Marine Pipelaying Friction Clamp with Spring-Supported Subframes
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Solution Overview
Problem
Existing marine pipelaying friction clamp devices fail to distribute the load exerted by the pipeline evenly across the clamping units, leading to uneven friction and elongation of the engaged pipeline sections.
Innovation Solution
The design incorporates movable subframes supported by a spring assembly, allowing for elastic adjustment and even load distribution, with adjustable spring characteristics and position control mechanisms to compensate for pipeline elongation and varying loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple annular arrays of clamping units simultaneously engage separate portions of the pipeline, then the contact area between the clamp device and the pipeline is increased, but the load is not evenly distributed over the arrays of clamping units
Solution Approach 1:
The patent makes the subframes mobile rather than fixed, allowing them to move longitudinally in response to pipeline elongation. This dynamic adjustment enables the clamping units to maintain even load distribution across all annular arrays as the pipeline expands under its own weight during laying operations.
Solution Approach 2:
The patent introduces spring assemblies that can be adjusted to modify the longitudinal stiffness of the subframes. By changing the spring characteristics (stiffness parameter), the system adapts to different pipeline weights and diameters, ensuring optimal load distribution across the multiple clamping arrays for each specific pipeline configuration.
2Length of moving object
If the pipeline weight causes elongation of the engaged pipeline section, then the pipeline experiences several millimetres to 10-20 millimetres of elongation, but this elongation creates uneven loading on the clamping units
Solution Approach 1:
The mobile subframes are designed to move longitudinally along with the pipeline as it elongates. This dynamic movement compensates for the 10-20mm elongation caused by pipeline weight, maintaining consistent contact and even load distribution across all clamping units throughout the laying process.
Solution Approach 2:
The spring assemblies act as intermediary elements between the rigid main frame and the mobile subframes. These springs provide the necessary compliance to accommodate pipeline elongation while transferring loads evenly to the clamping units, serving as a buffer that absorbs the dimensional changes.
3Device complexity
If the clamp device is designed with fixed subframes, then the structure is simpler, but it cannot accommodate pipeline elongation and achieve even load distribution
Solution Approach 1:
By converting fixed subframes to mobile subframes that can move longitudinally, the patent introduces necessary complexity to achieve even load distribution. The mobile design allows the structure to adapt dynamically to pipeline elongation, proving that the added complexity is justified by the significant improvement in load distribution stability.
Solution Approach 2:
The patent employs adjustable spring assemblies with variable stiffness parameters to balance the complexity of the mobile subframe structure. By optimizing the spring characteristics, the system achieves the desired load distribution while keeping the overall device complexity manageable and adaptable to different pipeline specifications.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution ensures a more even load distribution and flexible adjustment to accommodate different pipeline types and conditions, enhancing the stability and versatility of the clamp device during pipelaying operations.
Implementation Method 1
each of said one or more mobile subframes is supported by a spring assembly
Implementation Method 2
each clamping unit comprises a friction pad adapted to frictionally engage a portion of the pipeline
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
The invention relates to a marine pipelaying friction clamp device (10; 20) for frictionally retaining an offshore subsea pipeline (30) to be launched into the sea. The clamp device comprises a frame (1; 21) which comprises a main frame structure (2; 22) that is adapted to be supported by the pipelaying vessel. The frame supports multiple annular arrays (3; 23) of clamping units (4) adapted to simultaneously engage separate portions of the pipeline. According to the invention the frame further comprises one or more mobile subframes (11; 31) for one or more of said annular arrays of clamping units. Each of said one or more mobile subframes (11) is movably supported by the main frame structure (2) so as to be mobile relative to said main frame structure in said longitudinal direction of the clamp device, and each of said one or more mobile subframes (11) is supported by a spring assembly (12; 32).