Reduced Toxicity Pyrotechnic Strobe Composition

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Solution Overview

Problem

Conventional pyrotechnic strobe compositions are toxic and environmentally unfriendly due to the use of potassium dichromate and perchlorate oxidizers, and they struggle to produce a slow pulse rate of one pulse per second, which is difficult to achieve with their fast reaction kinetics.

Innovation Solution

A reduced toxicity pyrotechnic strobe composition is developed using strontium nitrate, a 50:50 blend of magnesium and aluminum (magnalium), and sulfur, with a nitrocellulose binder, allowing for a pulse rate of approximately one pulse per minute, and can be modified by varying particle size and substituting strontium nitrate with potassium nitrate, and is loaded into canisters at specific pressures for use in various pyrotechnic devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional pyrotechnic strobe composition (magnesium, ammonium perchlorate, potassium sulfate, potassium dichromate) is used, then distinct dark and light phases are produced, but the reaction rate is too fast to achieve one pulse per second and the composition is highly toxic

Engineering Contradiction:

Improvereaction rateVSAvoidtoxicity

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical parameters by substituting ammonium perchlorate with potassium nitrate and potassium dichromate with strontium nitrate. This parameter change achieves two objectives: it reduces the reaction rate to enable one pulse per second strobe effect, and it eliminates highly toxic materials while maintaining strobe performance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces expensive and toxic potassium dichromate with strontium nitrate, which is less toxic and more environmentally friendly. This substitution maintains the protective coating function on magnesium particles without the harmful effects of dichromate

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Illumination intensity

If sulfate is added to enhance burning characteristics and form crust layer, then strobe intensity is improved, but reaction rate increases making slow strobe difficult to achieve

Engineering Contradiction:

Improvestrobe intensityVSAvoidreaction rate

Core Design Contradiction:

Illumination intensityVSSpeed

Solution Approach 1:

The patent changes the oxidizer parameter from ammonium perchlorate/sulfate-based systems to potassium nitrate/strontium nitrate-based system. This parameter change allows the formation of crust layer and maintains strobe intensity while controlling the reaction rate to achieve one pulse per second

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite composition of strontium nitrate, magnalium (magnesium-aluminum alloy), and sulfur. This composite material system provides both the necessary burning characteristics for intense strobe effect and the controlled reaction rate for slow pulse operation

Inventive Principle:

Principle #40Composite materials

3Reliability

If potassium dichromate is used to coat magnesium particles, then degradation is prevented, but environmental harm and human toxicity increase

Engineering Contradiction:

Improvestability of magnesium particlesVSAvoidenvironmental toxicity

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces toxic potassium dichromate coating with strontium nitrate coating on magnesium particles. This substitution maintains the protective function preventing degradation while eliminating the environmental and health hazards associated with dichromate

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent converts the harmful toxic coating material into a beneficial non-toxic alternative. Strontium nitrate provides the same protective coating function while being environmentally friendly and safe for human exposure

Inventive Principle:

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

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 composition achieves a slow and bright strobe effect without toxic perchlorates or dichromates, is more environmentally friendly, and can be used in flares, grenades, smoke pots, and artillery rounds, providing a two-order-of-magnitude slower pulse rate than conventional solutions.

Implementation Method 1

The chemical reaction in the conventional mixtures proceed much faster than that of the slow strobe

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 2

The burning characteristics of the fuel/oxidizer mixture cause the formation of a crust on the surface layer

Methodology Applied

Scientific EffectExothermic Reaction: Exothermic Reaction

Data Source

PatentUS10913692B1Extremely slow pyrotechnic strobe composition with reduced toxicity

Publication Date: 2021.02.09 AMERICA AS REPRESENTED BY THE SEC OF THE ARMY

AI summary

A reduced toxicity pyrotechnic strobe composition and method includes creating a mixture of strontium nitrate, magnalium, sulfur, and no more than 10 parts by weight of a nitrocellulose binder. The strontium nitrate may comprise 27 percent of the mixture. The magnalium may comprise a 50:50 blend of magnesium and aluminum. The magnalium may comprise 18 percent of the mixture. The sulfur may comprise 55 percent of the mixture. The mixture may include a pulse rate of approximately one pulse per minute. The method may further include modifying the pulse rate of the mixture. The method may further include using a reduced particle size of the magnalium. The method may further include substituting no more than 12.5% of the strontium nitrate with potassium nitrate.