Tubular Heating Element with Segmented Resistive Wire
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electrical tubular heating elements face challenges in realizing a small resistance and large wire cross-section in a compact space, especially under low voltage and high current conditions, while ensuring mechanical stability and efficient heat transfer, particularly in applications like on-board electrical systems of passenger cars.
Innovation Solution
The electrical tubular heating element features a resistive wire with openings and a contoured peripheral surface, allowing for improved mechanical stability, increased contact surface area, and localized heat management through the use of electrically insulating materials like magnesium oxide, which can be filled to enhance durability and reduce thermal load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a small resistance and large wire cross section are realized in a compact space, then the heating output is improved under low voltage conditions, but the mechanical stability and thermal load resistance deteriorate
Solution Approach 1:
The resistive wire is segmented by creating openings that divide it into multiple sections. These segments are then independently supported by insulating material bars inserted into the openings, distributing mechanical and thermal loads across multiple points rather than concentrating them on the wire itself, thereby maintaining mechanical stability while preserving the large cross-section design for high power output
Solution Approach 2:
Electrically insulating material bars are introduced as intermediary elements that extend into the openings of the resistive wire. These bars provide mechanical support and thermal management without interfering with the electrical function, enabling the wire to maintain its large cross-section for high current carrying capacity while the intermediaries bear the mechanical and thermal stress
2Quantity of substance
If a large wire cross section is used to reduce resistance, then the current carrying capacity is improved, but the available packaging space is exceeded
Solution Approach 1:
The insulating material bars are nested within the openings of the resistive wire, and the entire assembly is nested within the tubular metal sheath. This nested configuration allows the large cross-section wire to be accommodated in a compact overall volume by utilizing the internal space efficiently and arranging components concentrically
Solution Approach 2:
The openings in the resistive wire are oriented primarily in the longitudinal direction rather than radially outward, allowing the insulating bars to extend along the length of the wire. This dimensional reorientation enables support structures to be integrated within the wire's length rather than increasing its radial footprint, maintaining a compact packaging volume
3Power
If high currents flow through the heating element, then the desired heating output is achieved under low voltage conditions, but the thermal load and connection reliability deteriorate
Solution Approach 1:
The insulating material bars are strategically positioned at specific locations along the resistive wire where connections are made or where thermal loads are highest. This localized reinforcement provides enhanced mechanical support and thermal management precisely where needed for connection reliability, rather than uniformly distributing the support structure throughout the entire wire
Solution Approach 2:
The insulating material bars are pre-installed into the openings of the resistive wire before final assembly and operation. This beforehand preparation ensures that mechanical support and thermal management are already in place to cushion against thermal expansion, contraction, and load stresses that will occur during high-current operation, preventing connection failures before they happen
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
This configuration enables the heating element to withstand thermal and mechanical loads effectively, reduces surface load, and allows for adaptable heating output, ensuring long-term reliability and efficient operation in constrained spaces.
Implementation Method 1
electrically insulated in the radial direction relative to the tubular metal sheath by being embedded in an electrically insulating, but good heat-conducting material, in many cases, e.g., magnesium oxide, in order to prevent undesired short circuiting
Implementation Method 2
electrically insulating, but good heat-conducting material
Implementation Method 3
an electrical heating element is arranged within a tubular metal sheath... formed from a resistive wire
Data Source
AI summary
An electrical tubular heating element is disclosed with a tubular metal sheath, in whose interior an electrical heating element is arranged, which is formed from a resistive wire and is electrically insulated from the tubular metal sheath at least in sections by an electrically insulating material, in which the resistive wire, from which the electrical heating element is formed, is penetrated by at least one opening and/or has a contoured peripheral surface. A method for manufacturing such an electrical tubular heating element is also disclosed.