Printable PTC Heater for Self-Regulating Temperature Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Point-of-care (POC) diagnostic tests require stable heating for extended periods, which is currently achieved with costly and complex heating platforms, necessitating external monitoring systems to maintain temperatures between 60° C. and 70° C. for 30-40 minutes, posing a challenge for simplicity and affordability.
Innovation Solution
A heater with positive thermal coefficient of resistance (PTC) elements, comprising a substrate with electrodes and conductive strips, where resistive elements are printed to create a self-regulating heating system that can maintain stable temperatures using a voltage source, allowing for selective temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If external monitoring systems (PI controllers, PID controllers) are used to maintain stable temperatures, then temperature stability is improved, but device complexity and cost increase
Solution Approach 1:
The heater employs a self-regulating mechanism where the heating element's resistance automatically adjusts based on temperature changes. As temperature increases, the resistance increases (positive temperature coefficient), reducing current flow and preventing overheating. This eliminates the need for external controllers like PI or PID controllers, resolving the contradiction between temperature stability and device complexity.
Solution Approach 2:
The heating element provides inherent feedback through its temperature-dependent resistance. The resistance changes with temperature, creating a natural feedback loop that stabilizes the heating process without requiring external monitoring systems. This feedback mechanism maintains temperature stability while avoiding complex control hardware.
2Measurement precision
If external monitoring systems are used to control heating, then temperature control precision is improved, but cost increases
Solution Approach 1:
The heating element serves its own control function through its intrinsic temperature-dependent resistance properties. This self-regulating characteristic provides precise temperature control without requiring expensive external monitoring and control systems, thereby reducing manufacturing costs while maintaining control precision.
Solution Approach 2:
The patent replaces complex mechanical/electronic control systems (controllers, sensors, monitoring equipment) with a passive physical property-based control mechanism. The temperature-dependent resistance of the heating element provides precise control through a simple electrical principle, eliminating the need for costly external control hardware.
3Device complexity
If simple heating elements are used without external control, then device complexity is reduced, but temperature stability deteriorates
Solution Approach 1:
The heating element is designed to regulate its own temperature through its positive temperature coefficient resistance. As the element heats up, its resistance increases, automatically reducing current flow and preventing temperature runaway. This self-service mechanism maintains temperature stability without adding external control complexity.
Solution Approach 2:
The heating element utilizes changes in its electrical resistance parameter with temperature to achieve self-regulation. The resistance increases with temperature (positive temperature coefficient), creating a natural balancing act that stabilizes temperature. This parameter-based control achieves temperature stability while keeping the device simple.
4Duration of action of moving object
If conventional heating platforms are used for extended heating, then heating duration is improved, but cost and complexity increase
Solution Approach 1:
The heating element maintains stable temperature throughout extended heating periods through its self-regulating resistance mechanism. The positive temperature coefficient ensures that as temperature rises, current automatically reduces, preventing overheating during long-duration heating. This enables extended operation (30-40 minutes) without requiring complex external monitoring or control systems.
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 PTC-based heater provides a cost-effective and stable heating solution, maintaining temperatures between 63-78° C. with self-regulating properties, demonstrating robustness through 10,000 cycles of bending without failure and efficient current management, thus addressing the complexity and cost issues of existing heating systems.
Implementation Method 1
a voltage source coupled with both the first and second electrodes, whereby selective voltage of the voltage source determines temperature of the heater
Implementation Method 2
heater with positive thermal coefficient of resistance (PTC) elements
Data Source
AI summary
A heater with positive thermal coefficient of resistance (PTC) elements is disclosed, which includes a substrate and a first and second electrodes spaced apart a predetermined distance from one another and disposed on the substrate, a plurality of conductive strips alternatingly i) extending from the first electrode towards the second electrode terminating by forming an air gap with the second electrode, and ii) from the second electrode towards the first electrode terminating by forming an air gap with the first electrode, one or more resistive elements disposed on each of said alternating conductive strips, thereby making electrical connectivity with a neighboring alternating conductive strip, and a voltage source coupled with both the first and second electrodes, whereby selective voltage of the voltage source determines temperature of the heater.