Collapsible Drug Container Air Spring Mechanism
Solution Overview
Problem
Existing drug delivery devices, such as nebulizers, face issues with the formation of vapor and gas bubbles when withdrawing liquid from collapsible containers, particularly with low vapor pressure solutions like ethanol-based ones, leading to potential leakage during non-use.
Innovation Solution
A collapsible container mechanism incorporating an air spring, friction engagement, or ratchet arrangement to support the collapsing process and prevent expansion, combined with an air leak pathway and non-return valve to manage pressure, ensuring minimal leakage and bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a collapsible container is used to store liquid drug, then the device compactness is improved, but vapor and gas bubbles form during liquid withdrawal
Solution Approach 1:
The patent applies pneumatic principles by introducing an air spring mechanism that uses compressed air to exert downward force on the piston, facilitating liquid withdrawal from the collapsible container. This pneumatic assistance prevents vacuum formation and eliminates the need for complex mechanical pumps, while maintaining compact container volume.
Solution Approach 2:
The patent changes the pressure parameter within the container by using an air spring to maintain positive pressure during liquid withdrawal. This pressure parameter change prevents vapor and gas bubble formation by ensuring the liquid remains under slight pressure, thus improving withdrawal reliability while maintaining container compactness.
2Speed
If the container is pressurized to facilitate liquid withdrawal, then the withdrawal speed is improved, but leakage occurs during non-use
Solution Approach 1:
The patent employs a dynamic pressure control system where the air spring provides pressure only during the withdrawal phase. A check valve dynamically controls the pressure release, allowing high-speed withdrawal when needed while automatically releasing pressure during non-use periods to prevent leakage. This dynamic operation enables both fast withdrawal and leakage prevention.
Solution Approach 2:
The system uses periodic pressure application through the air spring mechanism, activating pressure during withdrawal cycles and releasing it during non-use periods. This periodic action pattern ensures high withdrawal speed when required while minimizing leakage during storage and non-use intervals.
3Reliability
If a mechanism is added to prevent container expansion, then bubble formation is reduced, but device complexity increases
Solution Approach 1:
The patent extracts the complex pump mechanism from the system and replaces it with a simpler air spring-based pressure system. By removing the need for complex mechanical pumping components and using a straightforward air spring-check valve arrangement, the device achieves reliable bubble-free liquid withdrawal with reduced overall complexity.
Solution Approach 2:
The patent substitutes complex mechanical pump systems with a pneumatic air spring mechanism. This replacement simplifies the device by using elastic potential energy storage and release rather than complex mechanical pumping components, thereby reducing device complexity while maintaining effective bubble formation control.
4Measurement precision
If overfilling is used to prevent gas/vapor suction, then dose accuracy is improved, but device volume increases
Solution Approach 1:
The air spring mechanism creates positive pressure that actively pushes liquid toward the withdrawal point, preventing vapor and gas bubbles from being drawn into the dosing chamber. This pneumatic pressure control ensures accurate dosing without requiring overfilling, thereby maintaining compact device volume while achieving dose accuracy.
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 effectively prevents the formation of vapor and gas bubbles, allows for easier use in any orientation, reduces the need for overfilling, and minimizes leakage during non-use, enhancing the reliability and usability of drug delivery devices.
Implementation Method 1
The mechanism may comprise an air spring which is adapted to pressurize the container content temporarily, in particular at least essentially only during withdrawal of the content and/or of a predetermined amount therefrom
Implementation Method 2
The mechanism may comprise a non-return valve or gap or passageway which allows air to enter into a cavity of the air spring during pressurization of the container content
Implementation Method 3
a friction engagement and/or a ratchet arrangement, to support the collapsing/compressing process, in particular pushing a cartridge plunger or piston, and/or to prevent the collapsed/compressed container expanding again
Data Source
AI summary
A drug delivery device, in particular a nebulizer or inhaler, for dispensing a fluid includes a cartridge having a collapsible container within which the fluid is disposed, a mechanism to help the collapsing process and to prevent the collapsed container from expanding again, hence preventing the forming of vapor and gas bubbles within, where the mechanism is adapted to pressurize the fluid within the container during withdrawal of the fluid.