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You are here: BAILII >> Databases >> England and Wales High Court (Chancery Division) Decisions >> Rockwater Ltd v Coflexip SA & Anor [2003] EWHC 812 (Ch) (15 April 2003) URL: http://www.bailii.org/ew/cases/EWHC/Ch/2003/812.html Cite as: [2003] EWHC 812 (Ch) |
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CHANCERY DIVISION
PATENTS COURT
Strand, London, WC2A 2LL |
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B e f o r e :
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| ROCKWATER LIMITED |
Claimant/Part 20 Defendant |
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| - and - |
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| (1) COFLEXIP S.A. (2) TECHNIP OFFSHORE UK LIMITED (formerly COFLEXIP STENA OFFSHORE LIMITED) |
Defendant/Part 20 Claimant Part 20 Claimant |
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Mr R Miller QC and Mr J Turner (instructed by Norton Rose for Coxlexip S.A. and Technip Offshore UK Limited)
Hearing dates: 17 - 26 March 2003
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Crown Copyright ©
Mr Justice Laddie:
The technical background
"15. Rigid pipe has a finite bending stiffness. That is to say, if a sufficient load is applied to a length of rigid pipe it will deflect (i.e. bend). A rigid pipe can be bent elastically up to its elastic limit. This means that provided the pipe is not bent beyond its elastic limit (or yield stress), it will return to its original shape after the bending force has been removed. If a rigid pipe is bent beyond its elastic limit, this will result in the pipe being plastically deformed. This means that if the bending force is removed, the pipe will not return to its original profile, ie a permanent curvature will be induced into the pipe.
"18. The bending stiffness of flexible pipe is several orders of magnitude less than that of rigid pipe. This is due to the lower bending stiffness of the materials which make up the flexible pipe and also because each layer is, to a degree, able to move relative to its neighbouring layer (in non-bonded flexible pipe). This means that flexible pipe can be bent to a much smaller radius of curvature than rigid pipe without exceeding its elastic limit. If one were to bend a flexible pipe beyond its elastic limit (also referred to as damaging bend radius or minimum bend radius), the pipe would be irreparably damaged so that it could not be straightened back to its original shape and its pressure containing properties would probably be impaired. However, flexible pipe can be bent to a very much smaller radius of curvature than rigid pipe without reaching its damaging bend radius. There is no plastic deformation with flexible pipe."
Laying rigid submarine pipes
Figure 1:
Figure 2:
Figure 3:
In this illustration, the pipe is loaded onto the ship in short straight lengths. Individual lengths of pipe are lifted onto the angled ramp at the stern of the vessel, held by clamps and welded onto the upstanding end of the pipe which leads down into the sea.
Laying flexible submarine pipes
Figure 4:
Figure 5:
"Crushing of the pipe at the overboarding point
36. As the water depth increased, the tensile load in the pipe also increased due to the greater weight of suspended pipe. The increased tensile load became a particular concern where the pipe passed across the overboarding gutter (or wheel). The gutter provided the reaction to a combination of the tensile load in the pipe between the gutter and the installation reel or tensioner, and the free hanging pipe suspended from the gutter. This reaction was spread approximately uniformly over the length of the contact between the pipe and the gutter. If the radius of the gutter and, therefore, the pipe contact length, were to remain the same, the crushing force per unit length of contact increased as the water depth and pipe suspended weight increased. To avoid or minimise the increase in crushing load as the water depth increased, one had to increase the radius of the gutter, and hence the contact length. In this way the increased crushing load was compensated by an increase in the support length."
Figure 6:
"In order to prevent the pipe buckling at the sagbend a horizontal tension was applied to the pipe by tensioners situated on the deck of the vessel. In this way a minimum radius of curvature was maintained at the sagbend. This avoided the risk of the weight of the pipe tending to straighten itself vertically and creating overstress in the sagbend (caused by a small radius of curvature)." (First Report paragraph 85)
Although in this passage he was discussing the sagbend problem in relation to rigid pipes, the same principles apply to flexible conduits as well.
Overboarding accessories
Figure 7:
Figure 8(a):
Figure 8(b):
Figure 8(c):
Figure 8(d):
Figure 9:
Figure 10:
Summary of the relevant problems in laying flexible pipe.
The Coflexip Patent
"establishes that the words "flexible conduit" should be interpreted as including more than what was known as flexible pipe, but not so widely as to cover what was known in the industry as rigid pipe." (paragraph 18)
"For the purpose of being able to lay flexible conduits with relatively large diameters in great depths of water, one has to use tensioning means and deflecting elements whose dimensions and cost pose problems and which create an excessive space requirement on the bridge of the laying vessel" (page 1 lines 33 to 36)
"Such a winch, as well as the deflecting element, assume dimensions and space requirements that are excessive when the diameter of the conduit and the depth of water increase. As the diameter of the tubular flexible conduit and the depth increase, the size of the wheel becomes increasingly larger. Such a wheel may have a diameter of the order of 10 metres for a depth substantially equal to 500 metres." (page 1 lines 43 to 49).
"With the devices of the known type, it is not possible to exceed this order of depth. Wheels with a larger diameter are difficult to make." (page 1 lines 51 to 54)
"The object of the present invention is the laying of flexible conduits at depths that are substantially greater than those which are feasible by using the known means, as, for example, a depth of the order of 1000 to 2000 metres. The device in accordance with the present invention must be capable of withstanding considerable tractive forces which may reach and even exceed 250 tons in the case of a conduit with a diameter substantially equal to 30 cm for a depth of 1000 metres." (page 2 lines 37 to 44)
Figure 11:
"In these conditions, the tension ahead of the tensioning means being exerted on the portion of the flexible conduit up the line and coming from the storage means is very low and preferably virtually negligible. It has been found that in these conditions, it becomes possible to subject a portion of the conduit situated in the portion ahead, between the storage means and the tensioning means, to relatively extensive bending, this being explained by the fact that in this case, there is no combination of the bending with an axial tractive load" (page 2 line 52 to page 3 line 7)
Figure 12:
"One of the original features of the invention lies in the absence of any means for guiding the tubular flexible conduit after it has left the main tensioning means. However, it should be noted that the main tensioning means 6 can themselves ensure guidance for the tubular flexible conduit and a deviation relative to the vertical. For example, the multi-caterpillar tensioning means generally permit a deviation of more or less 10 to 15o relative to the vertical." (page 10)
The Claims
"A process for laying from a floating support (1), a flexible conduit (3) comprising a rigid accessory (21, 21a, 21b) mounted on the said flexible conduit (3) and having an outer dimension larger than the outer diameter of the latter, wherein one unrolls a flexible conduit (3) gripped at its outer surface by linear winch-type tensioning means (6) with a substantially vertical axis, and wherein
(a) to cause the section of the flexible conduit (3) whereon the accessory is mounted to pass through the said tensioning means (6), the said rigid accessory (21) is connected to auxiliary tensioning means (19, 20), so as to take up the pull exerted by the flexible conduit (3) by the said auxiliary tensioning means (19, 20), while the flexible conduit (3) is lowered through the free space between the said laterally moved-apart tensioning means (6),
(b) the outer surface of the flexible conduit (3) is gripped ahead of the rigid accessory by the said tensioning means (6) after they have been brought together, so that the pull exerted by the flexible conduit (3) is again taken over by the said tensioning means (6);
(c) after the auxiliary tensioning means (19) have been released, the unrolling of the flexible conduit (3) is resumed by the said tensioning means (6), the latter comprising the last means for guiding the conduit at the level of the floating support."
Figure 13:
"21. The pull referred to in the claim is that exerted by the flexible conduit seaside of the main tensioners. Thus the words "the pull" refer to all the tension caused by the part of the pipe seaside of the main tensioners. The sentence bridging pages 2 and 3 of the specification, relied on by Stolt, does not suggest a contrary meaning. All that is said is that, if the seaside pull is taken by the main tensioners, the tension in the pipe after the main tensioners "is very low and preferably virtually negligible". There will inevitably be some tension due for example to the weight of the pipe and the friction, but that does not detract from the teaching of the specification that the tension from the pipe seaside of the tensioners is to be taken by the main tensioners or, when an accessory is passed, by the auxiliary tensioner.
22. Of course, the words "the pull" have to be construed in context. As Lord Diplock pointed out in Catnic Components Limited v Hill & Smith Limited [1982] RPC 183 a word such as "vertical" had to be construed in context; in that case in the context of manufacture of lintels for the building trade. Thus the requirement that a metal beam should be vertical did not mean that it should be exactly 90o to the horizontal. A similar approach should be adopted in the present case so that the requirements as to "the pull" should be construed in the context of pipelaying from a ship."
"A device for operating the process according to any one of the claims 1 and 2, comprising;
- linear winch-type tensioning means (6) with a substantially vertical axis, capable of ensuring the normal lowering of the flexible conduit (3) by gripping the outer surface of the flexible conduit (3) and capable of being laterally moved apart, the said tensioning means (6) comprising the last means for guiding the flexible conduit (3) on board the floating support (1),
- auxiliary tensioning means (19, 20) comprising at least one elongate movable traction element (20) capable of being connected to the rigid accessory (21, 21a, 21b) mounted on the flexible conduit (3)."
"By the end of the trial, only one issue on infringement remained. Claim 1 ends with a requirement that the vertically disposed tensioning devices are "the last means for guiding the conduit at the level of the floating support." Similar wording is to be found at the end of Claim 3. This wording reflects the fact that since the patented system delivers the flexible conduit at the same angle as the catenary below the vessel, no further guides, such as stingers or overboarding wheels or chutes, are required. As the drawing in the patent (Figure 14 above) illustrates and the text describes, below the lowest tensioner there is the working table (7) and the moonpool (8). Neither the table nor the sides of the moonpool are described or referred to in the specification as guides. In normal and stable conditions, they do not even touch the conduit.
The layout of the Seaway Falcon, the Stolt Comex vessel which is alleged to infringe, is essentially the same as that illustrated in Figure 14. It includes bumpers or deflectors located below the tensioners to prevent pipe which is being laid from hitting the moonpool or moonpool doors. It was accepted by Stolt Comex that in normal use these devices do not touch the pipe. They are used to prevent the pipe from being damaged, for example by smashing against the edge of the moonpool doors during stormy weather. Mr. Willis, who had never seen the Seaway Falcon in operation, said that the pipe would touch the deflectors "every other second". I do not accept that evidence. When the whole of his cross examination on this subject is reviewed and read in the light not only of Mr. Seeley's evidence but also Mr. Coutarel's evidence, it is apparent that the vessel is designed to be operated without the pipe contacting the deflectors at all. The same point comes out of the written instructions given to the operators of the Seaway Falcon. They are told to set up the vessel to ensure that there is no "clashing with the bottom edge of the moonpool". Those instructions go on to explain that if the pipe does come into contact with the bottom edge:
"This will not cause any damage to the [pipe] if performed in a fully controlled manner as the base of the vessel moon pool has a 7.5 metre radius"
This means that because the edge of the moonpool is rounded (because of the presence of the deflectors) pulling the pipe past it will not cause damage if done carefully.
I do not accept that the deflectors in the Seaway Falcon can reasonably be called guides. They are no more guides than the bumpers at the front of a car or a crash helmet worn by a motorcyclist. The defendants infringe."
"which directs or diverts the angle [of the conduit] under conditions of average contact. By "average contact" I mean that the "flexible conduit" is in contact with it for the majority of the time. This element directs the angle of the "flexible conduit" into the angle of the catenary in the water column."
"The arrangement in the Patent may include a working table which may be opened or closed when the pipe is being laid. There may be occasions when the pipe comes into contact with the closed working table as a result of vessel motions but this does not mean the working table acts as a means for guiding, as it is not designed for average contact. This is clear from the Patent which refers to the linear tensioner as the last means for guiding the pipe. If the working table was designed for average contact, it would in my view be the last means for guiding the pipe." (Second Report paragraph 14)
Figure 14:
Infringement
Figure 15:
Figure 16:
Figure 17:
Is the flared device (12) in the Toisa Perseus a "means for guiding"?
"185. During normal lay there will be an angle of lay which is dependent upon the submerged weight of the pipe, the depth of water and the bottom tension applied by the pull of the vessel. A lay angle of 1º-2º would be typical for the sizes of pipe and water depth of Foinaven. Vessels such as the Toisa Perseus can lay in the forward, sideways or reverse directions. The frequency of contact, and forces operating, between the pipe guide and the pipe will depend upon the direction of lay because the pipe guide is offset from the centre line of the tensioner. In the case of the Foinaven contract when laying in the forward direction, once a catenary is established, it is likely there would have been some contact between the pipe guide and the pipe but the extent to which the pipe was bent around the guide cannot be known for certain (because the angle of lay is not known for certain) although in normal circumstances it could be very small. If laying is taking place with the vessel moving in reverse then, under median conditions, the pipe would not contact the pipe guide up to an angle of lay of 1.2º (see table 6 below)." (First Report paragraph 185)
"Q. … Let us get to the stage where we make contact with the seabed, which is paragraph 185 of your statement. As I understand it, you accept that in this state, with a lay angle of one to two degrees, there is likely to be some contact with the guide means, and that is [paragraph 185]. I just read it wrong. "... it is likely there would have been some contact between the pipe guide and the pipe but the extent to which the pipe was bent around the guide cannot be known for certain". A. Yes, that is right.
Q. At that stage the horizontal tension due to the catenary will be taken on that pipe guide. A. Yes. Making the assumption that the vessel was going forward and you have an angle, yes, that is correct" (Transcript Day 4 page 525)
The Improver argument
"One of the consequences of using a linear tensioner as the last means of guiding (as in the Patent) is that the catenary top angle is directed or diverted over the fore of the tensioner from the vertical (see Fig [14] above ). In effect, the pipe is bent under tension over an arc at the fore of the linear tensioner. The associated bend radius is relatively small. It is generally undesirable to bend pipe at such relatively small radii under high tension, particularly for larger angles as this increases the risk of pipe collapse and wear and tear on the linear tensioner. An advantage of the pipe guide is that it has a radius which is larger than the radius of the fore of typical linear tensioners. This results in a reduced risk of collapse of the pipe, particularly at larger angles and alleviates the linear tensioner's components from the mechanical demands placed by the horizontal force." (Second Report paragraph 24)
Validity
The Prior Art
The disclosure in Recalde US
"These smaller lines were not required to be passed through the pipe handling equipment with the main reel pipeline according to the suggestion …" (Column 3 lines 58 to 60)
"To be commercially viable a pipelaying vessel must also be capable of laying either single or multiple operational lines in shallow waters of less than 200 ft. up to 3,000 ft. depth." (Column 4 lines 2 to 5)
"A principal feature of the present multi-reel pipelaying vessel is that an operational lines laying device is mounted adjacent to the stern of the vessel. A plurality of operational lines are unspooled from the reels mounted on the vessel and are laid out into simultaneous contact with the laying device which includes an operational lines supporting means adapted for providing moving contact with the operational lines. The preferred laying device of the present invention changes the direction of movement of the plurality of operational lines from horizontal to vertical and can be used for laying operational lines in shallow waters of under 200 ft down too much greater depths of 7,500 ft and beyond. The supporting means is adapted for gathering the operational lines into an initial juxtaposed configuration which is parallel with the direction of forward vessel motion. All of the operational lines are moved at the same linear velocity due to the contact thereof with the supporting means of the operational lines laying device.
The preferred operational lines laying device also includes straightening and tensioning devices which are adapted to straighten and provide tension for the operational lines while maintaining the same in a juxtaposed array which is aligned with the direction of forward vessel motion. The straightening means is adapted for imparting a reverse bending force to the rigid walled pipeline(s) which are among the operational lines being laid out." (Col 4 lines 16 to 44)
"All of these operational lines are gathered together into an initial horizontal juxtaposed configuration at the top of the take-off drum 26 and are maintained in continuous contact with the periphery thereof as the direction of movement of these operational lines is changed from horizontal to vertical at the stern end of the pipe take-off drum 26.
The contact between the operational lines 22, 44 and 46 with the periphery of the pipe take-off drum 26 results in the linear velocity of layout of all of these lines being equal. Upon changing of the direction of movement from horizontal to any angular pipe take-off position the operational lines are then passed through the straightening means 32 and the tensioning device 34 so that the array of these lines passes downwardly over the stern 28 at nearly a 90o angle as shown in FIG 1 for deep water layout." (Col. 10 lines 13 to 30)
"A preferred configuration of a straightener/tensioner track assembly which can be used for assembly 102 and, with some modification to provide for adequate hydraulic power, also for assemblies 104 and 106 is shown in FIGS. 17 – 19." (Col 19 lines 29 to 33)
"These jactuators adjustments permit the turning of internally mounted screws in order to position the multiple roller guides independently." (Col. 30 lines 1 to 4)
"As shown in FIG 38[2] nine roller guide sets are provided for each of three endless sprocket chains which are employed to support the pipe pads for three pairs of lines which constitute the pipeline array 35 as shown in FIGS 37[3] and 38." (Col. 30 lines 4 to 8).
How does Recalde US work?
"There is no technical reason why Recalde US would wish to have the tensioners grasp the operational lines which are not rigid pipes." (First report paragraph 153).
"The storage reels are fitted with hydraulic motors for imparting motive power to the reel flanges or rims in order to provide for spooling up of the lines. The hydraulic motors are also fitted with hydraulic braking systems for controlling tension of the lines during unspooling and to control the rate of line(s) layout." (Col. 6 lines 17 to 23)
"In deep waters beyond 3,000 ft the weight of the pipeline(s) is sufficient to elastically straightening the rigid walled pipe. In this embodiment it is possible to use the hydraulic braking systems on the operational lines reel motors to provide tensioning of the lines, thus permitting pipe layout in the absence of separate straightening and/or tensioning devices." (Col 5 lines 3 to 9)
"The preferred operational lines laying device also includes straightening and tensioning devices which are adapted to straighten and provide tension for the operational lines while maintaining the same in a juxtaposed array which is aligned with the direction of forward vessel motion. The straightening means is adapted for imparting a reverse bending force to the rigid walled pipeline(s) which are among the operational lines being laid out." (Col 4 lines 36 to 44)
"The tensioning device 34 is formed by a second track assembly 104 and a third track assembly 106 which act on opposite sides of the operational line array 35, respectively, in order to provide tension for supporting the pipeline weight which is suspended from the pipe take-off assembly 24." (11-1, 11-8)