each metal bent portion is disposed at least one reinforcing collar making it possible to avoid flattening of the metal bent portion under the effect of high loads. In the embodiment represented in <FIG>, the reinforcing collar is constituted by a metal circle welded to the periphery of the bent portion.

It will be noted in this connection that a section of pipe may in practice be represented just by a bent portion.

Moreover, the arrangements of the axes and planes as mentioned supra correspond in practice to those of the structures <NUM> and <NUM> when they are placed side by side without being either inclined or offset longitudinally relative to each other.

It will furthermore be noted that each extension pipe towards the edge of the structure and its connection coupling form a connection device for the transfer pipe.

The connection means are cryogenic swivel joints here with a rotational axis. As a variant, it may be envisaged to use flexible sections of pipe.

Furthermore, each pipe or section of pipe <NUM> to <NUM> here is of uniform construction, of preferably between <NUM> and <NUM> inches (<NUM> inch = <NUM>). However, as a variant, they may be variable.

The extension pipe <NUM>, on the second floating structure <NUM>, is carried by a support <NUM> and linked to a device for storage of cryogenic product (not shown in <FIG>) by a collecting device <NUM>.

The extension pipe <NUM> is carried at the first floating structure <NUM> by a support mounting <NUM> making it possible to take up part of the bending stresses to which a collecting device <NUM> of the floating structure <NUM> is subjected when the transfer system is connected via the extension pipe <NUM>.

The two extension pipes <NUM>,<NUM> are linked to the transfer system by bolted couplings <NUM>, <NUM> making it possible to provide the cryogenic link of the transfer system. As a variant, one of the couplings of each pair of couplings (or of one of the two pairs only) may be replaced by a coupler.

In practice, at least two transfer systems are installed when a fluid transfer is carried out. A transfer system provides the transfer of the useful cryogenic fluid, that is to say the liquefied gas. A second transfer system of the same type provides the return of cold vapor (which is cryogenic in practice) in parallel with the transfer of cryogenic fluid.

As can still be seen in <FIG>, the short chain transfer system comprises a self-supporting short chain <NUM>. In other words, no hoisting device is required during the phase of transferring cryogenic fluid.

As already indicated, this short chain <NUM> comprises at least three rigid bent sections of pipe, here four <NUM>, <NUM>, <NUM>, <NUM>, situated in the vertical plane, able to transport cryogenic fluid.

In this case, by bent it is meant that the sections are bent at their end or that bent portions are welded to the ends of straight sections.

The four bent sections of pipe <NUM> to <NUM> are linked together each to the next by three cryogenic joints <NUM> to <NUM>.

As also indicated supra, the short chain <NUM> is next linked to the extension pipes <NUM>, <NUM> via the section of pipe <NUM>, bent portions and connection means <NUM>-<NUM> and <NUM>-<NUM>.

In the embodiment represented in <FIG>, an Emergency Release System <NUM>, commonly called ERS system, is disposed at the bent portion <NUM>. Of course, in an alternative embodiment, the Emergency Release System <NUM> could be disposed at another section of pipe such as the section of pipe <NUM> linked to the extension pipe <NUM> on the first floating structure <NUM>.

The ERS <NUM> comprises two parts: an upper part <NUM> linked to the bent portion <NUM> and a lower part <NUM> linked to the connection means <NUM>. In case of emergency stoppage, the two parts of the ERS <NUM> detach. The lower part <NUM> is kept from free fall by a cable - not shown - linked to a winch <NUM> disposed on the deck <NUM> of the second floating structure <NUM>.

The winch makes it possible to control the fall of the short chain <NUM> towards its position of vertical equilibrium along the hull of the LNGC <NUM>. Bumpers <NUM>- <NUM>, here of neoprene, disposed on the short chain (at the location of the connection means) enable the hull to be protected.

The cable is not fastened to the winch drum and is naturally released from the drum at the end of unreeling.

The extension pipe <NUM> is linked here to the moored or floating structure <NUM> via a support mounting <NUM> comprising two vertical rigid arms <NUM> linked at one end of the deck of the second floating structure <NUM> and at a second end to a cross-bar <NUM> for supporting the extension pipe <NUM>.

In the embodiment represented in <FIG>, a support mounting for the connection pipe <NUM> is represented.

The support <NUM>, represented here, comprises a rectangular base <NUM> on which rest two substantially vertical beams <NUM>. These beams bear a horizontal beam <NUM> on which is placed, here, a shim <NUM>. The bearing of the extension pipe <NUM> is made via a roller <NUM>.

The support mounting <NUM> makes it possible to reduce the stresses on the collecting device <NUM> when the transfer system is connected.

Play exists before connection of the short chain <NUM>. When the short chain <NUM> is connected, the extension pipe <NUM> is bent and comes to bear on the shim <NUM>.

This is a means for reducing the vertical load transmitted to the platform of the LNGC by acting on the collecting device <NUM> to the maximum of its capacity at the time of bending.

The support <NUM> is furthermore provided to allow for the thermal shrinkage of the extension pipe <NUM>.

If required, the support mounting can comprise lateral stops <NUM> to take up the lateral loads of the short chain <NUM>. In the normal way, these loads are small and do not generate excessive bending moment on the collecting device <NUM>.

In one alternative embodiment, the support mounting <NUM> forms part of the extension pipe <NUM> and the space enabling the shim to be fitted is located between the deck <NUM> of first floating structure <NUM> and the base <NUM> of the support mounting <NUM>.

In the embodiment represented in <FIG> a linkage system <NUM> is represented.

The linkage system <NUM> makes it possible to facilitate the connection between the extension pipe <NUM> and the section of pipe <NUM> at the time of the connection phase. Thus, the maintenance time is in particular optimized.

More specifically, the linkage system <NUM> comprises two parts cooperating with each other: a male part <NUM> linked to the section <NUM> and a female part <NUM> linked to the extension pipe <NUM>. The female part <NUM> comprises an upwardly open cut-out <NUM>, which is hook-shaped here, and configured receive the male part <NUM> forming the complementary part and comprising for such purpose a ring-shaped part <NUM> (here two parallel lugs fastened to the section <NUM>, between which extends a rod, perpendicularly to the lugs).

When the two parts <NUM>, <NUM> are linked, the fastening of the link is maintained by means of screw-nut type fastening by virtue of the bores <NUM>.

This linkage system has the advantage of guiding the end of the transfer system but also of keeping the ends linked when the hoisting device, enabling the connection to be established, is no longer used.

In the embodiment represented in <FIG>, a linking method is represented in different steps.

In <FIG>, the transfer system is already linked to the floating structure <NUM> by the section of pipe <NUM> and is held in elevation at its other end above the level of the pipe <NUM> by means of a hoisting device, such as a crane, by a ring <NUM> or an equivalent hitching means for a hook of a hoisting device. There are may be a second one, as a variant, on the opposite side of the transfer pipe.

When the male and female parts <NUM>, <NUM> are placed in communication, with reference to <FIG>, the transfer arm comes to a higher level than the free end of the extension pipe <NUM>. Thus, these parts <NUM>, <NUM> of the linkage system <NUM> may cooperate before the transfer pipe and the extension pipe <NUM> are face to face for them to be bolted.

In the embodiment represented in <FIG>, a purging method is represented in different steps.

In <FIG>, the pipe <NUM> linked to the collecting device on the floating structure <NUM> comprises a two-way valve <NUM> enabling the cryogenic liquid to be stopped or allowed to be conveyed to the second floating structure <NUM>. The extension pipe <NUM> linked to the collecting device of the second floating structure <NUM> also comprises a two-way valve <NUM> enabling the cryogenic liquid to be stopped or allowed to be conveyed to the storage device - not shown -. The extension pipe <NUM> is linked to a nitrogen supply pipe <NUM> linked to a pressurized nitrogen network enabling nitrogen to be forcefully inlet into part of the extension pipe <NUM> of the second floating structure <NUM> and into the transfer system. The nitrogen supply pipe <NUM> also comprises a two-way valve <NUM> enabling the nitrogen to be stopped or allowed to pass into the fluid transfer system.

When cryogenic liquid is transferred, with reference to <FIG>, the cryogenic fluid transfer valves <NUM>, <NUM> are open and the nitrogen supply valve <NUM> is closed. Thus, the cryogenic liquid can flow between the two floating structures <NUM>, <NUM>.

With reference to <FIG>, when the transfer of cryogenic liquid has terminated, the valve of the second floating structure <NUM> is closed and the valve of the first floating structure <NUM> stays open. The nitrogen supply valve <NUM> is open allowing nitrogen to pass into the transfer system. Thus, the amount of cryogenic liquid is reduced in the sections of pipe forming the transfer system.

With reference to <FIG>, the nitrogen supply valves and the first floating structure <NUM>, <NUM> are closed when the cryogenic liquid is totally evacuated or evaporated and the pipe rendered inert. The valve and the second floating structure <NUM> is kept closed. Next, the transfer system is linked to a hoisting device (not shown). Then the transfer system is disconnected at the location of the extension pipe <NUM> of the first floating structure. The purge is then terminated.

As a variant, the transfer pipe can also include, at the LNGC, one (or two) manual valves enabling isolation of the pipe and the disconnection of the pipe <NUM> with residual cryogenic liquid which will be evaporated on storage.

In the embodiment represented in <FIG>, a method of storing the transfer arm is represented in different steps. With reference to <FIG>, the transfer system is transported onto a standard container platform by means of a hoisting device. The linking means between the hoisting device and the transfer device comprises a rigid beam <NUM> enabling the transfer system to be raised using the connection means <NUM>, <NUM>.

When the transfer system is laid on the container platform <NUM>, the connection means <NUM> is the first to enter into contact with the container platform <NUM>. Next, the connection means <NUM>, <NUM> are connected to cables <NUM>, <NUM> by an operator. The cables <NUM>, <NUM> enable an acute angle to be formed, by pulling on the connection means <NUM>, <NUM>, between the rigid sections of pipes <NUM>,<NUM> and between the rigid sections of pipe <NUM>, <NUM>.

In a same phase or after having disposed the sections of pipe so as to form an acute angle, the hoisting system lowers the transfer system in order for the sections of pipe <NUM>,<NUM> to rest on the container platform. The cables <NUM>, <NUM> which maintain the acute angle are detached.

Cables <NUM>, <NUM>, such as those used to pull on the preceding connection means <NUM>, <NUM>, are used to pull on the following connection means <NUM>, <NUM>. These cables <NUM>, <NUM> also enable an acute angle to be formed, by pulling on the connection means <NUM>, <NUM>, between the rigid sections of pipes <NUM>, <NUM> and between the rigid sections of pipe <NUM>, <NUM>.

In the same way as described above, the hoisting system lowers the transfer system for the sections of pipe <NUM>, <NUM> to lie on the container platform. The cables <NUM>, <NUM> are then detached.

The connection means <NUM>, <NUM> then lie on the vertical rigid supports <NUM>, <NUM>.

The hoisting bar <NUM> is detached from the transfer arm at the end of the maneuver.

It will furthermore be observed that posts <NUM>, <NUM> for supporting the sections of pipe are provided on the container platform.

Thus, the transfer arm occupies the place of a container of standard size. The transfer arm does not encumber the hull of a floating structure and is not stowed on a hoisting device, such as a crane.

The temporary storage of the transfer pipe can also be made along the hull of the FSRU by rotation of the transfer pipe through <NUM>° around the "vertical" axis of the connection means <NUM>. The section of pipe <NUM> is then locked on a mounting at the location of the platform of the FSRU.

Numerous other variants are possible according to circumstances, and in this connection it is to be noted that the present invention is not limited to the examples represented and described.

Claim 1:
Floating structure (<NUM>) for storage and transport of cryogenic product, comprising a system for transferring cryogenic product from the floating structure, called first floating structure (<NUM>), to a second fixed or floating structure (<NUM>) for storing cryogenic product, the system comprising a transfer pipe suitable for transporting the cryogenic product, the transfer pipe being self-supporting and comprising at least three rigid sections of pipe (<NUM>-<NUM>), fluidically connected each to the next by connection means (<NUM>-<NUM>) suitable for transporting the cryogenic product, each of the two end sections of the transfer pipe (<NUM>, <NUM>) having a free end configured as a tip for connection to a connection device of the first floating structure (<NUM>) and respectively of the second floating structure (<NUM>);
wherein the system comprises (i) the connection device, which is intended to be disposed on the first structure (<NUM>), and comprises an extension pipe (<NUM>,<NUM>) configured to be connected to a collecting device (<NUM>, <NUM>) of the associated first structure and to one of the tips of the transfer pipe; and (ii) a support mounting (<NUM>, <NUM>) for the free end of the extension pipe, wherein the free end of the extension pipe is the end of the extension pipe to be connected to the transfer pipe, characterized by the support mounting being disposed on the first floating structure and an interstice being provided between the extension pipe of the first structure and its support mounting or between the support mounting and the first structure intended to carry it so as to enable predetermined bending of the extension pipe after connection of the tip of the transfer pipe to that extension pipe, the interstice closing once the transfer pipe is connected.