Injection Device Drive Member Flow Restrictor Pressure Control
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Solution Overview
Problem
Existing automatic injection devices face challenges in delivering large volumes of high viscosity medicaments efficiently, leading to variable flow rates and potential patient discomfort, particularly in miniaturized portable devices where pressurized gas sources are limited and prone to pressure drops during use.
Innovation Solution
The injection device incorporates a drive member with a flow restrictor that maintains a high pressure level by reducing the input pressure to a desired level, ensuring consistent medicament dispensing through a porous restriction member, which is adjustable and provides a well-defined pressure drop, allowing for efficient delivery of large volumes without significant flow rate decreases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a pressurized gas cylinder is used to deliver large volumes of high viscosity medicament, then the delivery volume and viscosity handling capability are improved, but the pressure level continuously decreases during injection causing variable flow rates
Solution Approach 1:
The system dynamically adjusts the pressure differential by transitioning from a closed pressurized system to an open atmospheric pressure system. The puncture event transforms the sealed cartridge environment, allowing atmospheric pressure to act on the medicament surface, thereby maintaining consistent pressure differential and flow rate throughout the injection process
Solution Approach 2:
The invention changes the pressure parameter from a decreasing pressurized gas environment to a stable atmospheric pressure environment. By puncturing the cartridge seal, the system transitions to using atmospheric pressure as the driving force, which remains constant throughout the injection, ensuring consistent flow rate despite large delivery volumes
2Reliability
If the pressure container size is increased to maintain pressure level, then the pressure stability is improved, but the device miniaturization is compromised
Solution Approach 1:
The invention introduces atmospheric pressure as an intermediary force to replace the pressurized gas cylinder. By puncturing the cartridge to expose the medicament to atmospheric pressure, the system uses the ambient environment as a pressure source, eliminating the need for large internal pressure containers while maintaining pressure stability
Solution Approach 2:
The system utilizes the surrounding atmospheric environment to provide the necessary pressure for medicament delivery. Instead of carrying its own pressurized gas supply, the device leverages the external atmospheric pressure available in the injection environment, thereby reducing device size while maintaining functional reliability
3Reliability
If a flow restrictor is added to control pressure drop, then the pressure control is improved, but the device complexity increases
Solution Approach 1:
The invention extracts and eliminates the flow restrictor component from the system. By removing this intermediate pressure control element, the system achieves pressure control through the simpler mechanism of direct atmospheric pressure exposure via cartridge puncture, reducing device complexity while maintaining functional effectiveness
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 enables the efficient and consistent delivery of large volumes of medicament with minimal pressure drop, maintaining a high flow rate throughout the injection process, thus improving the operational reliability and patient experience in miniaturized portable devices.
Implementation Method 1
a flow restrictor that maintains a high pressure level by reducing the input pressure to a desired level... which is adjustable and provides a well-defined pressure drop
Data Source
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Figure 5~6
AI summary
The present invention relates to an injection device for dispensing of a liquid medicament, the device comprising: - an elongated housing (12) extending in an axial direction (z) to accommodate a cartridge (14), wherein the axial length of the interior of the housing (12) exceeds the axial length of the cartridge (14) to axially displace the cartridge (14) inside the housing (12) between an undeployed proximal position (P) and a deployed distal position (D), - a drive member (50; 150; 250; 350) axially displaceable inside the housing (12) and being in sealed engagement (57) with a side wall (13) of the housing (12), wherein the drive member (50; 150; 250; 350) has an abutment face (60; 160; 260; 360) to axially abut with a proximal end (17) of a barrel (15) of the cartridge (14) to displace the cartridge (14) from the undeployed position (P) towards the deployed position (D), - wherein the drive member (50; 150; 250; 350) has an outlet (51; 151; 251; 351) located distally from the sealed engagement (57) and further has an inlet (53; 153; 253; 353) located proximally from the sealed engagement (57), wherein the inlet (53; 153; 253; 353) and the outlet (51, 151; 251; 351) are in flow connection with each other via a flow path (68) extending through the drive member (50; 150; 250; 350) and wherein at least one flow restrictor (55; 155; 255; 355) is arranged across or in the flow path (68).