Pipe Joint Insulation Ring Prevents Corrosion
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Solution Overview
Problem
Contact corrosion of dissimilar metals occurs when using aluminum pipes with Cu system alloy components in conventional flare joints, leading to reduced sealability and loosening issues, and the flare formation process is inefficient and prone to cracks.
Innovation Solution
A pipe joint design featuring a flare joint main body with a forward-diminishing tapered portion, a cap nut with a sealing groove and stop ring, and an insulation ring to prevent contact corrosion and improve connection quality, eliminating the need for flare formation on the pipe end.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flare joint main body and cap nut made of Cu system alloy are used with aluminum pipe, then connection is achieved, but contact corrosion of dissimilar metals occurs
Solution Approach 1:
The patent introduces an intermediary component (insulation ring or protective coating) between the aluminum pipe and Cu system alloy components to prevent direct contact between dissimilar metals, thereby eliminating contact corrosion while maintaining connection functionality
Solution Approach 2:
The patent applies protective coatings or uses insulation rings made of materials that create a homogeneous protective layer between dissimilar metals, preventing electrochemical reactions by isolating the aluminum pipe from Cu system alloy components
2Reliability
If flare work is performed on the pipe end, then connection to flare joint main body is achieved, but working efficiency is reduced and quality dispersion increases
Solution Approach 1:
The patent extracts the flare formation requirement from the pipe end by designing a connection interface that accepts straight pipe ends, eliminating the need for flare work while maintaining secure connection through alternative sealing mechanisms
Solution Approach 2:
Instead of requiring the pipe to be flared to match the tapered joint main body, the patent inverts the approach by designing the joint main body to accommodate straight pipe ends through complementary sealing structures, reversing the traditional flare joint configuration
3Reliability
If flare work is performed on the pipe end, then connection is achieved, but cracks are generated on the flared portion
Solution Approach 1:
The patent removes the flare formation process entirely from the connection method, using straight pipe ends instead, which eliminates the source of crack generation while maintaining connection integrity through alternative sealing and fastening mechanisms
4Reliability
If the pipe thickness is reduced during cap nut fastening, then connection is achieved, but seal ability is reduced and loosening occurs
Solution Approach 1:
The patent incorporates protective measures in advance, such as properly designed cap nut geometry and fastening torque specifications, to prevent excessive compression of the pipe wall that would lead to thickness reduction, seal degradation, and loosening
Data Source
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AI summary
A pipe joint suitable for use particularly in refrigerant piping, the pipe joint not causing corrosion due to contact between different kinds of metals even if a pipe consisting of aluminium or other metal is used, improving the efficiency of pipe connection work and the quality of the connection by eliminating the need of forming a flare on the pipe, and not likely to become loose. A pipe joint comprising a flare joint body (1), a cap nut (2), and a stop ring (3). The rounded pressure-contact sloped surface (32) of the stop ring (3) makes contact under pressure with a diameter reducing tapered section (5) at the tip of the flare joint body (1) to form a seal by mutual contact between the metal surfaces. The stop ring (3) is provided integrally with a claw section (36) which bites into the outer peripheral surface (10A) of the straight tip (10) of the pipe.