Riser Connector with Locking Ring and Removable Pins
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Solution Overview
Problem
Deepwater oil drilling risers face challenges with excessive weight due to the need for larger diameters in auxiliary lines to manage pressure drops, leading to increased mass and size, and existing connectors cause tensile stresses in auxiliary lines, making them costly and difficult to inspect and maintain.
Innovation Solution
A compact connector design featuring a locking ring with bayonet-type connections and removable pins allows for simultaneous engagement and disengagement of riser sections, reducing the need for thick auxiliary lines and enabling easier inspection and maintenance by positioning the locking ring close to the main tube, thus minimizing the size and weight of the riser.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the riser length is increased to reach greater water depths, then the drilling capability is improved, but the weight of the riser increases significantly
Solution Approach 1:
The riser is divided into multiple tubular elements (15-27m each) that are assembled in sections. This segmentation allows the riser to reach great depths through assembly of multiple segments rather than using a single long tube, making handling and assembly more manageable while achieving the required length for deepwater operations
Solution Approach 2:
The locking ring is positioned radially outward from the main tube elements, creating a compact three-dimensional arrangement. This spatial optimization allows the connector to engage multiple tubular elements (main tube and auxiliary lines) in a compact volume, reducing the overall footprint and weight of the connector assembly
2Loss of energy
If the inside diameter of auxiliary lines is increased to maintain pressure for long risers, then the pressure drop is reduced, but the mass and size of the riser increase
Solution Approach 1:
The auxiliary lines are integrated into the segmented tubular elements design, where each section includes both main tube and auxiliary lines as complete units. This allows for optimized diameter selection in each segment while maintaining overall pressure management through the assembled riser system
Solution Approach 2:
The auxiliary lines are positioned within the structural framework of the main tube elements, with locking rings and connectors arranged to accommodate multiple lines in a nested configuration. This nesting allows efficient space utilization, enabling adequate pressure management without excessive increase in overall riser mass
3Strength
If the auxiliary lines are fastened to the main tube to withstand tensile stresses, then the structural integrity is improved, but the thickness and cost of the auxiliary lines increase
Solution Approach 1:
The connector design merges the fastening function into a unified locking ring structure that simultaneously secures both the main tube elements and auxiliary lines. This combined approach allows auxiliary lines to be fastened with appropriate strength while avoiding excessive thickness, as the locking mechanism distributes stresses efficiently across all connected elements
Solution Approach 2:
The locking ring采用环形结构 surrounding the tubular elements, providing uniform radial support and stress distribution. This curved geometry efficiently manages tensile stresses in the auxiliary lines without requiring excessive line thickness, as the ring structure naturally distributes loads around the circumference
4Reliability
If the locking ring is made non-removable to ensure secure connection, then the connection reliability is improved, but the inspectability and maintainability of the locking ring deteriorate
Solution Approach 1:
The locking ring is designed with removable pins that allow it to be temporarily disengaged from the tubular elements. This dynamic design enables the locking ring to function as a secure connector during operation while allowing for removal and inspection during maintenance, transforming a static non-removable design into a dynamically controllable system
Solution Approach 2:
The removable pin is extracted as a separate component from the locking ring assembly, allowing the pin to be removed to enable locking ring disengagement. This extraction of the blocking element provides a simple mechanism to transition from a locked secure state to an unlocked maintainable state, ensuring both connection reliability and ease of repair
5Volume of moving object
If the connector design is made compact to reduce riser size, then the overall riser dimensions are reduced, but the complexity of preventing simultaneous disconnection increases
Solution Approach 1:
The removable pin is positioned at a specific asymmetric location on the locking ring, creating a unique engagement geometry with the tubular elements. This asymmetric positioning ensures that the pin blocks the locking ring from disengaging from both elements simultaneously, providing inherent disconnection control through geometric design rather than complex mechanical mechanisms
Solution Approach 2:
The removable pin acts as an intermediary element between the locking ring and the tubular elements, mediating the disconnection process. By positioning the pin to engage with specific features on the tubular elements, it prevents simultaneous disconnection while allowing controlled sequential separation, simplifying the overall disconnection control mechanism
Data Source
AI summary
The present invention relates to a connector comprising an external locking ring (11) allowing bayonet type connection on either side with two male (9) and female (8) connector elements, by means of studs having identical angular ranges. Furthermore, the connector comprises at least one removable pin (12) for translationally blocking locking ring (11), notably upon locking and unlocking.