Sealing device and method for sealing between a chain and a chain pipe

1. A sealing device for sealing between a chain and a chain pipe, said chain for example being an anchor chain on a marine offshore platform or on a ship, and said chain pipe leading for example to a chain locker for onboard storage of the chain in said platform or ship, the sealing device comprising at least two opposing cover lids positioned at the mouth of the chain pipe, said cover lids being movably arranged from an open position into a closed position in which the cover lids abut each other and seal the chain pipe from water intrusion by sealingly engaging a chain link of the chain, the cover lids being provided -in mutual abutment sides thereof, with one or more recesses shaped in conformity with the contacting outer periphery of said chain link, wherein:

the cover lids each exhibit at least one inflatable seal element, said seal element extending along a respective mutual abutment side of the cover lids and being adapted to expand upon pressurization with a fluid such as pressurized air, into a radial sealing engagement with the chain link, and

the cover lids are attached to an extension collar of the chain pipe, said extension collar being movably arranged with respect to the rest of the chain pipe by means of a flexible interconnection collar mounted therebetween.

2. The sealing device according to claim 1 , wherein each said inflatable seal element, in an deflated state, is retracted to a level inside of the outer periphery of the respective cover lid in such a way that a gap is defined between the chain link and the cover lids, whereby positioning of said cover lids is facilitated and the seal elements are protected from contact with the chain link until they are inflated into engagement therewith.

3. The sealing device according to claim 1 or 2 , wherein a further seal element extends between the cover lids and the extension collar of the chain pipe.

4. The sealing device according to claim 3 , wherein said further seal element is attached along the inner periphery of the extension collar of the chain pipe.

5. The sealing device according to claim 3 , wherein said further seal element is divided into two sections, each section being attached along the outer periphery of a respective cover lid.

6. The sealing device according to claim 4 , wherein said further seal element is made of a compressible material and adapted for a radial sealing engagement between the cover lids and the inner periphery of the extension collar of the chain pipe.

7. The sealing device according to claim 3 , wherein said further sealing element is inflatable and adapted to expand upon pressurization with a fluid such as pressurized air, into a radial sealing engagement between the cover lids and the inner periphery of the extension collar of the chain pipe.

8. The sealing device according to claim 7 , wherein said further seal element is in communication with the seal element extending along said respective mutual abutment side of the cover lids.

9. The sealing device according to claim 1 , characterized in that the cover lids are pivotably hinged to the extension collar of the chain pipe.

10. The sealing device according to claim 9 , wherein pneumatic or hydraulic actuators are coupled to the cover lids for opening or closing of said cover lids.

11. The sealing device according to claim 10 , characterized in that a control system is provided for controlling the operation of the actuators and the inflation of the seal elements, said control system including position indicator means for determining whether the cover lids are open or closed, wherein the output from said position indicator means determines the operation of an anchor winch coupled to the chain, in such a way that operation of the anchor winch is allowed when the cover lids are open and not allowed when they are closed.

12. The sealing device according to claim 11 , wherein said control system is adapted for remote control of multiple sealing devices with corresponding anchor winches.

13. The sealing device according to claim 11 or 12 , wherein said control system further includes fluid pressure monitoring -and replenishment means adapted to maintain a predetermined sealing pressure in the inflatable seal elements.

14. The sealing device according to claim 9 , wherein the cover lids are provided with balancing counterweights projecting from the hinge side thereof in order to facilitate manual opening of the cover lids.

15. The sealing device according to claim 1 , characterized in that the cover lids are provided with one or more handles for manual movement of said cover lids in or out of the closed position at the mouth of the chain pipe.

16. The sealing device according to claim 1 , wherein downwardly extending guide projections are provided on the mutual abutment sides of the cover lids, said guide projections being adapted for guidance through contact with the chain link during closing of the cover lids.

17. The sealing device according to claim 1 , wherein said extension collar and said flexible interconnection collar are each divided into two halves in order to enable the sealing device to be mounted in situ on a chain pipe around the chain.

18. The sealing device according to claim 1 , wherein said flexible interconnection collar has a longitudinal cross section which bulges radially outwards.

19. The sealing device according to claim 1 , characterized in that the extension collar is further secured to the rest of the chain pipe by means of at least three spring biased bolt assemblies positioned radially outside of the flexible interconnection collar, said bolt assemblies being mutually arranged to strive to center the extension collar with respect to the rest of the chain pipe whilst still allowing movement of said extension collar with respect to the rest of the chain pipe.

20. The sealing device according to claim 19 , wherein said spring biased bolt assemblies substantially extend in the axial direction of the extension collar.