Pressurized Material Dispensing Device Piston Retention
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Solution Overview
Problem
Devices for delivering pressurized materials using pyrotechnic gas generators face issues with piston damage due to thermal expansion and vibrations, which can compromise safety and reliability by causing the piston to impact the gas generator and reduce sealing effectiveness.
Innovation Solution
A holding element is introduced that axially connects to the piston and the device's bottom, maintaining piston position during storage and transport but releasing it when the gas generator is triggered, ensuring the piston can move freely under the force of pressurized gases, with a holding force calibrated to withstand shocks and vibrations while being lower than the gas-generated force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the piston is mechanically supported on the gas generator during transport, then the piston remains stable against vibrations, but the piston may shift and strike the gas generator causing damage
Solution Approach 1:
A retaining element is introduced as an intermediary component between the piston and the gas generator. This retaining element mechanically couples the piston to the gas generator body, preventing the piston from shifting during transport while distributing impact forces to avoid damage to the pyrotechnic charge.
Solution Approach 2:
The retaining element is pre-installed in the device before use, establishing the mechanical connection between piston and gas generator body in advance. This preliminary positioning ensures the piston is held stable during transport without requiring active control during operation.
2Reliability
If a retaining element is used to hold the piston stationary during transport, then vibration damage is prevented, but the piston must be reliably released when the gas generator is activated
Solution Approach 1:
The retaining element is designed with dynamic characteristics that allow it to transition from a rigid holding state during transport to a flexible state during operation. The element can deform or disengage under the high pressure forces generated by the activated gas generator, enabling automatic piston release without complex mechanical release mechanisms.
Solution Approach 2:
The retaining element's mechanical properties are designed to respond to changes in pressure parameters. During transport, normal pressure conditions maintain the retaining element in a rigid holding position. When the gas generator activates and pressure increases dramatically, the element's properties change to allow piston movement.
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 effectively prevents piston-induced damage and maintains sealing integrity during transport and storage, ensuring reliable operation and safety by securely holding the piston until the gas generator is activated.
Implementation Method 1
a pyrotechnic gas generator (130) attached to a first base (120) of the device, the gas generator being configured to produce pressurized gases to drive the piston (150)
Implementation Method 2
The retaining element is elastically deformable, and the clamping force results from its elasticity
Implementation Method 3
When the device is exposed to high temperatures, the fluid stored in the reservoir can expand and put stress on the piston
Data Source
Figure 1~4
Figure 5~6
AI summary
The invention relates to a device (100) for dispensing a pressurised material comprising a body defining a pressurisation chamber (160) comprising a gas generator (130) , a tank (170) intended to contain the material to be supplied and a piston (150), the gas generator being configured to, when triggered, move the device from a first configuration, in which the material is stored, to a second configuration, in which the material is no longer dispensed. The device is characterised in that, in the first configuration, the piston is held in position in the body by an elastically deformable holding element (180), extending axially, said holding element being secured to the first end wall and the piston being held fixed in relation to the first end wall by a holding force provided by the holding element, and in that the gas generator is configured to, when triggered, exert a force opposing the holding force on the piston, by means of which the piston is moved and released from the first end wall, and thus move the device from the first configuration to the second configuration.