Abstract: In order to enhance the efficiency of charging in a friction charger, it is proposed to precharge the particles before the first collision with the walls by making use of the photoeffect. This is performed, preferably, through irradiating the particles using UV radiation from a UV excimer radiator.

Abstract: The irradiation device for drying and/or curing paints, varnishes and similar coatings (13, 14) has at least one UV high-power radiator having a discharge space (3) filled with filling gas. The filling gas contained therein emits radiation under the effect of silent electrical discharges. The discharge space (3) is bounded by walls (1, 2), at least one wall consisting of dielectric material and being transmissive to the radiation generated in the discharge space (3). A pair of electrodes (4, 5), with an AC source (10) connected to the two electrodes, serves for feeding the discharge. The treatment space (6) is immediately adjacent to the dielectric (1, 2). The electrodes (4, 5) are positioned at a distance from the immediately neighboring dielectric. The coupling of the electrical energy from the electrodes into the discharge space takes place essentially capacitively.

Abstract: In a UV high-power radiator, the electrodes (6', 6") consist of wires embedded in a glass dielectric (3). The dielectric is arranged spaced between two UV-transparent sheets (1, 2). The discharge spaces (8, 9) are filled with a filler gas emitting radiation under discharge conditions. The surface discharges (10) form on the dielectric surface in each case between two adjacent electrode wires (6', 6"). A high-power radiator constructed in this manner is characterized by simple and economical construction and high UV yield.