Coupling Seal With Angular Lobes For Pipe Joints
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Solution Overview
Problem
Mechanical couplings for joining pipe elements face challenges with non-elastomeric materials like thermoplastics and metals, which have low elasticity and resilience, making it difficult to achieve fluid-tight seals over manufacturing tolerance ranges without warping or buckling, especially at extreme temperatures, and requiring impractical bolt torque or heavy coupling housings.
Innovation Solution
A coupling design featuring segments with angularly oriented lobe surfaces and keys that engage with pipe elements, using materials with low elasticity and spring elements to ensure a fluid-tight seal, allowing for adjustable tightening and accommodating manufacturing tolerances without excessive force, and using materials like thermoplastic resins and fluoropolymers for improved chemical compatibility and temperature resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If non-elastomeric materials (thermoplastics, metals, composites) are used for ring seals, then chemical compatibility and temperature resistance are improved, but elasticity and resilience deteriorate, making it difficult to achieve fluid-tight seals over manufacturing tolerance ranges
Solution Approach 1:
The patent changes the geometric parameters of the seal, specifically introducing an interference fit between the seal and the coupling housing. The seal has an outer diameter that is larger than the inner diameter of the coupling housing, creating an interference fit that generates radial compressive force. This parameter change allows non-elastomeric materials to achieve reliable sealing without requiring high elasticity, as the interference fit provides the necessary sealing force.
2Reliability
If significant radial compressive deformation is applied to ensure sealing over tolerance ranges, then sealing force is improved, but the risk of seal warping or buckling increases
Solution Approach 1:
The patent changes the geometric parameters by creating an interference fit where the seal's outer diameter is larger than the coupling housing's inner diameter. This generates controlled radial compressive force that ensures sealing without excessive deformation. The interference fit parameter is designed to provide sufficient sealing force while maintaining seal structural integrity.
Solution Approach 2:
The seal is pre-formed with an outer diameter that is intentionally larger than the coupling housing inner diameter, creating a preliminary interference condition. This preliminary action ensures that when the seal is installed, the interference fit automatically generates the necessary radial compressive force for sealing, eliminating the need for excessive post-installation deformation.
3Reliability
If high forces are applied to achieve required radial compression on alternative materials, then sealing force is improved, but installation difficulty and risk of surface damage increase
Solution Approach 1:
The patent changes the geometric parameters to create an interference fit that generates radial compressive force through the interference itself, rather than requiring high external compression forces. The seal's outer diameter is designed to be larger than the coupling housing inner diameter, so the interference fit automatically provides the necessary sealing force during normal installation, reducing installation difficulty and preventing surface damage.
4Manufacturing precision
If precision machining is used to reduce the effect of manufacturing tolerances, then sealing precision is improved, but cost and practicality deteriorate
Solution Approach 1:
The patent changes the geometric parameters by designing an interference fit where the seal's outer diameter is intentionally larger than the coupling housing's inner diameter. This parameter change compensates for manufacturing tolerances by ensuring that even with tolerance variations, the interference fit generates sufficient radial compressive force for reliable sealing. This approach eliminates the need for precision machining while maintaining sealing effectiveness.
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 achieves a reliable, fluid-tight seal over a range of manufacturing tolerances with reduced radial compression force, preventing warping and buckling, and is suitable for high- and low-temperature applications with improved chemical compatibility, using materials that can withstand significant deformation without damage.
Implementation Method 1
spring elements, which apply elastic force to the lobe surfaces of the seal
Implementation Method 2
radial compressive deformation of the seal so that there is sufficient sealing force over the entire combined range of manufacturing tolerances
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A mechanical coupling for joining pipe elements end to end has a channel that receives a ring seal. The channel is defined by oppositely disposed sidewalls and the ring seal has lobes on opposite sides. The lobes have surfaces facing the side surfaces of the channel. When the ring seal is seated within the channel, each lobe surface contacts a respective side surface such that the lobes deform inwardly toward the center of the channel.