Cartridge Ammunition Pressure Chamber Segmentation
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Solution Overview
Problem
Conventional subsonic cartridge ammunition suffers from incomplete combustion of propellant charges, leading to inconsistent propellant gas pressures and muzzle velocities, which results in inaccurate firing and potential damage to weapons due to high pressure peaks.
Innovation Solution
The design incorporates a high-pressure chamber centrally located within the cartridge case, surrounded by an intermediate pressure chamber with annular configuration, and a low-pressure chamber, featuring venting holes and rupturable burst membranes to control and attenuate pressure peaks, ensuring efficient combustion and consistent gas pressure release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a dual chamber propulsion system is used, then propellant combustion efficiency is improved, but combustion consistency deteriorates
Solution Approach 1:
The propulsion system is divided into a high-pressure chamber and a low-pressure chamber with distinct functions. The high-pressure chamber ensures complete and consistent combustion of the propellant charge, while the low-pressure chamber provides a controlled expansion environment. This segmentation resolves the contradiction by allowing each chamber to optimize its specific function rather than attempting to perform both combustion and expansion in a single chamber.
Solution Approach 2:
A diaphragm separates the high-pressure and low-pressure chambers, acting as an intermediary element. The diaphragm allows propellant gases to pass from the high-pressure to the low-pressure chamber while maintaining pressure differential control. This intermediary structure enables consistent combustion in the high-pressure chamber while providing controlled expansion in the low-pressure chamber, thereby resolving the combustion consistency issue.
2Speed
If internal free volume in cartridge case is increased, then projectile acceleration is improved, but pressure peak attenuation deteriorates
Solution Approach 1:
The cartridge case internal volume is segmented into a high-pressure chamber with smaller volume for combustion and a low-pressure chamber with larger volume for expansion. This segmentation allows the combustion chamber to maintain high pressure peaks for efficient propellant combustion while the expansion chamber provides pressure attenuation, resolving the contradiction between projectile acceleration and pressure peak control.
Solution Approach 2:
Different regions of the cartridge case are assigned different pressure characteristics. The high-pressure chamber near the propellant charge is designed for high pressure and complete combustion, while the low-pressure chamber toward the projectile is designed for pressure attenuation and controlled expansion. This local differentiation of pressure qualities allows simultaneous optimization of both projectile acceleration and weapon chamber safety.
3Length of moving object
If propellant charge is increased for extended range, then firing range is improved, but weapon chamber pressure safety deteriorates
Solution Approach 1:
The propulsion system segments the pressure management function, allowing a larger propellant charge to be used in the high-pressure chamber for extended range while the low-pressure chamber provides pressure attenuation. This segmentation enables increased propellant quantity without proportionally increasing weapon chamber pressure peaks, thereby improving firing range while maintaining safety.
Solution Approach 2:
The diaphragm and chamber configuration act as intermediaries that decouple the propellant charge size from the weapon chamber pressure peaks. By allowing combustion to occur in a contained high-pressure chamber and then expanding into a larger low-pressure chamber, the system can accommodate larger propellant charges for extended range while the intermediary structures prevent excessive pressure transmission to the weapon chamber.
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 configuration ensures almost complete combustion of propellant charges, providing consistent muzzle velocities, reducing thermal and acoustic signatures, and preventing high pressure peaks from reaching the weapon chamber, thus enhancing safety and accuracy.
Implementation Method 1
The cartridge includes a high pressure chamber for holding a propellant charge, a low pressure chamber surrounding the high pressure chamber and having a larger volume than the high pressure chamber. The high pressure chamber has at least one vent hole extending therethrough from an open end of the high pressure chamber to the low pressure chamber.
Implementation Method 2
The low pressure chamber has a volume which is larger than a volume of the high pressure chamber when the ammunition is in the fired state. The cartridge further includes a propelling charge for generating propellant gases upon combustion.
Data Source
Figure 1~2
Figure 3~5
Figure 6
AI summary
Cartridge ammunition (10) including a projectile (12) and a cartridge case (14). The cartridge includes a primer chamber (26) located adjacent a base wall (24) for holding a primer (28), a high pressure chamber (30) for holding a propellant charge (32), an intermediate pressure chamber (34) which surrounds the high pressure chamber, for receiving expanding propellant gases from the high pressure chamber and a low pressure chamber (36) at a rear end of the projectile for receiving expanding propellant gases from the intermediate pressure chamber. The pressure chambers are delimited by walls defining venting hole through which expanding gases can flow. The three pressure chambers provide for controlled release of gas pressure resulting in attenuation of peak gas pressures within the cartridge.