Electrostatic plate separators

Electrostatic-Separation Machines The first electrostatic machines to be used commercially employed the principle of contact elec trification. These were free-fall devices incorporating large vertical plates between which an electrostatic field was maintained. Tribo-elec tric separation (contact charging) has experienced an increase in apphcations due to advances in mechanical self-cleaning and electrical design as well as the development of efficient precharging techniques. 

FIG. 19-59 Conductive-induction plate-type electrostatic separator. Courtesy of Mineral Technology, Ltd.)... 

Electrostatic separation, of a granulated mixture of polymers from electronic products, can separate polymers of similar density. The particles are charged by passing through an inclined rotating drum, then separate during free fall between two charged plates. 

Apart from the corona discharge unit, two common types of electrostatic separators are the plate separator and the screen-plate separator, illustrated in Figure 9.17. Induction is used in both units to charge the feed... 

Electrostatic separators (a) plate type and (b) screen-plate type. 

Figure 7.3.10. (a) Free-fall electrostatic separator with vertical plates (b) free-fall electrostatic separator with inclined vertical plates. (After Wei and Realff (2003).) (c) Drum-type electrostatic separator (d) tubular free-fall separator. (After Beier and Stahl (1997).)... 

Non-covalent interactions between molecules often occur at separations where the van der Waals radii of the atoms are just touching and so it is often most useful to examine the electrostatic potential in this region. For this reason, the electrostatic potential is often calculated at the molecular surface (defined in Section 1.5) or the equivalent isodensity surface as shown in Figure 2.18 (colour plate section). Such pictorial representations... 

Fig. 17. Electroseparators (a) high tension separator, and (b) plate-type electrostatic (6).

The two-stage electrostatic precipitators used in light-industry applications are compact devices which can be fitted into the ventilation system. These air cleaners are normally used to clean air from dusts, smokes, and fumes in industrial workplaces. The basic features of these devices are the separate sections for particle charging and collection. The charging section consists of thin metal wires installed between grounded metal plates. The distance... 

Electrostatic precipitators are generally used to separate particulate matter that is easily ionized from a gas stream3,8,10. This is accomplished by an electrostatic field produced between wires or grids and collection plates by... 

Recently, Rumpf (R5) has considered the forces of attraction between a plate and a sphere and between irregular shape particles. His conclusions are that the capillary bonds are relatively insensitive to the particle shape, but the van der Waals force of attraction is extremely sensitive. Although weaker in magnitude than the two aforementioned bonds, the electrostatic bonds may persist over long separation distances. 

For our example, this means that the benzenesulfonate ions are adsorbed in a surface layer and that the sodium ions form an atmosphere of counter ions in which their concentration gradually decreases with the distance from the benzenesulfonate layer. A small separation between the negative and the positive charges has been created at the interface between the mobile and the stationary phases. As in a plate capacitor, this charge separation creates a difference in electrostatic potential between the charged stationary phase and the surrounding mobile phase. By convention, the surface has a negative electrostatic potential in this case. 

The electrostatic force (F ) between two charged plates separated by an electrolyte solution can be determined from an existing imphcit solution to the nonlinear Poisson-Boltzmann equation and can be expressed in the form [187]... 

In order to determine which expls are capable of ignition by an electrostatic discharge of an energy amounted to 100000 ergs, or less it. is necessary to subject each prospective expl to the following energy requirement test . For this a layer of the expl is spread in thickness of 0.010 inch on a steel plate and is separated by a a short gap from a steel needle. This needle is so arranged that it can be thrown into a closed circuit with a condenser of known capacity, on... 

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