Foamed Medium Electrostatic Particle Formation
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Solution Overview
Problem
Electrostatic techniques for forming sub-micron particles or droplets face issues with non-uniform deposition, unstable jet formation, low production rates, and susceptibility to electrostatic discharge, particularly in the paper and board industry.
Innovation Solution
The use of a foamed medium in electrostatic processing allows for higher production speeds and more uniform deposition by enabling the application of higher electric field strengths without discharge, and facilitates the formation of particles or droplets from a foamed surface, which can be deposited uniformly on a substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional electrospray/electrospinning techniques are used with liquid medium, then particles or droplets can be formed, but the deposition is non-uniform and production rate is low
Solution Approach 1:
The patent changes the physical state of the medium from liquid to foam. This parameter change allows the medium to be processed electrostatically while avoiding the problems of liquid medium such as non-uniform deposition and low production rate. The foam structure enables better charge distribution and more controlled particle formation.
Solution Approach 2:
The patent introduces foam as an intermediary medium between the liquid polymer solution and the final particles. The foam acts as a carrier that can be electrostatically processed more effectively, enabling uniform deposition while maintaining high production rates through better charge utilization.
2Productivity
If higher electric field strength is applied to increase production rate, then more particles can be produced, but electrostatic discharge occurs
Solution Approach 1:
The patent changes the electrical properties of the medium by using foam instead of liquid. The foam structure has different dielectric properties that allow higher electric field strengths to be applied without causing electrostatic discharge. This enables increased production rate while maintaining system reliability.
3Manufacturing precision
If small orifice diameter spray nozzles are used, then finer particles can be produced, but nozzles are susceptible to clogging and drying
Solution Approach 1:
The patent extracts the medium from the nozzle system by using foam that can be applied without traditional spray nozzles. This eliminates the clogging and drying problems associated with small orifice nozzles while still achieving fine particle production through electrostatic processing of the foam medium.
4Adaptability or versatility
If meniscus initiators are used in electrospinning, then fibre formation can be directed, but the system is limited to upward direction and performance depends on initiator configuration
Solution Approach 1:
The patent changes the medium from liquid to foam, which fundamentally alters how the medium responds to electric fields. This eliminates the need for meniscus initiators and their complex configuration, while still enabling controlled fibre formation in various directions through the electrostatic processing of foam.
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 method achieves high-speed, uniform coating and sizing of paper or paperboard with improved production rates and reduced energy requirements, while avoiding issues with electrostatic discharge and nozzle interference, resulting in enhanced filtering efficiencies and more consistent particle distribution.
Implementation Method 1
A high voltage electric field is applied to a surface of a liquid causing the emission fine charged droplets
Implementation Method 2
The electrostatic field created between the nozzles and the collector plate causes the medium to overcome cohesive forces that hold the medium together
Implementation Method 3
The electrostatic field stretches the jet and, depending on the properties of the liquid medium, such as viscosity, surface energy, polymer concentration, and the strength of the electric field, fibres (electrospin) or droplets (electrospray) are formed which are deposited on the collector plate
Data Source
AI summary
The invention refers to a method for forming particles or droplets of at least one substance comprising the steps of providing a foamed medium, which foamed medium comprises said substance, and forming particles or droplets of said substance at least partly by electrostatic processing. The use of foamed medium in electrostatic processing enables higher production speeds and increases the evenness of a coating layer formed by electrospinning or electrospraying the particles or droplets on a substrate.