Rising centralizing spider
AssigneeShell Oil Company
InventorGeorge W. Peppel
Life of this patent
Estimating the term…
Abstract
A mechanical device for centralizing a subsea riser in an opening in a floating drilling vessel. The centralizing device includes at least three arms that are pivotally connected at one end to the vessel and pivotally connected at the other end to a rotating collar with the riser extruding through the collar.
Claims7
An apparatus for centralizing a riser in an opening in a floating drilling vessel as said riser raises and falls in response to wave and wind forces on the drilling vessel, said apparatus comprising:
- a rotary bearing collar adaptable for positioning around the riser and disposed to rotatively follow the vertical movement of the riser;
- and
- a plurality of spider arms, one end of each arm being pivotally mounted on said collar and the other end of each arm being pivotally mounted at a fixed position on the portion of the drilling vessel surrounding the opening.
An apparatus for centralizing a riser in an opening in a floating drilling vessel as said riser raises and falls in response to wave and wind forces on the drilling vessel, said opening being surrounded by the structure of said drilling vessel, said apparatus comprising:
- a collar member disposed to surround the riser a rotary bearing means connecting the collar to the riser;
- four mounting means equally spaced around the outer periphery of the collar;
- four spherical bearing means, one of said bearing means being disposed on each of said mounting means;
- a second set of four spherical bearing means, said second set of spherical bearing means being mounted in fixed positions on the structure of the drilling vessel surrounding said opening, said second set of spherical bearings, in addition, being positioned in a common horizontal plane perpendicular to the axis of the riser;
- and
- four spider arms, each of said spider arms being connected at one end to one of the spherical bearing means on said collar member, the other end of each of said spider arms being connected to one of the spherical bearing means mounted on the structure of the drilling vessel surrounding said opening.
Dependencies are inferred from the claim text.