Solid-Fuel Heating Unit for Sub-Second Drug Vaporization
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Solution Overview
Problem
There is a need for a device capable of rapid heat production, achieving temperatures within seconds and fractions of seconds, suitable for use in articles intended for human use, as existing self-heating methods are slow and inefficient, particularly in small portable devices.
Innovation Solution
A self-contained heating unit with a thin layer of solid fuel, typically comprising a metal reducing agent and a metal-containing oxidizing agent, disposed on a thermally conductive substrate, which undergoes an exothermic oxidation-reduction reaction to rapidly heat the substrate surface to temperatures above 200°C, facilitated by an igniter system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ohmic heating is used in small portable devices, then precise control of energy applied is achieved, but heating time is delayed by seconds or minutes and device size becomes bulky
Solution Approach 1:
The patent changes the heating mechanism from ohmic heating to combustion of a solid fuel composition. This parameter change enables rapid heating (achieving maximum temperature in less than 1 second) while maintaining precise control through the design of the fuel composition and combustion chamber. The solid fuel composition includes specific ratios of metal powder, oxidizer, and binder that control the combustion rate and temperature profile.
Solution Approach 2:
The patent extracts the heating function from a bulky battery-powered ohmic heating system to a compact solid fuel combustion system. By removing the battery and electrical components, the device achieves rapid heating without the time delays and bulk associated with ohmic heating, while the solid fuel composition provides the necessary energy density in a compact form.
2Temperature
If exothermic chemical reaction is used for heating, then heat production is mild and suitable for food and drink, but heating speed is slow and cannot achieve rapid temperature increase
Solution Approach 1:
The patent changes the chemical reaction type from mild exothermic reactions (suitable for food heating) to controlled combustion reactions. The solid fuel composition uses metal powder (e.g., aluminum, magnesium) combined with oxidizers (e.g., potassium perchlorate, ammonium nitrate) in specific ratios to achieve rapid combustion that produces high temperatures (exceeding 200°C) within less than 1 second, while the thin layer application controls the overall heat output.
Solution Approach 2:
The patent applies partial action by using a thin layer (0.001 to 0.030 inches) of solid fuel composition on the substrate. This thin layer provides sufficient heat for rapid heating applications without producing excessive temperatures that would be harmful, achieving the right balance between heating speed and temperature control for drug vaporization.
3Speed
If thin layer of solid fuel is used, then rapid heating is achieved within 1 second, but uniformity of temperature across substrate surface becomes challenging
Solution Approach 1:
The patent applies local quality by designing the solid fuel composition and substrate interaction to ensure uniform heat distribution. The fuel composition is applied as a thin, relatively uniform layer across the substrate surface, and the combustion propagates evenly through this layer, providing consistent temperatures across the heated area. The substrate material and thickness are also optimized to distribute heat uniformly.
Solution Approach 2:
The patent uses a thin layer of solid fuel (0.001 to 0.030 inches) that provides just enough fuel for rapid heating without creating excessive temperatures or uneven heat distribution. This controlled amount of fuel ensures complete combustion across the substrate surface within less than 1 second, achieving both rapid heating and temperature uniformity.
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 heating unit achieves rapid and uniform temperature increase across the substrate surface, with 90% of the area reaching the desired temperature within 1 second of ignition, suitable for applications such as drug vaporization in medical devices.
Implementation Method 1
A self-contained heating unit with a thin layer of solid fuel, typically comprising a metal reducing agent and a metal-containing oxidizing agent, disposed on a thermally conductive substrate, which undergoes an exothermic oxidation-reduction reaction to rapidly heat the substrate surface to temperatures above 200°C
Implementation Method 2
A self-contained heating unit with a thin layer of solid fuel, typically comprising a metal reducing agent and a metal-containing oxidizing agent, disposed on a thermally conductive substrate, which undergoes an exothermic oxidation-reduction reaction to rapidly heat the substrate surface to temperatures above 200°C
Data Source
AI summary
Heating units, drug supply units and drug delivery articles capable of rapid heating are disclosed. Heating units comprising a substrate and a solid fuel capable of undergoing an exothermic metal oxidation reaction disposed within the substrate are disclosed. These heating units can be actuated by electrical resistance, by optical ignition or by percussion. Drug supply units and drug delivery articles wherein a solid fuel is configured to heat a substrate to a temperature sufficient to rapidly thermally vaporize a drug disposed thereon are also disclosed.