Aerosol Delivery Heater Resistance Sensing for Low-Liquid Detection
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Solution Overview
Problem
Existing aerosol delivery devices struggle with inaccurate detection of low liquid levels in the tank, leading to reduced aerosol generation and undesirable changes in aerosol properties when the aerosol precursor is depleted.
Innovation Solution
The device employs a controller to determine resistance values of the heater based on a reference resistance, measured voltage, and a constant voltage, and detects a low liquid level by analyzing the rate of resistance change, ensuring accurate detection through a constant voltage source and resistance monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the device uses simple liquid level detection methods, then the device complexity is reduced, but the measurement precision of low liquid level detection deteriorates
Solution Approach 1:
The patent uses the heater as an intermediary element for detection. Instead of directly measuring liquid level with dedicated sensors, the system monitors the heater's electrical resistance properties, which change in response to liquid level conditions. This indirect measurement approach allows the heater to serve dual purposes: heating the aerosol precursor and providing detection functionality.
Solution Approach 2:
The heater is designed to perform multiple functions: it serves as both the heating element for aerosol generation and the sensing element for liquid level detection. By monitoring the heater's resistance characteristics, the system achieves multi-functionality without adding separate detection components, thereby reducing overall device complexity while maintaining detection accuracy.
2Productivity
If the device continues to operate when liquid level is low, then productivity is maintained, but harmful factors are generated due to insufficient aerosol precursor
Solution Approach 1:
The system implements a feedback mechanism where the controller continuously monitors the heater's resistance and compares it against reference values to detect low liquid level conditions. When insufficient liquid level is detected, the controller provides feedback by preventing further operation or alerting the user, thereby avoiding the generation of harmful aerosols while maintaining productivity during normal operation.
3Measurement precision
If the device uses constant voltage measurement, then measurement precision is improved, but use of energy increases due to continuous monitoring
Solution Approach 1:
The system employs periodic action by measuring the heater's resistance at specific intervals rather than continuously. The controller performs resistance measurements at discrete time points during device operation, which maintains measurement precision for detecting liquid level changes while minimizing energy consumption compared to continuous monitoring approaches.
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
This method allows for precise detection of low liquid levels, preventing device operation under insufficient conditions and maintaining consistent aerosol quality by providing user feedback and preventing power supply to the heater when necessary.
Implementation Method 1
a heater for heating the aerosol precursor... heated by a heater to produce an aerosol vapour which is inhaled by a user
Implementation Method 2
determine a plurality of resistance values of the heater, wherein each of the plurality of resistance values is determined based on a reference resistance of a sense resistor, a measured voltage at a first point between the sense resistor and the heater
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3
AI summary
The present disclosure relates to an aerosol delivery device and system e.g. a smoking substitute device and system. In particular, the present disclosure relates to an aerosol delivery device for forming an aerosol delivery system comprising the aerosol delivery system, a tank for containing an aerosol precursor, and a heater for heating the aerosol precursor. The aerosol delivery device comprises a controller configured to determine a plurality of resistance values of the heater, wherein each of the plurality of resistance values is determined based on a reference resistance of a sense resistor, a measured voltage at a first point between the sense resistor and the heater, and a constant voltage at a second point located at an opposite side of the sense resistor to the first point. The controller is further configured to determine a rate of change of resistance of the heater based on the plurality of resistance values of the heater, and to detect a low liquid level of the aerosol precursor in the tank based on the rate of change of resistance of the heater. An aerosol delivery system comprising the aerosol delivery device as well as a method for detecting a low liquid level of aerosol precursor in an aerosol delivery system are also described. A computer program configured to cause an aerosol delivery system to perform the method for detecting a low liquid level of aerosol precursor is also provided.