Guiding assembly for a piping system

1. A guiding assembly for a riser piping system ( 2 ) in an opening in the bottom ( 8 ) of a floating structure, said assembly permitting limited axial and angular displacement of the riser piping system ( 2 ) in said opening, said assembly comprising:

a prismatic anchor ( 1 ) surrounding a portion of the riser piping system ( 2 ) and being connected thereto,

an outer prismatic guide tube ( 4 ) receiving the prismatic anchor ( 1 ), the outer prismatic guide tube ( 4 ) having inner surfaces that are parallel to and equally spaced from outer surfaces on the prismatic anchor ( 1 ), the anchor and guide tube being at least substantially triangular in cross-section, and

rollers ( 3 ) arranged in at least two different levels and confined in spaces ( 2 ) formed between said inner and outer surfaces, the rollers ( 3 ) permitting relative axial movement between the prismatic anchor ( 1 ) and the outer prismatic tube ( 4 ) without being fixed to any of said inner and outer surfaces.

2. A guiding assembly according to claim 1 , wherein said confined rollers ( 3 ) are in the form of flexible tubes.

3. A guiding assembly according to claim 1 , wherein said guide tube ( 4 ) is supported in the bottom ( 8 ) of the floating structure by a bearing comprising a surrounding component ( 7 ) with a spherical surface, and a section of the guide tube ( 4 ) with a spherical enlargement ( 6 ) supported in a similar confining surface, permitting limited free rotation of the guide tube.

4. A guiding assembly according to claim 1 , wherein said guide tube ( 4 ) is supported in the bottom of the floating structure by flexible supports accommodating deformation in the axial direction of the guide tube ( 4 ).

5. A guiding assembly according to claim 1 , wherein the guide tube ( 4 ) is supported in the opening in the bottom ( 8 ) of the floating structure.

6. A guiding assembly according to claim 4 , wherein said anchor ( 1 ) for the piping system ( 2 ) is connected to the piping system ( 2 ) by a bearing which permits limited free rotation.

7. A guiding assembly according to claim 1 , wherein said rollers ( 3 ) are covered with resilient material.

8. A guiding assembly according to claim 1 , wherein the space between the anchor ( 1 ) and the piping system ( 2 ) is filled with grout or other solidifying material for stiffening the combined structure.

9. A guiding assembly according to claim 1 , wherein the prismatic anchor ( 1 ) and guide tube ( 4 ) have substantially triangular cross sections.

10. A guiding assembly according to claim 5 , wherein said anchor ( 1 ) for the piping system ( 2 ) is connected to the piping system ( 2 ) by a bearing which permits limited free rotation.

11. A guiding assembly according to claim 2 , wherein said guide tube ( 4 ) is supported in the bottom ( 8 ) of the floating structure by a bearing comprising a surrounding component ( 7 ) with a spherical surface, and a section of the guide tube ( 4 ) with a spherical enlargement ( 6 ) supported in a similar confining surface, permitting limited free rotation of the guide tube.

12. A guiding assembly according to claim 2 , wherein said guide tube ( 4 ) is supported in the bottom of the floating structure by flexible supports accommodating deformation in the axial direction of the guide tube ( 4 ).

13. A guiding assembly according to claim 2 , wherein the guide tube ( 4 ) is supported in the opening in the bottom ( 8 ) of the floating structure.

14. A guiding assembly according to claim 2 , wherein said rollers ( 3 ) are covered with resilient material.

15. A guiding assembly according to claim 3 , wherein said rollers ( 3 ) are covered with resilient material.

16. A guiding assembly according to claim 4 , wherein said rollers ( 3 ) are covered with resilient material.

17. A guiding assembly according to claim 5 , wherein said rollers ( 3 ) are covered with resilient material.

18. A guiding assembly according to claim 6 , wherein said rollers ( 3 ) are covered with resilient material.

19. A guiding assembly according to claim 2 , wherein the prismatic anchor ( 1 ) and guide tube ( 4 ) have substantially triangular cross sections.

20. A guiding assembly for a riser piping system ( 2 )in an opening in the bottom ( 8 ) of a floating structure, said assembly permitting limited axial and angular displacement of the riser piping system ( 2 ) in said opening, said assembly comprising:

a prismatic anchor ( 1 ) surrounding a portion of the riser piping system ( 2 ) and being connected thereto,

an outer prismatic guide tube ( 4 ) receiving the prismatic anchor ( 1 ), the outer prismatic guide tube ( 4 ) having inner surfaces that are parallel to and equally spaced from outer surfaces on the prismatic anchor ( 1 ), and

rollers ( 3 ) arranged in at least two different levels and confined in spaces ( 2 ) formed between said inner and outer surfaces, the rollers ( 3 ) permitting relative axial movement between the prismatic anchor ( 1 ) and the outer prismatic tube ( 4 ),

wherein said confined rollers ( 3 ) are in the form of flexible tubes, wherein the fexible tubes of the rollers are each rotatably arranged on a shaft ( 9 ), the shaft being provided with a toothed wheel ( 10 ) at either end engaging in at least one rack ( 11 ) extending axially along at least one of said inner and outer surfaces for maintaining the alignment of the roller ( 3 ) when moving between said surfaces.