Soft Magnetic Susceptor Assembly for Curie-Limited Aerosol Heating
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Solution Overview
Problem
Existing aerosol generation devices in heat-not-burn tobacco products face challenges in achieving efficient and safe heating without combustion, as the susceptor materials used in these devices can exceed 400°C, leading to harmful component release and combustion risks due to insufficient or excessive heating.
Innovation Solution
A susceptor assembly made of a soft magnetic alloy with a single-layer structure, composed of specific elements like iron, molybdenum, nickel, and optionally chromium, manganese, silicon, and aluminum, is used to induce heating. This alloy has controlled grain size and composition to ensure rapid temperature rise and ferromagnetic-paramagnetic transition before reaching 400°C, preventing overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the susceptor material is designed to maintain high magnetothermal conversion ability and Curie temperature to achieve rapid temperature rise in preheating stage, then heating efficiency is improved, but the temperature may exceed 400°C causing harmful component release and combustion risk
Solution Approach 1:
The patent applies parameter changes by precisely controlling the Curie temperature of the susceptor material through alloy composition design (Fe-Ni-Mo system with specific ratios) and grain size control (50-70 μm). By adjusting these parameters, the material achieves optimal heating efficiency while ensuring temperature remains below 400°C, preventing harmful component release and combustion risks.
Solution Approach 2:
The patent uses composite materials by developing a specialized Fe-Ni-Mo soft magnetic alloy with controlled composition ratios (Fe: 60-70%, Ni: 25-35%, Mo: 0.5-2%). This composite alloy structure provides both high magnetothermal conversion ability for efficient heating and a Curie temperature that prevents overheating, thus resolving the contradiction between heating efficiency and safety.
2Speed
If the susceptor material is designed with high magnetothermal conversion ability to maintain rapid temperature rise, then preheating performance is improved, but the material may lose magnetism above Curie point causing temperature control instability
Solution Approach 1:
The patent applies parameter changes by optimizing the Curie temperature through alloy composition and grain size control. The Curie temperature is set to a specific range that ensures rapid temperature rise during preheating while maintaining magnetism below 400°C. This parameter optimization allows the material to achieve both fast heating and stable temperature control, preventing the loss of magnetism that would cause temperature control instability.
3Reliability
If the susceptor material uses traditional multilayer structure to achieve desired magnetic properties, then magnetic performance is improved, but manufacturing complexity and element distribution uniformity deteriorate
Solution Approach 1:
The patent applies segmentation by dividing the susceptor material into a single-layer structure with controlled grain size (50-70 μm) rather than using traditional multilayer structures. This segmentation approach simplifies manufacturing while maintaining magnetic performance, as the single layer with controlled grain size achieves the desired magnetic properties without the complexity of multiple layers and their associated manufacturing challenges.
Solution Approach 2:
The patent applies homogeneity by ensuring uniform element distribution within the single-layer susceptor structure. The Fe-Ni-Mo alloy is designed with controlled composition ratios and uniform grain size distribution, creating a homogeneous material that simplifies manufacturing while maintaining consistent magnetic performance throughout the susceptor, thereby reducing manufacturing complexity.
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 provides effective non-contact heating with automatic temperature control, reducing the risk of harmful substance release and combustion, enhancing user safety and satisfaction by maintaining the susceptor's magnetic properties within a safe temperature range.
Implementation Method 1
The Magnetic Coupling Resonance Wireless Power Transfer (MCR-WPT) system offers excellent energy conversion efficiency and non-contact heating, making it capable of efficiently heating tobacco products
Implementation Method 2
the susceptor assembly is made of a soft magnetic alloy... the susceptor assembly inductively heats the aerosol generation substrate under the influence of an alternating magnetic field
Implementation Method 3
the material of the susceptor is expected to have the appropriate high-frequency permeability, resistivity and material size to match the specific coil parameters... maintain the resonance state in the basic constant temperature stage
Implementation Method 4
during the preheating stage, the temperature of the core materials can continuously rise to the Curie point, after which the core materials lose their magnetism and cool down because they can no longer absorb energy from the external magnetic field
Data Source
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AI summary
The application discloses an aerosol generating product, including an aerosol generation substrate segment, the substrate segment includes an aerosol generation substrate and a susceptor assembly; the susceptor assembly inductively heats the aerosol generation substrate under the influence of an alternating magnetic field, and the susceptor assembly is made of a soft magnetic alloy, and the soft magnetic alloy has a single layer with an uniform distribution of elements; the soft magnetic alloy has an average grain size of 50-70 µm, and a grain size number of 5.5-4.5. This micro-structured susceptor assembly meets the requirements for aerosol generator susceptor regarding magnetic properties and Curie temperature, ensuring that the temperature rises rapidly in the preheating stage, and ferromagnetic-paramagnetic transition occurs before reaching 400°C and completely loses its magnetism. It can be used in the field of heated cigarettes using an electromagnetic heating process with automatic temperature control based on the non-contact radio transmission concept, considerably lowering the risk of heating cigarettes in this mode.