Slimline Tieback Connector with Segmented Locking Mandrel
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Solution Overview
Problem
Tieback connectors used to secure production risers to subsea wellheads face challenges in maintaining a sealed connection under significant separation forces, leading to large overall diameters that are undesirable for certain surface vessels.
Innovation Solution
A slimline tieback connector design featuring a cylindrical body with a locking mandrel and split lock ring, providing two distinct bearing surfaces to distribute separation forces evenly, allowing for a reduced overall diameter while maintaining a secure connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the locking mandrel and lock ring are made sufficiently large to withstand separation forces, then the connection strength is improved, but the overall diameter of the tieback connector becomes relatively large
Solution Approach 1:
The locking mandrel is segmented into multiple annular portions (first annular portion and second annular portion) that engage with corresponding cylindrical portions of the lock ring. This segmentation allows the load to be distributed across multiple engagement points rather than concentrated at a single interface, enabling the connector to withstand separation forces with a smaller overall diameter.
Solution Approach 2:
The invention transitions from a single bearing surface to multiple bearing surfaces by adding axial dimensionality to the locking interface. The stepped interface creates two distinct bearing surfaces at different axial positions, effectively using the third dimension (axial direction) to distribute loads and reduce the required radial dimension (diameter).
Data Source
AI summary
A connector for securing a first cylindrical member to a second cylindrical member comprises a cylindrical body which includes a first end that is attached to the first member and a second end that is positioned proximate the second member, a cylindrical housing sleeve which is positioned concentrically over the body and which includes an upper end portion that is secured to the body and a lower end portion that is disposed adjacent the second member, a cylindrical primary piston that is positioned between the body and the housing sleeve, a locking mandrel which is connected to or formed integrally with the primary piston and which includes at least first and second annular portions that have different diameters, and a split lock ring which is supported by the lower end portion adjacent a number of locking grooves in the second member and which includes at least first and second cylindrical portions that correspond to the first and second annular portions of the locking mandrel. In operation, movement of the primary piston from a first position to a second position will force the first and second annular portions of the locking mandrel into engagement with the first and second cylindrical portions of the lock ring, respectively, and consequently force the lock ring into engagement with the locking grooves to thereby lock the connector to the second member.