Wedging Groove Pipe Coupling for Higher Axial Load Resistance
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Solution Overview
Problem
Existing mechanical pipe couplings fail to maximize the strength of pipe elements under internal pressure and axial tensile forces without the need for external welded rings, which adds cost and complexity to fabrication.
Innovation Solution
A mechanical pipe coupling system featuring adjustable segments with arcuate projections that engage circumferentially oriented grooves in the pipe elements, allowing for improved load distribution through angled sub-surfaces and mating surfaces, enabling better resistance to internal pressure and tensile forces without external rings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional circumferential grooves are used in pipe elements, then mechanical coupling engagement is achieved, but the joint cannot withstand full tensile strength of the pipe under internal pressure and axial loads
Solution Approach 1:
The circumferential groove is segmented into multiple inclined surfaces (first inclined surface, second inclined surface, third inclined surface) that engage with corresponding portions of the arcuate projection. This segmentation allows progressive engagement of the coupling key with the pipe element under axial load, enabling the joint to withstand higher tensile forces up to the full strength of the pipe.
Solution Approach 2:
The groove cross-section is designed with asymmetric inclined surfaces at different angles relative to the pipe axis. The first inclined surface has a different angle than the second and third inclined surfaces, creating an asymmetric geometry that optimizes load distribution and engagement mechanics, allowing the joint to achieve full pipe strength under axial loading.
2Strength
If external welded rings with grooves are added to pipe elements, then greater percentage of full pipe strength is realized at the joint, but fabrication cost and complexity increase due to welding requirements
Solution Approach 1:
The invention extracts and eliminates the external welded ring component from the system. Instead of adding a separate welded ring to provide groove engagement, the groove is directly formed in the pipe element itself. This removes the welding operation entirely while maintaining the enhanced strength benefits through the multi-surface groove geometry that engages progressively with the coupling key under load.
Solution Approach 2:
The groove structure is merged with the pipe element by forming the multi-surface groove directly in the pipe element wall. This integration eliminates the need for a separate external ring component and the associated welding process, while the complex multi-surface geometry provides the same load-bearing function that would have been provided by a welded ring with grooves.
3Force
If arcuate projections engage simple circumferential grooves, then mechanical coupling is achieved, but axial load distribution is insufficient to maximize pipe element strength
Solution Approach 1:
The groove cross-section is segmented into multiple inclined surfaces (first, second, and third inclined surfaces) at different angles. This segmentation creates multiple engagement zones for the arcuate projection, allowing progressive load transfer from the coupling key into the pipe element wall, thereby improving axial load distribution and maximizing the pipe element's strength utilization.
Solution Approach 2:
Different portions of the groove cross-section have different local geometries with inclined surfaces at specific angles optimized for their respective functions. The first inclined surface engages at a different angle than the second and third surfaces, creating localized engagement characteristics that optimize stress distribution and load transfer throughout the pipe element wall thickness.
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 system enhances the axial load distribution and internal pressure resistance, allowing pipe elements to realize a greater portion of their potential strength, thus increasing the joint's performance without the need for external welded rings, simplifying fabrication and reducing costs.
Implementation Method 1
the first sub-surface (74) of the groove (54) contacts a first portion of the arcuate projection (52)... the second sub-surface (76) of the groove (54) contacts a second portion of the arcuate projection (52)... other portions (third and seventh mating surfaces 106, 114) of the arcuate projections (52, 50) contact the third and seventh sub-surfaces (78, 94)
Implementation Method 2
The groove (54) comprises a first sub-surface (74)... oriented perpendicular to the longitudinal axis (60)... a second sub-surface (76)... oriented at an angle with respect to the longitudinal axis (60)
Data Source
Figure 1~2
Figure 3
Figure 3A
AI summary
A pipe element (22, 24; 22a, 24a) has a circumferential groove (54) with a surface portion oriented at an angle with respect to its longitudinal axis. A surface portion of the groove adjacent to the angled surface portion is oriented perpendicular to the longitudinal axis. A mechanical coupling has projecting keys (50, 52) that engage the groove. The keys have mating surfaces that contact both the perpendicular and angled surface portions of the groove. When the pipe element and coupling are used in combination to form a pipe joint, axial load on the pipe, resisted by the mechanical coupling, is shared between the perpendicular and angled surface portions which results in a pipe joint that can withstand higher internal pressure than if the axial load were borne by the perpendicular surface portion alone.