Heater
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Solution Overview
Problem
Traditional hand-held appliance heaters, such as those for hair care, face challenges with high power output requiring complex packaging and are often heavy due to the use of insulating and heat-resistant materials with resistive wires, and when using PTC materials, thermal expansion mismatches between ceramic and metal components lead to stress and potential failure.
Innovation Solution
A high power density ceramic heater with discrete connecting portions between the ceramic heating element and thermally conducting fins, made from materials like copper or aluminum, to manage thermal expansion and stress, allowing for efficient heat dissipation and reduced weight, using methods like EDM and brazing with specific filler materials to ensure a strong bond and stress relief.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional resistive wire heaters are used to achieve high power output (1200-1500 W), then the power requirement is met, but the heater becomes heavy and requires complex packaging
Solution Approach 1:
The invention changes the fundamental parameters of the heating element by transitioning from resistive wire to PTC ceramic material, enabling high power density (up to 1800 W) in a lightweight form factor. The ceramic material inherently provides both heating capability and structural integrity without requiring heavy insulation packaging
Solution Approach 2:
The invention uses composite construction by bonding metal fins to the ceramic heating element, creating a hybrid structure that combines the high power density of ceramic with the excellent thermal conductivity of metal, achieving both lightweight design and efficient heat dissipation
2Weight of moving object
If PTC ceramic heating elements are used to reduce weight, then the heater becomes lightweight, but thermal expansion mismatch between ceramic and metal fins causes stress and potential failure
Solution Approach 1:
The invention segments the bonding interface by creating discrete connecting portions between the metal fin and ceramic element instead of continuous bonding. This segmentation allows localized stress relief while maintaining adequate heat transfer, preventing catastrophic failure from thermal expansion mismatch
Solution Approach 2:
The invention introduces a bonding layer as an intermediary between the ceramic heating element and metal fin. This intermediate layer acts as a stress buffer that accommodates thermal expansion differences while maintaining the structural and thermal connection between the two materials
3Strength
If high temperature bonding is used to attach fins to ceramic, then strong bonding is achieved, but residual stresses and cracking occur during cooling
Solution Approach 1:
The invention performs preliminary stress relief by bonding the fin to the ceramic element at a lower temperature before the ceramic is fully cooled to room temperature. This preliminary bonding action allows the ceramic to contract more uniformly during cooling, reducing residual stresses and preventing cracking while still achieving adequate bond strength
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 results in a lightweight, high-power ceramic heater capable of withstanding 400°C and up to 1800 W, with improved thermal management and reduced risk of cracking or debonding, enabling efficient heat dissipation and extended appliance lifespan.
Implementation Method 1
the term heater element refers to the resistive track which is embedded into a ceramic material
Implementation Method 2
The fins may be made from a thermally conducting material, for example copper, aluminium or their alloys which are attached to the heating element
Data Source
AI summary
A heater comprising a ceramic heater element and at least two fins for dissipating heat from the ceramic heater element, wherein the ceramic heater element extends along a plane in one dimension and the at least two fins extend away from the plane, and wherein the at least two fins are connected to the ceramic heater element via discrete connecting portions.