GB2192040A - Transferring fluids or electricity between relatively rotating bodies - Google Patents

Abstract

Apparatus for transferring fluids or electricity between two relatively rotating bodies, for example a mooring turret and a storage vessel in a floating oil production system, which eliminates the need for elastomeric dynamic seals, uses a flexible hose 77 or cable 87 capable of being wrapped in one or other direction around a generally heart- shaped path. A number of such hoses or cables may be used for a multi-transfer system, and by-pass means are provided to permit servicing and replacements to be readily effected. <IMAGE>

Description

SPECIFICATION Means for transferring fluids between relatively rotating bodies This invention relates to means for the transfer of one or more fluids in either direction between two relatively rotatable bodies, for example between a rotatable body and a non-rotating body.

The fluids in question may be in the liquid, vapour or gaseous phases. The invention has a wide field of application but a typical example would be its use as a means for conveying crude oil and a variety of other fluids between a mooring turret and a storage vessel in a floating oil production system. In this particular application the turret may be moored to the sea bed by means of a pattern of chains or cables each of which descends in catenary formation from the underside of the turret to the sea bed, each chain or cable being terminated at the sea bed end by means of a suitable anchor, pile, clump weight or other anchorage device.Under these circumstances the turret is the non-rotating member, while the storage vessel which surrounds it is allowed to rotate in response to wind, tide, wave and current forces so that it adopts the most favourable attitude towards the combination of these various influences. It will be apparent to those versed in the art that the most favourable resolution of this combination of force vectors will vary from season to season and from day-to-day dependent upon changes in any or all of the parameters above listed.

It will be clear that this state of affairs gives rise to the need for a means whereby a number of fluids may be passed in either direction between the turret and the vessel, these various fluids being at working pressures ranging typically between 100 p.s.i. and 5,000 p.s.i. it being noted however that this band of working pressures may vary both above and below these limits.

A number of means by which such rotational fluid transfers can be achieved will be well known to those versed in the art. Frequently such means incorporate fluid seals of various designs, the adoption of which confers upon the system the freedom for one element to rotate about the other continuously in either direction. However, it is also known that such systems employing as they do, relatively large diameter fluid seals, are subject to a number of practical difficulties, particularly in those# cases where the working pressure of the fluid is at or above the upper limit of the typical range indicated.Some examples of difficulties encountered with typical multi-path high pressure swivels of the type conferring continuous rotation are as follows: a) The metallic components of the swivel system must be produced to exacting standards of accuracy and finish if extrusion of the seal material between rotating and non-rotating elements is to be avoided.

b) Some of the fluids (particularly crude oil) may be contaminated with particles of sand or other abrasive materials. Hence to avoid rapid abrasion of the elastomeric elements of the seal system at least one further or "inner" seal becomes necessary to protect the main seal or seals from the abrasive influences. Such an-arrangement gives rise to significant design complexity and manufacturing difficulty.

c) In view of the inevitability of wear taking place in the main pressure seals, it is necessary (or at least highly desirable) for the design to be so arranged that a single fluid path may be taken out of service for seal renewal or other maintenance work without disturbing the operation of the remaining paths. Again this requirement adds to the complexity of the assembly and increases its cost.

d) It is frequently necessary for multi-path swivel assemblies designed primarily for the transfer of fluids to provide in addition a number of electrical circuits. Typically these may be for power, control and communication purposes. The fact that the elements of such a multi-path swivel are capable of continuous rotation relative to each other implies that such electrical circuits must be conveyed through the relatively rotating elements by means of sliprings and brushes of known layout and design. This requirement, when it arises, may considerably complicate the design of a multi-path swivel assembly.

e) Frequently one or more of the fluids being -conveyed will be hot. It is therefore necessary for great care to be taken at the design stage to ensure that the hot path is so positioned in the assembly that it produces the minimum possible temperature distortion and it will immediately be clear that this consideration is incompatible with point (a) above. That is to say the very small clearances associated with functional seals of large size allow very little margin for temperature distortion of the assembly as a whole.

It is an object of the present invention to overcome these difficulties and limitations by the elimination of elastometic and/or other forms of continuous dynamic seals and to make use, as the pressure resisting element, of flexible hoses of known design and commercial manufacture.

According to the invention, means for transferring one or more fluids between two relatively rotatable bodies comprises at least one flexible hose connected between respective pipes on the two bodies, storage means for an excess length of hose carried by one body and from which the hose may be partially withdrawn without rotation, means carried by the other body and providing a generally heart shaped peripheral path around which the hose can wrap in either direction from a point on or adjacent the cusp of the path as the two bodies rotate relative to each other, so as to cause a section of the hose to be withdrawn from the storage means, the latter including means for returning the hose to the storage means as the hose is unwrapped from said path on relative rotation of the bodies in the reverse direction.

It will be seen that, by suitably shaping the peripheral path of the wrapping means, relative rotation of the bodies in either direction can be achieved by an amount depending upon the excess length of hose, whilst maintaining an allowable bend radius in the hose.

Although in such an arrangement continuous rotation of the two bodies relative to each other is not available by an appropriate choice of hose and take up means, a relative rotation in excess of i 1 complete revolution can readily be achieved, and studies have indicated that such a relative rotational allowance, exceeding in total two revolutions, is satisfactory in the vast majority of locations where equipment of this nature would be required. Against this limiting consideration may be set the fact that this degree of rotational freedom is achieved without the necessity to make use of any dynamic elastomeric seals or similar devices, so far as the main circuit paths are concerned.In fact, in accordance with the invention an individual fluid path is constituted essentially from rigid piping and flexible piping, both of known and established construction together with static seals and various pipe fittings, valves, flanges, etc., all of known and established types. A further feature of the primary elements of the invention is the fact that electrical circuits can; if desired, be handled in precisely the same manner as that adopted for the fluid paths. That is to say, flexible electrical cables are in those cases substituted for the flexible pipes.

Preferably the first body carries suitably curved guide means around which the excess length of hose is guided as it is withdrawn from the storage means and wrapped in one or other direction around the peripheral path of the wrapping means. Such guide means may consist, for example, of a plurality of suitably dimensioned and positioned grooved rollers, conveniently of a diabolo shape.

The excess length of hose within the storage means preferably passes over pulleys at least one of which is tensioned so as to cause the hose to be withdrawn into the storage means when the relative rotation of the bodies is such that the hose is unwrapped from the wrapping means.

The peripheral path around which the hose is arranged to be wrapped may be in the form of a groove in a generally heart-shaped surface of an appropriately shaped relatively rigid body, or it may alternatively be provided by a series of grooved rollers dispersed in appropriate positions around the wrapping means.

As discussed earlier it is a desirable# if not essential feature of multi-path high pressure fluid swivel systems that it shall be possible to take any one path out of service and deflect its flow through a temporary path while the normal path is being repaired and or maintained. In practice it may be convenient, in some circumstances, to provide more than one such temporary or bypass path.

In a transfer arrangement according to the invention this temporary or by-pass fluid path may be formed in any of a number of different ways. Some methods of arranging the temporary path or paths will now be described by way of examples. As a first example the by-pass path could be achieved by means of a mechanical swivel of known design and construction. This would be placed on the vertical centre line of the assembly and would have dimensions and pressure capacity such that it could handle both maximum flow and maximum pressure to be found in any of the fluid paths which passed through the assembly. This by-pass fluid path would be brought into use by means of valves for the more important flows and possibly by means of jumper hoses for the less important.

As a second example a two path concentric swivel (again of known design) could be used. In this case the two paths so prdvided could be made use of in a variety of ways. For example one path could be permanently allocated to a particular duty. This might require a specially large capacity, pressure or temperature and hence there would be no need to pass that particular fluid through a path consisting partially of flexible hose. Alternatively the two paths formed by the concentric swivel could both be allocated to stand-by or by-pass duties or yet again one could be allocated as a route for electrical connection between turret and vessel leaving the second to constitute the single by-pass path.

As a third example a by-pass path could be arranged using the same configuration as that disclosed for the remaining paths. That is to say the path would consist of pipe, flexible hose etc. as described above. However, in this case the flexible hose would not normally be under pressure and hence could be relied on to be available and in a sound condition whenever required under emergency conditions. It will be appreciated that with one temporary path or at most two temporary paths being useable for any fluid flow in either direction it is necessary during the process of design to take due account of the need to ensure that the temporary path or paths can be drained and if appropriate blown down before changing the fluid being handled therein.

It will also be understood that in a typical oil industry application it would be considered desirable to ensure that primary crude oil production should continue so far as possible with no interruption.

In such a case therefore the crude production paths would be the ones which would be arranged for deflection through to the temporary path or paths by valving only so that even in the event of a relatively rapidly developing fault in a production path its flow could be deflected through the temporary path without interruption. In the most sophisticated system envisaged these diversion valves would be power operated and remotely controlled. Under these circumstances the production flow could be deflected through the temporary path without even the necessity for operators to visit the swivel installation. However, it will be appreciated that in any cases involving the use of jumper hoses some preliminary fitting up would always be necessary such work involving not only the assembly of the jumper hoses themselves but also the disabling of the relevant take up assembly.This aspect of the invention is described in detail later in this specification.

A number of embodiments of the invention will now be described by way of example with reference to Figs. 1 to 20 of the following drawings in which: Figure 1 represents a side elevation in diagrammatic form of a turret moored, floating, crude oil production vessel with a rotary, multi-path, fluid transfer system arranged in accordance with the invention; Figures 2 to 5 represent a series of diagrams illustrating the principle features of the invention; Figures 6 and 7 illustrate a plan section and a sectional elevation of a typical turret installation surmounted by a rotary multi-path fluid transfer system according to one embodiment of the invention; Figures 8 and 9 illustrate further sections of part of the turret installation;; Figure 10 illustrates an exploded view of part of one form of unit of a typical "heart" stack as employed in the installation illustrated in Figs. 6 and 7; Figure 11 illustrates part of an alternative form of "heart" unit; Figures 12 and 13 illustrate the units of Figs. 10 and 11 in more detail; Figure 14 illustrates a method of installing a flexible hose; Figure 15 illustrates an alternative method for use with a different form of heart unit; Figures 16 and 17 represent alternative embodiments of the invention; Figure 18 is a diagrammatic layout of the pipe runs and valves arranged in accordance with the invention and with the system in the normal running condition.

Figure 19 is a diagrammatic layout of the pipe runs and valves arranged in accordance with the invention and with the system running with an important flow by-passed by valving through a rotary swivel to fixed pipework.

Figure 20 is a diagrammatic layout of the pipe runs and valves arranged in accordance with the invention and with the system running with one flow by-passed by jumper hoses to fixed pipework.

Referring first to Figs. 1 to 5-Fig. 1 illustrates diagrammatically a vessel fitted with a rotary fluid transfer arrangement in accordance with the invention. The assembly consists of a turret 1 mounted towards the forward end of a floating production/storage vessel 2. The turret and hence the vessel is moored to the sea bed by means of a pattern of mooring chains or cables 3. These chains or cables are arranged in catenary formation and suitably terminate#d at the sea bed end. Fluids which need to be conveyed from or to the vessel are ultimately passed from or to the sea bed or some intermediate level by means of a series of risers 4. The rotary fluid transfer assembly 5 in accordance with the invention is positioned, as shown, at the top of the turret 1 and is surmounted by a pipe bridge 6.It will therefore be understood that in the arrangement illustrated the turret 1 is non-rotating relative to the sea bed while the vessel 2 is free to rotate or can be servo-rotated under the influence of the various parameters listed earlier.

The fundamental objective of the invention therefore is to provide a means whereby the various fluids can pass from or to the vessel to or from the turret while allowing this relative rotation to take place. It will be noted that the pipe bridge 6 is connected to the vessel at main deck level 7 and hence clearly constitutes part of the rotating assembly.

it will be understood that in the typical application illustrated the principal fluid to be conveyed from sea bed level to the vessel 2 is crude oil-but on the other hand in an oil field installation it may be necessary to convey other fluids frown the vessel to sea bed level. Typically these "contra flowing" fluids might be injection water, injection gas, lift gas, kill fluid or dosing chemicals. All of these fluids as well as the crude oil may have to be handled at a wide range of flow rates, pressures and temperatures. To clarify this point further a list of typical flow path diameters and pressures is given as follows:

Path No Nominal Pressure Service Typical Temp. 0C Bore 1 8" 1 600 p.s.i. Crude Oil 100 2 8" 600 p.s.i. Crude Oil 100 3 6" 4,500 p.s.i. Gas Injection 50 4 6" 2,500 p.s.i. Water Injection 60 4 6" 2,500 p.s.#. 5 4" 600 p.s.i. Test 100 600 Test 6 4" 10,000 p.s.i. Kill/Service 30 7 2" 600 p.s.i. Chemical 30 Injection 8 - - Electrical Cable - 9 - - Electrical Cable

As previously explained the hull of the vessel 2 rotates about the turret 1 in response to wind and wave forces as previously described, and Figs. 2 to 5 illustrate the results of such relative rotation. In Fig. 2 the vessel may be considered to be in its starting or "neutral" position. This is, in practice, likely to be the attitude corresponding to the prevailing wind direction, this having been determined in advance for the site in question. It will be noted that under these conditions the "heart end" termination point 34 of a flexible hose 9, the main part of which is carried within the hull of the vessel 2, is directly lined up with the forward end 13 of the pipe bridge 6.

From this position relative rotation of the vessel 2 to the turret 1 will cause hose to be wrapped around the characteristically "heart shaped" take up element 8. The extra hose is derived from a hose take-up or storage assembly 120 as requried. Fig. 3 shows this process after 1200 rotation, Fig. 4 after 270 and Fig. 5 after approximately 4150this being the maximum for the configuration shown. This can be seen to be the case since in Fig. 5 the "heart" unit has almost reached the limit of its hose carrying capacity. In the sequence of diagrams 2, 3, 4 and 5 rotation of the vessel is shown as taking place in a clockwise direction. However it will be clear to those versed in the art that rotation of the vessel could also take place in an anticlockwise direction.Hence the overall rotational capacity of the system illustrated is +415 approximately.

Figs. 6 and 7 illustrate the construction of the turret installation in greater detail. The turret 1 and the pipe bridge 6 are shown, the latter supported on the main deck 7 of the vessel 2 as before described. The rotary fluid transfer assembly 5 can be seen to consist of a stack of characteristically shaped "heart like" non-rotating elements 8 around which are wrapped flexible hoses 9 or electrical cables 10. The hoses and cables are supported on either side of the "heart" stack by systems of closely spaced "diabolo" shaped support rollers 11 and immediately adjacent to the fluid transfer assembly 5 are constrained in plan by further groups of vertical axis constraint rollers 12. These groups of support and constraint rollers are themselves carried on supporting steelwork which is in turn carried on the pipe bridge 6.Typically each succeeding layer in the "heart" stack may be arranged such that its respective hose may be transferred along its roller path to respectively the forward end 13 or the aft. end 14 of the pipe bridge. Considering as a typical example the hose 15 which is associated with the "heart" unit 16 it will be seen that in this case the hose passes across the horizontal member of the pipe bridge in the forward direction and upon arrival at the forward vertical leg of the pipe bridge it passes over a fixed pulley 17 and hence downwards to a vertically moving pulley 18 which is constrained by guides 19 and tensioned by a hydraulic cylinder 20 via a suitable system of ropes and pulleys 21, the hose finally terminating at a point such as 21A. This latter system comprising items 17 to 21A constitute a take-up assembly for the hose 15 as it is wrapped on or off the "heart" unit 16 these effects occurring as a result of rotation of the ship 2 relative to the turret 1.

As will be seen in the plan view (Fig. 6) each path is similarly provided with a combination of items constituting a take-up assembly the disposition of the respective take-up assemblies 22, 23, 24, 25, 26, 27, 28 and 29 being so arranged that they can be conveniently accommodated in the forward 13 and aft. 14 vertical members of the pipe bridge 6. To this end the plan layout of the various runs of the systems of support rollers of which 11 is an example are so arranged as to direct the hoses or electrical cables which they respectively support in an appropriate direction to enable them to be deflected through approximately 900 to a vertical attitude via their respective fixed deflection rollers of which 17 is an example.This arrangement of the runs of closely spaced support rollers which are angled in plan in the direction of the appropriate fixed deflection pulley is illustrated at 30 and 31. It will be understood that each layer is similarly equipped with similarly disposed constraint rollers 12 the purpose of which is to ensure that each of the hoses or cables is constrained correctly to wrap on to or off its respective "heart" unit 8, 16, etc.

At point 32 of the plan view Fig. 6 is illustrated a typical case where a hose or cable 33 has been terminated approximately at the centre point of a "heart" unit 34 and where 1800 of relative rotation between vessel and turret has taken place. In this case the hose 33 is supported and constrained by its respective systems of closely spaced support and constraint rollers on its way to the fixed pulley 27 of its respective take-up system at the aft. end 14 of pipe bridge 6.

In the arrangement illustrated a total of nine normal fluid or electrical paths may typically be accommodated. However, any reasonable number of fluid and/or electrical circuits can alternatively be provided for. It will be seen that in certain cases the characteristic arcuate "heart" shape illustrated at 5 in Fig. 6 is formed by means of a further series of closely spaced "diabolo" shaped rollers 35 (Fig. 7) whereas in other cases such as at 37 the "heart" is of plain flat sided construction. These two constructions of the "heart" assembly may be chosen to suit the bending and frictional characteristics of the various hoses which are handled by the system.The roller type "heart" 35 is adopted in those cases where the stiffness and frictional characteristics of the hose would be such as to preclude the fitting of a new hose once the hose termination point 34 had moved out of direct alignment with its respective take-up unit such as 27. This situation is illustrated at Fig. 6 except that in the specific case illustrated a plain rather than a roller "heart" is shown. It will be understood that the necessity to replace a flexible hose or cable will arise due to the failure of one of these elements in the working system. That is to say typically the need to replace a hose could arise due to a failure causing a leak whereas in the case of a multi-core electrical cable the necessity to install a replacement could arise for example due to the failure of any one core.It will equally be appreciated that the necessity to undertake such replacements could arise at any time there being no guarantee that the rotational relationship existing at that time between the non-rotating part and the appropriate take-up assembly in the rotating pipe bridge 6 is most convenient for the installation of the new hose or cable. Fig. 6 illustrates at 39 a connector unit which in this case is for a multi-core electrical cable. However, a similar arrangement and configuration is adopted for fluid path connections.It will be seen that the connections having been made at the point 34 emerge again in the form of a fixed electrical conduit or cable 40 which then passes to the inside of one of a pair of large diameter circular section structural column members 41, 42. From their point of entry through the wall of the structural tubular members such-as 43 the electrical or fluid connections pass downwards on their way to the interior of the turrent assembly 1 and thence pass to their respective and appropriate manifolds valves electrical distribution boxes etc. etc.

Fig. 8, which is a section at "C" "C" of Fig. 7, illustrates this principle more clearly. The tubular vertical column members 41, 42 are again illustrated together with the vertically descending rigid fluid pipe lines such as 44 and 45. This section also illustrates the swivel unit 46 which is used to form the by-pass path or paths. In the case illustrated the swivel unit 46 is of the single path type. The path through the swivel is connected at the upper end to a rigid pipe 47 which is attached to a pipe carried across the pipe bridge 6 and hence is a "rotating" element.

This pipe 47 defines a path which passes vertically through the swivel 46 and terminates at a flange 47A on the side of the assembly. At this point "non-rotating" pipework, valves, etc. may be connected to allow by-pass flows to join or leave the system. Such valves are shown at 49 and 50. Provision is also made here to handle the by-passing of other less important flows by means of a jumper hose such as 53.

If it be assumed that the crude oil flows are the most important in the system, these would be connected to the by-pass path by fixed piping and valves such as 49 and 50. In normal circumstances these flows pass upwards inside the structural columns 41, 42 and at the appropriate level bend through 90 and pass out through the wall of the structural column finally joining their appropriate connector box such as 39. If on the other hand it is desired to by-pass one or other of these important flows they are connected by valving at the lower end to other vertical connections such as 45 and- 48. These in turn are connected via other valves 49 or 50 to the outer part of the swivel 46 and hence pass across the pipe bridge via the rigid pipe connection 47.On the other hand should it be desired temporarily to by-pass any of the other flows this is done by deflecting the connection containing the failure to the appropriate one of a number of vertical rigid pipe connections which pass downwards through the structural columns 41 or 42 and which normally commence in a valve and capping plate at points such as 51 or 52. The paths for the respective flows are diverted from the rigid pipe connection across the pipe bridge 6 by means of a jumper hose 53 which may temporarily be connected to any one of the flange and valve combinations provide at points such as 51 or 52.

Fig. 9 is a section at "D" "D" of Fig. 7 and ilustrates one arrangement which may be made for the temporary diversion of multicore electrical cable connections. In this case the electrical connections are diverted to plug and socket connectors at points such as 54 and 55 and hence to looped electrical cables 56, 57 which are supported on a flat circular plate 58. This arrangement allows relative rotation to take place between the plate 58 which is attached to and forms part of the central assembly and which is therefore non-rotating and the pipe bridge which carries the temporary electrical cables 56 and 57. In this way it is possible to arrange the temporary multicore cable connections without the need to introduce sliprings at any point in the electrical sub-system of the assembly as a whole.

Fig. 10 illustrates in more detail one form of "heart" member. This consists of a circular flat base 59 to which is attached a characteristically shaped vertical abutment 60 which supports the hose or cable as it is wrapped around the "heart" member as a result of the rotation of the vessel relative to the turret. It will be appreciated that the radius of each of the two characteristic lobes of the "heart" member as represented at 61 and 62 are set at the minimum permissible bending radius for the hose of that particular path when under the loaded condition.

Likewise in the case of an electrical cable the radii 61 and 62 are set at the minimum value appropriate for the cable in question. As will be appreciated the plain sided "heart" unit as illustrated is appropriate for those cases where the hose or cable may be wrapped around the "heart" unit starting from any predetermined angular relationship between fixed and rotating bodies. The object being to bring the replace hose or cable round to the point such as 63 where the connector is latched in to the appropriate receiver by means of a probe attached to the end of the connector in question.

The base 59 of the "heart'' member is arranged to be supported on a support structure 59A.

This carries a connector assembly 65 arranged to receive the probe on the end of the hose or cable. A box 66 contains the latches which will retain the probe in position when hauled into place by a light wire rope 67 which is deflected on to the centre line of the oncoming hose 68.

The assembly 65, 66 is supported by a crossmember 69 which in turn is supported by an arrangement of vertical column members such as 71 and 73 which pass vertically upwards through the vertical structural tubes illustrated at 41 and 42 of Fig. 8. The vertical structural tubes are cut away locally in way of the "heart" members thus allowing the receiver unit crossmember 69 to pass between the pair of inner vertical column members 71 and 73.

Likewise the vertical column members 70 and 72 may support the crossmember corresponding to 69 on the "heart" layer above or below that illustrated.

Fig. 11 illustrates a "heart" unit in accordance with an alternative construction in which the characteristic shape is defined by means of a series of vertical axis diabolo shaped rollers such as 64. The disposition of the rollers in such cases is so arranged as to provide the minimum loaded bending radius of the hose in question. It will be apparent that with such an arrangement it will be comparatively easy to haul a replacement hose into position from any starting angular relationship.

In the case of "hearts" defined by arrangement of diabolo shaped rollers such as Fig. 11, it will be understood that it is structurally necessary to provide flanges such as 74 for the support of the vertically disposed spindles of the rollers such as 64. To ensure the smooth passage of an oncoming replacement hose around the roller array, it is necessary that the hose be prevented at any stage from slipping down on to the surface of the structural plate 75 of a "heart" unit of this type. For this purpose a false floor plate 76 of appropriate shape is provided. This is illustrated in Fig. 11 and rests upon the surface 75 of a roller type "heart".The presence of this plate has the effect of preventing the hose at any stage in the hose replacement process from dropping down and resting directly on the upper surface 75 of the circular foundation plate of the roller type "heart" illustrated at Fig. 11. In this way frictional contact between the hose and the flange 74 is avoided. The plate 76 also has the effect of providing under normal operating conditions a smooth transition for the hose as it passes between one lobe of the "heart" and the other as ship rotation takes place.

Fig. 12 illustrates a complete assembly of a roller type "heart" with a hose 77 wrapped around through a total angular rotation of vessel versus turret amounting to 1800. The series of vertical spindle diabolo shaped rollers such as 64 are shown the minimum loaded bending radius of the hose in question being defined by the radius 78. This illustration shows more clearly the arrangement of the latch box 66, the light wire hauling rope 67 and deflection pulleys such as 79, 80. Such arrangements of pulleys are provided at every level and in each case the hauling rope 67 is deflected into a vertical path by a p#ulley such as 80 to a small winch arranged at the lower end of the structural vertical tubular member 41 or 42 as appropriate (not shown).Also shown in this figure is the system of constraint rollers 12 the purpose of which is to ensure that the hose 77 is directed to the centre line 80A of the assembly as it enters or leaves the "heart" unit. In the case of a fluid flow passing in the same direction as the crude oil as defined by the arrow 81, the flow passes vertically upwards through the pipe 82 around the curved pipe 83 and into the annulus 84 surrounding the probe unit 85. Thence it passes inwards through a series of orifices such as 86 and into the hose 77.

Fig. 13 shows a similar layout of "heart" to that shown in Fig. 12. The difference in this case being that the "heart" is of the plain sided type as shown in Fig. 10. In this case, the flexible element 87 is an electrical cable. This is terminated at 88 by a suitable plug of a plug and socket connector, the socket being shown at 89. The increased flexibility of the electrical cable, as compared to a high pressure hose, enables a new cable to be rigged from any angular relationship, without the need for the "heart" shape to be defined by a system of rollers, as is the case in Fig. 12. The haul in arrangements for the new electrical cable are identical to those shown in Fig. 12 for a flexible hose. That is to say, the hauling cable 67 and deflection pulleys 79 and 80 are again arranged to co-operate with a small winch mounted at the lower end of the structural tube 43.The arrangement of centring rollers 12 and support rollers 30 is similarly adopted.

The complete stack conveniently and typically may consist of nine layers of hoses or cables.

The electrical cables 87 and relatively small bore flexible hoses are conveniently supported by plain sided "hearts" whereas larger diameter flexible hoses are supported by "hearts" whose arcuate form is composed of a multiplicity of diabolo shaped rollers as hereinbefore explained.

Fig. 14 is a plan view of a "heart" of the roller variety and illustrates a specific technique which can be used during the process of installation of a new flexible hose under circumstances where the centre point of the "heart" unit 95 is out of alignment with the corresponding roller assembly on the pipe bridge, this state of affairs having arisen, due to relative rotation, between vessel and turret. The rigging technique consists of initially placing the new hose in position on the fixed supporting rollers 30 across the pipe bridge. The hauling rope 67 is next attached to the probe 85 on the end of the hose and led round the arcuate shape of the "heart" rollers and hence over the pulley 96 and finally downwards to the hauling winch.Upon starting up the winch the probe/connector unit and hence the hose will be hauled around the arc until the probe is captured at the point 97 by means of the clamping unit 98. This unit is pivotted at the point 99. When the probe has been duly captured at the initial position 98 the clamping unit can be rotated by hand or under power, to a second position 100 leaving the probe directly facing the centre point 95 of the "heart" and hence upon releasing the clamping unit the probe can be finally hauled into its connected position.

Fig. 15 illustrates a further technique according to the invention which may be used for the installation of a relatively heavy hose or flexible cable without the need to have recourse to the multiple roller form of "heart" as shown at Fig. 12. If needs be, to ease the frictional load between the hose and the "heart", a series of freely moving skate assemblies 103 may be inserted between "heart" and hose at points such as 104 and removed again at points such as 105. This operation taking place smoothly as the new hose is hauled into position by the hauling rope 67.

Figs. 16 and 17 illustrate different forms of another embodiment of the invention. It will be seen in Fig. 16 that the "heart" assembly is replaced by a group of large diameter pulley wheels such as 106. The radius of these pulleys is based on the minimum loaded bending radius of the hose or cable as the case may be. The object is to create a low friction "pull in" method for a new hose or cable such as 108 and it will be seen that relative rotation between turret and vessel produces a wrap around effect very similar to that achieved making use of the characteristic "heart" shape of the previous embodiments. In this case the probe receiver 66 and probe 85 are in principle identical to those described #in connection with the earlier embodiment.

Fig. 17 illustrates a configuration similar to that of Fig. 16 except that the group of 4 pulleys 106 of the latter is reduced to a group of 3 as at 107. In all other respects the arrangements of Figs. 16 and 17 are similar; It will be noted that in Fig. 17 a second layer of large diameter pulleys is indicated by dotted lines at 108. This arrangement indicates the relationship between succeeding layers of "heart" assemblies so that, for example, if the hose 110 were to be considered to be moving across the pipe bridge in a generally forward direction, the hose 111 associated with the next lower layer would be moving across the pipe bridge in an aft. direction.

In each of the arrangements illustrated in Figs. 16 and 17 the floor plate 76 is mounted on a cylindrical column and carries a trunkway 137 with a characteristic shape designed to provide a vertical passageway for the rising runs of internal distribution pipes. Structurally each pulley is supported by a pair of bracket members such as 139 which are welded to the outside of the trunkway 137. Each layer of pulleys forming a "heart" assembly as in 17, is suitably plated in to form a single level of the stack assembly and between pulleys arrangements are made to support thickening plates (not shown) which are intended to prevent the hose from losing contact with its respective pulley or pulleys should the hose, for any reason, be temporarily deprived of the tension normally afforded by its respective take-up assembly.

The housing cylindrical support column is arranged to accommodate many of the valves associated with the temporary or by-pass paths and the trunkway vertical pipe runs include the normal connections to the centre points of the respective "hearts" as well as the connections to the by-pass swivel in the cases where this component is used as part of the by-pass path.

Fig. 18 is a diagrammatic illustration of the hose based rotary connection system in accordance with the invention. In this arrangement two flow paths can be seen to exist between the turret 112 and the vessel 113. In the case of the first flow path 114, 124 the valve assembly 115 is open whereas the valve assembly 116 is closed. Hence the fluid flow arrives at the centre point of the "heart" unit 117 at the point 118. At this point the pipeline changes to a flexible hose 119 and passes across the bridge being supported and constrained by diabolo shaped rollers as hereinbefore described, to arrive at a take-up assembly 120 finally terminating at fixed pipework at point 121.At this point a further valve group 112 is installed and when this valve group is open, as is the case in the illustration, the flow may pass out through the connection 123 finally emerging into ships pipework at the point 124. Providing the valve group 125 is closed this arrangement provides a simple flow path from point 114 to point 124 between which the flow has passed across the pipe bridge and has been connected to the normal distribution piping system of the ship. It will be seen that a second flow path is also illustrated in this Figure but this time starting at the turret 112 at the point 126 and finishing at the foot of the vertical member of the pipe bridge at the point 127.An important difference between the two flow paths is that the first path starting at point 114 is provided with a bypass starting at the point 128 which can be brought into action merely by opening valve groups 116 and 125 and closing valve groups 115 and 122. When this change has been made, the flow passes through valve group 116 to the swivel 127A and hence can pass along the fixed pipe line 128A to open valve group 125 finally reaching point 124.

On the other hand in the case of the second circuit i.e. the circuit starting at 126, arrangements must be made for a jumper hose to be connected between points 129 and 130 before the flow can in this case be by-passed to the circuit 127A, 128A. For these purposes it is clearly necessary to open valve groups 129 and 130.

Likewise a similar jumper hose must also be set up between points 133 and 134. When these valve groups are opened together with 129 and 130 and, at the same time 131 and 135 are closed the flow round the by-pass route is established and the original route starting at point 126 is completely isolated.

Fig. 19 illustrates the circuit layout which results when arrangements are made to by-pass the circuit starting at point 114, that is to say, valve group 115 is now closed as also is valve group 122. On the other hand valve group 116 has now been opened as also has valve group 125. In this way the flow commencing at point 114 has been deflected from its normal path and arrives at point 124 as a result only of these valve operations.

Likewise Fig. 20 illustrates the circuit layout which results when arrangements are made to bypass the flow path commencing at point 126. In this case a jumper hose 132 has been set up between valve groups 129 and 130, these two valve groups now being open. Valve group 131 is next closed so deflecting the flow across the pipe bridge through the jumper hose 136 and the fixed pipeline 128A. At the end of the pipe bridge a second jumper hose 136 has been set up and valve groups 133 and 134 have been opened. In this way the flow is deflected from pipeline 128A to point 127. It will be noted that valve group 135 has been closed to enable this deflection to take place.

Claims (17)

1. Means for transferring one or more fluids between two relatively rotating bodies comprising at least one flexible hose connected between respective pipes on the two bodies, storage means for an excess length of hose carried by one body and from which the hose may be partially withdrawn without rotation, means carried by the other body and providing a generally heart shaped peripheral path around which the hose can wrap in either direction from a point on or adjacent the cusp of the path as the two bodies rotate relative to each other, so as to cause a section of the hose to be withdrawn from the storage means, the latter including means for returning the hose to the storage means as the hose is unwrapped from said path on relative rotation of the bodies in the reverse direction.

2. Transfer means according to Claim 1 wherein the first body carries curved guide means around which the excess length of hose is guided as it is withdrawn from the storage means and wrapped in one or other direction around the peripheral path of the wrapping means.

3. Transfer means according to Claim 2 wherein the guide means comprises a plurality of grooved pulley or rollers.

4. Transfer means according to Claim 1, 2 or 3 wherein the excess length of hose passes over pulleys at least one of which is tensioned so as to cause the hose to be withdrawn into the storage means when the relative rotation of the bodies is such that the hose is unwrapped from the wrapping means.

5. Transfer means according to any preceding Claim wherein the peripheral path around which the hose is arranged to be wrapped is in the form of a groove in a generally heart shaped surface of a single relatively rigid body.

6. Transfer means according to any preceding Claim wherein the peripheral path around which the hose is arranged to be wrapped is provided by a plurality of grooved pulleys.

7. Transfer means according to any preceding Claim wherein the peripheral path around which the hose is arranged to be wrapped is provided by a series of grooved rollers disposed around the wrapping means.

8. Transfer means according to Claim 7 wherein the rollers are each of diabolo shape.

9. Transfer means according to any preceding Claim incorporating a by-pass path and valve means for enabling fluid normally carried by a said flexible hose to be diverted through said bypass path.

10. Transfer means according to Claim 9 wherein the by-pass path incorporates a mechanical swivel joint disposed on the common axis of rotation of the two relatively rotatable bodies.

11. Transfer means according to Claim 9 wherein the by-pass path comprises a further flexible hose.

12. Transfer means according to any preceding Claim including a plurality of flexible hoses, and the wrapping means comprises a corresponding plurality of generally heart shaped peripheral paths around which the respective hoses are arranged to be wrapped as they are withdrawn from respective storage means on relative rotation of the bodies.

13. Transfer means according to any preceding Claim including at least one flexible electric cable and storage means for an excess length of said cable carried by said one body, and the wrapping means comprises a respective heart shaped peripheral path around which the cable is arranged to be wrapped in either direction on relative rotation of the bodies such as to cause the excess length of cable to be withdrawn from the storage means, means being provided for returning the cable to the storage means as the cable is unwrapped from said path on relative rotation of the bodies in the reverse direction.

14. Transfer means according to Claims 1 to 12 including slip ring means for the completion of electrical connections between the relatively rotatable bodies, the ship rings being located on the common axis of rotation of the relatively rotatable bodies.

15. Means for transferring one or more fluids between two relatively rotatable bodies substantially as shown in and as hereinbefore described with reference to Figs. 1 to 5 of the accompanying drawings.

16. A floating oil production vessel incorporating a turret carried by the vessel but rotatable relatively to the hull of the vessel about a nominally vertical axis, and means in accordance with any preceding Claim for transferring one or more fluids between the turret and the vessel hull.

17. A floating oil production vessel incorporating a turret carried by the vessel but rotatable relatively to the hull of the vessel about a nominally vertical axis, and means for transferring one or more fluids between the turret and the vessel, substantially as shown in and hereinbefore described with reference to Figs. 1 to 10, or as modified in accordance with any one of Figs.

11 to 20, of the accompanying drawings.