Fluid Coupling Nut and Fitting Lock for Low-Torque Sealing
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Solution Overview
Problem
Existing fluid connection systems face challenges with threaded connections, including operator fatigue from applying high torque, thread galling, and leakage due to loose connections, especially in tight spaces and under high pressure or vibration.
Innovation Solution
A fluid connection system using a fitting with radial ears and a coupling nut featuring annular grooves and channels, along with anti-rotation elements, allowing for axial and rotational retention without threads, enabling low-torque assembly and maintaining a sealed connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tapered threads are used to create a mechanical seal connection, then a sealed connection is achieved, but large torque is required to tighten the threads
Solution Approach 1:
The connection system is divided into separate functional elements: the fitting with tapered outer threads, the nut with tapered inner threads, and a separate seal member (O-ring or gasket). This segmentation allows the sealing function to be independent from the fastening function, enabling hand-tightening without requiring high torque that would damage the seal or threads.
Solution Approach 2:
A seal member (O-ring, gasket, or sealing ring) is introduced as an intermediary element between the fitting and the tube/manifold. This intermediary provides the sealing function without requiring the threads to bear the sealing load, allowing the threaded connection to be tightened by hand torque while maintaining a reliable seal.
2Reliability
If large torque is applied to tighten the threads, then a sealed connection is achieved, but thread galling occurs
Solution Approach 1:
The connection system separates the sealing function from the fastening function by using a dedicated seal member. This allows the threaded connection to be tightened by hand torque without requiring high torque that would cause thread galling, while the seal member independently provides the sealing function.
Solution Approach 2:
The friction coefficient between mating surfaces is reduced by introducing the seal member, which acts as a low-friction interface. This parameter change allows the threaded connection to be tightened with minimal torque, preventing thread galling while maintaining seal integrity.
3Ease of operation
If minimal torque is applied for hand assembly, then ease of operation is improved, but connection looseness and leakage occur
Solution Approach 1:
A seal member (O-ring, gasket, or sealing ring) is introduced as an intermediary element that provides the sealing function independently of the threaded connection tightness. This allows the connection to be tightened by hand torque while the seal member prevents leakage, even under pressure and vibration.
Solution Approach 2:
The seal member is pre-installed in the fitting or on the tube/manifold before assembly. This beforehand cushioning provides a backup sealing mechanism that compensates for any potential looseness in the threaded connection, preventing leakage even if the connection is not tightly secured.
4Strength
If threaded connections are used, then connection strength is achieved, but difficulty in tight spaces increases
Solution Approach 1:
The connection system is divided into a fitting with integrated seal member and a nut, both designed with reduced size and simplified geometry. The seal member is integrated into the fitting design, eliminating the need for separate sealing components. This segmentation allows for compact design that can be assembled in tight spaces by hand without requiring large wrenches.
Solution Approach 2:
The connection system uses simple, inexpensive components (fitting, nut, and seal member) that can be easily replaced if needed. The design prioritizes ease of assembly and disassembly over permanent installation, allowing for quick replacement in tight spaces without requiring complex tools or procedures.
Data Source
AI summary
An example fluid connection system includes: a fitting comprising one or more ears protruding radially outward; a coupling nut comprising at least one helical groove and one or more channels, wherein the one or more channels are configured to allow the one or more ears of the fitting to pass therethrough and reach the at least one helical groove as the coupling nut is slid axially relative to the fitting to mount the coupling nut to the fitting, and wherein the one or more ears are configured to rotationally traverse the at least one helical groove when rotating the coupling nut relative to the fitting, thereby pulling the coupling nut and the fitting toward each other; and an anti-rotation element configured to rotationally couple the fitting to the coupling nut when the coupling nut reaches a predetermined rotational position relative to the fitting.