Heat units using a solid fuel capable of undergoing an exothermic metal oxidation-reduction reaction propagated without an igniter

Solution Overview

Problem

Heat units using solid fuels for exothermic metal oxidation-reduction reactions require igniters, which increase complexity, cost, and safety risks, while also limiting the design and reliability of self-contained heating devices.

Innovation Solution

A heating unit design that employs a solid fuel layer with a metal reducing agent and oxidizing agent coated on a conductive substrate, where a voltage is applied between the substrate and the solid fuel surface to initiate and propagate the exothermic reaction without the need for an igniter, using electrodes connected to a power supply.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an igniter system is used to initiate the exothermic metal oxidation-reduction reaction, then the heating unit can be activated, but the device complexity, manufacturing cost, and safety risks increase

Engineering Contradiction:

Improveactivation reliabilityVSAvoidigniter system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the igniter system entirely from the heating unit design. Instead of using an igniter to initiate the exothermic reaction, the invention relies on the spontaneous reaction between the metal reducing agent and metal containing oxidizing agent when brought into contact, eliminating the need for separate ignition components and thereby reducing device complexity while maintaining activation reliability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The heating unit is designed to activate automatically through the self-contained chemical reaction between the metal reducing agent and metal containing oxidizing agent. The system serves itself by utilizing the inherent reactivity of the solid fuel components without requiring external ignition assistance, thus eliminating the igniter system and reducing overall device complexity

Inventive Principle:

Principle #25Self-service

2Reliability

If an igniter system is used to initiate the exothermic metal oxidation-reduction reaction, then the heating unit can be activated, but the manufacturing cost increases

Engineering Contradiction:

Improveactivation reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent removes the igniter system entirely from the heating unit design. Instead of using an igniter to initiate the exothermic reaction, the invention relies on the spontaneous reaction between the metal reducing agent and metal containing oxidizing agent when brought into contact, eliminating the need for separate ignition components and thereby reducing device complexity while maintaining activation reliability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses simple, inexpensive solid fuel components (metal reducing agent and metal containing oxidizing agent) that can be directly applied to the substrate without requiring expensive igniter components. This approach reduces manufacturing costs by substituting complex, costly igniter systems with simple, inexpensive reactive materials

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If an igniter system is used to initiate the exothermic metal oxidation-reduction reaction, then the heating unit can be activated, but the safety risks increase

Engineering Contradiction:

Improveactivation reliabilityVSAvoidsafety risks

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes the igniter system entirely from the heating unit design. Instead of using an igniter to initiate the exothermic reaction, the invention relies on the spontaneous reaction between the metal reducing agent and metal containing oxidizing agent when brought into contact, eliminating the need for separate ignition components and thereby reducing device complexity while maintaining activation reliability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention converts the potentially harmful aspect of requiring high-energy ignition sources into a benefit by using the controlled spontaneous reaction of the solid fuel components. The metal reducing agent and metal containing oxidizing agent react safely and predictably when brought into contact, eliminating the safety risks associated with igniters while maintaining reliable activation

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Reliability

If an igniter system is used to initiate the exothermic metal oxidation-reduction reaction, then the heating unit can be activated, but the number of components and manufacturing processing steps increase

Engineering Contradiction:

Improveactivation reliabilityVSAvoidnumber of components

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the igniter system entirely from the heating unit design. Instead of using an igniter to initiate the exothermic reaction, the invention relies on the spontaneous reaction between the metal reducing agent and metal containing oxidizing agent when brought into contact, eliminating the need for separate ignition components and thereby reducing device complexity while maintaining activation reliability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the activation function into the solid fuel components themselves. The metal reducing agent and metal containing oxidizing agent are designed to react spontaneously when brought into contact, combining the fuel, oxidizer, and ignition function into a single integrated system, thereby reducing the number of separate components needed

Inventive Principle:

Principle #5Merging (Combining)

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 simplifies the manufacturing process, reduces costs, enhances safety by eliminating ignition components, and improves the reliability and efficiency of heat units, enabling rapid and controlled heating for applications like drug delivery devices.

Implementation Method 1

a solid fuel layer comprising a metal reducing agent, a metal containing oxidizing agent and a binder is coated on a surface of the substrate... the voltage (and a small amount of current) acts to propagate an exothermic metal oxidation-reduction reaction

Methodology Applied

Scientific EffectOxidation-reduction reaction: Redox Reactions

Implementation Method 2

the solid fuel to heat the substrate to several hundred degrees Celsius very rapidly, i.e., on the order of seconds and fractions of seconds

Methodology Applied

Scientific EffectExothermic reaction: Exothermic Reaction

Data Source

PatentUS11839714B2Heat units using a solid fuel capable of undergoing an exothermic metal oxidation-reduction reaction propagated without an igniter

Publication Date: 2023.12.12 ALEXZA PHARMACEUTICALS INC

AI summary

A heating unit comprising an electrically conductive substrate. A solid fuel layer comprising a metal reducing agent, a metal containing oxidizing agent and a binder is coated on a surface of the substrate, the solid fuel layer having a solid fuel surface spaced from the substrate. A first electrode coupled to the substrate. A second electrode coupled to the solid fuel surface. A power supply is configured to be selectively coupled to the first and second electrodes to provide a voltage between the metallic substrate and the solid fuel surface. The voltage acts to propagate an exothermic metal oxidation-reduction reaction without the use of an igniter.