Abstract: An electrostatic powder-coating gun is provided which comprises a powder duct which is connected to a supply conduit for a powder-air-mixture and arranged along the longitudinal axis of the gun barrel and having an open mouth towards the work to be coated, a high-voltage generator, an electrode supporting tube extending through the powder duct in axial direction thereof, and a high-voltage electrode located on the supporting tube and protruding beyond the mouth of the powder duct towards the work. The high-voltage generator and the powder duct are disposed in series along the longitudinal axis of the powder tube in such a way that the powder duct is adjacent the muzzle of the gun barrel. The powder duct is comprised of a toroidal duct and an annular channel extending therefrom and opening to the outside.

Abstract: An apparatus for feeding powder coating apparatus with a powder-air mixture, whereby the powder is fluidized in a reservoir, the powder-air mixture that has thereby arisen is conveyed to a dosing container via conveyor lines and is prepared in this dosing container. The fluidization air is eliminated from the powder-air mixture coming from the reservoir, the remaining powder is re-fluidized and re-dosed in defined fashion, and the powder-air mixture produced is conveyed to the allocated powder coating apparatus.

Abstract: A method of fluidizing, conveying and/or atomizing powdery or liquid coating material in surface coating, particularly in electrostatic surface coating. An inert gas under high pressure is reduced to a lower, operating pressure, whereby it cools to a temperature below the ambient temperature, and is employed as compressed gas for fluidizing, conveying and/or atomizing coating material.

Abstract: The control apparatus has an antenna (10) for the reception of electromagnetic radiation emitted from the alternating current transmission line. The antenna (10) is connected to an amplifying device (20) the signal output (22) of which is connected to an oscilloscope (30) in such a manner that the output signals of the amplifying device (20) effect both vertical and horizontal deflection of the image spot on the image screen of the oscilloscope (30). The amplifying device (20) is constructed for the amplification of a broad frequency range extending from below the line frequency to at least 20 kHz, wherein the amplification in the frequency range below about 10 kHz is reduced. The whole frequency spectrum of the output signals of the amplifier device (20) is fed to the oscilloscope (30).

Abstract: A versatile spraying gun includes main tool and several attachment tools any one of which can be inserted in the main tool. Each attachment tool is designed to atomize powder particles that are to be sprayed on an article in accordance with a specific spraying method and atomization principle and method. The main common tool is comprised primarily of a body that defines a powder delivery channel and a coupling piece and discharge electrode located upstream in the delivery channel. The attachment tools have a flow guide member disposed axially within the delivery channel and an attachment piece for attaching the attachment tool to the coupling piece of the main tool. In some attachment tools, the flow guide member also houses a high voltage circuit and appropriate electrodes needed for electrostatic charging of the powder which passes through an electrical field set up between the electrodes.

Abstract: A spraying gun for electrostatic spraying of coating material on an article contains a discharge electrode which is disposed entirely outside the region where the coating material flows. The coating material is accelerated through an annularly shaped and axially extending channel in which the coating material is electrically charged by friction between itself and the insulated walls that define the channel. A gas conduit extends from the discharge electrode and reaches into the annular feed channel of the coating material. Location of the gas conduit between the discharge electrode and the feed channel allows the gas flowing in the gas conduit toward the feed channel to serve the dual purposes of preventing coating material from flowing to and settling on the discharge electrode and providing an electrically conductive path through which undesired electrical charges which develop on the walls of the feed channel discharge to the discharge electrode.

Abstract: A feed channel is provided upstream of a powder-spraying discharge opening in a spray device, with a pipe having an injector which coaxially surrounds such pipe length for the coaxial introduction of accelerating gas. Downstream of the injector an elongated guide member is present in the feed channel. In this way the complete cross-sectional shape of the feed channel is progressively changed along the longitudinal axis of the feed channel to a cross-sectional shape which is annular and has a smaller cross section of flow passage. This results in a further accelerating of the stream of powder. The guide member and the region of the wall of the feed channel which surrounds the guide member at a distance therefrom consists of an insulating material on which powder particles which move past are charged electrically by friction.