Pipe Joint Thermal Shrinkage Compensation
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Solution Overview
Problem
Existing pipe joint systems face challenges in maintaining a reliable seal under varying thermal conditions due to differing thermal shrinkage rates between plastic and metal components, leading to potential leaks and structural integrity issues.
Innovation Solution
A pipe joint system incorporating a tubular plastic body with a metal reinforcement ring, where a radial gap is provided to accommodate thermal shrinkage differences, and a spigot member with plastic ribs forming a gasket channel to ensure a secure connection, utilizing overmolding or extrusion processes to encase the metal reinforcement within the plastic body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal reinforcement ring is encased within a tubular plastic body wall, then the structural strength and rigidity of the pipe joint is improved, but the thermal shrinkage mismatch between metal and plastic causes sealing failures and leaks
Solution Approach 1:
The pipe wall is segmented into distinct functional layers: an inner plastic layer for flexibility and sealing, a metal reinforcement ring for structural strength, and an outer plastic layer for protection. This segmentation allows each material to perform its optimal function without the thermal shrinkage mismatch affecting the overall sealing reliability.
Solution Approach 2:
The invention uses a composite structure combining plastic and metal materials in a layered configuration. The plastic-metal-plastic composite allows the metal ring to provide reinforcement while the plastic layers accommodate thermal expansion differences, preventing sealing failures that would occur with simple encasement.
2Ease of operation
If plastic ribs are used to form a gasket channel, then the ease of assembly and alignment is improved, but the thermal shrinkage causes the gasket channel dimensions to vary with temperature
Solution Approach 1:
The gasket channel region is designed with local quality considerations, using plastic ribs that provide sufficient structural definition for assembly while being positioned and dimensioned to accommodate thermal movement. The ribs provide alignment features during assembly but their design allows for dimensional variation without compromising the sealing function.
Solution Approach 2:
The design accounts for parameter changes due to thermal shrinkage by configuring the gasket channel dimensions and rib geometry to maintain functional tolerance across temperature variations. The plastic material's thermal properties are considered in the dimensional design to ensure the gasket channel remains effective despite temperature-induced dimensional changes.
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 effectively maintains a durable and leak-proof seal across temperature variations by accommodating thermal expansion differences between plastic and metal, enhancing the structural integrity and longevity of pipe connections.
Implementation Method 1
A radial gap may be provided between the plastic ring portion and the metal reinforcement ring to accommodate differing thermal shrinkage rates as between the two different materials.
Data Source
AI summary
A pipe joint for plastic pipe includes a bell member and a spigot member. The bell member includes a tubular plastic body wall having a metal reinforcement ring. The spigot member, which is insertable into the bell member, includes a tubular plastic body wall having an internal surface and an external surface and a longitudinal axis and metal reinforcement encased within the tubular plastic body wall. A plurality of plastic ribs extend from the external surface of the tubular plastic body wall and form a gasket channel.