Method of forming heating elements that are coupled together to a voltage source
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Solution Overview
Problem
Existing smoking articles with resistance heating elements indirectly heat tobacco material, leading to inefficient heating and potential overheating due to indirect contact.
Innovation Solution
A heater with a plurality of elongate heating elements arranged in an elongate array, where the middle portion has a greater dimension than the support and heating ends, allowing direct contact with the aerosol-forming substrate for efficient heating, and includes an external heating element for additional temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a resistance heating element is used to heat tobacco material indirectly via air, then the heating process is simpler to implement, but the heating efficiency decreases and the device may overheat
Solution Approach 1:
The patent introduces air as an intermediary medium to transfer heat from the heating element to the tobacco material. The heating element heats the air, and the heated air then contacts the tobacco material to transfer thermal energy, solving the contradiction by maintaining manufacturing simplicity while improving heating efficiency through the intermediary air flow.
Solution Approach 2:
The patent utilizes pneumatic flow of air to enhance heat transfer. By controlling air flow through the heating element and over the tobacco material, the system achieves efficient indirect heating without direct contact between the heating element and tobacco, resolving the contradiction between manufacturing ease and heating efficiency.
2Ease of manufacture
If a resistance heating element is used to heat tobacco material indirectly via air, then the heating process is simpler to implement, but the device temperature becomes uncontrolled and may overheat
Solution Approach 1:
The patent incorporates temperature sensing and control mechanisms that monitor the temperature of the heating element and adjust power delivery accordingly. This feedback system prevents overheating while maintaining the simple indirect heating structure, resolving the contradiction between manufacturing simplicity and temperature control.
Solution Approach 2:
The air flow acts as a thermal intermediary that absorbs and distributes heat away from the heating element, preventing excessive temperature buildup. This intermediary mechanism provides passive temperature regulation while maintaining the simplicity of the indirect heating design.
3Productivity
If heating elements are arranged in an elongate array with expanded middle portion, then direct contact with substrate improves heating efficiency, but the device complexity increases
Solution Approach 1:
The heating elements are formed with a curved or elongate array configuration where the middle portion has a larger dimension than the ends. This curved geometry enables the heating elements to conform to the substrate surface, maximizing contact area and heating efficiency while maintaining a relatively simple single-piece construction.
Solution Approach 2:
The patent varies the dimensional parameters of the heating elements along their length, with the middle portion having a larger cross-sectional dimension than the support and heating ends. This parameter change optimizes the contact pressure and surface area for efficient heat transfer while keeping the overall structure manageable.
4Force
If the middle portion of the heating element array has greater dimension, then the heating elements are pressed towards each other to exert force on substrate, but manufacturing precision requirements increase
Solution Approach 1:
The heating elements are pre-formed with the elongate array configuration and dimensional variations built into the structure during manufacturing. This preliminary action ensures that when the heating elements are installed, they automatically exert the necessary contact force on the substrate without requiring precise adjustment during assembly, reducing manufacturing precision requirements.
Solution Approach 2:
The patent incorporates dimensional variations along the length of the heating elements as a design feature rather than a precision requirement. The larger middle portion dimension is intentionally designed to create the desired contact force, transforming a potential precision challenge into a robust design feature that tolerates manufacturing variations.
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 direct contact with the substrate enhances heating efficiency, reduces the need for high temperatures and power, and minimizes the risk of overheating, while ensuring robustness and effective condensate removal.
Implementation Method 1
a plurality of elongate heating elements arranged in an elongate array... all the heating elements are connectable to one of the first and second voltages at the support end and all the heating elements are connectable to the other of the first and second voltages at the heating end
Data Source
AI summary
A heater for heating an aerosol-forming substrate includes a plurality of elongate heating elements arranged in an elongate array. The elongate array has a support end with a first dimension, a heating end with a second dimension and a middle portion with a third dimension. The array is arranged to heat the substrate to form an aerosol. The third dimension is greater than the first dimension and greater than the second dimension. An electrically heated aerosol generating system can include the heater.