Recoilless Weapon Cooling Device Gas-Driven Reservoir

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Solution Overview

Problem

Hand-held recoilless bazooka-type weapons generate high sound pressure levels due to combustion gas expansion, impairing the firer's capability and causing damage, especially in tight spaces, and existing cooling solutions only cool gases during the initial combustion phase.

Innovation Solution

A cooling device with a coolant reservoir integrated into the rocket motor, connected to the combustion chamber and nozzle, allows controlled coolant transfer throughout the combustion process via gas inlets and outlets, regulated by a gas-driven piston and rupture discs, ensuring continuous cooling of combustion gases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a reservoir containing coolant is arranged behind the propellent powder charge in the barrel with explosive opening, then cooling of combustion gases is achieved during the first part of the combustion process, but further cooling during the later part of the combustion process is not possible

Engineering Contradiction:

Improvecombustion gas temperatureVSAvoidcooling duration

Core Design Contradiction:

TemperatureVSDuration of action of moving object

Solution Approach 1:

The cooling system is divided into multiple independent coolant reservoirs positioned at different locations in the barrel, each equipped with its own rupture disc. This segmentation allows different parts of the combustion process to be cooled at different times - the first reservoir cools initial combustion gases while the second reservoir cools later combustion gases, thereby extending the total cooling duration throughout the entire combustion process.

Inventive Principle:

Principle #1Segmentation

2Temperature

If coolant is transferred instantaneously to combustion gases, then rapid cooling is achieved, but controlled cooling throughout the whole combustion process cannot be implemented

Engineering Contradiction:

Improvecombustion gas temperatureVSAvoidcooling control

Core Design Contradiction:

TemperatureVSAdaptability or versatility

Solution Approach 1:

Different locations in the barrel are equipped with coolant reservoirs having different rupture disc pressure thresholds. The first reservoir (behind the charge) has a lower pressure threshold and ruptures earlier, providing cooling during initial combustion. The second reservoir (in the forward part of the barrel) has a higher pressure threshold and ruptures later, providing cooling during later combustion phases. This creates localized cooling zones adapted to different stages of the combustion process.

Inventive Principle:

Principle #3Local quality

3Temperature

If multiple separate components are used for cooling, then controlled cooling is possible, but device complexity increases

Engineering Contradiction:

Improvecombustion gas temperatureVSAvoidcooling device structure

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

Multiple coolant reservoirs are integrated into a single unified cooling device structure. The reservoirs are positioned at different locations along the barrel but are combined into one coherent assembly with coordinated rupture discs and coolant delivery systems. This merging approach maintains the benefits of multi-stage controlled cooling while reducing overall device complexity compared to completely separate cooling systems.

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 reduces sound pressure levels by maintaining controlled cooling throughout the combustion process, allowing for a safer firing distance and weight reduction in the weapon, as the coolant can be adapted and mixed optimally with combustion gases.

Implementation Method 1

A pressure increase in the barrel caused by the propellent powder charge leads to an explosive opening of the coolant reservoir

Methodology Applied

Scientific EffectPressure increase: Pressure Increase

Implementation Method 2

the propellent powder charge

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 3

One way of reducing the sound pressure is to cool the combustion gases

Methodology Applied

Scientific EffectCooling: Cooling

Implementation Method 4

the coolant, usually water, mixes with the combustion gases

Methodology Applied

Scientific EffectMixing:

Implementation Method 5

connected by at least two gas inlets to a combustion chamber arranged in the rocket motor, for pressurization of the coolant, and by at least two coolant outlets to a rocket motor nozzle

Methodology Applied

Scientific EffectPressure-driven flow: Pressure Gradient

Data Source

PatentUS9291410B2Cooling device for cooling combustion gases from recoilless anti-tank weapons

Publication Date: 2016.03.22 SAAB AB

AI summary

The present invention relates to a cooling device (2) for cooling combustion gases from a rocket motor (1) in an antitank weapon. The cooling device (2) comprises a coolant reservoir (3, 21) containing a coolant (4). The coolant reservoir (3, 21) is arranged such that the coolant (4) is transferred from the coolant reservoir (3, 21) to the combustion gases in the gas outlets (6) of the rocket motor (1) in response to a pressure increase in the rocket motor (1). The coolant reservoir (3, 21) constitutes an integral part of the rocket motor (1) and is connected to the combustion chamber (7) by at least two gas inlets (8) for pressurization of the coolant (4). The coolant reservoir is furthermore connected to the rocket motor nozzle (9) by at least two coolant outlets (10) for transfer of coolant (4) from the coolant reservoir (3, 21) to the rocket motor nozzle (9).