Apparatus and method for spooling umbilical cable or wire rope

Abstract

 Apparatus (101) for spooling umbilical cable (102) or wire rope onto a winch drum (202) without exceeding the minimum bend radius of the cable or wire rope, comprising a carriage (401) mounted on a screw thread (402). The carriage is configured to move on the screw thread across the winch drum and the carriage comprises two sheave wheels (403) in a diametrically opposed arrangement with reference to the vertical tangent line between the two sheave wheels. A first sheave wheel (502) is a lower fixed sheave wheel, and a second sheave wheel (501) is an upper sheave wheel configured to pivot about two bearings (505, 506) positioned on the vertical tangent line (507) between the lower fixed wheel and the upper sheave wheel.

Description

[0001] The present invention relates to apparatus and a method for spooling umbilical cable or wire rope onto a winch drum in a manner that does not exceed the minimum bend radius of the umbilical cable or wire rope.

[0002] It is known to spool umbilical cable or wire rope onto a winch drum. Umbilical cable may be used, for example, as a means to allow submersible remotely operated vehicles to perform underwater investigations and explorations at a distance from a vessel and in any direction. The umbilical cable thus needs to be spooled onto a winch drum for storage when not in use. However, known apparatus and methods of spooling umbilical cable or wire rope cause the minimum bend radius of the umbilical cable or wire rope to be exceeded, leading to damage of the umbilical cable and failure of electrical or optical elements within the cable, and also damage of the wire rope. Therefore known apparatus and methods decrease the lifespan of the umbilical cable and wire rope. The present invention overcomes the problems of the prior art by providing apparatus and a method which spool umbilical cable and wire rope onto a winch drum without exceeding the minimum bend radius of the umbilical cable. Advantageously, the present invention enables umbilical cable and wire rope to be spooled onto a winch drum in a manner that neither damages the umbilical cable/wire rope nor causes failure of electrical or optical elements within the cable. Consequently, the apparatus and method of the present invention allow the lifespan of the umbilical cable or wire rope to be prolonged. Furthermore, in contrast to known apparatus and methods of spooling umbilical cable or wire rope, the present invention allows for spooling of any wrap and layer arrangement of umbilical cable or wire rope on a winch drum, in a manner that never exceeds the minimum bend radius of the umbilical cable or rope.

[0003] According to an aspect of the present invention, there is provided apparatus for spooling umbilical cable or wire rope onto a winch drum without exceeding the minimum bend radius of the cable or wire rope, comprising a carriage mounted on a screw thread, wherein said carriage is configured to move on said screw thread across said winch drum and said carriage comprises two sheave wheels, wherein a first sheave wheel is a lower fixed sheave wheel, and wherein a second sheave wheel is an upper sheave wheel in a diametrically opposed arrangement to said first sheave wheel with reference to the vertical tangent line between the lower fixed sheave wheel and the upper sheave wheel, and wherein said second sheave wheel is configured to pivot about two bearings positioned on said vertical tangent line.

[0004] According to a second aspect of the present invention, there is provided a method for spooling umbilical cable or wire rope onto a winch drum without exceeding the minimum bend radius of the cable or wire rope, comprising the step of passing the cable or wire rope straight down between an upper sheave wheel and a lower fixed sheave wheel configured in a diametrically opposed arrangement with reference to the vertical tangent line between the lower fixed sheave wheel and the upper sheave wheel, wherein said upper sheave wheel and said lower fixed sheave wheel are in a carriage mounted on a screw thread. The carriage is configured to move on the screw thread across the winch drum. The upper sheave wheel is configured to pivot about two bearings positioned on the vertical tangent line between the lower fixed wheel and the upper sheave wheel, and the cable or wire rope has an entry point on said upper wheel in the same vertical plane as the entry point of said cable or wire rope on said lower fixed wheel.

[0005] The invention will now be described by way of example only, with reference to the accompanying drawings, of which:

Figure 1 shows a boat containing apparatus embodying the present invention for spooling umbilical cable;

Figure 2 shows umbilical cable spooling around a winch drum;

Figures 3A and 3B show two examples of prior art;

Figure 4 illustrates the apparatus embodying the present invention for spooling umbilical cable;

Figure 5 shows a cross section of the apparatus embodying the present invention;

Figure 6 shows a cross section of the apparatus embodying the method of the present invention for spooling umbilical cable onto a winch drum; and

Figure 7 shows umbilical cable spooling around a sheave wheel.

Figure 1

[0006] The apparatus 101 embodied by the present invention is shown in Figure 1, spooling umbilical cable 102 which is attached to submersible remotely operated vehicle (ROV) 103. The submersible ROV 103 is fitted with cameras, lights and manipulating devices to enable underwater investigations to be performed. Apparatus 101 is bolted to standard A-frame 104 which itself is attached to vessel 105.

[0007] Umbilical cable 102 acts as a means to allow submersible ROV 103 to perform underwater investigations and explorations at a distance from vessel 105 and in any direction. Umbilical cable 102 may be up to 3000 metres long and is a load-bearing steel armoured cable containing electrical conductors and fibre optics to allow power, video and data signals to be transmitted back and forth between submersible ROV 103 and vessel 105.

Figure 2

[0008] When not in use, umbilical cable 201 is spooled onto winch drum 202 which is attached to frame 203, itself configured to be secured to a vessel (not shown). Umbilical cable 201 may be up to 3000 metres long and is a load-bearing steel armoured cable. Umbilical cable 201 weighs between 10 and 15 tonne and provides up to six kilovolt (6kV). Umbilical cable 201 is therefore an extremely valuable piece of equipment and must be spooled onto winch drum 202 in a manner that does not damage umbilical cable 201. As shown in Figure 2, umbilical cable 201 must be spooled around winch drum 202 in a manner that does not lead to kinking or internal damage of umbilical cable 201.

Figure 3A

[0009] A standard spooling system of the prior art is illustrated in Figure 3A, comprising winch drum 301 having two rollers 302. Umbilical cable 303 is spooled via the two rollers 302 onto winch drum 301. However, the diameter of rollers 302 is too small for the size of umbilical cable 303, meaning that the minimum bend radius (as set out by the manufacturer of said umbilical) of umbilical cable 303 is always exceeded, leading to failure of internal electric elements of umbilical cable 303 as it is wound onto winch drum 301. This known spooling apparatus therefore does not handle umbilical cable 303 correctly, leading to damage of umbilical cable 303 and consequently decreasing the lifespan of umbilical cable 303. Furthermore, this known spooling apparatus does not cater for spooling any desired layer or wrap arrangement of umbilical cable and is therefore limited in its use.

Figure 3B

[0010] An alternative known spooling system of the prior art is illustrated in Figure 3B, which comprises single sheave wheel 304. Umbilical cable 305 ought theoretically to position onto sheave wheel 304 in a straight alignment. However, in practice, umbilical cable 305 comes onto sheave wheel 304 at an angle 306, potentially causing a kink. The kink causes the minimum bend radius of the umbilical cable to be exceeded, adding stress to umbilical cable 305. This alternative known spooling apparatus therefore does not handle umbilical cable 305 correctly, leading to damage of umbilical cable 305 and consequently decreasing the lifespan of umbilical cable 305. Furthermore, this known spooling apparatus does not cater for spooling any desired layer or wrap arrangement of umbilical cable and is therefore limited in its use.

[0011] Active Heave Compensation describes the paying out and paying in of the umbilical cable that is required to keep a submersible ROV stationary at a depth underneath the surface. Active Heave Compensation is thus required because the ROV is connected to its host vessel and therefore moves up and down with wave and tidal movement. These two known prior art spooling systems are especially prone to causing kinking of the umbilical cable in the rapid movements of Active Heave Compensation.

Figure 4

[0012] The apparatus embodied in the present invention is illustrated in Figure 4. The apparatus embodied in the present invention advantageously overcomes the problems of the prior art spooling systems. The apparatus comprises carriage 401 mounted on screw thread 402, allowing carriage 401 to move back and forth across winch drum (not here shown). Carriage 401 includes two sheave wheels in a diametrically opposed arrangement. A first sheave wheel is lower sheave wheel 404 which is fixedly secured into carriage 401. A second sheave wheel is an upper sheave wheel 403 configured to pivot about two bearings (not shown).

[0013] Lower sheave wheel 404 is fixed in carriage 401 and moves across winch drum as carriage 401 moves across winch drum on screw thread 402. The manner in which carriage 401 moves across winch drum is known as "levelwind" and this is known.

[0014] Upper sheave wheel 403 is always the upper wheel and pivots about two bearings, the positioning of which is critical. The two bearings are in line with the vertical tangent point between the lower fixed wheel 404 and the upper sheave wheel 403. The umbilical cable has an entry point on the upper wheel 403 in the same vertical plane as the entry point on the lower wheel 404.

[0015] The apparatus embodied by the present invention thereby overcomes the problems presented by the prior art. The apparatus embodied by the present invention provides a spooling system that neither allows the umbilical cable to kink during spooling nor causes internal elements of the cable to be damaged as it is wound onto the winch drum, because the minimum bend radius of the cable is never exceeded. The present invention allows for the umbilical cable to always be correctly handled. This correct handling means that no damage is inflicted on the umbilical cable during spooling, thereby increasing the lifespan of the umbilical cable and requiring it to be replaced less frequently than in known spooling systems. Furthermore, unlike prior art spooling systems, the apparatus and method embodied by the present invention is advantageously universally applicable to all arrangements of umbilical cable in any particular layer or wrap. This is because when the umbilical cable is spooling onto a full drum, the umbilical cable runs tangentially onto the drum from the lower sheave wheel.

Figure 5

[0016] A cross section of the apparatus embodied in the present invention is shown in Figure 5. Upper sheave wheel 501 and lower sheave wheel 502 are contained in carriage 503, which itself moves back and forth over winch drum 504 during the spooling process as the umbilical cable wraps around winch drum 504.

[0017] Lower sheave wheel 502 is fixed in position in carriage 503 and moves only across drum 504 as carriage 503 moves across drum 504.

[0018] Upper sheave wheel 501 pivots about two bearings, an upper bearing 505 and a lower bearing 506. Bearings 505 and 506 are in line with the vertical tangent point 507 between the lower fixed wheel 502 and the upper sheave wheel 501. This means that the entry point of the umbilical cable on the upper sheave wheel 501 is on the same vertical line 507 as the entry point on the lower sheave wheel 502. The umbilical cable therefore moves straight up or down between upper sheave wheel 501 and lower sheave wheel 502, and bearings 505 and 506 are totally in line with the umbilical.

Figure 6

[0019] As illustrated in Figure 6, when spooling onto winch drum 601, umbilical cable 602 comes onto upper sheave wheel 603 in accordance with arrow 606, around upper sheave wheel 603 and through bottom bearing 604, then passes straight down between upper sheave wheel 603 and lower sheave wheel 605 and onto drum 601. Therefore, umbilical cable 602 always passes straight down between the two sheaves 603 and 605 in accordance with arrow 607 and there is never any movement of umbilical cable 602 between the two sheaves 603 and 605. This is to ensure that there is no kinking or twisting of umbilical cable 602. This movement of umbilical cable 602 also ensures that the minimum bend radius of the umbilical cable is never exceeded whilst umbilical cable 602 is spooled onto winch drum 601. The pivoting action of upper sheave wheel 603 ensures umbilical cable 602 is sent off in the right direction (to either the drum or overboarding of sheave wheel).

[0020] Therefore, as shown in Figure 6, the present invention also provides a method for spooling umbilical cable onto a winch drum without exceeding the minimum bend radius of the cable, comprising the step of: passing the cable straight down between an upper sheave wheel and a lower fixed sheave wheel configured in a diametrically opposed arrangement in a carriage mounted on a screw thread, wherein said carriage is configured to move on said screw thread across said winch drum, wherein said upper sheave wheel is configured to pivot about two bearings positioned on the vertical tangent line between the lower fixed wheel and the upper sheave wheel, and wherein said cable has an entry point on said upper wheel in the same vertical plane as the entry point of said cable on said lower fixed wheel.

[0021] The method also comprises the step of spooling the umbilical cable around a winch drum, forming a wrap of cable around each circumference of drum. The method also comprises the step of spooling the umbilical cable around the winch drum, forming a plurality of layers on the winch drum.

[0022] The umbilical cable winds around the drum, and the winding of umbilical cable around a single circumference of drum constitutes a wrap. The umbilical cable then winds on top of itself in layers (akin to a hosepipe), up to ten layers and possibly more.

[0023] When the lower fixed sheave wheel moves across winch drum, lower fixed sheave wheel is always directly vertically above one wrap each time the umbilical cable winds around the drum. This ensures that the umbilical cable is always in line and there is never any kinking of the umbilical cable during the spooling process.

[0024] When unspooling from winch drum 601, umbilical cable 602 moves up past lower sheave wheel 605, through bottom bearing 604 and around upper sheave wheel 603, before being lowered into the water, moving in a direction which is opposite to arrows 606 and 607. Therefore, the umbilical cable always passes straight up between the two sheaves 603 and 605 and there is never any movement of umbilical 602 between the two sheaves 603 and 605.

Figure 7

[0025] As illustrated in Figure 7, umbilical cable 702 always lies within the "valley" of sheave wheel 701. During the spooling process, the umbilical cable on the upper sheave wheel is in the same vertical plane as the entry point of the umbilical cable on the lower sheave wheel. There is thus no movement between the upper and lower sheave wheels, and the umbilical simply moves up between the two sheaves. The fact that umbilical cable 702 lies within the "valley" of sheave wheel 701 aids in the fact that there is no movement between the upper and lower sheave wheels, and the umbilical simply moves up between the two sheaves.

Claims

1. An apparatus for spooling umbilical cable or wire rope onto a winch drum without exceeding the minimum bend radius of the cable or wire rope, characterised by:

a carriage mounted on a screw thread, wherein said carriage is configured to move on said screw thread across said winch drum and said carriage comprises two sheave wheels,

wherein a first sheave wheel is a lower fixed sheave wheel,

and wherein a second sheave wheel is an upper sheave wheel in a diametrically opposed arrangement to said first sheave wheel with reference to the vertical tangent line between the lower fixed sheave wheel and the upper sheave wheel,

and wherein said second sheave wheel is configured to pivot about two bearings positioned on said vertical tangent line .

2. The apparatus of claim 1, wherein said Umbilical cable is connectable to a submersible remotely operated vehicle.

3. The apparatus of claim 2, wherein said umbilical cable conveys power, control signals and communication signals to said submersible remotely operated vehicle.

4. The apparatus of claim 1, wherein said umbilical cable or wire rope spools around said winch drum, forming a wrap of cable or wire rope around each circumference of drum.

5. The apparatus of claim 4, wherein said lower fixed wheel is always vertically above a wrap of cable or wire rope on said winch drum when said umbilical cable or wire rope spools around said winch drum.

6. The apparatus of claim 4, wherein said umbilical cable or wire rope forms a plurality of wraps on said winch drum.

7. The apparatus of any of claims 1 to 6, wherein said umbilical cable or wire rope spools around said winch drum, forming a plurality of layers of cable or wire rope on said winch drum.

8. The apparatus of claim 4 or claim 7, wherein said apparatus is configured to operate for any wrap or layer configuration of cable or wire rope.

9. The apparatus of any of claims 1 to 8, wherein said upper sheave wheel moves only under tension of the umbilical cable or wire rope.

10. The apparatus of any of claims 1 to 9, wherein said umbilical cable or wire rope has an entry point on said upper wheel in the same vertical plane as the entry point of said cable or wire rope on said lower fixed wheel.

11. A method of spooling umbilical cable or wire rope onto a winch drum without exceeding the minimum bend radius of the cable or wire rope, characterised by the steps of:

passing the cable or wire rope straight down between an upper sheave wheel and a lower fixed sheave wheel configured in a diametrically opposed arrangement with reference to the vertical tangent line between the lower fixed sheave wheel and the upper sheave wheel,

wherein said upper sheave wheel and said lower fixed sheave wheel are in a carriage mounted on a screw thread, and wherein said carriage is configured to move on said screw thread across said winch drum,

wherein said upper sheave wheel is configured to pivot about two bearings positioned on the vertical tangent line between the lower fixed wheel and the upper sheave wheel,

and wherein said cable or wire rope has an entry point on said upper wheel in the same vertical plane as the entry point of said cable or wire rope on said lower fixed wheel.

12. The method of claim 11, further comprising the step of spooling said umbilical cable or wire rope around said winch drum, forming a wrap of cable or wire rope around each circumference of drum.

13. The method of in claim 12, wherein when said carriage moves on said screw thread across said winch drum, said lower fixed sheave wheel is always vertically above a wrap of cable or wire rope in said winch drum when said umbilical cable or wire rope spools around said winch drum.

14. The method of claim 12, wherein said umbilical cable or wire rope forms a plurality of wraps on said winch drum.

15. The method of claim 12, further comprising the step of spooling said umbilical cable or wire rope around said winch drum, forming a plurality of layers of cable or wire rope on said winch drum.

Drawing