Abstract: Strewing apparatus (1) for even distribution of small hard particles of semi-conducting material. The strewing apparatus (1) comprises an upper charge plate (2) and a lower charge plate (3), the upper charge plate (2) having an inlet opening (20) for the introduction of the particles while the lower charge plate (3) have an outlet gap (30) for ejection of the particles. A distance DII between the upper charge plate (2) and the lower charge plate (3) at a position where the outlet gap (30) is arranged is larger than a distance DI between the lower charge plate (3) and the upper charge plate (2) where the inlet opening (20) is arranged. There is a voltage potential between the upper charge plate (2) and the lower charge plate (3).

Abstract: A coating is applied to a substrate by conveying the substrate past a number of liquid spraying nozzles (32) to which high voltage is applied to produce spray in the form of liquid ligaments which deposit as such, or in the form of droplets, on the substrate to form generally parallel tracks which merge with each other to produce a substantially uniform thickness coating. The nozzles (32) are operable in two modes: a normal spraying mode and a deflect mode in which the ligaments are deflected away from the substrate and towards a collector electrode (34). Operation of the nozzles (32) may be co-ordinated so that different formulations are deposited as separate panels in succession lengthwise of the substrate. The coating system is particularly suitable for coating multicoloured dyesheets for use in thermal transfer printing.

Abstract: Apparatus, for example an inhaler, is disclosed in which a spray is formed electrostatically from an outlet 6 to achieve uniform droplet size. The spray is then discharged for its intended use--in the example inhaling. The spray is discharged completely by corona produced by a sharp discharge electrode 16 which is charged to a polarity opposite that of the liquid. In order to prevent the corona from spoiling the formation of the spray itself, the liquid of the outlet 6 is protected by a neutral shield electrode 8. The spray issues through a hole 14 in the shield electrode. The hole is sufficiently small to prevent corona getting through, yet sufficiently large to allow the spray through.

Abstract: A process for the production of solid particles, characterized by the solidification in flight of an electrically charged spray of fluid droplets of narrow particle size distribution, and an apparatus for that process comprising a sprayhead with a channel for the fluid communicating with an outlet; means for subjecting the fluid to an electrical field such that the fluid will move from the sprayhead under the influence of the field to produce a spray of the fluid, the means including means for applying a first potential to the fluid; an electrode mounted spaced from but adjacent to the sprayhead with means to apply a second potential to that electrode; and a spray chamber, so positioned that in use the sprayhead delivers the spray to the chamber interior, and provided with means to apply a third potential to the chamber, and so dimensioned and arranged that in use the majority of the spray droplets solidify before impinging on any surface of or within the chamber.