Abstract: A pharmaceutical composition is described that is suitable for delivery from a pressurised container. The composition is preferably free of polar excipients and comprises: (a) a propellant component that consists essentially of 1,1-difluoroethane (R-152a); (b) a surfactant component that comprises at least one surfactant compound other than oleic acid; and (c) a drug component that consists of salbutamol sulphate. The pharmaceutical composition can be delivered using a metered dose inhaler (MDI).

Abstract: An electrostatic spray gun including a housing for receiving a replaceable fluid container, a nozzle from which fluid is to be sprayed, apparatus for expelling the fluid from the container and a high voltage generator for applying electrostatic potential to the fluid to form an electrically charged atomized spray at the nozzle. The replaceable fluid container is externally insulating and the electrical path from the generator passes through the fluid entering it at a point remote from the nozzle. A piston is employed to expel the fluid from the nozzle during spraying. The electrostatic spray gun has the advantage that it does not employ propellants and the paint need not be stored in a flexible plastic container thereby preventing loss of solvent during storage.

Abstract: An electrostatic device for spraying liquids comprises a nozzle in the form of a wick which is contacted with a reservoir containing the liquid to be sprayed, high electrical potential being applied to the liquid in the vicinity of the spraying tip of the nozzle whereby the liquid is drawn out preponderantly under the influence of electrical forces into ligaments which break up to form a spray of electrically charged liquid droplets. The wick is fabricated from sheet of a resiliently deformable polymeric foam material of open celled structure and an edge of the sheet material is profiled to form a plurality of sites at which liquid ligaments can be produced. Typically a toothed profile is employed in which a plurality of teeth form the sites at which ligament formation occurs.

Abstract: Relatively low resistivity liquids are formed into sprays under the influence of an applied electric field acting between a nozzle and the nozzle surroundings which may be at earth potential. The liquid issues from the nozzle as a ligament which undergoes necking to a diameter smaller than that of the nozzle orifice, thereby producing droplets with a volume median diameter less than the orifice diameter.

Abstract: An electrostatic spray gun includes a housing for receiving a replaceable fluid container, a nozzle from which fluid is to be sprayed, a device for expelling fluid from the container, and a high voltage generator for applying electrostatic potential to the fluid to form an electrically charged atomized spray at the nozzle. An electrical path from the generator to the nozzle passes through the fluid, entering the fluid prior to its emergence from the nozzle. The container is rigid and fluid is expelled from the container by a piston under pressure exerted thereon through a forward part of the generator.

Abstract: An electrostatic spraying device comprises a housing (10) incorporating a cartridge (16) containing liquid, such as a fragrance-producing oil, which is to be sprayed via a vertically disposed capillary structure (22), electrical potential being applied to the liquid so that the liquid is drawn across the end face of the capillary structure and is sprayed as a plurality of ligaments which break up into droplets.

Abstract: Relatively low resistivity liquids are formed into sprays under the influence of an applied electric field acting between a nozzle and the nozzle surroundings which may be at earth potential. The liquid issues from the nozzle as a ligament which undergoes necking to a diameter smaller than that of the nozzle orifice, thereby producing droplets with a volume median diameter less than the orifice diameter.

Abstract: Apparatus and method for projecting liquid in the form of a sheet for deposition on a target comprises a nozzle having a slot 10 of width not less than 250 microns to which the liquid is supplied. High voltage is applied to the liquid and the liquid is supplied to the slot at a flow rate such that the liquid is formed as, and is maintained in the form of, a sheet by preponderantly electrostatic forces thereby effecting deposition of the sheet on to the target.

Abstract: An electrostatic spraying device in which liquid emerging from an outlet (24) of the device nozzle (12) is subjected to an electrical field sufficiently high for the liquid to be drawn from the outlet as one or more ligaments which break up into charged droplets to form the spray. In order to provide shock suppression, the electrical field is produced by means of high voltage circuitry having a bi-polar output with a frequency no greater than 10 Hz.

Abstract: An electrostatic spraying device in which liquid emerging from an outlet of the device nozzle (12) is subjected to an electrical field sufficiently high for the liquid to be drawn from the outlet as one or more ligaments which break up into charged droplets to form the spray. The device is adapted for the spraying of targets which are conventionally difficult to coat electrostatically, eg. targets of insulating material. This is achieved by the use of circuitry (18, 20, 22, 24) which generates a bi-polar high voltage output having a frequency such that successive clouds of particles are charged with opposite polarity but do not discharge each other in flight. In this way, the charge applied to the particles is effective to assist seeking of the target without leading to build-up of charge on the target.

Abstract: Liquid to be dispensed is supplied to a dispensing nozzle (88) from a compressible container (30) such as a sachet with a valve-controlled outlet (66) by compressing the sachet through the agency of a pad (46) of resiliently deformable material. The dispensing device is embodied in a hand held unit having a trigger (102) and electrical circuitry (91, 96, 106, 98, 106) for applying high voltage to the liquid in order to effect dispensing of the liquid in the form of an electrostatically charged, atomised spray.

Abstract: An electrostatic spraying apparatus is in the form of a device suitable for hand held use. The device uses a high voltage generator of the rectified pulsed type and includes an earth return path which is completed via the operator through a contact (38) associated with the hand grip (4) of the device. Resistance (36), typically of the order of 50 megohm, suppresses pulsed electrical sensations that may be experienced by the operator in the event that the nozzle (12) is contacted with an earthed object, and the nozzle (12) is designed so that the liquid therein presents, by virtue of the length and cross-sectional area of a liquid conducting passage(s) in the nozzle, a high resistance between the voltage generator (26) and the nozzle thereby reducing the energy that can be drawn to earth by electrical discharge.

Abstract: An electrostatic spraying device is designed in such a way that potential surface leakage paths (FIG. 1b) along which current may leak from the HT generator (2b) are sufficiently long to allow the use of a generator having a smaller than conventional maximum current output.

Abstract: A liquid crystal device comprises a layer of fibers or filaments (15) permeated with liquid crystal material, the layer (15) being located between electrodes (13, 14) by means of which an electric field can be applied across the layer to vary the transmissivity of the liquid crystal/fiber composite. The diameters of the fibers/filaments are selected so that the light transmissivity of the composite has reduced sensitivity with respect to mismatch of the refractive indices of the liquid crystal and the fibers/filaments.

Abstract: An apparatus is disclosed suitable for electrostatic spraying from fixed wing aircraft. The apparatus includes a linear electrostatic spraying nozzle 2 and electrodes 4 placed near the nozzle's spraying edge to intensify the electric field strength at the spraying edge sufficiently to produce ligaments of the liquid to be sprayed from the spraying edge. In order that the airstream due to the aircraft's movement does not destroy the ligamets, the sprayhead and the electrodes are positioned so that part of the airstream flows between them. The spray head and the electrodes are so shaped and positioned that when directed to spray in substantially the same direction as the airstream, a turbulence free wake is left in the region of the ligaments.

Abstract: A method of making a liquid crystal device comprises producing, for example by means of electrostatic spraying, ligaments of a curable liquid which are deposited as such or as droplets (as a result of breaking up of the ligaments) on a sheet which is to form one boundary wall of the device. Curing of the liquid may be initiated while the liquid is in flight and completed after deposition. Liquid crystal material is applied to the deposited ligaments or droplets and a second sheet is laminated with the first sheet to encapsulate the liquid crystal material. The deposited ligaments or droplets serve to space the sheets apart and/or provide surfaces with which, in the field-off condition, the liquid crystal molecules can align in directions different to the direction of alignment induced by application of an electric or magnetic field.

Abstract: An electrostatic spraying apparatus in which an electrode is mounted adjacent to the sprayhead, means are provided for causing a first electrical potential to be applied to liquid emerging from the sprayhead, and further means are provided for applying a second electrical potential to the electrode. The difference between the first and second potentials is sufficient to cause an intense field to be developed between the emerging liquid and the electrode, sufficient to atomise the liquid. The electrode has a core of conducting or semiconducting material sheathed in a "semi-insulating" material. This "semi-insulating" material has a dielectric strength and volume resistivity sufficiently high to prevent sparking between the electrode and the sprayhead and a volume resistivity sufficiently low to allow charge collected on the surface of the material to be conducted through the "semi-insulating" material to the conducting or semiconducting core.

Abstract: An electrostatic spraying apparatus for spraying liquid has a spraying edge 8 provided with teeth 12. No parts of the apparatus provide a low potential influence near the spraying edge, keeping leakage losses to a minimum. At the voltage provided by a high voltage supply, the field strength at the tips of the teeth 12, is sufficient to form one ligament of liquid per tooth. The ligaments break up into droplets which have a size largely independent of fluctuations in field strength caused by varying the distance from the target to be sprayed.

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: An apparatus and process for the electrostatic spraying of a mixture of a plurality of liquids, suitably liquids which react together rapidly to form a solid, liquids which are physically imcompatible, or liquids, such as paints, to provide novel optical effects. The apparatus includes a sprayhead formed with a plurality of channels which communicate with a common outlet means. The liquids are supplied to respective channels and meet at the outlet means. There they are subjected to an electrical field which causes a mixture of the liquids to be drawn from the sprayhead in the form of one or more filaments, the or each filament constaining a mixture of liquids in the proportions equal or substantially equal to the proportions in which the liquids were supplied to the sprayhead.