Pipe Connection Assembly With Angled Thread Ends
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Solution Overview
Problem
Existing connection assemblies for pipes during drilling suffer from reduced tensile and circumferential strength due to thinner walls, leading to cracking and increased costs, with solutions like ceramic coatings or welding being complex and time-consuming.
Innovation Solution
A connection assembly featuring internal and external threads on pipes with a tubular connection member having an outer diameter matching the pipes, where the tubular member's angled end portions distribute tensile yield strength and maintain the pipe's outer diameter, using the same material as the pipes, and with thread dimensions that prevent material loss and simplify manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the thickness of the pipe wall is reduced by 50% to provide threads, then internal threads can be screwed on external threads, but the tensile, circumferential and elastic stress causes the material to crack and rupture
Solution Approach 1:
The connection member is inserted into the bore of the pipe, with the connection member having a smaller outer diameter than the pipe's outer diameter. The connection member is nested within the pipe structure, allowing the threaded connection to be formed without reducing the pipe wall thickness, thereby maintaining tensile strength while enabling manufacturable threaded connections.
2Strength
If welding is used to connect pipes together, then tensile yield strength is maintained, but the process is time consuming and expensive
Solution Approach 1:
The patent replaces the welding process (thermal/chemical joining) with a mechanical threaded connection system. The connection member with external threads engages with internal threads formed in the pipe bore, providing a mechanical attachment method that maintains strength while significantly reducing connection time and cost compared to welding.
3Ease of operation
If a coupling device with smaller outer diameter at end portions is used, then engagement inside the bore is enabled, but the centre part is subjected to high tensile yield stress and the thinner wall reduces strength
Solution Approach 1:
The connection member is designed with varying dimensions: the centre portion has a smaller outer diameter to enable engagement inside the pipe bore, while the end portions have larger diameters with angled surfaces for proper positioning and stress distribution. This local variation in geometry allows the connection member to fit within the bore while maintaining adequate circumferential strength at critical locations.
Data Source
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Figure 2
AI summary
The present invention relates to a connection assembly for connecting pipes, comprising two pipes (1a, 1b) having internal threads (3) on an inner surface of the pipe arranged at an end portion (2) of the pipe over a distance (d), and a tubular connection member (5) having external threads (3) at an outer surface adapted to engage with the internal threads of the pipes (1a, 1b). The tubular connection member (5) has an outer diameter adapted to be inserted into bores of the pipes (1a, 1b), whereby the pipes (1a, 1b) are in contact with each other when the tubular connection member (5) is arranged in the bores and both pipes are fully engaged in the tubular connection member. The tubular connection member has an end portions (6) comprising an angled surface, whereby the angle (α) of the angled surface in relation to longitudinal axis is more than 125°.