Segmented Pipe Coupler for Airtight Thermoplastic Electrofusion
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Solution Overview
Problem
Current methods for joining polyethylene and other thermoplastic pipes, such as polypropylene and polybutylene, using solvent welding are impractical, and existing electrofusion techniques with resistive heating elements are limited in their ability to form reliable and air-tight connections.
Innovation Solution
A pipe coupler with a circumferentially segmented collar and inward radial projections, combined with a band clamp and annular gasket, allows for axial translation and compression to create a secure, air-tight joint using a unitary plastic molding made from glass-filled polyphenylene sulfide, which engages with an electrofusion collar or fitting to facilitate electrofusion welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solvent welding is used to join polyethylene and other thermoplastic pipes, then the joining process is simple and fast, but it is impractical for many thermoplastic materials including polyethylene, polypropylene, polystyrene, and polybutylene
Solution Approach 1:
The patent replaces solvent welding (chemical method) with electrofusion welding (thermal method). The electrofusion collar with embedded heating element applies controlled heat to melt and join thermoplastic pipes, making the process applicable to polyethylene, polypropylene, polystyrene, and polybutylene materials that cannot be solvent welded, while maintaining operational simplicity
Solution Approach 2:
The invention changes the joining parameter from chemical solvent reaction to controlled thermal heating. The heating element in the electrofusion collar provides precise temperature control to melt thermoplastic materials, enabling reliable joints across multiple thermoplastic types without requiring material-specific solvents
2Adaptability or versatility
If existing electrofusion techniques with resistive heating elements are used, then thermal welding can be applied to thermoplastics, but the ability to form reliable and air-tight connections is limited
Solution Approach 1:
The electrofusion collar is divided into functionally segmented components: a body portion for structural support, a circumferentially segmented collar for controlled compression, and finger projections for positioning. This segmentation allows each component to perform its specific function optimally, ensuring reliable and air-tight connections
Solution Approach 2:
The patent introduces a gasket as an intermediary sealing element between the electrofusion collar and the pipe/fitting interface. The gasket enhances the air-tight seal by filling microscopic gaps and providing a dedicated sealing surface, complementing the thermal welding process to ensure connection integrity
3Reliability
If a clamp is tightened around the fitting to radially compress the fitting and collar to the pipe, then no air enters the welding zone, but the device complexity increases with multiple components including collar, clamp, and gasket
Solution Approach 1:
The patent merges the collar and gasket into a unitary single-piece plastic molding, reducing the number of separate components while maintaining the sealing function. The integrated design eliminates assembly steps between collar and gasket, simplifying the overall device structure while preserving air-tight sealing capability
Solution Approach 2:
The electrofusion collar is designed as a multi-functional component that simultaneously provides: (1) heating element support for thermal welding, (2) radial compression interface for clamp engagement, (3) positioning features via finger projections, and (4) integrated gasket for sealing. This consolidation reduces component count while maintaining all necessary functions for reliable, air-tight connections
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 solution enables reliable and efficient electrofusion welding of thermoplastic pipes by ensuring a secure, air-tight seal and axial tension in the fingers, enhancing the joint's mechanical strength and sealing capabilities.
Implementation Method 1
resistive heating elements are at least partially embedded in fittings. A pipe may be inserted into the fitting so as to be encircled by the heating element.
Implementation Method 2
The clamp is tightened around the fitting (or collar outer wall) to radially compress the fitting and collar to the pipe to insure no air enters the welding zone.
Implementation Method 3
The heating element may be energized by an electric power source to heat the fitting and the pipe sufficiently to weld the two together.
Data Source
AI summary
A pipe coupler has: an axis; and a body portion surrounding the axis. A circumferentially segmented collar extends from a first axial end of the body portion and has an inner diameter surface and an outer diameter surface. A plurality of fingers project from a second axial end of the body portion, axially opposite the first end and have inward radial projections.