Particles under the Influence of an ac Electric Field

Conditions for the Detachment of Particles. An alternating high-frequency field is sometimes used for removing contaminations from a surface [465], and in particular for cleaning the rails in front of a moving locomotive [466]. 

In order to discover how the efficiency of an ac electric field in this respect depended on the conditions of particle detachment, the properties of the electrode, the properties of the surface being cleaned, and other factors, some special experiments were carried out with an apparatus (Fig. X.7) delivering a current with a frequency between 50 and 2000 cps and a voltage of 3-5 kV and enabling either one or several electrodes of the needle type to be used at the same time, and also allowing the distance between the electrode and the treated surface to be varied from 1 to 5 mm. 

In all the experiments the surface (first made dusty to the extent of 3-5 g/ m by free settling) was held for 20-30 min before imposing the electric field. The dimensions of the surface to be treated were no greater than 40 x 60 mm. 

The efficiency of the operation of the ac electric field was estimated by reference to the area, or rather the diameter, of the sharply defined dust-free spot formed on the grounded surface opposite to the detaching electrode. 

35 mm frequency, 400 cps voltage, 3.0 kV period of action of the electric field, 4 sec). 1) Plexiglas 2) painted metal 3) metal (a, copper b, tin plate c, aluminum). 

---

AC) Electrophoresis is the motion of electrically charged particles under the influence of an AC electric field. For thin electrical double layers a Ad 1), dynamic mobility of spherical particles can be expressed as [9]... 

Detachment of Particles Under the Influence of an ac Electric Field... 

---