Insulated Pipe Coupling Structure for Dissimilar Metal Isolation
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Solution Overview
Problem
The existing metal alloy waterworks couplings that connect dissimilar metal pipes often lead to bi-metallic corrosion, causing lead to leach into water due to direct metal-to-metal contact, which is harmful and needs to be prevented.
Innovation Solution
The use of non-metallic insulating sleeves and gaskets in the couplings to create physical barriers between dissimilar metal pipes, preventing direct contact while allowing fluid flow, with components made from materials like acetal, polypropylene, and polyethylene, and metal parts made from brass alloys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal alloy waterworks couplings are used to connect dissimilar metal pipes, then mechanical coupling strength is improved, but bi-metallic corrosion occurs causing lead to leach into water
Solution Approach 1:
A non-metallic insulating liner is introduced as an intermediary component between the metal coupling body and the dissimilar metal pipes. This liner prevents direct metal-to-metal contact, thereby eliminating galvanic corrosion and lead leaching while maintaining the mechanical coupling function through the liner's gripping and sealing features
2Object-affected harmful factors
If non-metallic insulating liners are added to prevent bi-metallic corrosion, then lead leaching is prevented, but device complexity increases
Solution Approach 1:
Multiple functions are merged into the insulating liner component: it provides electrical insulation to prevent galvanic corrosion, mechanical gripping to secure the pipe, and sealing to prevent leaks. This consolidation reduces the number of separate components needed while achieving all necessary protective and functional requirements
3Ease of manufacture
If direct metal-to-metal contact is maintained in couplings, then manufacturing simplicity is preserved, but bi-metallic corrosion occurs
Solution Approach 1:
The non-metallic insulating liner serves as a mediator that can be easily manufactured and installed within the coupling body, providing corrosion protection without significantly complicating the manufacturing process. The liner can be produced as a separate component and inserted into the coupling, maintaining manufacturing simplicity while dramatically improving reliability
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
Prevents bi-metallic corrosion by isolating dissimilar metal pipes, ensuring no direct contact and thus reducing lead leaching into water, while maintaining fluid flow and secure mechanical coupling.
Implementation Method 1
The insulating sleeve and split insulating gripper sleeve are made of non-metallic materials and serve as physical non-metallic barriers between the first/second metal materials of the coupling/first pack joint nut, and the dissimilar metal material of the first pipe
Data Source
AI summary
A coupling body having an opening and configured to receive a pipe in the opening. The coupling body is made of a metal material and the pipe is made of a different metal material to the metal material of the coupling body. An insulating sleeve lines at least a portion of an inner periphery of the coupling body adjacent the opening. The insulating sleeve is made of non-metallic material and is configured to serve as a physical non-metallic barrier between the metal material of the coupling and the different metal material of the pipe so the different metal material of the pipe does not contact the metallic material of the coupling body.