Inductive Heating Assembly with Dual Susceptor for Aerosol Substrate
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Solution Overview
Problem
Existing inductive heating assemblies for aerosol-forming substrates face challenges in accurately controlling temperature, as the change in electrical current due to the Curie temperature of the susceptor material can be misinterpreted as a user's puff, leading to undesired overheating.
Innovation Solution
An inductive heating assembly with a susceptor assembly comprising a first susceptor for heating and a second susceptor with a Curie temperature at least 20°C below the operating temperature, utilizing materials like mu-metal or permalloy, to create a significant temperature gap and ensure reliable temperature control by monitoring the resistance profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the Curie temperature of the susceptor material is used as a temperature marker for controlling heating temperature, then temperature control is improved, but the system may erroneously interpret current changes during user puffs as Curie temperature events, causing overheating
Solution Approach 1:
The susceptor assembly is segmented into two distinct susceptors: a first susceptor optimized for heating efficiency and a second susceptor with a specific Curie temperature serving as a temperature marker. This segmentation allows the temperature monitoring function to be separated from the heating function, enabling more reliable temperature control by using the second susceptor's Curie temperature event as a distinct signal that can be differentiated from normal operational variations during user puffs.
2Loss of time
If the Curie temperature is set close to the operating temperature for efficient control, then response time is improved, but the distinction between Curie temperature events and user puff events becomes difficult
Solution Approach 1:
The second susceptor is designed with specific local properties (Curie temperature at least 20°C below operating temperature) that differ from the first susceptor. This local quality difference creates a distinct, identifiable signal when the second susceptor reaches its Curie temperature, allowing the control system to reliably distinguish this temperature marker event from the electrical current changes that occur during normal user puffs, thereby improving event detection 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
This solution allows for precise temperature control of the aerosol-forming substrate, preventing overheating by distinguishing the Curie temperature change from a user's puff, ensuring accurate and stable heating.
Implementation Method 1
The induction source is configured for generating an alternating electromagnetic field that induces at least one of heat generating eddy currents or hysteresis losses in the susceptor
Implementation Method 2
The induction source is configured for generating an alternating electromagnetic field that induces at least one of heat generating eddy currents or hysteresis losses in the susceptor
Implementation Method 3
The induction source is configured for generating an alternating electromagnetic field that induces at least one of heat generating eddy currents or hysteresis losses in the susceptor
Implementation Method 4
inductive heating assembly for inductive heating of an aerosol-forming substrate
Implementation Method 5
the second susceptor material is chosen such as to have a Curie temperature corresponding to a predefined operating temperature of the susceptor assembly. At its Curie temperature, the magnetic properties of the second susceptor change from ferromagnetic or ferrimagnetic to paramagnetic, accompanied by a temporary change of its electrical resistance
Data Source
AI summary
An inductive heating assembly is configured to inductively heat an aerosol-forming substrate to a pre-determined operating temperature, the heating assembly including an induction source configured to generate an alternating electromagnetic field; and a susceptor assembly configured to inductively heat the aerosol-forming substrate under influence of the alternating magnetic field generated by the induction source, the susceptor assembly including a first susceptor including a first susceptor material and a second susceptor including a second susceptor material having a Curie temperature at least 50 degrees Celsius below an operating temperature of the heating assembly. An aerosol-generating device and an aerosol-generating system include the inductive heating assembly.