WO2004065203A1

WO2004065203A1 - Tensioner system for offshore platform anchoring chain

Info

Publication number: WO2004065203A1
Application number: PCT/FR2004/050008
Authority: WO
Inventors: François Desprez
Original assignee: Hydralift - Blm
Priority date: 2003-01-09
Filing date: 2004-01-08
Publication date: 2004-08-05
Also published as: FR2849843A1; FR2849843B1

Abstract

The invention concerns a tensioner system for buck stay-free chain (1) whereof the wire diameter ranges between 70 and 170 mm, said tensioner system including a device (4) for tensioning the anchoring chain, associated with a device (5) for locking said chain. The invention is characterized in that the tensioning device (4) includes a frame (8) supporting a drive wheel (6) with horizontal axis (10), said wheel (6) is driven in rotation by means of electric gear motor assemblies, and comprises a plurality of teeth (16) calibrated so as to enable their insertion in the slot of the chain links (3) of the anchoring chain (1) whereof the plane is parallel to the axis (10) of the wheel (6), for gripping said links (3) and causing the chain (1) to be tensioned when the wheel (6) is rotated. The profile of the teeth (6) and the spacing of said teeth are adapted to match the contour of the links (3) of the chain (1) whereof the plane is perpendicular to the axis of rotation (10) of the drive wheel (6).

Description

TENSIONER FOR “OFF SHORE” PLATFORM DRIVE CHAIN

The present invention relates to the general field of stowage structures for “off shore” platforms, of the petroleum platform type for the extraction of oil, gas or other. This invention relates more particularly to a tensioning device for a lashing chain.

The “off shore” platforms are generally fixed to the bottom of the seas by means of lashing chains, in particular large chains of the unsupported type whose wire diameter is between 70 and 170 mm; and these large chains are associated with means which allow them to be tensioned, called “tensioning devices”.

The tensioning devices for this kind of chain are traditionally operated by hydraulic type systems. This is particularly the case of the tensioning device described in document EP-A2-0 831 053. This device comprises means for tensioning the lashing chain formed by a frame which supports a vertical semicircle structure guiding the chain. The semicircle structure is articulated along a horizontal axis at one of its ends; its other end is secured to a hydraulic system which allows its articulation between a high active position and a low passive position. The drive of the chain on the semicircle structure is obtained by a latch in pressure on the external curved surface of one of the links of the chain whose plane is perpendicular to the axis of articulation of the structure in Semi circle. This tensioning device also includes a chain blocking device, consisting of two opposite latches, articulated along parallel horizontal axes; these latches are also actuated by an auxiliary hydraulic system.

The corresponding tensioning devices have high maintenance costs, and they can cause pollution to the environment due to the presence of oil in hydraulic systems. The present invention aims to remedy these drawbacks by proposing a tensioning device in which the chain tensioning means comprise a support frame for a drive wheel with a horizontal axis, which wheel is rotated by means of '' at least one motor-reduction unit of the electric type, and which wheel comprises a plurality of teeth of a caliber adapted to allow their insertion into the lumen of the links of the lashing chain, the plane is parallel to the central axis of the wheel, in order to grip said links and ensure the tensioning of said chain during the rotation of said wheel.

The device, in accordance with the invention, results in a particularly compact and light device, which is of great interest for oil platform equipment.

This electric tensioning device also has the advantage of a low installation cost, and also of a low operational cost by limiting the maintenance costs; it eliminates the risks of pollution in the absence of oil.

Still according to the invention, the tensioning device comprises a drive wheel whose teeth have a spacing corresponding substantially to the length of a link in the lashing chain.

In a preferred embodiment of the invention, the drive wheel has teeth whose profile and spacing are adapted to match the outline of the chain links whose plane is perpendicular to the axis of rotation of said wheel.

In a particularly advantageous embodiment, the teeth of the drive wheel have lateral flats whose surface is parallel to the axis of rotation of said wheel. These flats form a bearing face for the links inserted in said teeth. The drive wheel of the lashing chain has at least three teeth regularly distributed around its periphery.

In an advantageous embodiment of the invention, the tensioning device comprises a drive wheel associated with a co-axial wheel, the peripheral surface of which forms a rack, which rack is actuated by the motor-reduction unit (s).

More preferably, the drive wheel of the lashing chain is maneuvered by two gear-motor assemblies each consisting of an electric type motor associated with a gear train, which gear trains are arranged on a line. substantially horizontal, and each arranged on one side of the horizontal plane passing through the axis of rotation of said wheel.

Still according to a preferred embodiment of the invention, the tensioning system comprises a device for blocking the lashing chain consisting of two opposite lugs, articulated along parallel horizontal axes, which lugs each have a sector toothed allowing their coupling one to the the other ; one of these two latches is actuated by an electric-type motor-reducer assembly, in particular to ensure the synchronized opening of said latches. By “toothed sectors coupled to each other” is meant two lateral sectors coupled directly to one another without intermediate elements, but also two sectors coupled by intermediate elements, in particular of the gear type.

In a preferred embodiment, the two latches are kept at rest in the closed position by the action of an elastic return means. These two latches are brought into the open position by the action of the associated geared motor assembly.

More preferably still, the chain blocking device comprises a tension sensor ensuring local and continuous control of the tension of the securing chain, and allowing, if necessary, automatic actuation in one direction or the other. the drive wheel.

The invention will be further detailed with the aid of the following description and of the appended drawings, relating to a particular embodiment, given by way of example, and in which:

- Figure 1 is a front view in slight perspective of a tensioning device for lashing chain according to the present invention;

- Figure 2 shows a front view of the tensioning device illustrated in Figure 1;

- Figure 3 is a top view of the tensioning device shown in Figures 1 and 2;

- Figure 4 is a side view of the tensioning device shown in Figures 1 to 3;

- Figure 5 is a perspective view of the drive wheel of the securing chain associated with a crenellated peripheral surface wheel, present in the tensioning device of Figures 1 to 4;

- Figure 6 shows a perspective view of the locking device of the lashing chain isolated from the frame of the tensioning device shown in Figures 1 to 4, which locking device is illustrated in the closed position;

- Figure 7 is a perspective view of one of the latches of the locking device shown in Figure 6;

- Figure 8 is a rear view of the locking device of the lashing chain in the closed position, as shown in Figure 6;

- Figure 9 is a rear view of the same locking device shown in the open position. Figures 1 to 4 show the tensioning device according to a particular embodiment of the invention, associated with a large lashing chain 1. This lashing chain 1 consists of a succession of oblong links 2, 3 without props, nested one inside the other, oriented in two perpendicular planes, the wire of which has a diameter preferably between 70 and 170 mm.

In a particular embodiment of the invention, the chain in question is of the 138 mm NVR4 type without struts, whose minimum tensile strength is 17200 kN.

The tensioning device consists of the combination of a device 4 for tensioning the securing chain 1 and a device 5 for blocking said chain.

The tensioning device 4 consists of a wheel 6 for driving the chain 1, associated with a geared motor unit 7. The assembly is carried by a support frame 8 which comprises in particular two lateral vertical arms 9 in screw -to screw, the upper end of which supports and rotates the wheel 6. This wheel 6 is rotatably mounted about a horizontal axis 10 materialized by a shaft

11.

To facilitate understanding of the remainder of the description, the links 2 whose plane is perpendicular to the axis 10 are called "vertical links", and the links 3 whose plane is parallel to the axis 10 are called "horizontal links ".

The frame 8 has a steel structure; it is arranged on an intermediate fixing plate, not shown, which is itself welded to the deck of the platform. This frame 8 is adapted to ensure resistance to the stresses developed during the tensioning operation. The wheel 6 for driving the lashing chain 1, FIG. 5, is associated with a coaxial wheel 12 of greater diameter, and the peripheral surface 13 of which forms a rack with straight teeth. This crenellated wheel 12 is intended to cooperate with the geared motor unit 7.

The crenellated wheel 12 is surrounded on the frame 8 in a casing structure 14, FIGS. 1 to 3, ensuring the protection of the peripheral toothed surface 13.

The drive wheel 6 comprises a central orifice 15, ensuring the reception of the articulation shaft 11. This orifice 15 is surrounded by four teeth 16 ensuring the reception and the gripping of the horizontal links 3, FIGS. 1 to 4. The distance separating two teeth 16 ensures the intercalation of a single vertical link 2, of intermediate position between the horizontal links 3 inserted in said teeth.

On each front and rear face of the wheel 6, four structures 17 of generally triangular shape are arranged, arranged at each of the teeth 16.

The side of the triangle 17 opposite the central axis 10 of the wheel 6 forms a flat 18 whose surface is parallel to said axis 10. This flat 18, as shown in Figures 1 and 2, forms a bearing surface for the horizontal links 3, inserted in the teeth 16.

Each flat 18 also forms a projection 20 at the level of the space 21 separating the gripping teeth 16. Two projections 20 facing two flat 18, on the front and rear face of a tooth 16 , form a groove 22, making it possible to enclose one of the two portions of curved ends of a vertical link 2. Two grooves 22 facing each other, at each end of the space separating two gripping teeth 16, make it possible to enclose the two portions of opposite curved ends of a vertical link 2.

The vertical links 2 which immediately precede and follow the horizontal link 3 inserted on a tooth 16, are then held in a vertical plane by the grooves 22, which contributes to the maintenance and gripping of the lashing chain 1 on the drive wheel 6.

In addition, the side faces 24 of the teeth 16 are shaped to best match the shape of the vertical links 2.

In this embodiment, the grooves 22 and the curved shape of the sides 24 of the teeth 16 cooperate to ensure a maximum contact surface with the vertical links 2.

This structure of the drive wheel 6 ensures, in a particularly advantageous manner, a maximum contact surface both with the horizontal links

3, and with the vertical links 2; this characteristic limits the local tensions on the chain 1, which tensions could be the cause of deformations or risks of rupture of the links 2, 3.

The geared motor unit 7 comprises two independent geared motor assemblies, each arranged on one side of the horizontal plane passing through the articulation axis 10 of the drive wheel 6. This arrangement of each geared motor assembly ensures an optimal distribution of the forces on the castellated wheel 12.

Each gear motor assembly consists of an electric motor 25, 25 'associated respectively with a gear train 26, 27, 28, 29 and 26', 27 ', 28', 29 '. Each motor 25, 25 'is disposed in a casing 30, 30' which projects from the frame 8, on the same lateral face of this frame 8, namely on the side of the drive wheel 6. This arrangement contributes to a minimum space requirement of the tensioning device.

Each motor 25, 25 'is associated with a gear train 26, 27, 28, 29 and 26', 27 ', 28', 29 ', Figures 2 and 3, formed of a set of wheels and pinions parallel type; the axes of rotation of the gears are on a substantially horizontal plane, FIG. 2.

In this particular embodiment of the invention, the gear trains 26, 27, 28, 29 and 26 ', 27', 28 ', 29', Figure 3, comprise a set of four pinions; the end pinions 29 and 29 ′ constitute the drive pinions on the rack 13 of the peripheral surface of the castellated wheel 12.

These gearmotor assemblies can provide a reduction coefficient of around 2000.

The gearmotor assemblies 26, 27, 28, 29 and 26 ', 27', 28 ', 29' operate the castellated wheel 12, which allows the rotation of the drive wheel 6 in a determined direction in order to ensure the tensioning or tensioning of the chain 1.

As shown in FIG. 2, the tensioning of the chain 1 is obtained by the rotation of the drive wheel 6 in an anti-clockwise direction. In practice, the speed of rotation of the drive wheel 6 in the direction of tensioning can be of the order of 3 m / min or 1.5 m / min, for a respective force of 1800 kN or 2000 kN .

The speed ensuring a reduction in the tensioning of the lashing chain can also be of the order of 3 m / min or 5 m / min for forces of 1800 kN and 2000 kN.

Preferably, the motors 25, 25 'include safety systems consisting of disc brake devices.

When starting, the brake is released only when the engine torque reaches a sufficient determined level, which torque is detected by a control board. When the engine slows down, the brake is only engaged when the engine speed is below a determined level, said engine being slowed down by a suitable system of the electrical type.

The blocking device 5 of the chain 1, detailed in FIGS. 6 to 8, is integral with the frame 8 and is located under the drive wheel 6, on the gear-motor block side 7.

This device 5 consists of the association of two lugs 32 facing each other, articulated along parallel horizontal axes 33.

The latches 32, FIG. 7, have a generally triangular shape, the base of which has a transverse orifice 34 ensuring the reception of the articulation shaft 33.

The upper apex 35 has two lateral extensions, resulting in a generally parallelepiped shape. The central part of said parallelepiped 35 has a semi-circular notch 36, and the lateral extensions each have on one of their sides a small curved notch 37.

In addition, each latch 32, FIGS. 6, 8 and 9, is associated with a toothed lateral sector 38, juxtaposed with the articulation axis 33, forming a quarter of a circle whose curved peripheral edge has straight teeth. This lateral toothed sector 38 is itself coupled to a pinion 39 present at the end of an intermediate piece 40; the other end of said piece 40 being provided with a toothed wheel 41. The two toothed wheels 41 of each intermediate piece 40 are coupled with one another. One of the two toothed wheels 41 is operated by a geared motor unit 42.

The latches 32 are operated by the motor-reduction unit 42 between, on the one hand, a closed position, FIGS. 6 and 8, the ends of said latches 32 coming to be positioned under the curved part of a vertical link 2, and d 'other hand, an open position, Figure 9, where the ends of said lugs 32 release the links of the lashing chain 1.

As shown in Figures 6 and 8, the latches 32 in the closed position enclose the links 2 and 3 of the lashing chain 1: the central notch 36 is intended to receive the lower curved part of a horizontal link 3; the lateral notches 37 are intended to rest on the external linear part of the vertical link 2 immediately below.

The latches 32 are held in the closed position by the action of an elastic return means 44 consisting of a compression spring 45 surrounding a vertical rod 46; the compression spring 45 is clamped between, on the one hand, an element 47 in the form of a lid secured to the upper part of the rod 46, and on the other hand, the upper surface of a bracket 48, which bracket 48 allows the rod 46 to be secured to the frame 8, and provides articulation in translation vertical of said rod 46.

The lower end of the rod 46 is articulated along a horizontal axis 49 on the external surface of the base of one of the latches 32, near its axis of rotation 33.

In this closed position, the rod 46 is in the high position and the spring 45 is in the rest position.

To pass into the open position, FIG. 9, the latches 32 are actuated by the geared motor unit 42; the synchronized movement of the two latches is obtained thanks to the toothed sectors 38 and to the coupling of the two intermediate parts

40.

The rod 46 of the elastic return means 44 is driven downwards by the rotation of the associated latch 32; this vertical movement of the rod 46 causes compression of the spring 45 between the cover element 47 and the horizontal surface of the bracket 48. In this open configuration, the compressed spring 45 provides a force tending to return the lugs 32 to the position closed, the engine. allowing maintenance in the open position.

Advantageously, the device comprises a tension sensor, not shown in the figures, allowing local and continuous control of the tension of the lashing chain.

In practice, the platform tensioning devices are preferably arranged in groups of four at each angle of the “off shore” platform.

The tensioning devices can be operated by a control system consisting of a local console, installed near each group of tensioning devices. These systems work in cooperation with electrical connection boxes, arranged in a sealed site.

Conventionally, these tensioning devices are installed in association with devices of the fairlead or hawser type, ensuring a determined orientation of the mooring lines.

Claims

- CLAIMS - 1.- Tensioning device for a strut type without prop whose wire diameter is between 70 and 170 mm, ensuring in particular the securing of an "off shore" platform of the petroleum platform type for the extraction of oil or gas, which tensioning device comprises a device (4) for tensioning the securing chain, associated with a device (5) for blocking said chain, characterized in that the tensioning device ( 4) comprises a frame (8) supporting a drive wheel (6) with a horizontal axis (10), which wheel is rotated by means of at least one electric gear motor assembly (25, 26, 27, 28, 29; 25 ', 26', 27 ', 28', 29 '), and comprises a plurality of teeth (16) of a caliber adapted to allow their insertion into the lumen of the links (3) of said chain (1) whose plane is parallel to the axis (10) of the wheel (6), with a view to gripping said links (3) and ensuring the positioning nsion of said chain (1) during the rotation of said wheel (6).

2.- tensioning device according to claim 1, characterized in that it comprises a drive wheel (6) whose teeth (16) have a spacing corresponding to the length of a link (2, 3) of the chain lashing (1).

3.- tensioning device according to claim 2, characterized in that the drive wheel (6) has teeth (16) whose profile and spacing are adapted to match the outline of the links (2) of the chain ( 1) whose plane is perpendicular to the axis of rotation (10) of said wheel (6).

4.- tensioning device according to any one of claims 1 to 3, characterized in that it comprises a drive wheel (6) whose teeth (16) have lateral flats (18) whose surface is parallel to the axis of rotation

(10) of said wheel (6), constituting a bearing face for supporting the links (3) inserted in said teeth (16).

5.- tensioning device according to any one of claims 1 to 4, characterized in that the wheel (6) for driving the lashing chain (1) comprises at least three teeth (16) regularly distributed around its periphery .

6. A tensioning device according to any one of claims 1 to 5, characterized in that it comprises a drive wheel (6) associated with a coaxial wheel (12) whose peripheral surface (13) forms a rack, which rack is actuated by the gear-motor unit (s) (25, 26, 27, 28, 29; 25 ", 26 ', 27', 28 ', 29').

7. A tensioning device according to any one of claims 1 to 6, characterized in that the drive wheel (6) of the lashing chain (1) is operated by two electric type motors (25, 25 ') each associated with a gear train (26, 27, 28, 29; 26', 27 ', 28', 29 '), said gear trains each being arranged on a substantially horizontal line, and each being arranged on one side of the horizontal plane passing through the axis (10) of rotation of said wheel (6).

8. A tensioning device according to any one of claims 1 to 7, characterized in that it comprises a device (5) for blocking the chain (1) consisting of two lugs (32) facing each other, articulated along parallel horizontal axes (33), which lugs (32) each have a toothed sector (38), which toothed sectors (38) are coupled with each other, one of the two lugs (32) being actuated by a geared motor assembly (42) in particular to ensure the synchronized opening of said lugs (32).

9. A tensioning device according to claim 8, characterized in that the two lugs (32) at rest are maintained in the closed position, by the action of an elastic return means (44), the open position being obtained by l action of the gear motor assembly (42).

10.- Tensioning device according to any one of claims 1 to 9, characterized in that the device (5) for blocking the chain (1) comprises a tension sensor ensuring local and continuous control of the tension of the chain stowage.