Abstract: An electrostatic spray coating apparatus is disclosed which comprises a spray nozzle containing both air and liquid discharge ports, an inductive charging device or charging electrode located exteriorly of the discharge ports and attached to the spray nozzle, and electrical connections for applying an electric potential to the inductive charging device. The inductive charging device or charging electrode creates a charging zone, and is preferably positioned so that ambient air is mixed with air and fluid exiting from the discharge ports within the charging zone.

Abstract: An improved electrostatic spray gun, particularly of the hand-held type, is disclosed including an electrically insulative barrel and nozzle assembly, an electrically insulative air valve module mounted to the rear of the barrel assembly and externally thereof, and an electrically conductive metal handle assembly enclosing the rear end of the barrel and the air valve module. A charging electrode protrudes from the discharge orifice of the nozzle assembly. The flow of air through the barrel and nozzle assembly is controlled by a trigger which actuates the air valve. Actuation of the air valve in turn controls a needle and seat valve assembly close to the discharge orifice of the nozzle assembly to control the flow of coating material through the gun. A resistor is disposed inside the needle valve immediately upstream of the charging electrode.

Abstract: An air atomizing nozzle assembly for electrostatic spray guns is disclosed. The nozzle assembly includes an air cap having a central bore which surrounds a fluid tip nozzle. The bore has a plurality of axially aligned holes evenly spaced about its circumference and intersecting the edge thereof thereby defining a plurality of uniformly dimensioned, circumferentially spaced axial gas flow passages with spaced, radially extending ribs therebetween. The ribs between the holes engage the outside diameter of the nozzle to align its center axis on the axis of the central bore. The air cap and nozzle tip thus cooperate to form a plurality of uniform gas flow passages around the nozzle thereby producing a uniform atomizing air flow pattern around the nozzle. The air cap is retained in a one-piece resilient retaining ring by snapping the air cap into position over an annular lip of the ring. The air cap and retaining ring form a seal which prevents control air from escaping to the atmosphere.

Abstract: Disclosed is a spray gun having a gas nozzle and a fluid nozzle, each of the nozzles being in cooperative spatial relationship with the other to cause a fluid stream issuing from the fluid nozzle to be atomized and sprayed as fluid particles by gas issuing from the gas nozzle. In a preferred embodiment the fluid nozzle orifice has therein an axially disposed rod to increase surface area from which the fluid particles can be found, the rod being a corona discharge electrode of a first polarity. The spray gun additionally has an induction charging electrode of a second polarity opposite the first polarity and disposed adjacent the gas and fluid nozzles, the induction charging electrode defining a charging zone wherein an electrostatic charge is imparted to atomized electrically-chargeable fluid particles. Relatedly disclosed is a method of applying a liquid coating composition having an electrical conductivity of less than about 0.06 .mu.

Abstract: A nozzle tip especially useful with airless sprayers is formed from a plurality of parts, all of which are fabricated from blanks of hard, wear-resistant materials such as ceramics or powdered metals. Exterior surface portions of the nozzle tip parts are final-formed during formation of the blanks, typically during a sintering operation. Mating interior surface portions of the nozzle tip parts, as well as a nozzle orifice portions, are formed quickly and inexpensively by machining. Principles of the invention are also applicable to spray nozzles of the electrostatic type. A thin, electrically conductive blade may be clamped between or among adjacent nozzle tip parts with a portion of the blade extending forwardly of the nozzle tip parts to charge liquid particles being sprayed.

Abstract: A system and method for electrostatic coating of articles with paint particularly suited for coating irregular surfaces from a substantial distance. Water-borne conductive paint may be handled from an electrically grounded supply. Plural paint particle charging mechanisms are established by a DC potential applied to an electrode physically divorced from the paint stream. The articles being coated are electrically charged.

Abstract: A hand-held manually operable deposition gun for projecting electrostatically charged particles. The gun includes at its front end means for discharging the particles, which may be either liquid or solid, and an electrode for electrostatically charging the particles. The electrode is maintained at a high unidirectional voltage of several tens of kilovolts by connection to a piezoelectric generator through a voltage integrating device, both mounted at the rear of the gun. The piezoelectric generator is actuated by a motor-driven impulse means also located at the rear of the gun. A trigger mounted on the gun activates both the motor and the flow of particles from the gun.

Abstract: A nozzle for an electrostatic airless coating spray gun comprises a circular orifice and a cylindrical holder provided concentrically with the orifice and defining an annular electrode.

Abstract: This invention is in an improvement in electrostatic spraying apparatus for coating objects with electrostatic powder, or dust. The apparatus includes a housing or body member having a discharge nozzle at one end and internal flow passages for conducting compressed gas supplied from an external source to the discharge nozzle and a deflector element coaxially disposed adjacent the discharge end of the nozzle. A source of powder or dust is provided and is mixed with the compressed gas to produce a powder gas mixture which is fed to the flow passage. Electrodes connected to a high voltage source are provided within the flow passage and at the discharge end of the nozzle to ionize the powder gas mixture. The invention provides a hollow oval shaped charging chamber within the nozzle communicating with the flow passage so that the powder gas mixture passes therethrough and is ionized therein.

Abstract: The disclosure concerns an atomizer head used for atomizing wet lacquer, or the like. The atomizer head has an air conduit communicating with an air outlet part and has a liquid conduit communicating with a liquid outlet part. The air outlet part is radially outside the liquid outlet part. There is an inner part of the atomizer head which adjoins the outlet end of the liquid conduit. The inner part has an outside which is preferably trumpet shaped. The liquid conduit outlet end communicates with the outside of the inner part through obliquely extending ducts. There is an intermediate part that is outside the outlet end of the liquid conduit and outside the inner part. A cap is positioned outside the intermediate part. The air conduit is in part defined between the intermediate part and the cap. The intermediate part has a peripheral flange which is engaged by the interior of the cap. The flange has grooves extending along it for passage of air. The flange is in the air conduit.

Abstract: An electrostatic powder painting gun head in which a needle electrode is provided at a central portion in the proximity of a cylindrical powder ejection port made of insulator, an annular strip electrode is disposed outside of the powder ejection port, also a gas injection port for forming a gas flow layer along the surface of the annular strip electrode is provided, and further there is provided a high voltage power supply for applying a predetermined voltage between the needle electrode and the annular strip electrode.

Abstract: A device for painting by electrostatic powder spraying wherein a passage for triboelectrifying powder particles is formed in an electrically conductive housing and is surrounded by an electric insulator layer of a synthetic macromolecular material, such as nylon or fluorocarbon resin, containing powder of an electrically conductive material, such as copper, aluminum or carbon. As the electrostatic powder moves through the passage, it frictionally engages the insulator layer and causes an electric charge on the surface of the electric insulator, due to the triboelectrification movement in the electric insulator, and a current flows to the powder. Therefore, powder particles can be continuously triboelectrified without suppling any voltage or with supplying a very low voltage for forming an electric field.

Abstract: An electrostatic spray coating apparatus including means for mechanically atomizing coating materials and means for electrostatically charging the atomized material for deposit onto articles, is characterized by an improved material-charging means and an improved means for sealing material passages from the remainder of the apparatus in a manner which contributes to efficient and effective charging of the material, yet minimizes the capacitance of the material charging means, whereby the energy capable of being stored by the charging means is significantly reduced. The spray coating apparatus also includes means ensuring safety of the apparatus, and enhanced overall construction of the apparatus for greater service life, more reliable and safe operation, and economy.

Abstract: An electrostatic spray coating gun has an improved high voltage charging system which includes a flexible and resilient electrode in the form of an elongated coil spring. This form of electrode substantially eliminates the likelihood of scratching or puncturing the skin of an operator or repairman, and allows the electrode to return to its proper orientation after being bumped, while exhibiting good paint charging characteristics for use in electrostatic spray coating.

Abstract: An induction-charging adapter head may be quickly and easily mounted on, or demounted from, a conventional spray device equipped with a plate-like adapter of the type disclosed. The plate-like adapter also provides for safe connection or disconnection of a high voltage source to the induction-charging adapter head electrode by providing means for maintaining an electrical path to ground between the adapter head and plate-like adapter during the making or breaking of the high voltage connection.

Abstract: Electrostatic spraying apparatus comprises a rotary spraying head and a multiple electrode arrangement which includes two high voltage electrodes one of which has an uninsulated portion, and a grounded electrode. A paint flow space is defined between the uninsulated portion and the grounded electrode as well as the remainder of the one high voltage electrode and the grounded electrode. The second high voltage electrode is spaced outwardly from the grounded electrode and has an insulating layer both on its outer side and on its side facing the grounded electrode.

Abstract: An air-assisted electrostatic round-spray nozzle for liquids, wherein, except for the charging electrode(s), the diffuser, as also the whole of the outer part of the nozzle, is made of electrically insulating material, and whereon the said electrode(s) is/are formed by one or more points or pin-point zones located substantially in the atomizing plane, on or very near the axis of the nozzle.

Abstract: An electrostatic sprayer for spraying water-based paints has two or more electrodes mounted on an insulating holder and disposed in the path of the spray between the object to be coated and the outlet of the sprayer. The electrodes are at varying distances from the sprayer outlet and are connected to different potentials.

Abstract: An electrostatic spray coating gun for applying coating materials which have high to moderately high electrical conductivity is disclosed. The gun has an improved high voltage electrical system, improved hydraulic seals, and is adaptable to apply porcelain enamel coatings in slurry form. The gun has a flexible and resilient electrode in the form of an elongated coil spring. This form of electrode substantially eliminates the likelihood of scratching or puncturing the skin of an operator or repairman, and allows the electrode to return to its proper orientation after being bumped, while exhibiting proper paint charging characteristics for use in electrostatic spray coating. The electrode is positioned forward of a flat-fan spray nozzle and is displaced from the axis of the spray by means of an extension assembly which can be angularly displaced about the axis of the spray.

Abstract: An electrostatic spray apparatus wherein a charging chamber is formed as an enlargement in the conduit feed to the spray nozzle. The charging electrode is disposed axially of the conduit with a pointed end located at the exit end of the enlargement and facing upstream of a particle stream flow and opposed to a counterelectrode end located at the inlet side of said enlargement. The counterelectrode may be an obtuse end of an elongated element or may be formed as a grid extending across the conduit or as an annular element formed about a wall of the conduit. Optionally shown are a plurality of enlarged charging chambers, as annular element forming a constricted flow path and a charging electrode second end extending beyond the spray nozzle. Means introduce an air flow into the particle stream at both the nozzle and at the charging chamber.