Radiant Heating Element Geometry to Prevent Edge Spalling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric resistance heating elements in furnaces suffer from premature failure due to passivation layer spalling at sharp edges and material depletion, leading to reduced longevity, especially at high temperatures.
Innovation Solution
Designing electric resistance heating elements with rounded corners or curved surfaces in the end sections to reduce the surface-to-volume ratio, increasing the material reservoir and improving passivation layer formation, thereby preventing spalling and extending the element's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If band-like electric resistance heating elements are used for high energy applications, then heat radiation efficiency is improved, but passivation layer spalling occurs at sharp edges leading to reduced longevity
Solution Approach 1:
The patent applies curvature by rounding the corners of the band-like heating element. Instead of sharp 90-degree corners, the elements have rounded corners with a specified radius (e.g., R1, R2). This curvature prevents passivation layer spalling that occurs at sharp edges during high-temperature operation, thereby extending element longevity while maintaining the efficient heat radiation characteristics of the band-like geometry.
2Object-affected harmful factors
If aluminium content is increased to form protective passivation layer, then corrosion protection is improved, but material depletion occurs faster at sharp edges
Solution Approach 1:
By rounding the corners of the heating element, the patent reduces the surface area at locations where passivation layer spalling is most likely to occur. This geometric modification decreases the rate of material depletion from the aluminium reservoir, allowing the protective passivation layer to form and persist longer without being compromised by edge spalling.
3Temperature
If electric heating elements operate at high temperatures, then heating performance is improved, but passivation layer spalling accelerates
Solution Approach 1:
The rounded corner design specifically addresses high-temperature operation by eliminating the sharp edges that are most susceptible to thermal stress and passivation layer spalling. The curved geometry distributes thermal stresses more evenly and prevents the formation of cracks that would compromise the passivation layer during prolonged high-temperature heating 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 modified heating element design enhances the longevity and stability of electric resistance heating elements by reducing passivation layer spalling and maintaining material integrity, ensuring consistent performance at high temperatures.
Implementation Method 1
The electric heating element (30) comprises an electric resistance heating element (31)
Implementation Method 2
there are also concepts for so-called indirect electrical heating. Such indirect electrical heating can, as explained in WO2020/002326 A1, among others, but already known from earlier publications, be carried out using electrical radiant heating elements ('radiant heaters')
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
The invention relates to an Electric heating element (30), in particular for arrangement in a furnace, configured to provide radiant heat, in particular to a heat sink (20). The electric heating element (30) comprises an electric resistance heating element (31) having in its cross section a width and a thickness, wherein the width is greater than the thickness, wherein the electric resistance heating element (31) comprises a middle section (31a), and two end sections (31b) on opposite sides of the middle section (31a) in a width direction (W) of the electric resistance heating element (31). An angle of each corner of at least one of the two end sections (31b) is greater than 90° and/or the outer surface of the at least one of the two end sections (31b) is a curved surface. The invention further relates to a furnace and a method for performing a chemical process and/or for heating a process medium.