FLUID TRANSFER APPARATUS

Abstract

A fluid transfer apparatus for transferring fluids such as hydrocarbon fuel is disclosed. The fluid transfer apparatus comprises a support member and at least one catenary hose, wherein a proximal end of each catenary hose is suspended from the support member. A distal end of each catenary hose is coupled to a transfer manifold. A tensioning member is arranged for applying a tensile force to the transfer manifold during a transfer operation.

Claims

1. A fluid transfer apparatus, comprising a support member; at least one catenary hose having a proximal end suspended from the support member; a transfer manifold coupled to a distal end of the or each catenary hose; and a tensioning member for applying a tensile force to the transfer manifold during a transfer operation.

2. An apparatus according to claim 1, wherein the tensioning member is extensible.

3. An apparatus according to claim 2, further comprising a tension drive mechanism arranged to maintain tension in the tensioning member during the transfer operation.

4. An apparatus according to claim 3, wherein the tension drive mechanism is arranged to maintain a constant tension in the tensioning member during the transfer operation.

5. An apparatus according to claim 1, further comprising a support arm from which the tensioning member is suspended.

6. An apparatus according to claim 5, wherein the support arm comprises a plurality of rigid elements movable relative to one another.

7. An apparatus according to claim 1, further comprising a suspended hose coupled between the catenary hose and the transfer manifold and a restraining member which prevents tension being applied to the suspended hose.

8. An apparatus according to claim 1, wherein the support member further comprises one or more rigid pipes coupled to the at least one or each catenary hose.

9. An apparatus according to claim 1, further comprising a pedestal, wherein the support member is pivotally mounted to the pedestal.

10. An apparatus according to claim 1, wherein the transfer manifold further comprises an emergency release system for preventing transfer of fluid in an emergency.

11. An apparatus according to claim 10, wherein the emergency release system comprises a double isolation valve.

12. An apparatus according to claim 1, wherein the fluid is a hydrocarbon fuel.

13. An apparatus according to claim 12, wherein the fluid is liquid natural gas.

14. An apparatus according to claim 1, comprising at least two catenary hoses.

15. An apparatus according to claim 1, wherein the apparatus is housed in a bunker vessel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Embodiments of the present invention will now be described with reference to the accompanying drawings, in which:

[0027] FIG. 1 is a perspective view of a fluid transfer apparatus according a first preferred embodiment of the present invention;

[0028] FIG. 2 is a side view of the first preferred embodiment, showing the operating envelope in a vertical plane;

[0029] FIG. 3 is a top down view of the first preferred embodiment, showing the operating envelope in a horizontal plane;

[0030] FIG. 4 illustrates a bunker vessel comprising the fluid transfer apparatus of the first preferred embodiment;

[0031] FIG. 5 illustrates the transfer apparatus of the first preferred embodiment during a transfer operation; and

[0032] FIG. 6 illustrates a fluid transfer apparatus according to a second preferred embodiment of the present invention.

DETAILED DESCRIPTION

[0033] Referring to FIG. 1, a perspective view of a fluid transfer apparatus 100 is shown. The fluid transfer apparatus 100 is designed to provide fluid, particular liquid natural gas (LNG) to a receiving vessel and to receive boil-off gas (LNG vapour) therefrom. The fluid transfer apparatus 100 is designed to accommodate movement of the receiving vessel.

[0034] The fluid transfer apparatus comprising two catenary hoses 110 each suspended from a support member 120 at a proximal end. The support member 120 comprises two sections of rigid pipe 130, each coupled to the proximal end of one of the catenary hoses 110. The rigid pipe 130 may be coupled to a bunker vessel gas system (not shown) or other source of fluid for transfer.

[0035] The distal end of each catenary hose 110 is coupled to a transfer manifold 140. The transfer manifold 140 can be coupled to the systems of a receiving vessel. As such, the apparatus 100 may transfer fluid to and from a receiving vessel through a path comprising the rigid pipe 130, the catenary hose 110 and the transfer manifold 140. The apparatus 100 allows the position of the transfer manifold 140 to move through an operating envelope in order to accommodate the relative movement of the receiving vessel.

[0036] The transfer manifold 140 comprises an emergency release system 150, which is hydraulically powered via a hydraulic supply line 155, which is suspended from the support member 120. The emergency release system comprises a double isolation valve, particularly a double ball valve for each fluid path which is activated to prevent transfer of fluid in the case of an emergency.

[0037] A tensioning member 160 is also provided. The tensioning member 160 comprises two wire elements which are maintained under constant tension by a constant tension winch 170. In the embodiment show, the tensioning member 160 is coupled to the transfer manifold 140, and exerts a tensile force on the distal end of each catenary hose 110 via the manifold 140. The tensioning member 160 is extensible, in the sense that its longitudinal extent may vary. In the preferred embodiment shown in FIG. 1, this is achieved through the constant tension winch which releases more or less wire according to the current level of tension.

[0038] The tensioning member 160 is suspended from a support arm 180 comprising a plurality of rigid elements which are movable relative to one another and are hydraulically controlled. The movable elements are pivotally mounted to each other. In the preferred embodiment, the pivotal mounting of the rigid elements is around a horizontal axis, although other axes or forms of movement are possible. By controlling the support arm 180, the position of the tensioning member 160 and thus the transfer manifold 140 can be controlled.

[0039] The support member 120 and the support arm 180 are pivotally mounted to a pedestal 190. The pedestal enables rotational movement of the support member 120 and support arm 180 around a vertical axis.

[0040] In use, the apparatus 100 is brought to the vicinity of a receiving vessel. During a connection stage, the tension winch 170 may be configured to maintain a constant length of the tensioning member (rather than a constant tension) in order for the position of the transfer manifold 140 to be readily manoeuvred towards a receiving manifold of the receiving vessel. The support arm 180 may be used to move the transfer manifold 140 close to the receiving manifold of the receiving vessel. An automatic or manual procedure can be followed to secure the transfer manifold 140 to the receiving manifold. A guidance system may be provided to facilitate this operation. The tension winch may then be controlled to enter a mode in which tension in the tensioning member 160 is kept constant.

[0041] Once the transfer manifold is secured to the receiving manifold of the receiving vessel, transfer operations can begin. For example, LNG can be transferred to the receiving vessel through one of the catenary hoses while boil-off gas can be received through the other. If the receiving vessel moves during the transfer operation, this is accommodated by flexibility in the transfer apparatus 100. In particular, the catenary hoses 110 provide flexible fluid paths that can accommodate relative movement. Moreover, while the transfer manifold 140 is also coupled to the tensioning member 160, the extensible nature of the tensioning member 140 enables movement of the transfer manifold 140 as does the movable support arm 180 from which the tensioning member 160 is supported.

[0042] During the transfer of fluid, the tensioning member 160 applies a tensile force to the transfer manifold 140. In the preferred embodiment, the tensile force is constant throughout the transfer operation, although it may be variable in alternative embodiment. As a result, if the transfer manifold should become disengaged from the receiving manifold of the receiving vessel then the tensioning member 160 will act to pull the transfer manifold away, preferably upwards, from its current location. Accordingly, in the case of an unexpected disengagement, the transfer manifold 140 will automatically move away from the receiving vessel. This fulfils a safety requirement during fuel transfer.

[0043] In addition, in the case of an unexpected disengagement, the emergency release system 150 will act to prevent the transfer of fluid through the transfer manifold 140. In particular, the double ball valve of the emergency release system is engaged using power from hydraulic supply line 155 to close the fluid path through the transfer manifold.

[0044] The range of movement of the transfer manifold 140 during a transfer operation can be understood with respect to FIGS. 2 and 3, which show side and top-down views of the apparatus 100 respectively. Also illustrated in FIGS. 2 and 3, is an operating envelope 200 in which the transfer manifold 140 can safely move during a transfer operation. In FIG. 2, the range of movement in a vertical plane is shown. This movement can be accommodated through movement of the support arm 180, flexibility of the tensioning member 160 and flexibility of the catenary hoses 110. In FIG. 3, the range of movement in a horizontal plane is illustrated; the pivotal mounting of the support arm 180 and support member 120 to the pedestal 190 enables movement around an axis in this plane.

[0045] The range of movement of the transfer manifold 140 may be monitored against the prescribed envelope or the given hose length to engage automatic disconnection before the system exceeds its limit.

[0046] FIG. 4 illustrates a bunker vessel 300 on which the apparatus 100 is mounted. The bunker vessel 300 can be used to re-fuel other vessels at sea. The apparatus finds particular utility in this environment as relative motion of the two vessels may be significant.

[0047] FIG. 5 illustrates the transfer apparatus 100 in place during a transfer operation. The transfer apparatus is mounted upon the bunker vessel 300 which is positioned adjacent to a receiving vessel 400. The transfer manifold 140 is connected to a receiving manifold 410 of the receiving vessel 400. The transfer manifold 140 is designed such that in use (i.e. during the transfer operation when the transfer manifold 140 is coupled to the receiving manifold 410) the isolation valve 150 is located outside the lateral extent of the hull of the receiving vessel 400.

[0048] FIG. 6 illustrates a perspective view of a second preferred embodiment of the present invention. Like features are represented by like reference numerals as compared to FIGS. 1 to 4 illustrating the first preferred embodiment.

[0049] The second preferred embodiment comprising an alternative tensioning member 160. In the second preferred embodiment, the tensioning member 160 comprises one or more hydraulic cylinders which are controlled by a hydraulic control mechanism (not shown). The hydraulic cylinders are extensible but are not otherwise flexible, and in order to allow for greater flexibility, the tensioning member is coupled to the transfer manifold 140 via one or more suspended hoses 210. In order to avoid the suspended hoses 210 coming under tension, a flexible restraining member 220 is provided which prevents over-extension of the suspended hoses 210. As shown in FIG. 6, the suspended hoses are deliberately bowed into a predefined shape prior to operation. This means that if the hose extends during operation (e.g. through the application of pressure) or retracts afterwards the manner in which this occurs is controlled so that no tension is applied to the hose and no bends in the hose occur which are under a minimum prescribed bending radius.

[0050] In the second preferred embodiment, the support arm 180 is integrated with the support member 120. In order to ensure a fluid path through articulated points in the support arm 180, hose jumpers 230 are provided at such points to connect sections of rigid pipe 130.

[0051] Other variations and modifications will be apparent to the skilled person. Such variations and modifications may involve equivalent and other features which are already known and which may be used instead of, or in addition to, features described herein. Features that are described in the context of separate embodiments may be provided in combination in a single embodiment. Conversely, features which are described in the context of a single embodiment may also be provided separately or in any suitable sub-combination.

[0052] It should be noted that the term comprising does not exclude other elements or steps, the term a or an does not exclude a plurality, a single feature may fulfil the functions of several features recited in the claims and reference signs in the claims shall not be construed as limiting the scope of the claims. It should also be noted that the Figures are not necessarily to scale; emphasis instead generally being placed upon illustrating the principles of the present disclosure.