Fluid Conduit Coupling With Reduced-Taper Threads and Retained Seals
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Solution Overview
Problem
Existing fluid conduit couplings are prone to breakage due to overtightening, and the sealing elements are often improperly positioned, leading to reduced service life and mechanical damage, with the added challenge of difficult replacement when damaged.
Innovation Solution
A coupling design featuring a tubular member with threads tapered at a less than standard rate, incorporating interchangeable sealing rings and a collar system that securely positions the sealing rings to prevent damage, allowing for easy replacement and reducing mechanical stress during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard NPT tapered threads are used for coupling, then the threaded interference fit engagement is achieved, but the risk of overtightening and conduit breakage increases
Solution Approach 1:
The patent modifies the thread geometry parameters by using a reduced taper rate (less than the standard 1 inch in 16 inches) and a smaller pitch diameter (0.006 to 0.008 inches below standard). This parameter change allows the threads to engage more gradually and distribute stress more evenly, preventing the sudden stress concentration that causes conduit breakage during tightening while still achieving a secure interference fit engagement.
2Reliability
If the sealing element is positioned within the coupling, then the seal is formed, but the sealing element may shift or fall out during assembly
Solution Approach 1:
The patent incorporates a collar that is pre-positioned on the male part to hold the sealing element in its correct position before the coupling assembly begins. This preliminary positioning action prevents the sealing element from shifting or falling out during the subsequent assembly operations, eliminating the need for technicians to manually position or secure the seal during installation.
Solution Approach 2:
The collar acts as an intermediary component between the male threaded body and the sealing element. It provides a mechanical interface that securely holds the sealing element in place while allowing the threading and tightening operations to proceed without disturbing the seal's position or integrity.
3Ease of operation
If the sealing element is exposed during assembly, then it can be positioned, but it accumulates dirt or debris and may be discarded
Solution Approach 1:
The collar pre-positions the sealing element within its recess before any assembly operations begin. This preliminary action ensures the seal remains protected and contained throughout the entire assembly process, preventing exposure to dirt and debris while still allowing proper positioning to occur during manufacturing rather than during field installation.
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 minimizes the risk of part breakage from overtightening, ensures secure and durable sealing, and facilitates easy replacement of sealing elements, enhancing the operational life and maintenance of fluid conduit couplings.
Implementation Method 1
the flanks of the threads of each fluid conduit sealingly engage or compress against each other
Implementation Method 2
tighten by hand until a loose interference fit engagement occurs between the conduit and the threaded body portion
Implementation Method 3
compressing a sealing element
Data Source
AI summary
A coupling including a first member having a first body portion with threads tapered at a less than standard taper rate extending along an exterior surface thereof and a first flange portion extending therefrom. A first recess extends axially into the first flange portion and a first seal is located within the first recess. A body flange portion extends from the first body portion and axially spaced apart therefrom. A second recess extends axially into the first body flange portion and a second sealing ring is located within the second recess. The second seal is identical in size and shape with the first seal and is interchangeable therewith.