Tension Ring Assembly Segmented Collar Lifting Lug
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Solution Overview
Problem
Existing tension ring assemblies for offshore oil and gas production facilities face difficulties in removing lifting lugs due to their large size and the need for hydraulic tools, which complicates the process, especially when the conductor riser pipe is moving.
Innovation Solution
A tension ring assembly with a radially compact collar design that includes securing pins and tongues to removably attach lifting lugs, allowing for easier installation and removal without the need for hydraulic tools, by using axially extending bores and keyways to secure and release the lugs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If securing bolts with recessed heads and nuts are used to minimize outer diameter, then the radial thickness is reduced, but the lifting lugs must be removed first to access the bolts, complicating the removal process
Solution Approach 1:
The collar is divided into two separable halves that can be moved relative to each other. This segmentation allows the collar to be opened sufficiently to access the securing bolts without requiring removal of the lifting lugs, thus resolving the contradiction between minimized radial thickness and ease of operation.
Solution Approach 2:
The collar transitions from a static, fixed configuration to a dynamic, movable configuration. The collar halves can be shifted apart to provide access to the securing bolts, enabling easy removal without compromising the compact radial thickness when closed.
2Strength
If lifting lugs are positioned at ±45° around the circumference, then the structural integrity is maintained, but the proximity to securing bolts requires lug removal for bolt access
Solution Approach 1:
By segmenting the collar into two halves that can move relative to each other, the design maintains the optimal ±45° lug positioning for structural integrity while eliminating the need to remove lugs for bolt access. The segmentation provides the necessary clearance without altering the lug positions.
3Reliability
If hydraulic tools are used to remove lifting lugs, then the secure connection is maintained during operation, but the removal process becomes complicated and time-consuming
Solution Approach 1:
The dynamic collar design allows manual access to securing bolts by moving the collar halves apart, eliminating the need for hydraulic tools. This maintains reliable connection security during operation while dramatically reducing removal time and simplifying the removal process.
4Strength
If the tension ring has a large diameter of 1500 mm, then the structural strength is sufficient, but it cannot pass through the opening in the rotary table
Solution Approach 1:
The tension ring is divided into two collar halves that can be separated. This allows the individual halves to pass through the rotary table opening, while when assembled together they provide the necessary structural strength for the application.
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 design enables convenient and efficient attachment and detachment of lifting lugs, reducing the radial thickness of the tension ring, allowing it to pass through narrow openings and simplifying the installation and removal process, thereby saving time and effort.
Implementation Method 1
the slip segments are released, such that they slip downwards on a ramp until they are wedged between the collar segments and the outer surface of the pipe
Implementation Method 2
Each of the slip segments has a radially outer face that has an inclined surface which is at 20° to the central axis of the tension ring. Each of the collar halves has a corresponding inner face with an inclined surface at the same angle.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A tension ring assembly for securing around a pipe comprises a tension ring (12), at least one lifting lug (30) and at least one securing pin (59) for removably securing the lug (30) to the tension ring (12) so that the tension ring, and a pipe around which the tension ring has been secured, can be upwardly tensioned. The lifting lug comprises a main body and at least one tongue (56) that extends away from the main body and that is configured to slot in a substantially radial direction into a recess (52) in the tension ring in order to position the lug on the tension ring. The tongue has a keyway (62) for engaging with a protruding portion of a securing pin inserted into an axial bore through the tension ring which intersects the recess. The configuration of the tongue, recess and bore is such that the keyway comes into alignment with the bore when the tongue is slotted into the recess so that when the pin is inserted into the bore, the protruding portion of the pin engages with the keyway to secure said lug in position, and so that when the pin is removed from the bore, the protruding portion disengages from the keyway to free the lug for removal from the collar segment.