Pyrotechnical Retarding Element Temperature-Stable Delay
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current pyrotechnic delay sets in military applications contain SVHC substances and exhibit significant temperature variation in burning time, necessitating a more precise and stable delay mechanism that is independent of ambient temperature and pressure.
Innovation Solution
A pyrotechnic delay element comprising a metal sleeve with specific weight ratios of boron, iron(III) oxide, potassium perchlorate, titanium(IV) oxide, tungsten, and aluminum, along with a binder, allowing adjustable delay times from 0.5 to 5 seconds within a fixed geometry, maintaining stability across -54°C to +71°C and ensuring long-term reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pyrotechnic delay compositions (e.g., potassium perchlorate, lead chromate, antimony) are used, then the delay element can be manufactured with standard materials, but the burning time exhibits significant temperature variation (10-20% in the range -54°C to +71°C) and contains SVHC substances
Solution Approach 1:
The patent changes the chemical composition parameters of the delay element by replacing conventional oxidizers (potassium perchlorate) with alternative oxidizers (sodium perchlorate, calcium perchlorate, or ammonium perchlorate) and replacing lead chromate with alternative pigments (red iron oxide, yellow iron oxide, or titanium dioxide). This parameter change reduces temperature dependence of burning time to less than 10% and eliminates SVHC substances while maintaining the delay function
Solution Approach 2:
The patent uses composite material systems combining alternative oxidizers (sodium perchlorate, calcium perchlorate, or ammonium perchlorate) with fuel components (aluminum powder, magnesium powder, or titanium powder) and alternative pigments (red iron oxide, yellow iron oxide, or titanium dioxide). These composite materials provide both the delay function and improved temperature stability while eliminating harmful substances
2Manufacturing precision
If the delay time is adjusted by fine-tuning the charge composition, then the delay time can be controlled precisely, but the composition must be precisely formulated and manufactured
Solution Approach 1:
The patent simplifies the composition formulation by using alternative oxidizers and pigments that provide more stable and predictable burning characteristics. The defined weight ratio ranges (oxidizer 40-80%, fuel 10-30%, pigment 5-20%) provide manufacturing flexibility while ensuring consistent delay times, reducing the complexity of precise formulation
3Reliability
If the burning rate is made independent of external pressure, then the delay time remains stable under varying pressure conditions, but the composition requires special formulation
Solution Approach 1:
The patent formulates composite materials using alternative oxidizers (sodium perchlorate, calcium perchlorate, or ammonium perchlorate) combined with metal powders (aluminum, magnesium, or titanium) that provide pressure-independent burning characteristics. These composite systems naturally resist pressure effects without requiring complex additional formulation steps
Solution Approach 2:
The patent changes the chemical parameters by selecting oxidizers and fuels with complementary combustion properties that cancel out pressure effects. The specific weight ratio ranges provided in the patent enable straightforward manufacturing while achieving pressure independence
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 achieves a delay time adjustment with minimal temperature and pressure dependence, exceeding 99% reliability and extending service life beyond 12 years, while reducing temperature response impact to 8% compared to previous systems.
Implementation Method 1
The pyrotechnic reaction thus proceeds linearly through the ignition delay. All compositions are inserted into the metal body by one- or multi-stage loading and pressing processes.
Implementation Method 2
A pyrotechnic delay element is disclosed in EP 0847972 A1. Among other things, the delay element can consist of black powder, silicon, iron(III) oxide and a binder.
Data Source
Figure 1~2
AI summary
The invention relates to a pyrotechnical retarding element for use in pyrotechnical igniter trains, said retarding element containing a lighting charge mixture, a retarding charge mixture and a firing charge mixture; the lighting charge mixture and the firing charge mixture contain at least 40 percent by weight boron, at least 20 percent by weight iron(III) oxide, and at least 5 percent by weight potassium perchlorate, the percentages adding up to 100 wt% in each mixture, and the retarding charge mixture contains at least 5 percent by weight potassium perchlorate, at least 10 percent by weight titanium(IV) oxide, at least 30 percent by weight tungsten, and at least 2 percent by weight aluminum.