Coextruded Polyethylene Pipe Structure for Solar Heat Control
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Solution Overview
Problem
Above-ground piping applications experience significant temperature fluctuations, leading to reduced pressure capability, increased chemical attack, and thermal expansion/contraction, with conventional solutions like painting the pipe surface being ineffective and requiring frequent reapplication.
Innovation Solution
A coextruded pipe design featuring an inner layer with a first material and an outer layer, where the outer layer has a higher hydrostatic design basis than the inner layer, is used to minimize solar radiation absorption and reduce temperature fluctuations, thereby enhancing pressure capability and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the pipe surface is painted to reduce solar radiation absorption, then solar absorptivity is reduced, but the paint requires frequent reapplication and is ineffective
Solution Approach 1:
The patent applies a multi-layer composite structure consisting of an inner layer (providing pressure containment) and an outer layer (providing solar radiation protection with lower solar absorptivity). This composite design integrates the protective function directly into the pipe structure, eliminating the need for separate paint applications and providing long-term durability.
2Ease of manufacture
If a single-layer pipe design is used, then manufacturing is simpler, but the pipe cannot simultaneously provide pressure containment and solar radiation protection
Solution Approach 1:
The patent employs a coextruded multi-layer composite structure where the inner layer provides pressure containment and the outer layer provides solar radiation protection. This integrated composite design achieves multiple functions (pressure containment and thermal protection) in a single manufacturing process, eliminating the need for separate painting operations while providing durable long-term protection.
3Strength
If the outer layer has higher HDB than the inner layer, then pressure capability is enhanced, but the structure becomes more complex
Solution Approach 1:
The patent utilizes a coextruded multi-layer composite structure where the outer layer has higher HDB than the inner layer. This design provides both solar radiation protection and enhanced pressure capability. The coextrusion process integrates multiple layers with different material properties in a single manufacturing operation, managing structural complexity while achieving superior performance.
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 coextruded pipe design effectively reduces pipe surface temperatures, minimizes thermal expansion and contraction, and increases pressure capability while providing increased longevity and wear resistance, eliminating the need for frequent surface treatments.
Implementation Method 1
the outer layer provides for decreased solar absorptivity relative to a same pipe absent the outer layer
Data Source
AI summary
A pipe having an inner layer and an outer layer. The inner layer includes a first material having a first hydrostatic design basis (HDB), and the outer layer is coextruded with the inner layer and includes a second material having a second HDB. The second HDB is greater than or equal to the first HDB, and the first HDB and the second HDB are as specified in ASTM Test Method D2387. Also provided re methods of making and using the pipe.