Inhaler Flow Control Mechanism with Dual Path Triggering
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Solution Overview
Problem
Conventional inhalers face challenges in coordinating inhalation flow rates with medicament dose release, leading to inconsistent drug delivery and reduced therapeutic benefits, particularly for patients with respiratory diseases like asthma and COPD, due to low or high inhaler resistance and variability in inhalation techniques.
Innovation Solution
The design incorporates a breath-actuated trigger mechanism with a dual fluid flow path system, where the trigger mechanism reduces or blocks the second flow path upon activation, allowing a higher triggering flow rate while governing the total inhalation flow, enabling independent selection of the governing flow rate and reducing variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional single flow path with fixed resistance is used, then the structure is simple, but the inhalation flow rate cannot be effectively controlled and varies significantly between patients
Solution Approach 1:
The single flow path is divided into two separate flow paths (first and second flow paths) with different resistance characteristics. The first flow path has higher resistance to limit maximum flow rate, while the second flow path has lower resistance to allow sufficient flow for triggering. This segmentation enables different portions of the inhalation flow to be governed differently, solving the contradiction between flow control and structural simplicity.
Solution Approach 2:
The system dynamically switches between different flow path configurations based on inhalation flow rate. During the triggering phase, the second flow path is open to allow high flow rates. After triggering, the second flow path is closed to govern the total inhalation flow through the first flow path. This dynamic behavior enables adaptive flow control without requiring complex continuous adjustment mechanisms.
2Ease of operation
If the inhaler resistance is increased to control inhalation flow rate, then flow rate control improves, but it becomes difficult for patients with weak inhalation to achieve sufficient flow for dose release
Solution Approach 1:
The flow paths are segmented such that the second flow path provides a low-resistance route during triggering, ensuring that even patients with weak inhalation can achieve sufficient flow rate to trigger dose release. The first flow path with higher resistance then governs the overall inhalation flow to maintain consistency. This segmentation resolves the contradiction between flow control and reliable triggering.
Solution Approach 2:
The system changes the effective resistance parameter of the inhaler by selectively opening or closing the second flow path. During triggering, the second flow path is open, resulting in lower total resistance to facilitate dose release. After triggering, the second flow path is closed, increasing resistance to govern inhalation flow rate. This parameter change enables the system to adapt to different operational phases.
3Ease of operation
If the inhaler resistance is decreased to allow easy inhalation, then patient compliance improves, but inhalation flow rate becomes uncontrolled leading to poor drug delivery
Solution Approach 1:
The flow paths are segmented to provide different resistance characteristics. The first flow path with higher resistance governs the inhalation flow to ensure consistency and prevent excessive flow rates that would cause poor drug delivery. The second flow path with lower resistance is available during triggering to reduce inhalation effort. This segmentation resolves the contradiction between easy inhalation and controlled flow rate.
Solution Approach 2:
The system dynamically adjusts the effective resistance by opening the second flow path during triggering to reduce inhalation effort, then closing it afterward to govern the inhalation flow through the first flow path. This dynamic adjustment ensures that patients can inhale easily during triggering while maintaining controlled flow rates for consistent drug delivery during the inhalation phase.
4Ease of operation
If a flow governor is added to control inhalation flow, then flow rate consistency improves, but the device complexity and manufacturing cost increase
Solution Approach 1:
Instead of adding a complex flow governor mechanism, the system segments the flow path into two parallel paths with inherently different resistance characteristics. The first flow path's higher resistance naturally governs the inhalation flow rate without requiring active control mechanisms. This segmentation achieves flow governance while maintaining structural simplicity.
Solution Approach 2:
The first flow path with higher resistance automatically governs the inhalation flow rate through its inherent resistance characteristics, without requiring an external flow governor or active control system. The system uses its own structural features (the resistance difference between flow paths) to achieve flow control, eliminating the need for additional complex components.
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 consistent and controlled inhalation flow rates, improving drug delivery to the lungs by allowing a high triggering flow rate while ensuring a larger portion of the inhalation flow is governed, thus enhancing therapeutic efficacy and patient compliance.
Implementation Method 1
a flow governor arranged to govern inhalation flow through the first fluid flow path; the flow governor having a first condition and a second condition, in which in the second condition the flow governor is capable of governing a larger flow area than in the first condition
Implementation Method 2
a breath actuated trigger mechanism reactive to an inhalation flow to trigger the release of a substance to be inhaled into the inhalation flow
Implementation Method 3
triggering the trigger mechanism reduces or blocks flow through the second fluid flow path
Data Source
AI summary
An inhaler (60) has a breath actuated trigger mechanism (100) reactive to an inhalation flow to trigger the release of a substance to be inhaled. The inhaler (60) has an inspiration flow which is subject to a higher degree of flow governing post-triggering than pre-triggering. This allows the triggering flow rate to be closer to, or even higher than, the governing flow rate of the inhaler.