Two-Part Composite Fitting Thermal Expansion
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Solution Overview
Problem
Conventional fittings for connecting to composite or multi-layer pipes often experience leaks due to thermal expansion differences between metal and plastic components, leading to reliability and durability issues, and existing solutions like additional sealing elements or complex overmolding processes are costly and inefficient.
Innovation Solution
A fitting design featuring a separate plastic support body with a higher thermal expansion coefficient than the metal base body, utilizing a circumferential recess and tooth mechanism for a permanently sealing connection, which also incorporates low-creeping plastic for durability and adaptability, ensuring tightness even under temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal supporting body is used for connection to composite or multi-layer pipes, then the fitting has high stability and durability, but thermal expansion differences cause leaks and reduce reliability
Solution Approach 1:
The fitting is divided into two separate parts: a metal base body providing structural strength and a plastic support body providing thermal compatibility. This segmentation allows each material to perform its optimal function without the drawbacks of thermal expansion mismatch that would occur in a monolithic metal design.
Solution Approach 2:
The invention uses a composite structure combining metal and plastic materials in a two-part design. The metal base body provides mechanical strength while the plastic support body provides thermal compatibility with composite pipes, creating a composite fitting system that leverages the advantages of both materials.
2Reliability
If additional sealing elements like O-rings are added to prevent leaks, then connection tightness is improved, but manufacturing costs increase and insertion difficulty increases
Solution Approach 1:
The invention extracts and eliminates the need for additional sealing elements like O-rings by designing a sealing mechanism that is integral to the plastic support body itself. The plastic material and its interaction with the metal base body create the sealing function without requiring separate sealing components.
Solution Approach 2:
The plastic support body serves its own sealing function through its material properties and geometric design, eliminating the need for separate sealing elements. The fitting structure itself provides the sealing action through the interaction between the plastic support body and the metal base body.
3Reliability
If the supporting body is encapsulated with plastic to prevent thermal expansion leaks, then connection tightness is improved, but manufacturing complexity and cost increase due to overmolding
Solution Approach 1:
Rather than encapsulating the metal supporting body with plastic through complex overmolding, the invention segments the fitting into two separate parts: a metal base body and a plastic support body. This avoids the manufacturing complexity of overmolding while achieving the same thermal compatibility benefit.
Solution Approach 2:
Instead of covering the metal part with plastic (overmolding), the invention inverts the approach by having the plastic part interact with the metal part through a defined interface. The plastic support body is designed to work with the metal base body rather than enclosing it, simplifying manufacturing.
4Ease of manufacture
If fittings are made entirely of plastic to simplify manufacturing, then production complexity is reduced, but the inner profile cannot be rounded off and pressure loss increases
Solution Approach 1:
The fitting is segmented into a metal base body that forms the flow paths with rounded profiles for low pressure loss, and a plastic support body that provides thermal compatibility. This segmentation allows the metal portion to optimize fluid dynamics while the plastic portion simplifies manufacturing and provides thermal expansion compatibility.
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 provides a reliable, durable, and cost-effective connection that maintains tightness across temperature variations, reducing material fatigue and manufacturing complexity, while allowing for easy installation and use in drinking water systems.
Implementation Method 1
the material of the support body has a greater coefficient of thermal expansion than the material of the base body
Implementation Method 2
the base body has a circumferential recess on its inside and the support body has a circumferential tooth on its outside which, in the connected state, latch together in a permanently sealing manner
Data Source
Figure 1a
Figure 1b
Figure 2
AI summary
The invention relates to a fitting (6, 61) for sealingly connecting to a pipe end of a pipe comprising a plastic, comprising a base member (12, 80) and a support member (10, 82), wherein the base member (12, 80) is made of a metal, the support member (10, 82) is designed as a separate part made of plastic and the base member (12, 80) comprises means (46, 48, 84, 86) on the inside thereof, and the support member (10, 82) comprises means (46, 48, 84, 86) on the outside thereof for connecting the base member (12, 80) and the support member (10, 82) in a sealing fashion. The invention also relates to a system comprising such a fitting with a composite or multi-layered pipe and a sleeve, and to a system comprising such a fitting with a plastic pipe and a sleeve. The invention further relates to the use of such a fitting for connecting to a composite or multi-layered pipe and to the use of such a fitting for connecting to a plastic pipe.