Patent ID: 11953138
Assignee: SINGLE BUOY MOORINGS INC.
Field: Mechanical elements (Mechanical engineering)
Classification: CPC F | IPC F

Claim 0:
1. Swivel stack for transfer of fluid across a rotary interface around a rotation axis between an incoming flow-line and an outgoing flow-line,
the swivel stack comprising:
a group of inner annular elements that comprises a lower annular element, an upper annular element and a central annular element;
the lower annular element being centered around the rotation axis with an inner radius and a first outer radius;
the upper annular element being centered around the rotation axis with the inner radius and the first outer radius;
the central annular element being centered around the rotation axis and having an outer cylindrical end surface, positioned between the lower annular element and the upper annular element, the central annular element having the inner radius and a second outer radius, with the second outer radius between inner radius and first outer radius, in a manner that a circular trench is present between an upward facing surface of the lower annular element and a downward facing surface of the upper annular element, the downward and upward facing surfaces each being perpendicular to the rotating axis;
the swivel stack further comprising:
an outer annular element centered around the rotation axis and having an inner end surface with a second inner radius and a third outer radius, with the third outer radius larger than the first outer radius and the second inner radius being substantially equal to the second outer radius with a gap between the outer annular element and the central inner annular element; the downward and upward facing surfaces of the outer annular element being directly adjacent to the upward facing surface of the lower annular element and the downward facing surface of the upper annular element, respectively;
the inner end surface of the outer annular element abutting the flat cylindrical end surface of the central annular element and provided with a circular trench, such that a toroidal chamber is formed between the central annular element and the outer annular element, wherein the upward facing surface of the lower annular element and the downward facing surface of the upper annular element have a first stepped surface and the upward and downward facing surfaces of the outer annular element have a second stepped surface, and the first and second stepped surfaces are configured in a manner that at least two annular cavities centered around the rotation axis and having a rectangular cross-section are provided, half of the at least two of the annular cavities at a first interface between the downward facing surface of the upper annular element and the upward facing surface of the outer annular element and the other half of the at least two annular cavities at a second interface between the upward facing surface of the lower annular element and the downward facing surface of the outer annular element, respectively, and wherein a radial width of the toroidal chamber is equal to or smaller than a height of the toroidal chamber, and the radial width of the toroidal chamber is smaller than a width of the two annular cavities combined.