Needleless Injection Device Low Pressure Profiles
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Solution Overview
Problem
Existing needleless injection devices face challenges in reducing operating pressures while ensuring mechanical integrity and reproducibility, particularly for single-use devices, and in optimizing injection depth and pressure profiles.
Innovation Solution
A needleless injection device with a gas generator, a reservoir sealed by upstream and downstream stoppers, and an injection nozzle with a receptacle and injection ducts, where the cavity height and duct length ratio are optimized to achieve lower initial pressure values (50-150 bars) and varied pressure profiles, minimizing mechanical stress and allowing precise control of injection depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional high pressure (200-500 bars) is used to ensure effective skin penetration and reliable injection, then injection reliability is improved, but mechanical stress on components increases and device durability deteriorates
Solution Approach 1:
The patent changes the pressure parameter from traditional high pressure (200-500 bars) to reduced pressure (50-150 bars) by optimizing the cavity height and duct length ratio. This parameter change maintains injection effectiveness while reducing mechanical stress on components, directly resolving the contradiction between injection reliability and component strength.
Solution Approach 2:
The patent applies local quality optimization by specifically designing the cavity height and duct length ratio to create favorable pressure distribution at critical locations. The optimized geometry ensures sufficient pressure at the injection ducts for reliable skin penetration while limiting pressure buildup that would stress other components, thus resolving the contradiction between injection reliability and component durability.
2Strength
If cavity height and duct length are optimized to reduce initial pressure values, then mechanical stress is reduced, but injection depth control precision may worsen
Solution Approach 1:
The patent establishes specific mathematical relationships between cavity height, duct length, and injection parameters to maintain precision. By defining the cavity height within specific ranges based on duct length, the invention ensures that pressure reduction does not compromise injection depth control, thus resolving the contradiction between mechanical stress reduction and injection precision.
Solution Approach 2:
The patent enables dynamic pressure management through the optimized cavity-duct geometry, allowing the system to adapt pressure profiles during injection. This dynamic characteristic ensures sufficient pressure for depth control while limiting peak pressures that cause mechanical stress, resolving the contradiction between stress reduction and precision control.
3Strength
If downstream stopper impact speed is reduced to protect mechanical components, then component durability is improved, but injection pressure buildup may worsen
Solution Approach 1:
The patent changes the impact speed parameter by optimizing the cavity height to match the downstream stopper travel distance. This ensures the stopper impacts at reduced speed, protecting components, while the optimized duct length compensates to maintain sufficient pressure buildup for effective injection, resolving the contradiction between component durability and pressure requirements.
Solution Approach 2:
The patent resolves the contradiction by introducing a geometric dimensioning relationship between cavity height and duct length. This dimensional optimization allows the system to manage the timing and magnitude of pressure buildup separately from the impact event, enabling low-speed impact without compromising pressure generation, thus resolving the contradiction between component protection and pressure requirements.
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 device achieves effective needleless injections with lower pressure profiles (50-150 bars) and flexible pressure management, reducing mechanical stress and ensuring reliable and reproducible injections with optimized injection depth control.
Implementation Method 1
a) a source of energy, in this case a gas generator, a reservoir closed off by an upstream stopper (4) and a downstream stopper (5) between which is housed a liquid active ingredient (6)
Implementation Method 2
when the downstream stopper impacts the bottom of said receptacle, it creates a shock wave which will propagate as far as the tube
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The present invention relates to a needleless injection device (1) comprising a reservoir (3), obturated by an upstream stopper (4) and a downstream stopper (5) between which a liquid active principle (6) is accommodated, and a receptacle (7) comprising at least one injection conduit (8), said receptacle comprising a cavity (10) whose height is equal to the distance travelled by the downstream stopper before each injection conduit is opened, - the height of the cavity in millimetres being between a minimum height and a maximum height, respectively defined by the following relationships, minimum height = 3, maximum height = 15 x exp. (-(V/9)2) + 10, where V is the initial speed of ascent of the pressure profile expressed in bar per microsecond, - the ratio between the length of each injection conduit and the height of the cavity being between 1 and 2.