Constant tension anchoring system

Abstract

A constant tension anchoring system mounted on a floating body in the ocean includes an anchor, an anchor chain, an anchor windlass, a towing cable, a load and a chain stopper. During the oscillatory motion of the waves, the constant tension anchoring system repeats the release and retraction so as to maintain a generally constant tension force and thereby ensure the safety of the anchoring system and the floating body.

Claims

1. A constant tension anchoring system mounted on a floating body in an ocean, comprising: an anchor, an anchor chain, an anchor windlass, a towing cable, a load and a chain stopper; wherein the floating body is provided with an accommodating space for accommodating the towing cable and the load, and the floating body is provided with a release switch for releasing the load; the anchor windlass is disposed on the floating body; a first end of the anchor chain is connected to the anchor, a second end of the anchor chain is connected to a first end of the towing cable after the second end of the anchor chain passes around a roller of the anchor windlass, and a second end of the towing cable is connected to the load; the chain stopper is disposed on the floating body and located on a first side of the anchor windlass for stopping a movement of the anchor chain or clamping the anchor chain, wherein the first side of the anchor windlass faces the anchor; during a normal operation, the towing cable and the load are disposed in the accommodating space, and the anchor, the anchor chain and the anchor windlass perform a normal anchoring operation; after the anchor chain is lowered, the anchor chain is secured by the chain stopper; when wind waves become stronger, the chain stopper stops securing the anchor chain, the load is released to a seafloor by turning on the release switch, and a velocity of the anchor chain is reduced by the towing cable.

2. The constant tension anchoring system according to claim 1, further comprising a supporting device; wherein the supporting device is disposed outside the anchor windlass and below an axial direction of the anchor or/and the towing cable; during the normal operation, the supporting device is not in contact with the anchor chain or/and the towing cable; when the wind waves become stronger and the release switch is turned on, the supporting device is raised by a lifting mechanism to contact and support the anchor chain or/and the towing cable, and raise the anchor chain or/and the towing cable so that the anchor chain or/and the towing cable is disengaged from the roller of the anchor windlass.

3. The constant tension anchoring system according to claim 1, further comprising a backstop; wherein an outer diameter of the anchor chain is greater than an outer diameter of the towing cable; the backstop comprises a supporting base and a backstop cover; the supporting base is provided with a backstop groove, a depth of the backstop groove is greater than the outer diameter of the towing cable and smaller than the outer diameter of the anchor chain; the supporting base is disposed on the floating body and positioned between the chain stopper and the anchor windlass; a first end of the backstop cover is hinged on the supporting base, and a plane of the backstop cover is capable of covering the supporting base to allow the backstop groove to form a backstop hole that only the towing cable can pass through; a second end of the backstop cover is capable of being fastened to the supporting base; during the normal operation, the backstop cover is opened, and the anchor chain is secured by the chain stopper after the anchor chain is lowered; when the wind waves become stronger, the chain stopper stops securing the anchor chain and the backstop cover is closed.

4. The constant tension anchoring system according to claim 1, wherein the accommodating space is a compartment disposed inside the floating body, and the release switch is a gate connecting the seafloor to the accommodating space.

5. The constant tension anchoring system according to claim 1, wherein the accommodating space is a fixing mechanism disposed outside the floating body, the release switch is a clamping mechanism disposed on the fixing mechanism and connected to the load, and the towing cable is wound around a winder on the fixing mechanism.

6. The constant tension anchoring system according to claim 2, wherein the supporting device comprises a supporting roller and a lifting mechanism; the supporting roller is provided at an upper end of the lifting mechanism, and the supporting roller is positioned on a second side of the anchor windlass and below the axial direction of the anchor or/and the towing cable; the lifting mechanism is hydraulically driven and configured to control an upward and downward motion of the supporting roller.

7. The constant tension anchoring system according to claim 1, wherein the floating body is a ship or a floating platform.

8. The constant tension anchoring system according to claim 7, wherein a weight of the load and a length of the towing cable are set to match a wave condition of a design limit of the floating body.

9. The constant tension anchoring system according to claim 2, wherein the floating body is a ship or a floating platform.

10. The constant tension anchoring system according to claim 3, wherein the floating body is a ship or a floating platform.

11. The constant tension anchoring system according to claim 4, wherein the floating body is a ship or a floating platform.

12. The constant tension anchoring system according to claim 5, wherein the floating body is a ship or a floating platform.

13. The constant tension anchoring system according to claim 6, wherein the floating body is a ship or a floating platform.

14. The constant tension anchoring system according to claim 9, wherein a weight of the load and a length of the towing cable are set to match a wave condition of a design limit of the floating body.

15. The constant tension anchoring system according to claim 10, wherein a weight of the load and a length of the towing cable are set to match a wave condition of a design limit of the floating body.

16. The constant tension anchoring system according to claim 11, wherein a weight of the load and a length of the towing cable are set to match a wave condition of a design limit of the floating body.

17. The constant tension anchoring system according to claim 12, wherein a weight of the load and a length of the towing cable are set to match a wave condition of a design limit of the floating body.

18. The constant tension anchoring system according to claim 13, wherein a weight of the load and a length of the towing cable are set to match a wave condition of a design limit of the floating body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows the structure of a constant tension anchoring system of embodiment 1.

(2) FIG. 2 shows the structure of a supporting device of embodiment 2 in a non-working state.

(3) FIG. 3 shows the structure of the supporting device of embodiment 2 in a working state.

(4) FIG. 4 shows the position of a backstop of embodiment 3 in a constant tension anchoring system.

(5) FIG. 5 shows a structure of the backstop of embodiment 3.

(6) FIG. 6 shows the structure of a constant tension anchoring system of embodiment 4.

(7) Reference signs: 1: floating body; 2: anchor; 3: anchor chain; 4: anchor windlass; 5: towing cable; 6: load; 7: chain stopper; 8: compartment; 9: gate; 10: supporting device; 11: lifting mechanism; 12: supporting roller; 13: backstop; 14: supporting base; 15: backstop cover; 16: backstop groove; 17: fixing mechanism; 18: clamping mechanism; 19: winder; 20: roller.

DETAILED DESCRIPTION OF EMBODIMENTS

(8) The invention will be further described with reference to the drawings and embodiments. The embodiments are explanation for the present invention, but not used for limiting the invention. Also, for the convenience of description, not all of the components related to the present invention are shown in the drawings.

Embodiment 1

(9) As shown in FIG. 1, the constant tension system is mounted on a floating body 1 on the ocean, comprising an anchor 2, an anchor chain 3, an anchor windlass 4, a towing cable 5, a load 6 and a chain stopper 7; the floating body 1 is provided with an accommodating space for accommodating the towing cable 5 and the load 6, and a release switch for releasing the load 6; the anchor windlass 4 is disposed on the floating body 1; one end of the anchor chain 3 is connected with the anchor 2, the other end of the anchor chain 3 is connected with one end of the towing cable 5 after passing around a roller 20 of the anchor windlass 4, and the other end of the towing cable 5 is connected with the load 6; the chain stopper 7 is disposed on the floating body 1 and located on one side of the anchor windlass 4 (the side that faces the anchor 2) for stopping the movement of the anchor chain 3 or clamping (holding) the anchor chain 3. During normal operation, the towing cable 5 and the load are disposed in the accommodating space, and the anchor 2, the anchor chain 3 and the anchor windlass 4 perform a normal anchoring operation; after the anchor chain 3 is lowered, it is secured by the chain stopper 7. When the wind waves become stronger, the chain stopper 7 stops securing the anchor chain 3, and the load 6 is released to above a seafloor by turning on the release switch while the velocity of the anchor chain 3 is reduced by the towing cable 5. The accommodating space is a compartment 8 disposed inside the floating body 1, and the release switch is a gate 9 connecting the seafloor and the accommodating space. The floating body 1 is a ship or a floating platform. The towing cable 5 is a steel cable.

Embodiment 2

(10) As shown in FIG. 2 and FIG. 3, the system is different from that of embodiment 1 in that, it further comprises a supporting device 10; the supporting device 10 is disposed outside the anchor windlass 4 and below an axial direction of the anchor 2 or/and the towing cable 5. During normal operation, the supporting device 10 is not in contact with the anchor chain 3 or/and the towing cable 5; when the wind waves become stronger and the release switch is turned on, the supporting device 10 is raised by a lifting mechanism 11 to support the anchor chain 3 or/and the towing cable 5, and raise it so that it is disengaged from the roller 20 of the anchor windlass 4.

(11) The supporting device 10 comprises a lifting mechanism 11 and a supporting roller 12. The lifting mechanism 11 is hydraulically driven, provided with the supporting roller 12 at the upper end and configured to control upward and downward motions of the supporting roller 12. The supporting roller 12 is positioned on one side of the anchor windlass 4 and below the axial direction of the anchor 2 or/and the towing cable 5.

Embodiment 3

(12) As shown in FIG. 4 and FIG. 5, the system is different from that of embodiment 2 in that, it further comprises a backstop 13, and an outer diameter of the anchor chain 3 is greater than an outer diameter of the towing cable 5. The backstop 13 comprises a supporting base 14 and a backstop cover 15. The supporting base 14 is provided with a backstop groove 16 having a depth greater than the outer diameter of the towing cable 5 but smaller than the outer diameter of the anchor chain 3. The supporting base 14 is disposed on the floating body 1 and positioned between the chain stopper 7 and the anchor windlass 4. One end of the backstop cover 15 is hinged on the supporting base 14 (i.e., the backstop cover 15 is connected to the supporting base 15 through hinges so that a plane of the backstop cover 15 can rotate relative to the supporting base 15), and the plane of the backstop cover 15 can be rotated to cover the supporting base 15 (and thereby the backstop groove 16 is covered) to allow the backstop groove 16 to form a backstop hole that only the towing cable 5 can pass through (the anchor chain 3 cannot pass through the backstop hole since the depth of the groove 16 is smaller than the outer diameter of the anchor chain 3). The other end of the backstop cover 15 can be fastened to the supporting base 14. During normal operation, the backstop cover 15 is opened (i.e., it is not covering the supporting base 14), and the anchor chain 3 is secured by the chain stopper 7 after the anchor chain 3 is lowered; when wind waves become stronger, the chain stopper 7 stops securing the anchor chain 3 and the backstop cover 15 is closed (i.e., the cover 15 is covering the supporting base 14 with the end fastened to the supporting base 14). The supporting device 10 adapts only a single supporting roller 12 and is disposed on the other side of the anchor windlass 4.

Embodiment 4

(13) As shown in FIG. 6, the system is different from that of embodiment 1 in that, the accommodating space is a fixing mechanism 17 disposed outside the floating body 1, the release switch is a clamping mechanism 18 disposed on the fixing mechanism 17 and connected with the load 6, and the towing cable 5 is wound around a winder 19 on the fixing mechanism 19.

(14) The above embodiments are explanation for the present invention, but not used for limiting the invention.