Steam Iron Thermal Fuse Layout for High-Power Heater Stability
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Solution Overview
Problem
Conventional irons with high heating capacity heaters experience nonuniform overheating, causing thermal fuses to accidentally break due to excessive temperature differences, leading to inefficient temperature control and potential damage.
Innovation Solution
An iron design that allows for a selectively attachable excessive temperature-rise preventing device with adjustable operation temperatures, either thermal fuse or bimetal-type, to be coupled with the heater circuit, preventing accidental breaks and accommodating different heating capacities while maintaining ease of manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a high heating capacity heater is used to heat the base quickly and maintain vaporization chamber temperature, then heating efficiency and productivity are improved, but nonuniform overheating occurs causing the excessive temperature-rise preventing device to accidentally break the circuit
Solution Approach 1:
A heat diffusion member (aluminum plate) is introduced as an intermediary between the heater and the excessive temperature-rise preventing device. This mediator distributes the heat uniformly across the base surface, preventing localized overheating that would trigger false circuit breaking while still allowing the high-power heater to operate effectively.
Solution Approach 2:
The excessive temperature-rise preventing device is strategically positioned to be cooled by steam from the vaporization chamber. The steam flow naturally cools this specific area, creating a self-regulating mechanism where the device monitoring that location remains stable while other areas experience higher temperatures necessary for effective ironing.
2Object-affected harmful factors
If a thermal fuse with low operation temperature is used to prevent overheating, then safety is improved, but the device cannot withstand high heating capacities without accidental circuit breaking
Solution Approach 1:
Different regions of the base are designed with different thermal characteristics. The area around the excessive temperature-rise preventing device is kept cooler through steam cooling and heat diffusion, while other areas can reach higher temperatures. This allows the use of a low-temperature thermal fuse without compromising the overall heating performance needed for high productivity.
Solution Approach 2:
The heat diffusion member acts as a thermal buffer between the high-power heater and the temperature-sensitive excessive temperature-rise preventing device. This intermediary component allows the system to operate at high temperatures for productivity while protecting the safety device from experiencing those extreme temperatures that would cause false tripping.
3Measurement precision
If the excessive temperature-rise preventing device is positioned to monitor the hottest area, then temperature control precision is improved, but the device breaks circuit during normal high-power operation
Solution Approach 1:
The excessive temperature-rise preventing device monitors a specific location that is naturally cooled by steam flow from the vaporization chamber. This self-cooling mechanism ensures the monitoring point remains within safe temperature ranges even when the rest of the base operates at high temperatures for effective ironing and steam generation.
Solution Approach 2:
The system accepts that temperature distribution will be nonuniform, with different regions serving different functions. The monitoring location is specifically chosen to be in a cooler zone created by steam flow, while other zones can reach higher temperatures. This spatial differentiation of thermal conditions allows accurate monitoring without false circuit breaking.
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
Prevents circuit breaks during high heating capacity use by ensuring the excessive temperature-rise preventing device does not reach its rated temperature, maintaining uniformity and ease of manufacturing by using either low-cost thermal fuses or high-temperature bimetal devices based on heater capacity.
Implementation Method 1
the thermal fuse operates (a eutectic alloy melts) when temperature of its base heated by a heater rises to exceed a normal service temperature
Implementation Method 2
when excessive temperature-rise preventing device 153 reaches a predetermined temperature, reverse bimetal 155 reverses upward to push and lift conductive metal part 158
Implementation Method 3
a high heating-capacity heater of 2 kW, for example, is employed
Implementation Method 4
the base of an iron is formed by aluminum die-casting. Therefore, the heater is buried during the die-casting of the base, which can improve the thermal conductivity to the base
Implementation Method 5
when water is instantly vaporized to increase an amount of steam generation
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
An iron according to the present invention includes an excessive temperature-rise preventing device coupled in series with a circuit of a heater, and an excessive temperature-rise preventing device securing part for attaching the excessive temperature-rise preventing device to a base. The base is disposed to be heatable by the heater with a different heating capacity. The excessive temperature-rise preventing device with a different operation temperature for breaking the circuit of the heater is selectively attached to the excessive temperature-rise preventing device securing part, in accordance with the heating capacity of the heater.