Composite Pipe Fitting With Conical Compression to Prevent Torsion
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Solution Overview
Problem
Existing fittings for joining smooth surface pipes to threaded terminal elements require significant screwing forces, leading to high friction and potential torsion of the pipe, which weakens the mechanical structure and compromises sealing over time.
Innovation Solution
A fitting design featuring a tubular core with a saw-toothed rear portion, an elastic sleeve with beveled annular ribs, and a ring nut with a frustoconical portion that minimizes friction and prevents torsion, allowing for snap-insertion and conical compression to ensure robust and hydraulic sealing without pipe swelling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ring nut with elastic sleeve is used to compress the pipe radially, then hydraulic sealing is improved, but screwing forces increase due to high friction from opposite surfaces
Solution Approach 1:
The patent replaces the traditional ring nut with a screwing mechanism with a conical compression mechanism. Instead of relying on friction-based screwing forces, the conical geometry converts axial movement into radial compression through geometric leverage, significantly reducing the screwing forces required while maintaining effective radial compression for hydraulic sealing.
Solution Approach 2:
The patent changes the compression geometry from cylindrical to conical. The conical portion of the core element creates a tapered compression path that reduces friction during installation while achieving the necessary radial compression. This geometric parameter change allows the same sealing function to be achieved with lower installation forces.
2Ease of operation
If a cross-sectional cut is provided on the elastic sleeve to allow rotation, then the sleeve can rotate during screwing, but the pipe swells in the cut and weakens its mechanical structure
Solution Approach 1:
The patent extracts and removes the cross-sectional cut feature from the elastic sleeve design. By eliminating this cut, the sleeve becomes a continuous, unbroken structure that prevents pipe swelling and maintains mechanical integrity while still allowing for the necessary compression and sealing functions through the conical geometry.
Solution Approach 2:
The patent introduces asymmetry through the conical geometry of the core element rather than through symmetry-breaking cuts in the sleeve. The conical shape provides the necessary mechanical advantage and compression direction without creating weak points or stress concentrations that would compromise pipe strength.
3Stress or pressure
If significant screwing forces are applied to compress the pipe, then radial compression is achieved, but torsion is induced in the pipe weakening its structure
Solution Approach 1:
The patent changes the compression geometry from cylindrical to conical, which fundamentally alters the stress distribution during installation. The conical geometry directs compression forces radially inward through geometric leverage, minimizing torsional moments and preventing the induction of harmful torsion stresses in the pipe structure.
Solution Approach 2:
The patent replaces the friction-based screwing mechanism with a conical compression mechanism that uses geometric leverage. This substitution changes the force vector distribution, achieving radial compression through axial movement along the cone surface rather than through high-friction rotation, thereby eliminating torsion induction.
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 reduces screwing forces, prevents pipe torsion, and maintains high mechanical and hydraulic sealing over time, ensuring the integrity of the pipe while simplifying installation and reducing operational stress.
Implementation Method 1
an elastomeric gasket (30) fitted on the core (10) and arranged peripherally with respect to the end (E) of the pipe (P), susceptible to provide hydraulic sealing between said end (E) of the pipe (P), the elastic sleeve (40) and the threaded terminal element (T)
Implementation Method 2
the screwing of the ring nut (20) and of the terminal element (T) with respect to each other, susceptible to drive the elastic sleeve (40) in conical compression
Data Source
Figure 1A~1D
Figure 2A~2E
Figure 3A~3B
AI summary
A fitting for the mutual joining of a threaded terminal element (T) and a smooth surface pipe (P) comprising a tubular core (10), a ring nut (20) which can be screwed on the threaded terminal element (T), an elastic sleeve (40) which can be fitted on the pipe (P) and an elastomeric gasket (30) arranged peripherally to the tubular core (10). The elastic sleeve (40) has a frustoconical portion (422) and a plastically deformable area (46). Upon the screwing of the ring nut (20) and terminal (T), the frustoconical portion (422) impacts the ring nut (20) in a single point of tangency (PT), translates axially and causes the differentiated, progressive and conical compression of the sleeve (40). This allows to obtain a mechanical sealing on the pipe (P). The axial translation causes an axial compression of the end (E) of the pipe (P) against the elastomeric gasket (30) to provide the hydraulic sealing.