Fail Safe Heater Assembly with Resistive Sensor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conduction-based heating systems using thermo-electric heaters face issues with localized diminished heat transfer due to loss of physical contact between the heater and heat sink, leading to temperature discrepancies and potential degradation or failure of the heating element, particularly at high temperature and power densities.
Innovation Solution
A fail-safe heating assembly comprising a resistive heating element on a dielectric substrate, coextensive with a resistive sensor that monitors changes in resistance to detect alterations in the conductive interface between the heater and heat sink or work piece, utilizing comparative zone resistance sensing or a thermal fuse for real-time monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a thermo-electric heater is used to provide high heat output, then the heating capability is improved, but the risk of localized overheating and degradation increases when contact is lost
Solution Approach 1:
The patent implements a monitoring system that continuously measures the electrical resistance of the heater element and thermal contact interface. When resistance changes indicate loss of thermal contact, the system provides feedback to reduce or shut off power to the heater, preventing localized overheating and degradation while maintaining high power capability during normal operation
Solution Approach 2:
The patent introduces a thermal interface material or compliant layer between the heater element and heat sink that acts as an intermediary. This intermediary maintains uniform contact pressure and thermal coupling even when surfaces are not perfectly flat, distributing the thermal load and preventing localized stress concentrations that lead to degradation
2Temperature
If the heater operates at high temperature, then the thermal processing capability is improved, but the risk of insulation failure and combustion increases
Solution Approach 1:
The patent employs protective measures in advance by selecting insulation materials with high thermal stability and fire resistance ratings that can withstand the maximum operating temperature plus a safety margin. Thermal barriers and heat-resistant coatings are applied beforehand to protect surrounding components from thermal damage
Solution Approach 2:
The monitoring system detects temperature rises or resistance changes that precede insulation failure. When abnormal conditions are detected, the system automatically reduces power or shuts down the heater before the insulation degrades or combustes, preventing catastrophic failure while allowing high-temperature operation
3Measurement precision
If thermal contact between heater and heat sink is lost locally, then the temperature sensing accuracy is improved at the sensing location, but the actual thermal condition of the system becomes inaccurate
Solution Approach 1:
The patent divides the thermal monitoring function into multiple distributed sensing zones across the heater and heat sink interface. Each zone independently monitors its local thermal contact condition, allowing the system to identify and isolate specific areas of poor contact while maintaining accurate overall thermal awareness through aggregated data from all segments
Solution Approach 2:
The patent introduces a thermal sensor array or thermocouple network as an intermediary between the heater and heat sink. These intermediary sensors directly measure the thermal conditions at the interface, providing accurate real-time data about actual heat transfer regardless of contact variations, thereby maintaining system-level thermal accuracy
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 effectively detects and prevents heater failure by ensuring continuous monitoring of the conductive interface, preventing temperature-related degradation and maintaining optimal thermal conditions for processes, even at high power densities and temperatures.
Implementation Method 1
a heater characterized by a resistive heating element
Implementation Method 2
a resistive sensor monitorable in real time for a detection of a change in a resistance related parameter
Implementation Method 3
conduction based heating systems (i.e., those characterized by a transfer of thermal energy between adjacent bodies or parts thereof owing to the presence of a temperature gradient)
Data Source
AI summary
A fail safe heating assembly for operative union with a heat sink and/or work piece is provided. The assembly generally includes a heater characterized by a resistive heating element and a dielectric substrate, and a resistive sensor, substantially coextensive with the resistive heating element of the heater and united therewith so as to define a composite heating assembly. The resistive heating element is supported upon the dielectric substrate, with the heater including leads for operative union with a current source. The resistive sensor is characterized by a first resistive sensor portion having a resistive material delimiting a first resistive pattern, and a second resistive sensor portion having a resistive material delimiting a second resistive pattern.