Sampling of Charged Fine Particles by Motion Control under AC Field

Chemical Engineering Science

Maruyama

Matsuyama

et al. 2010

499

336

Particles are often electrostatically charged by frictional contact during powder-handling operations. This phenomenon is called 'triboelectric charging' or 'contact electrification'. The charged particles cause problems such as particle deposition and adhesion. In addition, if particles are excessively charged, an electrostatic discharge may occur, which can pose a risk of fire and explosion hazards; thus, to mitigate the adverse effects, it is important to elucidate the underlying triboelectric charging mechanisms. The electrostatics is, on the other hand, very useful in a number of applications that have been developed using the principles. In this review, the basic concepts and theories of charge transfer between solid surfaces are summarized, and chemical factors depending on materials and environmental effects are described. To theoretically analyze the process of particle charging, relevant models are discussed. Using the models, particle charging by repeated impacts on a wall is formulated. To experimentally evaluate particle charging, measurement and characterization methods are outlined. Furthermore, important applications and computer simulations are described.

Section: Charge Distributionmentioning

confidence: 99%

Triboelectric charging of powders: A review

Chemical Engineering Science

Maruyama

Matsuyama

et al. 2010

499

336

“…When charged particles with the same polarity are extracted from the revised system, these particles are dispersed by their mutual electrostatic repulsion (Masuda, 2009). There are many electrostatic applications for the control of particle position (Matsusaka et al, 2008), separation (Dwari et al, 2015), classification (Kawamoto, 2008), and surface cleaning (Mazumder et al, 2007;Kawamoto et al, 2011). In addition, there are reports regarding particle levitation using various configurations of electrodes (Adachi et al, 2016;Blajan et al, 2017).…”

Section: Motion Of Charged Particles Between Parallel Electrodes and Other Applicationsmentioning

confidence: 99%

Agglomeration and Dispersion Related to Particle Charging in Electric Fields

Shoyama

2021

KONA

Self Cite

Electrostatic forces cause spontaneous movement of charged particles; subsequently, electrostatic technology is attracting attention because of its application in powder handling processes, such as separation, classification, dispersion, and collection. Dielectric and conductive particles are charged by induction in a strong electric field and moved by Coulomb forces. The magnitude and polarity of the transferred charges are controlled by the strength and direction of the electric field. The dielectric particles are also polarized in the electric field, and dipole interactions occur between particles or in the particle layers, complicating the particle behavior. This review paper presents induction charging, agglomeration, levitation, and other behaviors resulting from particle layers in electric fields. A series of particle phenomena occur in parallel electrode systems, which consist of a lower plate electrode and an upper mesh electrode. Charged agglomerates are formed on the particle layers, levitated by the Coulomb forces, and disintegrated with rotation when approaching the mesh electrode. The mechanisms of agglomeration and disintegration have been elucidated in multiple studies, including microscopic observations and theoretical analyses of particle motion, based on numerical calculations of the electric field. Furthermore, a new system is proposed for continuous feeding of dispersed particles using electric fields and vibration.

“…This lack of reliable information is due to the many relevant factors, such as chemical, physical, and electrical properties and environmental conditions, all of which affect the process. To analyze and control particle charging, the measurement of electrostatic charge 10,[31][32][33][34][35][36][37][38] and the evaluation of electrostatic characteristics [39][40][41][42][43][44][45][46][47][48] are important. To improve existing processes and to develop new applications, it is necessary to obtain an in-depth understanding of these qualities based on theoretical analyses.…”

Section: Introductionmentioning

confidence: 99%

Control of Particle Tribocharging

2011

KONA

Self Cite

When two dif ferent materials are brought into contact and separated, an electrical charge is transferred from one to the other. This phenomenon is called contact electrification, contact charging, or tribocharging. Charged particles cause various secondary phenomena during powder processing, such as deposition, adhesion, and electrostatic discharge. Additionally, charged particles are used in many industrial applications such as electrophotography, electrostatic powder coating, and separation; thus, particle charge control is very important for improving particle performance. However, there are still many unknown effects, and in some cases, inconsistent results have been reported. In this review, the basic concepts and theories of charge transfer between solid surfaces are summarized and a description of particle charging caused by repeated impacts on a wall is formulated. On the basis of these concepts and formulations, novel methods of controlling particle tribocharging are presented. In particular, a method using an applied electric field is expected to be applicable in industrial fields.