Pivoting Segmented Tensioner Latch for Riser Self-Centering
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Solution Overview
Problem
Conventional tension latching mechanisms for tubular assemblies, such as wellbore risers, face challenges in centering the riser within the drilling platform opening, require manual operation of heavy equipment, and are prone to mechanical failures and upward movement issues.
Innovation Solution
A tension latch assembly with pivotable latch segments forming an annular lower latch ring and a solid upper latch that self-centers upon installation, eliminating the need for manual intervention and preventing upward movement through a retaining clamp.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional segmented dogs are used for latching the riser, then the riser can be engaged, but it becomes difficult to engage when the riser is offset and requires manual operation of heavy equipment
Solution Approach 1:
The lower latch is divided into multiple movable latch segments that can independently pivot to accommodate offset risers. Each segment can move to engage with the riser even when the riser is not perfectly centered, eliminating the need for manual intervention and heavy equipment while maintaining reliable engagement.
Solution Approach 2:
The latch segments are designed to be movable rather than fixed, allowing them to dynamically adjust their positions to match the riser's location. This dynamic capability enables automatic engagement without manual operation, solving both the ease of operation and reliability issues simultaneously.
2Reliability
If conventional latching mechanisms with many moving parts are used, then the riser can be latched, but the mechanism becomes expensive and prone to mechanical failures
Solution Approach 1:
By dividing the latch into separate movable segments, the complexity is distributed across simpler individual components rather than concentrated in a complex assembly. Each segment has fewer moving parts, reducing the overall probability of mechanical failure while maintaining the latching function.
Solution Approach 2:
The latch segments automatically engage the riser through their own movement capabilities without requiring external manual operation or complex control mechanisms. This self-service feature reduces the number of moving parts needed for operation and monitoring, thereby improving reliability and reducing maintenance costs.
3Force
If conventional tension latches are used, then tension can be maintained, but they cannot prevent upward movement of the riser assembly
Solution Approach 1:
The invention combines the tension maintenance function with an upward movement prevention function into a single integrated latch assembly. The movable segments are designed to provide both downward support for tension and physical barriers against upward thrust, eliminating the need for separate mechanisms and improving adaptability.
4Ease of operation
If a solid annular latch is used for the lower latch, then the structure is simpler, but it cannot accommodate offset risers or allow easy passage through the platform opening
Solution Approach 1:
Dividing the lower latch into movable segments transforms a simple solid structure into a more complex but functional design that can pivot open to accommodate the riser during installation and then close to provide secure engagement. The segmentation enables both easy passage and secure latching, resolving the contradiction between operational ease and structural simplicity.
Data Source
AI summary
A tensioner assembly for applying tension to a tubular member, such as a riser, can include an upper latch connected to the tubular member, a platform with a bore, and a plurality of lower latch segments, each having a base that is pivotally connected to the platform. After applying tension to the tubular member, the segments pivot inward to form an annular lower latch ring having an inner diameter less than an outer diameter of the upper latch. The assembly can include a locking mechanism that prevents axial movement of the upper latch, relative to the lower latch ring, after engagement. The upper latch can self-center on the lower latch as it is moved into the latching position.