Toroidal Fluid Swivel With Axial Rotary Interface for High Pressure

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Solution Overview

Problem

Existing toroidal fluid swivels for high-pressure applications face challenges with excessive wall thickness and weight due to radial forces, complex seal designs, and maintenance issues, especially as swivel diameter increases, which affects design, size, cost, and manufacturing limitations.

Innovation Solution

A toroidal fluid swivel design with a fixed and rotating annular element, where one element features a toroidal cavity and the other a flat circular end surface, creating a rotary interface perpendicular to the rotation axis, reducing hoop stresses and allowing for counterbalancing radial forces, thus minimizing the need for thick walls and complex seals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a radial interface is used between fixed and rotating annular elements, then rotation is enabled, but wall thickness must increase to withstand fluid pressure

Engineering Contradiction:
Improverotation capabilityVSAvoidswivel weight
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The patent transitions from a radial interface (cylindrical surface) to an axial interface (flat circular surface perpendicular to rotation axis). This dimensional change in the interface orientation eliminates the need for thick walls to withstand radial pressure forces, as the pressure now acts parallel to the rotation axis rather than outward on the interface surfaces.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Instead of having the rotating element rotate around a radial interface as in conventional designs, the patent inverts the approach by creating an axial interface where the flat circular surface is perpendicular to the rotation axis. This inversion allows the pressure forces to be counterbalanced within the same structural element rather than requiring additional thickness.

Inventive Principle:
Principle #13The other way round (Inversion)

2Stress or pressure

If high pressure resistance is increased, then design pressure capability improves, but wall thickness and complexity increase

Engineering Contradiction:
Improvedesign pressure capabilityVSAvoidswivel complexity
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

By changing the interface from radial to axial orientation, the patent allows high pressure resistance without increasing wall thickness or complexity. The axial interface geometry naturally directs pressure forces along the rotation axis, enabling high pressure capability (500+ atm) with simpler, thinner-walled construction.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If swivel diameter increases, then flow capacity improves, but radial force and wall thickness requirements increase

Engineering Contradiction:
Improveflow capacityVSAvoidswivel weight
Core Design Contradiction:
ProductivityVSWeight of moving object

Solution Approach 1:

The axial interface orientation decouples the relationship between diameter and wall thickness requirements. Larger diameters can accommodate higher flow capacities without proportionally increasing radial forces on the interface, since pressure acts axially rather than radially outward on the interface surfaces.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Ease of operation

If radial interface is used, then rotation is enabled, but seal design becomes complex

Engineering Contradiction:
Improverotation capabilityVSAvoidseal design complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent inverts the conventional radial seal arrangement by using an axial seal interface. The flat circular surface perpendicular to the rotation axis creates a simpler sealing geometry where seals can be positioned at the interface between the fixed and rotating elements without requiring complex extrusion gaps or deformation-resistant seal designs.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP3314154B1A toroidal fluid swivel for transfer of fluid across a rotary interface
Publication Date: 2021.03.31 SINGLE BUOY MOORINGS INC
  • EP3314154B1 patent drawingFigure 1~1b
  • EP3314154B1 patent drawingFigure 2~3
  • EP3314154B1 patent drawingFigure 4~5

AI summary

A swivel for transfer of fluid across a rotary interface around a swivel rotation axis (R) between an incoming fluid line and an outgoing product piping, wherein he swivel includes a fixed annular element (20) and a rotating annular element (30), each arranged around a common rotation axis and having a substantially equal diameter, wherein one selected element from the fixed annular element (20) and the rotating annular element (30) includes an annular disk provided with a toroidal cavity (24) in a first of its circular end surfaces, and the other selected element from the fixed annular element and the rotating annular element is arranged with a flat circular end surface (32) that is adjacent to and in close proximity above said first circular end surface of said annular disk so as to close the toroidal cavity and form a toroidal chamber with the annular disk and wherein the rotary interface is formed by the flat circular end surface of the other selected element and the adjacent first circular surface of the one selected element, the rotary interface is perpendicular to the common rotation axis.