Cold Expansion Pipe Fitting With Sealing Barbs for Fast Cold Sealing
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Solution Overview
Problem
Cold expansion pipe connections in plumbing and heating applications face challenges in forming secure seals quickly, especially in cold conditions, due to the temperature-dependent shrinkage performance of pipe materials, which can lead to slow formation of sealed connections.
Innovation Solution
A pipe fitting with a tubular connecting part and radially extending circumferential sealing barbs, featuring a wedge-shaped longitudinal section with specific slope angles and a tip radius, is used to form a cold expansion pipe connection. The fitting includes a shoulder and additional retaining barbs to ensure secure engagement with the pipe end section during shrinkage, facilitating rapid sealing and preventing the pipe fitting from escaping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cold expansion is used to form pipe connections, then the connection can be made without heating, but the sealing formation becomes slow in cold conditions due to temperature-dependent shrinkage performance
Solution Approach 1:
The pipe end section is expanded before the fitting is inserted, preparing the space in advance. The fitting is then inserted into the pre-expanded space, and the shrinkage process automatically engages the sealing barbs with the pipe inner surface, eliminating the need for additional sealing actions and accelerating the overall connection process, especially in cold conditions where shrinkage is slower.
Solution Approach 2:
The invention changes the geometric parameters of the sealing barbs (wedge shape, slope angles, tip radius) to optimize their engagement with the pipe inner surface during shrinkage. The specific parameter ranges (first slope 10-30 degrees, second slope 55-90 degrees, tip radius 0.127-5.08 mm) are designed to ensure rapid and reliable sealing even when shrinkage performance is reduced by low temperatures.
2Reliability
If the pipe material shrinks slowly in cold conditions, then the memory properties still enable sealing, but the time required to form a secure sealed connection increases undesirably
Solution Approach 1:
The sealing process is segmented into multiple engagement points along the axial direction. The first sealing barb engages at a first distance from the pipe end, and the second sealing barb engages at a second distance, creating multiple sealing zones. This segmentation ensures that at least one sealing barb achieves reliable engagement even if shrinkage is slow, while the distributed arrangement reduces the time needed to establish secure sealing compared to a single-point engagement system.
Solution Approach 2:
The sealing barbs act as intermediaries between the shrinking pipe end section and the fitting. Their wedge shape and specific geometry allow them to progressively engage the pipe inner surface during shrinkage, translating the slow shrinkage motion into effective sealing force. The barbs mediate the interaction, ensuring that even slow shrinkage in cold conditions produces reliable sealing over time.
3Reliability
If sealing barbs are added to the tubular connecting part, then sealing performance improves, but the device complexity increases
Solution Approach 1:
The sealing barbs serve multiple functions: they provide sealing engagement with the pipe inner surface, guide the fitting during insertion, and distribute the shrinkage forces evenly. The same structural feature (the barbs) performs these different functions, eliminating the need for separate sealing elements, guides, and force distribution mechanisms, thus improving sealing performance without proportionally increasing device complexity.
Solution Approach 2:
The sealing function is merged with the structural connecting function. The sealing barbs are integrated directly into the tubular connecting part rather than being separate components. This merging combines the sealing mechanism with the fitting structure itself, achieving improved sealing performance while minimizing the increase in device complexity by using the same component for multiple purposes.
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 described pipe fitting enables rapid and secure formation of cold expansion pipe connections, even in low-temperature conditions, by ensuring consistent engagement of sealing barbs with the pipe's inner surface, thereby enhancing the efficiency and productivity of plumbing work.
Implementation Method 1
The memory properties of the pipe material make the initially expanded pipe end shrinkage back towards its original shape and dimensions, whereby it is pressed on the connecting part of the fitting.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3~4
AI summary
A pipe fitting (100) comprises a tubular connecting part (101); the tubular connecting part being configured to be inserted into an expanded pipe end section (111) of a pipe (110) having a first circumferential intact sealing region (113) on the inner surface (112) of the pipe end section (111); the tubular connecting part comprising a first radially outwards extending circumferential sealing barb (105') positioned for engaging, when in use, with the first circumferential intact sealing region during shrinkage of the pipe end section for forming a sealing between the pipe fitting and the pipe.