Reusable Flexible Pipe Pull Head With Collet Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current pull heads for flexible pipes offer either a loose fit that does not seal well or are permanently swaged, limiting their reusability and accessibility for pressure testing, with existing solutions being either expensive for single-use or inefficient for flexible pipes with composite materials.
Innovation Solution
A pull head assembly comprising a lead screw assembly, mandrel assembly, and collet assembly that securely engages and compresses flexible pipes, allowing for secure attachment, pressure testing, and easy removal for reusability, featuring a collet jacket with serrations and pressure ports for annular access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pull head is swaged onto the pipe to form a permanent connection, then sealing performance is improved, but reusability is lost and cost increases
Solution Approach 1:
The pull head is divided into modular components including a collet assembly with collet fingers, a mandrel, and a drawing cone. These segmented parts can be assembled and disassembled from the pipe, enabling the pull head to be reused while maintaining secure attachment during the pulling operation. The collet fingers grip the pipe internally without permanent deformation, allowing removal and reuse.
Solution Approach 2:
The pull head employs a dynamic gripping mechanism where the collet fingers can expand and contract. During installation, the collet assembly is drawn onto the pipe, causing the collet fingers to expand and grip the pipe securely. After use, the gripping force can be released, allowing the pull head to be removed and reused on other pipes.
2Adaptability or versatility
If a removable pull head with loose fit is used, then reusability is maintained, but sealing performance deteriorates
Solution Approach 1:
An intermediary sealing mechanism is introduced between the pull head and pipe through the use of a drawing cone and collet fingers that create a controlled interference fit. The drawing cone with its tapered surface and the collet fingers act as intermediaries that provide both secure gripping and effective sealing without requiring a permanent connection, enabling reuse while maintaining reliability.
3Ease of manufacture
If a conventional pull head is used on flexible pipe, then installation is possible, but pressure testing access is blocked
Solution Approach 1:
The sealing and gripping functions are extracted from a solid conventional pull head design and implemented through the collet finger mechanism that grips the pipe internally. This extraction allows the pull head to be removed after installation, enabling access to the pipe end for pressure testing and other operations while maintaining the ability to install the pipe through the borehole.
4Loss of substance
If a permanent pull head connection is made, then cost is reduced for single use, but reusability is eliminated
Solution Approach 1:
The pull head design enables discarding the temporary attachment state after use and recovering the pull head for reuse on subsequent pipes. The collet assembly and mandrel can be disassembled from the pipe after the pulling operation is complete, allowing the same pull head to be used multiple times on different pipes, reducing overall cost while maintaining reusability.
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
The solution provides a secure, reusable, and cost-effective means to attach and detach pull heads from flexible pipes, enabling efficient pressure testing and installation while maintaining the integrity of the pipe's composite structure.
Implementation Method 1
The lead screw assembly includes a lead screw having a distal end with outward facing threads and a proximal end
Implementation Method 2
the mandrel body applies an inward radial force to the collet jacket
Data Source
AI summary
A pull head assembly for quick attachment to a flexible pipe is provided. The pull head assembly has three subsections. A collet assembly is mounted to the end of a flexible pipe. A mandrel assembly is adapted to go over the collet assembly. A lead screw assembly positions the mandrel assembly over the collet assembly and acts as an attachment point for pulling the flexible pipe and pull head assembly from one location to another. After pulling the flexible pipe and pull head assembly from one location to another, the mandrel assembly and lead screw assembly can be removed, and the collet assembly can act as a temporary fitting for the flexible pipe.