Fairlead for guiding an anchoring element

Abstract

The invention relates to a fairlead for guiding an anchoring element, allowing the anchoring of a unit, such as a floating unit, to an anchoring point, and in particular being applicable to permanent anchoring devices of the submerged fairlead type with an integrated chain stopper, in fields such as the marine, offshore, and renewable marine energy industries. The fairlead comprises guide means 1 to 4 able to guide the translation of the anchoring element between the unit and the anchoring point, and blocking means 5 able to block the translation of the anchoring element in the guide means 1 to 4. The blocking means 5 are mounted on the guide means 1 to 4 at least partially freely rotating around an axis parallel to the longitudinal axis of the anchoring element when the latter is guided in the guide means 1 to 4.

Claims

1. A fairlead for guiding an anchor line having a longitudinal axis and allowing the anchoring of a unit to an anchoring point, said fairlead comprising a guider able to guide a translation of the anchor line between the unit and the anchoring point, and a lock able to block the translation of the anchor line in the guider along a local longitudinal axis of the anchor line where the lock acts on the anchor line, wherein the lock is mounted on the guider at least partially freely rotatable with respect to the guider around an axis parallel to the local longitudinal axis of the anchor line when the anchor line is guided in the guider.

2. A fairlead for guiding an anchor line having a longitudinal axis and allowing the anchoring of a unit to an anchoring point, said fairlead comprising a guider able to guide a translation of the anchor line between the unit and the anchoring point, and a lock able to block the translation of the anchor line in the guider along a local longitudinal axis of the anchor line where the lock acts on the anchor line, wherein the lock is mounted on the guider at least partially freely rotatable with respect to the guider around an axis parallel to the local longitudinal axis of the anchor line when the latter is guided in the guider, and wherein the guider comprises a bearing ring and a first rotation limiter, and wherein the lock-comprises a pivotable support mounted against the bearing ring and a second rotation limiter able to cooperate with the first rotation limiter to limit the rotation of the lock.

3. The fairlead according to claim 2, wherein the first rotation limiter comprises at least one circular groove forming at least one arc of a circle centered on the rotation axis of the lock, and wherein the second rotation limiter comprises at least one element able to be guided in the circular groove.

4. The fairlead according to claim 2, wherein the lock comprises at least one pivotable block of the gate type mounted on the support between a first blocking position in which the at least one pivotable block is able to block the anchor line from translating in the guider, and a second position without blocking in which the at least one pivotable block permits the anchor line to freely translate in the guider.

5. The fairlead according to claim 4, wherein the at least one block is provided with a mechanical, hydraulic or electric actuator, said actuator, allowing the passage of the at least one block from the blocking position to the position without blocking, and vice versa.

6. The fairlead according to claim 5, wherein the actuator comprises at least one jack wherein one end is connected to the support and the other end is connected to the at least one pivotable block, such that the deployment of the actuator drives the pivoting of the at least one pivotable block from the blocking position toward the position without blocking.

7. The fairlead according to claim 5, wherein the actuator comprises at least one cable fixed on the at least one pivotable block such that traction on the cable drives the pivoting of the at least one pivotable block from the blocking position toward the position without blocking.

8. The fairlead according to claim 1 wherein the guider comprises a first guide assembly configured to guide the anchor line in a first direction, the first guide assembly comprising a fastening interface configured to allow the fairlead to be fastened to the unit, and a second guide, the second guide being pivotably mounted relative to the first guide assembly around an axis and configured to guide the anchor line in a second direction in a nonzero angle relative to the first direction, and wherein the lock is mounted on the second guide.

9. The fairlead according to claim 8, wherein the first guide assembly comprises a guide support rotatably mounted relative to the fastening interface, the guide support being mounted around an axis parallel to the first direction, and a guide defining at least part of a passage for the anchor line.

10. The fairlead according to claim 9, wherein a pivot axis of the second guide relative to a pivot axis the first guide assembly is formed in a first part of the guide and substantially opposite the lock.

11. The fairlead according to claim 8 wherein the guider comprises a transitioner configured to guide the anchor line at the transition between the first and second guide directions.

12. The fairlead according to claim 11, wherein the transitioner comprises a guider wheel rotatably mounted around an axis formed in a second part of the guider.

13. The fairlead according to claim 8 wherein the guider comprises a guide cone configured to facilitate entry of the anchor line in the second guide.

14. The fairlead according to claim 1, wherein the unit is a floating unit.

15. The fairlead according to claim 7, wherein the at least one cable is fixed on the at least one pivotable block with a ring.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The features and advantages of the invention will appear upon reading the following description, provided solely as a non-limiting example, in reference to the following appended drawings:

(2) FIG. 1: diagrammatic illustration of one example guide fairlead according to the invention;

(3) FIGS. 2a and 2b: diagrammatic illustrations of an example of blocking means equipping the fairlead of FIG. 1;

(4) FIGS. 3a and 3b: diagrammatic illustrations of a second guide assembly forming part of the guide means of the fairlead of FIG. 1;

(5) FIGS. 4a, 4b: diagrammatic illustrations of the fairlead of FIG. 1, with precisions on one example of mechanical actuating means for the blocking means.

DETAILED DESCRIPTION

(6) The fairlead shown in FIGS. 1 and 4a first comprises a fastening interface 6 intended to interface with the floating unit.

(7) The upper and lower parts of this fastening interface 6, generally called foundations 6, incorporate a rotation axis oriented vertically.

(8) A guide support 7 pivoting around this axis is mounted between the two foundations 6. This guide support 7 constitutes a passage zone for the anchoring element C not shown in FIG. 1, but shown in FIG. 4A in the form of an anchoring chain C.

(9) In this example, the guide support 7 supports a guide 8, 9 that at least partially defines a first passage for the anchoring element C.

(10) The fastening interface 6, guide support 7 and guide 8, 9 assembly constitutes a first guide assembly 1 that makes it possible to guide the anchoring element C in a first direction.

(11) In the example where the fairlead is fastened on a hull clapboard, for anchoring of a floating unit two anchoring points situated on the seabed, the first guide direction is generally substantially vertical.

(12) Furthermore, a guide arm 2, extended by a guide cone 4 intended to facilitate the entry of the anchoring element C in the guide arm 2, form a second guide assembly 2, 4.

(13) The guide arm 2 is mounted pivoting on the first guide assembly 1 via a rotation axis 2a, preferably perpendicular to the pivot axis of the guide support 7 of the first guide assembly 1.

(14) In the example where the fairlead is fastened on a hull clapboard, for anchoring of a floating unit to an anchoring point situated on a seabed, the pivot axis of the guide support 7 of the first guide assembly 1 generally being substantially vertical, the axis 2a is substantially horizontal.

(15) The second guide assembly 2, 4 is intended to guide the anchoring element C in a second direction that forms a nonzero angle with the first guide direction.

(16) The second guide assembly 2, 4, in particular the arm 2, allows the system to accommodate elevation angle variations of the anchoring element C, which is an anchoring chain C in this example. This anchoring chain C passes in the arm 2 via the guide cone 4, then via blocking means not shown in FIGS. 1 and 4a, before going back up toward the first guide assembly 1.

(17) Transition means 3 are provided to guide the anchoring element C at the transition between the first and second guide directions, therefore between the first guide assembly 1 and the second guide assembly 2, 4.

(18) In the example shown in FIGS. 1, 4a, 4b, these transition means comprise an element of the cable wheel 3 type, provided with a groove in addition to its cavities. This cable wheel 3 is mounted freely rotating around an axis 8a formed in part 8 of the pivoting guide 8, 9 of the first guide assembly 1.

(19) Another possibility for these transition means consists of integrating, within the pivoting guide 8, 9, a curved guide that is then formed, or housed, in that pivoting guide 8, 9.

(20) Such a curved guide is comparable to a guide rail Incorporated in the pivoting guide 8, 9, with a given operating radius.

(21) The first guide assembly 1, the second guide assembly 2, 4 and the transition means 3 therefore constitute guide means 1 to 4, which make it possible to guide the translation of the anchoring element C between the unit one wishes to anchor and the anchoring point.

(22) Blocking means 5, visible in FIGS. 1 and 4b, but shown in more detail in one example in FIGS. 2a and 2b, are mounted on the guide means 1 to 4, with a certain degree of rotational freedom around an axis parallel to the longitudinal axis of the anchoring element C.

(23) These blocking means 5, which are also called chain stopper 5 when the anchoring element C is an anchoring chain C, are preferably mounted at the end of the arm 2 of the second guide assembly 2, 4, substantially opposite the pivot axis 2a of the arm 2 relative to the guide 8, 9 of the first guide assembly 1.

(24) In the example in particular shown in FIGS. 2a and 2b, the blocking means 5 comprise a pivoting support 12, 19. This pivoting support 12, 19 comprises a support element 12 provided with a ring 19, visible only in FIG. 2b. This ring 19 is mounted pivoting against a bearing ring 10 positioned in the guide means 1 to 4.

(25) More specifically, in this example, the bearing ring 10 is positioned at the end of the arm 2 of the second guide assembly 2, 4, as shown in FIG. 3a.

(26) Thus, the blocking means 5 can pivot on the arm 2, owing to the cooperation between the ring 19 and the bearing ring 10.

(27) Furthermore, the blocking means 5 comprise second rotation limiting means 13a to 13d that cooperate with first rotation limiting means 15a to 15d positioned in the guide means 1 to 4.

(28) More specifically, in this example, the first rotation limiting means 15a to 15d comprise circular grooves 15a to 15d centered on the rotation axis of the ring 19 relative to the bearing ring 10, therefore centered on the rotation axis of the blocking means 5.

(29) Furthermore, the second rotation limiting means 13a to 13d comprise elements 13a to 13d, such as studs 13a to 13d, that are each guided in rotation in the circular grooves 15a to 15d.

(30) The rotation and assembly of the blocking means 5 relative to the arm 2 can be obtained with a single circular groove 15a to 15d cooperating with a single element of the stud type 13a to 13d.

(31) However, 4 circular grooves 15a to 15d and 4 stud-type elements 13a to 13d, equidistant on a circle centered on the rotation axis of the blocking means 5, are preferably used.

(32) In the example in particular shown in FIGS. 2a and 2b, the blocking means 5 comprise two blocking elements 11a, 11b of the gate type 11a, 11b mounted pivoting on the support 12.

(33) More specifically, these blocking elements 11a, 11b pivot on the support 12 between the blocking position, in which the anchor element C is blocked in translation in the guide means 1 to 4, and a position without blocking, in which the anchoring element C freely translates in these guide means 1 to 4.

(34) In the example with two blocking elements 11a, 11b, of the gate type 11a, 11b, in the blocking position, the gates 11a and 11b stop the anchoring element C, which passes in an opening 20 in the support 12, thus blocking its translation. In the position without blocking, these gates 11a and 11b pivot while moving away from the support 12, which results in freeing the anchoring element C.

(35) The shape of the opening 20 in the support 12, and the gates 11a, 11b, depends on the nature of the anchoring element C.

(36) Thus, in the example illustrated in the figures, the anchoring element C is a chain C made up of several links, and the opening 20 has a shape adapted to the passage of each link of the chain C. Furthermore, the shape of the gates 11a, 11b is suitable for blocking the chain C between two of its links in the blocking position.

(37) In another example, like that shown in FIG. 4b, a single blocking element of the gate type is used (not shown) for the blocking means 5. In such an example in the blocking position, the single gate stops the anchoring element C against the edge of an opening formed in the support 12, thus blocking its translation. In its position without blocking, the single gate pivots moving away from the support 12, thus freeing the anchoring element C.

(38) Thus, the blocking means 5 or stopper 5 are allowed to pivot around the longitudinal axis of the anchoring line, at the end of the second guide assembly 2, 4, in a predefined angular range. In the described example, the authorized angular range is defined by the dimension of the studs 13a to 13d and the length of the groups 15a to 15d.

(39) Remote actuating means are provided on the blocking means 5, in order to allow the activation or deactivation of the translational blocking of the anchoring element C in the guide means 1 to 4.

(40) A first example of actuating means 14a, 14b is shown in FIGS. 2a and 2b. This involves electric or hydraulic means 14a, 14b, which allow the passage of the blocking element(s) 11a, 11b from the blocking position to the position without blocking, and vice versa.

(41) This may involve actuators of the hydraulic or electric jack 14a, 14b type. One actuator 14a, 14b of this type will therefore be used per blocking element 11a, 11b.

(42) Specifically, one of the ends of each actuator 14a, 14b is connected to the support 12, in rotation around an axis parallel to the main plane of the support part 12, and opposite the pivot axis of the associated blocking element 11a, 11b relative to the free end of that blocking element 11a, 11b. The other end of each actuator 14a, 14b is connected to the associated blocking element 11a, 11b, rotating around an axis parallel to the pivot axis of the blocking element 11a, 11b relative to the support part 12.

(43) The connection point of each actuator 14a, 14b to the associated blocking element 11a, 11b, is raised enough relative to the connection point of that actuator 14a, 14b with the support 12, and far enough from the pivot axis of that blocking element 11a, 11b relative to the support 12, such that the deployment of each actuator 14a, 14b effectively drives the pivoting of the associated blocking element 11a, 11b from the blocking position toward the unblocking position.

(44) The hydraulic or electric cabling, not shown in the figures, rises up to the deck ancillaries, such that these actuating means 14a, 14b can be actuated remotely.

(45) The actuating means can also be mechanical actuating means 16a, 16b, 17a, 17b, 18a, 18b, allowing the passage of the blocking element(s) 11a, 11b from the blocking position to the position without blocking, and vice versa.

(46) One example of such mechanical means is shown partially in FIG. 1, as well as FIGS. 4a and 4b.

(47) The principle of such mechanical means in particular consists of providing the entire system with cables and return accessories to allow remote actuation of the blocking elements 11a, 11b.

(48) More specifically, the guide means 1 to 4 are provided with rings 18a, 18b making it possible to guide the cables 16a, 16b along the guide means 1 to 4. Such rings 18a, 18b can for example be positioned on the arm 2 of the second guide assembly 2, 4.

(49) Each cable 16a, 16b is fastened on the blocking element 11a, 11b, for example by means of rings 17a, 17b.

(50) Thus, traction on one of the cables 16a, 16b drives the pivoting of the associated blocking element 11a, 11b from the blocking position toward the position without blocking.

(51) It is possible to provide forcible return means of the blocking elements 11a, 11b, such that when the cables 16a, 16b are released, these blocking elements 11a, 11b automatically return and stay in the blocking position.

(52) It is also possible to provide a system for controlling the tension in the anchoring lines by using force sensors for example positioned on the arm 2.

(53) The fairlead according to the invention therefore makes it possible to greatly reduce the forces due to the torsion on the part of the anchoring element C that is held at the blocking means 5. If an anchoring chain C is used, such forces are significantly reduced on the link that is held at the chain stopper 5.

(54) This fairlead allows a rotation of the anchoring element C around its longitudinal axis over a defined angular range. This relative rotational freedom reduces all of the problems on the units for which the anchoring line may have twisted.

(55) Furthermore, during operation, the possibility of freeing the link of an anchoring chain C from specific housings provided at the blocking element(s) 11a, 11b of the chain stopper 5 is greatly reduced.

(56) This fairlead therefore improves the behavior of the anchoring line C, reduces the stresses experienced by the held portion of the anchoring line C, such as the held link of an anchoring chain C, and facilitates the installation of the anchoring line C during the connection of that anchoring line C to a unit, such as a floating unit.

(57) The present description is provided as an example and is not limiting with respect to the invention.

(58) In particular, the invention is not limited to the exclusive use of two blocking elements 11a, 11b in the blocking means, a single element, as shown in FIG. 4b, or more than two also being able to be appropriate.

(59) The invention is also not limited to means for limiting the rotation of the blocking means 5 relative to the guide means 1 to 4, which consist of the cooperation between circular grooves 15a to 15d with studs 13a to 13d. Other solutions can be considered to obtain this limitation.

(60) Additionally, the invention is not limited to the exclusive use of a transition means 3 of the cable wheel type. A transition means of the curved guide type (not shown) that is formed, or housed, in the pivoting guide 8, 9 may also be appropriate.