Breath-Actuated Nebulizer Impingement Shield
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Solution Overview
Problem
Existing nebulizers face challenges in delivering consistent doses of high concentration and viscous medications due to material accumulation, leading to degraded performance and secondary exposure issues, especially with breath-actuated designs that require complex components and are costly.
Innovation Solution
A baffled nebulizer with a static baffle and a respiration-responsive impingement shield that oscillates to control aerosol production, ensuring medication is cycled through the nozzle only during inhalation, reducing accumulation and waste, and allowing for a simple, inexpensive, and disposable design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If breath-actuated designs are used to control aerosol production during inhalation, then dosing consistency and environmental exposure are improved, but device complexity and cost increase due to complex components
Solution Approach 1:
The nebulizer device utilizes the patient's own respiratory flow to automatically control the impingement shield position. During inhalation, the negative pressure moves the shield to allow aerosol delivery; during exhalation, positive pressure returns the shield to block aerosol. This self-actuating mechanism eliminates complex sensors and control systems while maintaining breath-actuated dosing consistency.
Solution Approach 2:
The impingement shield is positioned and returned using pneumatic pressure differentials created by patient breathing. The shield responds to negative pressure during inhalation and positive pressure during exhalation, converting respiratory flow directly into mechanical motion without electrical components or complex mechanisms.
2Ease of operation
If continuous aerosol formation is used, then aerosol is always available for inhalation, but liquid medicament is lost during exhalation and idle operation, causing environmental contamination and dosing variability
Solution Approach 1:
The nebulizer operates in periodic cycles synchronized with patient respiration. The impingement shield blocks aerosol during exhalation and idle periods, allowing only periodic aerosol delivery during inhalation. This eliminates continuous aerosol formation and associated medicament waste while ensuring aerosol is available when needed.
Solution Approach 2:
The impingement shield extracts and removes aerosol from the delivery path during exhalation and idle operation. By selectively blocking the aerosol stream when not inhaled, the device prevents medicament loss to the environment while maintaining aerosol availability during inhalation phases.
3Reliability
If high concentration and viscous medications are aerosolized, then therapeutic effectiveness is improved, but material accumulates in and around the nozzle, degrading performance over time
Solution Approach 1:
The impingement shield, which blocks aerosol during exhalation, simultaneously serves to prevent accumulation of high concentration and viscous medications in the nozzle area. By blocking the aerosol stream, it reduces material deposition on internal surfaces, converting a potential performance-degrading issue into a mechanism that maintains long-term device functionality.
Solution Approach 2:
The shield maintains continuous protection against material accumulation throughout the exhalation and idle phases, ensuring the nozzle remains clear for the next inhalation cycle. This continuous blocking action during non-delivery periods preserves therapeutic effectiveness over extended use.
4Ease of manufacture
If breath-actuated nebulizers are designed with simple components for disposability, then cost is reduced, but controlling aerosol production during varying inhalation efforts becomes difficult
Solution Approach 1:
The impingement shield responds dynamically to changing respiratory parameters including inhalation flow rate and pressure. The shield's position is determined by the magnitude of negative pressure during inhalation, automatically adapting to varying inhalation efforts without requiring complex sensors or adjustable mechanisms.
Solution Approach 2:
The simple impingement shield structure serves multiple functions: it blocks aerosol during exhalation, enables aerosol delivery during inhalation, and adapts to varying inhalation strengths. This multi-functional design achieves both manufacturing simplicity and adaptability to different patient respiratory patterns.
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 nebulizer achieves consistent delivery of high concentration and viscous medications with reduced waste and secondary exposure, maintaining performance over time and being suitable for a broad range of patients with varying inhalation efforts, while being cost-effective and easy to use.
Implementation Method 1
a respiration responsive impingement shield which responds to patient respiration forces to oscillate from an occluding position to an open flow position
Implementation Method 2
An entrainment orifice within the nebulizer utilizes pressurized gas to draw in liquid medicament from a reservoir and to entrain that liquid medicament into a continuous high velocity stream
Implementation Method 3
the high velocity jet strikes a target surface to atomize the medicament within the stream into micro-droplets
Implementation Method 4
When the shield is in a first position, the atomized medicament impinges upon the shield, losing jet momentum, which causes the micro-droplets to coalesce into macro-droplets
Data Source
AI summary
The present invention is directed generally to a nebulizer for the formation of micro-droplets from liquid medicaments for respiratory patient treatment, and more specifically, to a baffled nebulizer wherein a static baffle used to form an atomized medicament is proximal to a shied which responds to patient respiration force to oscillate from an aerosol flow occluding position to an aerosol flow open position. During inhalation, the shield moves into a first registration format to allow passage of the atomized medicament (nebula) to the patient. During exhalation/non-use, a biasing pressure maintains said shield in a second registration format such that the nebula is retarded from passing to the patient and is coalesced into macro-droplets which return to a supply reservoir for re-atomization. The present nebulizer design is particularly adaptable for controlling atomization in response to patient respiratory forces exceeding a defined threshold; allowing for opportunity to control inhalation airflow and enhanced therapy regimes.