Positive Pressure Laser Diffraction for Inhaler Plume Measurement
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Solution Overview
Problem
Existing laser diffraction systems for measuring particle size distribution in dry powder inhalers face challenges with non-uniform plume formation due to vacuum-induced high and low pressure areas, leading to inaccurate and irreproducible results, especially in high resistance inhalers, and require frequent cleaning due to turbulence and powder deposition.
Innovation Solution
A device adapted to laser diffraction apparatuses that uses positive pressure to create a plume in a chamberless environment, minimizing turbulence and powder deposition, allowing for accurate measurement of particle size distribution and density with reduced contamination and cleaning needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vacuum is used to generate plume in laser diffraction measurement, then powder can be drawn through the chamber for measurement, but non-uniform plume formation occurs due to high and low pressure areas leading to inaccurate results
Solution Approach 1:
The patent inverts the conventional vacuum-based approach by using positive pressure to generate the powder plume. Instead of drawing powder through vacuum, pressurized gas is introduced to propel the powder forward, creating a more uniform plume that eliminates measurement inaccuracies caused by pressure variations.
Solution Approach 2:
The patent changes the pressure parameter from negative (vacuum) to positive, fundamentally altering the plume generation mechanism. This parameter change transforms the flow dynamics, resulting in uniform plume formation without the high and low pressure areas that plague vacuum-based systems.
2Productivity
If vacuum is used to create plume, then powder flows through chamber, but turbulence and powder deposition occur requiring frequent cleaning
Solution Approach 1:
By inverting from vacuum to positive pressure, the patent eliminates the turbulence and deposition issues inherent in vacuum systems. The positive pressure approach creates laminar flow that prevents powder from settling on chamber surfaces, dramatically reducing cleaning requirements.
3Measurement precision
If chamber is used for measurement, then plume can be contained, but non-uniform pressure areas create measurement errors
Solution Approach 1:
The patent changes the pressure parameter from negative to positive, fundamentally altering the pressure distribution within the measurement chamber. This transformation creates uniform pressure conditions that eliminate measurement errors while maintaining plume containment.
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
Enables consistent and reproducible performance evaluations of inhalers by accurately measuring particle size distribution and density, reducing errors from turbulence and deposition, and eliminating the need for frequent cleaning, while allowing for controlled temperature, pressure, and flow rate conditions.
Implementation Method 1
the powder plume travels through the zone in which the laser is projected thus causing the laser beam to diffract after colliding with the particles
Implementation Method 2
using Mie theory (an analytical solution of equations for the scattering of electromagnetic radiation by spherical particles), interpret them to quantify particle size distribution
Implementation Method 3
providing positive pressure into the chamber of the device to create a flow of air or gas through the inhaler so that the dry powder formulation is discharged into a plume of powder exiting the inhaler
Data Source
AI summary
The present disclosure relates to an improved device and methods for adapting to a laser diffraction apparatus used for measuring particle size distribution and density of the plume of a powder composition emitted from a dry powder inhaler.