Inertial Particle Impactor Uniform Deposition
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Solution Overview
Problem
Existing inertial particle impactors are inefficient in detecting and characterizing small-sized particles in the nano regime (100 nm to 2.5 nm) due to uneven distribution and accumulation on impactor plates, leading to inaccurate representation of particle morphology and composition.
Innovation Solution
The design includes an impactor stage with a nozzle element and grid carrier, where the space above the plate or grid is limited by a top surface extending radially to the periphery, with a maximum axial distance from the plate or grid surface less than three times the orifice diameter, and an orifice diameter between 0.1 and 0.4 mm, ensuring a more even distribution of particles and reduced gas stream deceleration, allowing for effective sampling of particles down to 2.5 nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the space above the plate or grid is not limited (conventional design), then the gas stream has sufficient space to expand, but particles accumulate unevenly and form overload spots and empty areas on the impactor plate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the axial distance between the top surface and the plate/grid to be less than three times the orifice diameter. This specific dimensional parameter change transforms the gas flow characteristics and particle deposition pattern, achieving uniform particle distribution across the impactor plate surface while preventing both overload accumulation and empty areas.
2Measurement precision
If the orifice diameter is not optimized (conventional design), then the device structure is simpler, but the detection sensitivity for small particles in the nano regime is insufficient
Solution Approach 1:
The patent optimizes the orifice diameter parameter within the range of 0.1 to 0.4 mm to enhance detection sensitivity for nanoscale particles. This parameter optimization, combined with the controlled axial distance ratio, improves the gas stream velocity and particle impaction efficiency, enabling effective sampling and characterization of particles as small as 2.5 nm while maintaining manageable device complexity.
3Productivity
If the axial distance is too large, then particles have more space to travel, but gas stream deceleration increases reducing sampling efficiency
Solution Approach 1:
The patent maintains the axial distance parameter at less than three times the orifice diameter to optimize the balance between particle travel space and gas stream velocity. This parameter control prevents excessive gas stream deceleration, maintaining high sampling efficiency and ensuring that particles are effectively deposited on the impactor plate without loss of kinetic energy that would reduce sampling productivity.
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 results in a more even distribution of particles on the TEM-grid, enabling accurate analysis of individual particles' size and composition, preventing overload and empty areas, and effectively sampling particles as small as 2.5 nm, improving detection efficiency and accuracy.
Implementation Method 1
inertial particle impactor... the stream of gas exiting from said outlet orifice impinges on said impactor plate, such as a TEM-grid thereby depositing particles upon said impactor plate
Data Source
Figure 1
Figure 2a~2c
Figure 3
AI summary
The present invention is directed to an Inertial particle impactor (20) for the deposition of small size particles (P) having a mean diameter of less than 10 µm, comprising at least one impactor stage (10) (for receiving and passing a stream of ambient gas carrying said particles (aerosol), the impactor stage (10) including a funnel shaped inlet (11) and an outlet orifice (12) at the narrow end of the funnel shaped inlet having a maximum diameter of 3.5 mm an impactor plate, such as a TEM-grid, electron microscopy substrate, foil or disposable disc ((6) facing the outlet orifice (12) on the side remote from the funnel shaped inlet (11) and supported by a plate or grid carrier (1) at a distance to the outlet orifice (12) of less than twice the orifice diameter said plate or grid carrier (1) having a support (5) with a planar support surface for the plate or grid (6), the gas stream exiting from said outlet orifice (12), impacting on said plate or grid (6) and passing along the surface substantially radially from said outlet orifice (12), thereby depositing particles (P) upon said plate or grid (6), the stream of gas further flowing through outlet passages (7, 7') arranged about the periphery of said plate or grid support (5) and optionally further passing the gas towards another nozzle inlet of a succeeding further impactor stage (10') of the impactor. The invention in is also related to a corresponding method of sampling small particles. In order to improve the collection of individual particles on the impactor plate, such as a TEM-grid, electron microscopy substrate, foil or disposable discsurface for gas carrying small particles of a mean diameter down to about 5 nm, the particle impactor is characterized in that the space (15) above the plate or grid (6) and surrounding the outlet orifice (12) is limited by a top surface (16) extending radially at least to the passages (7, 7') and having a maximum axial distance (d) from the plane carrying the grid (6), which is less than three times and preferably less than twice the orifice diameter.