GB2028258A - A fluid transfer system - Google Patents

Abstract

The invention relates to a fluid transfer system for transferring fluid to and from a vessel. A counter-balanced pantograph system 18 supports two conduits 16 which are connected to couplings 20 for connection to flanges 12 on the vessel. To prevent yawing movement of the vessel from damaging the pantograph system, the couplings 20 are arranged on a sub-frame which is pivotable relative to the second section 36 of the pantograph system.To accommodate this movement, either the conduits include a flexible pipe 52 or alternatively the conduits are rigid and are connected to the couplings 20 by means of rotary couplings constituting a universal joint, two of the couplings being coaxial with one another and with the axis of rotation of the sub-frame. <IMAGE>

Description

SPECIFICATION A fluid transfer system The present invention relates to a fluid transfer system and is particularly concerned with transferring fluids to and from a tanker.

In transferring loads such as crude oil or liquefied gas between a tanker and an oil platform, it is necessary for the transfer hoses to be designed in such a manner as to allow a substantial degree of movement between the tanker and the platform. In order to support the weight of the hose whilst permitting the tanker to move, it has already been proposed when using a single hose to mount the hose or pipe on a centre pantograph counter balanced system. By this is meant a system which comprises a first strut pivotably mounted on the platform and a second strut pivotably balanced on the end of the first strut and two counterbalancing weights for the respective struts arranged such that the free end of the second strut may stably rest in any position.As the two struts are counterbalanced in all their positions, the free end of the second strut which carries the end of the hose to be attached to the tanker may freely allow movement of the tanker without applying any stress to the hose.

Though a centre pantograph counterbalance system has been used successfully to support one pipe an attempt to support two pipes on the same centre pantograph counterbalance system presents the additional difficulty that it is necessary to protect against stresses caused by lateral movement of the tanker as well as to and fro and up and downs movements.

According to the present invention, there is provided a fuel transfer system for transferring fluid to or from a vessel, comprising a counterbalanced pantograph system formed of a support column, a first strut pivotably mounted on the support column and counterbalanced by a first counterweight, and a second strut pivotably mounted on the end of the first strut and counterbalanced by a second counterweight, two fluid transfer conduits each formed of a first section mounted on the first strut and pivotably connected to a second section supported by the second strut, and a sub-frame mounted on the free end of the second strut and carrying two couplings for connecting the respective conduits to the vessel, wherein the sub-frame is pivotable relative to the second strut about an axis perpendicular to the pivotal axis of the second strut relative to the first.

By the provision of a pivotable sub-frame, the transfer system of the invention enables lateral movements of the vessel or yawing without transmitting any of the torsional stresses from the coupling to the counterbalanced pantograph system.

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side view of a first fluid transfer system in accordance with the invention; Figure 2 is a plan view of the system in Figure 1; Figure 3 is a side view similar to Figure 1 of a second embodiment of the invention; and Figure 4 is a plan view of the fluid transfer system of Figure 3.

In the accompanying drawings, like components are designated by like reference numerals.

In Figure 1, there is shown a fluid transfer system for transferring crude oil or a iiquefied gas from a tanker to a platform 10. The tanker has a coupling flange 12 which may move vertically and to and fro within an envelope designated 14. The transfer system includes two conduits 16 supported by a counterbalanced pantograph system 18 and having couplings 20 to be connected to the flanged connectors 12 on the tanker. The counterbalanced pantograph system 18 supports the weight of the conduits 16 so that the couplings 20 may readily follow movements of the flanged connector 12.

The counterbalanced pantograph system is formed of a first strut 30 pivotably mounted on a support column 32 and counterbalanced by a weight 34. A second strut 36 is pivoted about an axis which is generally horizontal at the free end of the strut 30 and is counterbalanced by means of a weight 38. The weight 38 is carried by an arm 40 which is itself pivoted to the first strut 30 and connected to an overhanging portion of the strut 36 by means of a rigid link 42. Mounting the second counterweight 38 in this manner as opposed to directly on the strut 36 reduces its moment about the pivotal axis of the strut 30.

The first strut 30 carries a rigid pipe 22 which is permitted by a rotary coupling 50 to a flexible hose 52 which constitutes the second half of the conduit 16, the end of the flexible hose 52 is connected through an elbow 54 and a rotary coupling 56 to the rotary coupling 20 to be connected to the flange on the tanker.

The two couplings 20 are mounted on a frame (not shown) so as to move together, the frame being pivotable relative to the second strut 36 about an axis which is perpendicular to the paper in Figure 2.

That is to say, the couplings 20 are permitted to move in such a manner that whilst the one of the couplings moves towards the support column 32 the other moves away. This will accommodate any lateral movement or yawing movement of the tanker connected to the conduits. The second section 52 of the conduit 16 supported by the second strut 36 is formed as a flexible hose for the purpose of accommodating such movement. It is of course alternatively possible in this embodiment to subsri- tute for the flexible hose two or more pipes articulatedly connected to one another.

In the embodiment of Figures 3 and 4, the flexible hoses 52 are replaced by rigid pipes 62. In this case, each of the rigid pipes 62 is connected to its coupling 20 by a combination of three rotary couplings rotatable about mutually perpendicular axes to constitute a form of universal joint. The rotary couplings are designated 64, 66 and 68 respectively.

The two rotary couplings 66 connected to the respective rigid pipes 62 are coaxial with one another and also with the axis of rotation of the sub-frame supporting the two coupings 20. By virtue of this arrangement, the sub-frame may rotate about an axis, coaxial with the rotary coupling 66 without interrupting the fluid communication and without transmitting any torsional stresses to the pantograph system.

The rigid pipe 16 carried by the strut 30 may be connected to the plafform 10 in a manner analogous to that described with reference to the couplings 20.

That is to say, a system of mutually perpendicular couplings 70,72 and 74 as shown in Figure 4 may be adopted to form a universal joint or alternatively a flexible hose may connected the pipes 22 to a conduit formed in the column 32. Where the conduits are intended to carry the same fluid they may be connected to one another in the column 32 but alternatively coaxial or separate conduits may be provided in the column 32 so that different fluids may pass through the respective conduits or possibly the same fluid may pass in different directions.

As opposed to the prior art arrangement of a pair of pipes provided with ample slack to allow movement of the tanker, the present invention enables two pipe conduits supported along their entire length to be used and even in the embodiment of Figure 1 where a flexible pipe is provided the extent of flexing is only minor accommodating small movement due to yawing of the vessel. The arrangement therefore lends itself readily to use in cryogenic applications where the low temperatures render the use of flexing hoses inadvisable.

Claims (7)

1. A fluid transfer system for transferring fluid to or from a vessel comprising a counterbalanced pantograph system formed of a support column, a first strut pivotably mounted on the support column and counterbalanced by a first counterweight, and a second strut pivotably mounted on the end of the first strut and counterbalanced by a second counterweight, two fluid transfer conduits each formed of a first section mounted on the first strut and pivotably connected to a second section supported by a second strut and a sub-frame mounted on the free end of the second strut and carrying two couplings for connecting the respective conduits to the vessel, wherein the sub-frame is pivotable relative to the second strut about an axis perpendicular to the pivotal axis of the second strut relative to the first.

2. Afluid transfer system as claimed in Claim 1, wherein the second section of each of said conduits is formed as a flexible hose or of articulated rigid pipes so as to accommodate rotary movement of the sub-frame with respect to the second strut.

3. A fluid transfer system as claimed in claim 1, wherein the second section of said conduits are found as rigid pipes each connected to a respective one of the two couplings mounted on the sub-frame by way of three mutually perpendicular rotary couplings constituting a universal joint, two rotary couplings consisting of one from each universal joint being coaxial with one another and with the axis of rotation of the sub-frame so as to accommodate movements of the sub-frame without applying stress to the conduits.

4. Afluid transfer system as claimed in any preceding claim, wherein the second counterweight is arranged on the same side of the column as the first counterweight and is pivotable about an arm connected to the second strut by way of a rigid link.

5. A fluid transfer system as claimed in any preceding claim, in which the first sections of the conduits are rigid pipes and are connected to conduits on the support column by way of respective sets of rotary couplings constituting universal joints.

6. A rotary coupling as claimed in any one of claims 1 to 4, in which the first sections of the conduits are rigid and are connected to conduits in the support column by way of respective flexible hoses.

7. A fluid transfer system constructed substan tiaily as hereinbefore described with reference to and as illustrated in Figures 1 and 2 or Figures 3 and 4 of the accompanying drawings.