Heatable Line Pipe Spiral Winding Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing heatable pipes for transporting liquids or gases face challenges in maintaining low-temperature functionality due to issues with electrode embedding, flexibility, and contact resistance, particularly in applications like AdBlue lines for diesel vehicles, where the urea solution freezes at low temperatures, and current heating methods are prone to faults and require complex embedding processes.
Innovation Solution
A heatable line pipe design featuring a spiral winding of current leads within two electrically conductive layers, with an outer insulating cladding, allowing for effective and durable electrical contact with reduced resistance, and easily detectable electrode positions for current feeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If leads are directly embedded in the plastics material, then electrical contact between matrix and lead is achieved, but the introduction of stranded cord or wire into the conductive layer becomes very difficult and flexibility deteriorates
Solution Approach 1:
The pipe is divided into multiple functional layers: an inner insulating layer, a first conductive layer for electrode embedding, a second conductive layer for additional embedding, and an outer insulating cladding. This segmentation allows leads to be embedded in the first conductive layer without compromising the outer cladding integrity, while maintaining electrical contact through the layered structure.
Solution Approach 2:
The current leads are nested within the first electrically conductive layer, which itself is nested within the pipe structure between the inner and outer insulating layers. The second conductive layer provides an additional embedding layer. This nested arrangement protects the leads while maintaining electrical contact and flexibility.
2Reliability
If leads are directly embedded in the plastics material, then electrical contact is achieved, but contact resistance changes during thermoforming, installation, and service
Solution Approach 1:
The first electrically conductive layer is formed from a conductive moulding composition that combines plastic material with conductive additives. This composite structure provides both mechanical protection and stable electrical contact, as the conductive properties are inherent to the molded layer itself rather than relying on separate contact surfaces.
3Temperature
If standard resistance heaters are wound around the fluid pipe, then heating is achieved, but the arrangement is susceptible to faults and requires resistance adaptation to line length and conditions
Solution Approach 1:
The heating function is merged with the pipe structure itself by embedding current leads within the pipe walls and using the conductive layers as heating elements. This eliminates the need for separate external resistance heaters and their associated complexity, while providing uniform heating throughout the pipe wall and medium.
4Ease of operation
If spiral winding of electrodes is used, then line flexibility is improved, but the embedding process becomes complicated requiring coating and cladding steps
Solution Approach 1:
The first electrically conductive layer is pre-formed with embedded current leads during the pipe manufacturing process before the outer cladding is applied. This preliminary embedding simplifies the overall process by integrating the complex electrode placement into the initial molding step, rather than requiring subsequent coating and cladding operations.
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 ensures reliable heating performance with improved flexibility and durability, maintaining the temperature of transported media, such as AdBlue, by minimizing contact resistance and simplifying the embedding process, while allowing for easy detection and connection of electrodes.
Implementation Method 1
The flow of current from one lead to the other produces heating in the conductive layer
Data Source
AI summary
A heatable line pipe useful for diesel fuel systems and fuel cell systems is provided. The heatable line pipe comprises in order from an inside of the pipe: a) an electrically insulating inner layer; b) a first electrically conductive layer; c) at least two current leads wound spirally around the first electrically conductive layer; d) a second electrically conductive layer over the at least two current leads forming a surface; and e) an outer cladding of an electrically insulating plastic material. The thickness of the second electrically conductive layer is 0.1 to 1.5 mm, and the at least two current leads form wave peaks in the surface of the second electrically conductive layer. The line pipe has the advantage that a fall in heating performance over the lifetime is effectively prevented.