Abstract: A process for coating a substrate such as a photoreceptor is performed by delivering at least two fluid streams to a bell of a rotary atomizer, combining the fluid streams substantially at the bell of the rotary atomizer such that the bell atomizes and mixes the fluid streams into a substantially homogenous atomized mixture, and depositing the mixture onto the substrate in the form of a layer on the substrate. The process is useful for depositing a plurality of different substances, such as two charge generating pigments, on the surface of a substrate such as a photoreceptor. Because the substances are combined substantially at the bell of the rotary atomizer and subsequently dried or polymerized, different substances can be incorporated into a single layer on the substrate that would normally not be combinable due to interaction between the plurality of substances such as agglomeration.

Abstract: An electrostatic spray coating apparatus for ejecting an atomized liquid paint toward an object to be coated with a paint has a rotary head for ejecting an atomized liquid paint toward the object. The rotary head comprises a rotary member, adapted to rotate about a center axis thereof, for discharging a liquid paint in the form of an annular thin-film therefrom toward the object during rotation thereof. A gas ejecting unit is provided for ejecting a gas flow so as to atomize the liquid paint discharged from the rotary member. The gas ejecting unit includes an adjusting portion for adjusting the direction of the gas flow, which is to be ejected from the ejecting unit, with respect to the center axis of the rotary member.

Abstract: Described herein is an electrostatic spray coating machine of the type which has a plural number of supporters (31) at intervals around the circumference of a housing (2) as electrode retainer rods for holding external electrodes (32). Each supporter (31) is formed with an oblique surface (31A) at the fore end thereof to provide a concealing projection (31B) on the inner side of the fore end of the supporter (31). As a result, when seen from the rotary atomizer head (5), the discharge distance (H') betweewn the fore end (32A) of each external electrode (32) and the rotary atomizer head (5) is increased to permit application of a higher voltage to the external electrodes (32).

Abstract: A centrifugal device for atomizing a coating product comprises a generally bowl-shape rotating member having an inside wall substantially perpendicular to the rotation axis of the rotating member between a drive hub and the interior surface of the bowl. The wall defines within the bowl a front cavity open in the spraying direction and a rear cavity surrounding the hub. A coating product nozzle and a cleaning product nozzle are accommodated in the rear cavity and are both directed towards the wall. Passages are formed at the outside periphery of the wall near the interior surface, and the wall incorporates an annular opening communicating with the rear cavity and within which is defined a reflector surface adapted to reflect some of a jet of liquid towards the central part of the wall. The cleaning product nozzle is oriented towards the reflector surface.

Abstract: An electrostatic coating product sprayer device is provided with quick cleaning means. The sprayer device comprises a rotatable sprayer member and at least one cleaning product nozzle fixed relative to the rotatable member. The nozzle is directed towards a generally convex surface of the rotatable member so that the jet from it impinges on the generally convex surface with a large angle of incidence. The nozzle is disposed in the immediate proximity of the generally convex surface, to its rear.

Abstract: A coating product sprayer installation enabling a rapid change of coating product. The installation includes two parallel distribution branches each containing a piston or membrane type intermediate storage tank defining an actuation chamber actuated by a liquid, the branches being connected by means of valves between a coating product change unit and at least one coating product sprayer. The apparatus can be used advantageously for electrostatic spraying of conductive coating products.

Abstract: An atomizing bell or cup for use in a rotary atomizing apparatus includes a generally frusto-conical-shaped wall having an outer surface and an inner flow surface which terminates at an annular atomizing lip. A plurality of radially outwardly extending fins or ribs are formed on the inner flow surface of the cup upstream from the atomizing lip which are circumferentially spaced from one another to provide flow paths therebetween for coating material flowing along the interior surface of the cup such that the coating material is divided into a number of individual streams before reaching the atomizing lip. These streams are emitted from between adjacent ribs a short distance upstream from the atomizing lip which allows centrifugal force to at least partially flatten the streams forming ribbon-shaped streams, which, when flung outwardly from the atomizing lip, form completely atomized coating particles which are substantially free of air bubbles.

Abstract: An electrode (60) for electrically charging dispensed coating material is electrically substantially isolated from the coating material dispensing device (16). Sources provide first (30-36) and second (70-76) coating materials, the first (30-36) of which is electrically substantially more conductive and the second (70-76) of which is electrically substantially less conductive. The first (30-36) or the second (70-76) coating material is alternately supplied to the coating material dispensing device (16). A high-magnitude electrostatic potential supply (58) provides electrostatic high potential to the electrode (60) and selectively to the coating material dispensing device (16).

Abstract: Particles of conductive coating material, such as the water-enamel type paint, are sprayed from a grounded bell-atomizer (2) and are electrostatically charged in the corona-discharge area by outer electrodes (10) which are inserted into a holding-arrangement (11, 12, 15) made of an insulating material. Potential-controls in the form of suitably selected materials for the holding-arrangement (11, 12, 15) and/or an atomizer-housing (4) are provided. The radial-potential pattern between the atomizer-housing (4, 6) and the outer electrodes (10) is approximated to the radial-potential distribution of the material sprayed. The insulating material of at least a portion of the apparatus consists of a fluorocarbon such as PTFE (polytetrafluorethylene). The subject invention reduces the danger of the apparatus coating itself.

Abstract: An inproved rotary paint atomizing device of the type having an internal chamber for receiving paint from a paint feed tube extending coaxially through a drive shaft which rotates the device at a high speed. An annular insert is clamped between the drive shaft and the device for forming a rear wall of the paint receiving chamber. The insert prevents paint from splashing into the annular space between the rotating drive shaft and the stationary paint feed tube. When the device is removed from the shaft. The separate insert permits easy access to the paint receiving chamber for cleaning.

Abstract: An improved rotary paint atomizing device in the form of a bell and a cover plate which is releasably attached to the front center of the bell. Paint fed along the axis of the device onto a conical projection on the back surface of the cover plate accelerates and flows outward in a radial direction. The cover plate surface is curved so that as the paint flows outwardly, it also flows first forward and then back until it reaches radial slots formed in a peripheral rim on the cover plate where the cover plate contacts an interior bell surface. Paint discharges from the slots onto a conical interior bell surface and flows in wide, closely spaced ribbons which merge into a uniform, continuous thin sheet before it is discharged from the bell edge. As the paint discharges from the bell edge, the sheet produces extremely fine uniform ligaments which break up to produce fine, uniform small paint particles.

Abstract: A high speed non-incendive rotary painting assembly including a high voltage power supply, an air supply means and a paint supply means is disclosed. The rotary painting assembly comprises a non-conductive body. A high speed, non-conductive turbine is connected to a non-conductive atomizer bell. In one embodiment, the non-conductive turbine is connected to a non-conductive rotatable shaft which mounts the non-conductive atomizer bell. In another embodiment, the non-conductive shaft is fixed. The non-conductive shaft rotatably mounts a non-conductive turbine and rotary atomizer bell assembly.

Abstract: Electrostatic liquid spray coating apparatus including a rotary atomizing cup of insulative material driven by an air turbine, is provided with a semi-conductive charging device extending through the cup, the inner portion of which is proximate the inner surface of the cup for contact charging liquid coating material supplied to the rear of the cup as it flows forwardly and outwardly over the rotating cup interior and contacts the charging device prior to atomization at the forward edge of the cup. A generally cylindrical insulative support body, housing a turbine and its associated air bearing and cup drive shaft, has a reduced diameter intermediate section which provides an annular cavity in which are located liquid coating and solvent valves for controlling the flow of liquid coating and solvent to the cup.

Abstract: A high-voltage electrostatic painting apparatus (10) for coating an article (12) inside a spray booth (14). The apparatus (10) includes a flow rate meter (34) disposed within the electrostatic environment for measuring the rate at which paint is supplied to a discharge atomizer (18). The meter (34) includes two intermeshing rotors (44, 46) disposed within a sealed non-ferromagnetic housing (54). The two rotors (44, 46) rotate in response to liquid paint flowing through the housing (54). A magnetic coupling (64) acts through the housing (54) to drive an optical signal producing disc (62). A pick-up sensor (82) senses the optical signal from the disc (62) and sends that signal outside the booth (14) to a master control unit (40) via a fiber optic conductor (90). The master control unit (40) automatically adjusts a flow rate regulator valve (92) to provide a constant rate of paint flow to the discharge atomizer (18).

Abstract: In an apparatus for the use of so-called water enamels or some other similarly conductive coating material, the electrical field for charging the sprayed particles is produced between the grounded spraying edge (6) of a bell-shaped atomizer (10) and a large number of external electrodes (10) inserted into an annular element (20) made of an insulating material.

Abstract: Electrostatically charged liquid such as water is supplied via rotating structure to impinge on a baffle. The latter deflects the charged liquid onto a rotating insulative, frusto-conical surface on which the charged liquid forms a film which flows forwardly to an annular edge. Gas such as air, sweeping past the edge, impacts the layer arriving at the edge and produces fine charged droplets of the liquid, forming a fog. This charged fog is usable for suppressing dust particles in the air.

Abstract: In an apparatus for the use of so-called water enamels or some other similarly conductive coating material, the electrical field for charging the sprayed particles is produced between the grounded spraying edge (6) of a bell-shaped atomizer (10) and a large number of external electrodes (10) inserted into an annular element (20) made of an insulating material.

Abstract: Spraying unit for spray coating articles with powdered or liquid material contains a spray head fastened to a front end of a tubular inner and axially extending support and an outer protective tube disposed concentrically about the inner support. The inner support and the outer protective tube are electrically insulative. One or more high-voltage generators are spacedly disposed about the inner support, axially rearward of the spray head, and within an elevated pressure chamber defined between the protective tube and the inner support. The arrangement is such that it produces a constant outwardly bound flow of gas from the elevated pressure chamber which flow prevents soilage of the internal parts by coating material.

Abstract: A color exchange and cleaning device of a minibell painting machine has two systems or sections, that is, a bell-side (first) color exchange and cleaning section and a counter-side (second) color exchange and cleaning section, and includes a manifold provided with a bell-side conduit and a counter-side conduit. The bell-side conduit is communicated with a trigger dump valve for the bell-side color exchange and cleaning section and a trigger valve for the counter-side color exchange and cleaning section. The counter-side conduit is connected via a connection hose with the trigger dump valve for the bell-side color exchange and cleaning section. The trigger valve for the counter-side color exchange and cleaning section is connected with a dump valve. The counter-side conduit is provided with a plurality of color valves, a low-pressure thinner valve and a low-pressure air valve. Thus, a manifold for the bell-side color exchange and cleaning section is eliminated, and the connection hose is made short.

Abstract: A rotary spray head comprises a shaft in a longitudinal cavity in a body with spray means mounted on one end of the shaft and projecting axially from the body. At least one magnetic bearing is provided to support the shaft at least partially in the radial direction. The magnetic bearing comprises two magnetized annular parts respectively forming a stator and a rotor. These are in face-to-face relationship to each other so as to define between them an airgap occupying a plane substantially perpendicular to the main axis of symmetry of the shaft. They have respective main axes of symmetry coincident with that of the shaft.

Abstract: The invention provides methods and apparatus for conducting electrostatic spray coating by which an improved coating layer made uniform in gloss, hardness, weather-tightness, and other characteristics is obtained on an object to be coated. The coating layer is formed with use of a rotary spray head device which is provided with a funnel-like body having an inner wall surface and an open end portion. The rotary spray head device is driven to turn on an axis of rotation surrounded by the inner wall surface of the funnel-like body, and supplied with plural kinds of coating material which are discharged to a substantially common location on the inner wall surface of the funnel-like body simultaneously through respective separate paths so as to form their respective layers superimposed on said inner wall surface of the funnel-like body and move toward said open end portion of the funnel-like body.

Abstract: A spray head of rotating type electrostatic spray painting device comprises a cup shaped inner circumferential wall and a tip portion from which paint particles are discharged. The outer periphery of the tip portion is formed as an annular flat face perpendicular to the rotating axis of the spray head. The inner periphery of the tip portion is formed as a conical face which diverges toward the outside of the spray head. A plurality of paint guide grooves are formed on only the inner periphery of the conical face.

Abstract: A coating applicator has a rotary atomizer detachably mounted directly on a front end of a rotor of an air driven turbine for convenient removal and cleaning of the atomizer. The rotor and atomizer are forward of bearings that rotatably mount a shaft for supporting the rotor, which isolates the bearings from coating material delivered to the atomizer, and turbine exhaust air augments shroud air in shaping the pattern of atomized material.

Abstract: An electrostatic spray coating assembly (10) for atomizing electrically conductive material comprises a rotary atomizer spray head (12) having an annular atomizing spraying edge (14). An external housing (22) supports the spray head (12) and a feed line (18) supplies the material from a supply system to the spraying edge (14) of the spray head (12). The feed line (18) and the material supplied thereby and the spray head (12) are electrically grounded. Three needle-shaped charging electrodes (36) are in spaced relationship circumferentially at uniform angular intervals with respect to the spray head (12). The charging electrodes (36) are connected to a source of high voltage potential for producing an electrical field charging the conductive material. The charging electrodes (36) are positioned from the spraying edge (14) of the spray head (12) a predetermined radial distance (R) at least twice the diameter (d) of the spraying edge (14) of the spray head (12).

Abstract: In the case of rotary atomizers, especially those having external electrodes on a grounded spray head, there is a danger of self-contamination of the front part of the atomizer housing; the latter is, therefore, provided with a rotating cover (10) which may be connected to the rotating spray head (2).

Abstract: A process and apparatus is disclosed comprising a high-speed rotation bell for applying quick-evaporating fluids, such as quick-evaporating liquid paint, wherein the impact deposition of largely evaporated paint particles on the high-speed rotation bell is prevented by affecting the flight path of the paint particles flying back in the zone of the toroidal vortex toward the high-speed rotation bell with electric or magnetic or aerodynamic forces or combinations of these forces.

Abstract: A rotary type electrostatic spray painting device including a rotary shaft driven by an air turbine. A reflecting face portion and a non-reflecting face portion are formed on the rear end face of the rotary shaft. A rotating speed sensor is arranged adjacent to the rear end face of the rotary shaft to detect the rotating speed of the rotary shaft from light reflected from the reflecting face portion. The amount of pressurized air fed into the air turbine is controlled in response to the output signal of the rotating speed sensor so that the rotating speed of the rotary shaft becomes equal to a desired rotating speed.

Abstract: A method and apparatus for suppressing smoke employs a fine spray of water droplets that are electrically charged opposite to the charge of soot particles in the smoke. A hand held housing contains a rotary shaft which carries a cup that spins within an air nozzle when the shaft is rotated. Electrically charged water is applied to flared inside surface of the cup and moves by centrifugal action to an annular lip on the end of the cup. An air driven turbine drives the shaft, and the compressed air used to power the turbine is passed through the nozzle where it helps to atomize and spray the water discharging from the lip on the spinning cup. The entire metal assembly within the insulated housing is maintained at a high electrical potential to effectively charge the water.

Abstract: A rotary type electrostatic spray painting device comprising a rotary shaft supported by static pressure air bearings in a non-contact state. A drive turbine wheel and a braking turbine wheel are fixed to the rotary shaft. A paint injection nozzle is provided for feeding paint onto a cup shaped inner wall of the spray head. The paint injection nozzle is connected to a paint suction device. When changing the color of the paint, pressurized air is injected towards the braking turbine wheel and, at the same time, paint remaining in the paint injection nozzle is sucked away by the paint suction device.

Abstract: A rotary type electrostatic spray painting device comprising a rotary shaft which is supported by static pressure air bearings in a non-contact state. A drive turbine wheel and a braking turbine wheel are fixed to the rotary shaft. The static pressure air bearings are connected to an air feed pump via an air supply conduit. Pressurized air is injected from air injection nozzles towards the turbine wheels only when the pressure or the flow rate of pressurized air flowing within the air supply conduit exceeds a predetermined level.

Abstract: An apparatus for generating fine liquid metal droplets from a liquid or molten metal comprises a rotatable member situated in a pressurized or evacuated chamber. Means are provided for generating an electric field at the edge of the member having sufficient strength to overcome the surface tension of the metal. A liquid metal delivery means directs liquid metal onto a surface of the member over which the metal flows toward the edge as the member is spun. As the liquid metal leaves the surface at the edge, the force of the electric field causes fine liquid metal droplets which are more uniform and smaller than those produced without an electric field to form. A method for forming fine liquid metal droplets is also disclosed.

Abstract: A rotating spraying type coating apparatus with wash shroud comprises a rotary drive device, a spraying head connected to the rotary drive device, a paint feed passage connected to base end of the spraying head, a paint radiating part formed at top end of the spraying head, an air jet device of annular shape for jetting an air flow to direct paint particles forward which are radiated from the paint radiating part, a coating pattern adjusting valve for varying the flow rate of the air jetting from the air jet device, a wash shroud covering outside of the spraying head and movable forward and rearward, and an opening formed at front end of the wash shroud.

Abstract: A rotary atomizer spray painting device having a nonconductive fixed, axial tube for feeding paint, and having a nonconductive rotor supported for rotation in a nonconductive housing about the tube on air bearings or nonconductive ball bearings, and having turbine drive blades proximate one end thereof, the rotatable rotor supported inside of a nonconductive housing which has a high voltage electrical path therethrough, electrically connected to one or more symmetrically spaced forwardly projecting needle electrodes, the rotatable rotor being fixedly attached to a nonconductive forwardly projecting bell-shaped atomizer, the housing having pressurized air inlets for directing air in driving relationship to the turbine blades.

Abstract: A sprayer, particularly for hand-held or vehicle-borne agricultural use, has a rotatable sprayhead having a liquid dispersing surface in the form of disc, dish or cup, a rotatable electrode spaced from the outer edge of said surface by a gap, means for supplying liquid to the liquid dispersing surface, connections for the poles of a source of electrostatic potential to apply one pole of the source to the electrode and to apply the other pole of the source to at least the outer edge of the surface to apply the potential of the source across the gap, and means to rotate the surface and the electrode to disperse liquid supplied to the surface as a charged spray. The potential may be applied to the outer edge via the liquid if conductive or via a suitable conductive path in the sprayhead.

Abstract: An electrostatic spraying apparatus for applying a liquid coating material to a work piece, and which comprises a rotating bell-like or disc-like atomizer head and an annular gap coaxial therewith which is connected to a compressed air source is provided with an improvement of a further annular gap connected to a compressed air source, the additional gap coaxially surrounding the first annular gap, and the gap width of at least one of the two annular gaps being adjustable.

Abstract: A coating applicator is disclosed which includes a rotary atomizer on a driven shaft. The shaft operates at high speeds. Coating material is supplied to the rotary atomizer. A pair of spaced bearings rotatably mount the shaft and a seal assembly is positioned between the rotary atomizer and the front bearing. The seal assembly includes a bearing cover having a cutting edge. A mating cap member surrounds the shaft and has a sealing shoulder which is engaged by the cutting edge. Exhaust air is used to cool the bearings, pressure the interior of the applicator and enhance the seal assembly.

Abstract: A rotary atomizer for coating workpieces with a fine layer of liquid material, and a method of operating the said atomizer.A rotary atomizer (10) for coating workpieces with a fine layer of liquid material fed at very low flow rates includes a bell-type rotatable atomizing device (12) for dispensing the liquid from an edge (17) in an atomized condition under the effect of centripetal forces. The liquid fed into a tube (21) having an outlet (20) within the bell (12) appears as discontinuous drops (40) at the outlet (20). Air is also fed into the bell (12) via a tub (25) having an outlet (26) disposed adjacent the liquid outlet (20) such that the air jet (41) breaks up the drops (40) and forms a spray (42) directed at the internal wall of the bell (12). The spray (42) coalesces into a continuous film of liquid as it travels on the internal wall of the bell (12) to the discharge edge (17).

Abstract: An electrostatic coating process which comprises feeding a liquid paint in thin film form toward the circumferential edge of a high-velocity rotating member having a high voltage applied thereto along the inner circumferential surface thereof and atomizing the paint from the circumferential edge of the high-velocity rotating member; characterized in that a number of cuts are formed on the circumferential edge, and a stream of the paint flowing forwardly substantially in the axial direction of the high-velocity rotating member is converted at said circumferential edge into a number of diametrically outwardly flowing divided paint streams and simultaneously atomized and discharged. Preferably, the paint is fed to the inner circumferential surface of the rotating member through an annular paint flow passage having knurled grooves formed over its entire outer circumferential surface.

Abstract: A rotatable, electrically chargeable, substantially bell-shaped sprayer for producing a paint mist from an axially fed liquid paint such as 2-component lacquers, for an apparatus for the electrostatic application of sprayed charged particles of the paint mist onto an article, the sprayer having an annular coaxial flowover surface for the liquid paint and an annular lip which projects axially forwardly on a radial and axial outer edge portion of the flowover surface. The lip is provided on its radial inside with grooves for channeling the flow of the liquid paint, the grooves being uniformly distributed on the circumference and extend approximately in the direction of the flow of the liquid paint. The grooves terminate open at a spray position of the lip and intersect in pairs.

Abstract: A rotary type electrostatic spray painting device comprising a rotary shaft and a spray cup-shaped head fixed onto the front end of the rotary shaft. Paint is fed onto a cup-shaped inner wall of the spray head. The rotary shaft is supported by a single thrust air bearing, a pair of radial air bearings, and a non-contact type rotary shaft supporting device having a permanent magnet. The permanent magnet is arranged near a circumferential outer wall of a hollow portion of the rotary shaft for supporting the rotary shaft by the attracting force of the permanent magnet. An electrode, continuously contacting the rear end of the rotary shaft, is provided. A negative high voltage is applied to the housing of the paint device. In addition, the negative high voltage is also applied to the spray head via the electrode and the rotary shaft.

Abstract: An electrostatically charged rotary paint atomizing device used in electrostatically coating an article with a smooth homogeneous film of paint and without the generation of foam or other surface irregularities on the article being coated, wherein an electrostatic field is established between the peripheral edge of the rotating atomizing device and the article to be coated and the liquid paint flows toward the edge of the atomizing device as a continuous thin film, which film is formed into a circumferential series of branch flows of narrow width flowing in the peripheral direction of the atomizing edge, and the liquid paint is atomized from the series of branch flows as they are projected beyond the edge of the atomizing device. The rotary atomizing device may be in the form of a bell or disk and includes a plurality of shallow grooves near its periphery preferably extending radially and of increasing depth in the direction of paint flow and terminating at the discharge edge.

Abstract: A thin freestanding oil film is produced in vacuum by directing an oil stream radially inward to the hollow-ground sharp outer edge of a rotating disc. The sides of the edge are roughened somewhat to aid in dispersing oil from the disc. Oil is removed from the surface of disc to prevent formation of oil droplets which might spin off the disc and disrupt the oil film. An ion beam is directed through the thin oil film so that electrons are stripped from the ions to increase their charge.

Abstract: An apparatus for electrostatically coating an object using electrostatically charged powder grains. The invention improves upon the spray bell sprayer by having a fixed hollow shaft providing a central supply line for the powder grains, the spray bell rotates about the hollow shaft and a plurality of compressed air nozzles pass radially into the hollow shaft.

Abstract: An apparatus for applying a coating of an atomizable material, such as a phosphor slurry, to the inside surface of a glass tube comprises a rotatable member having a surface for receiving material, a device for rotating the member and conduct for delivering material to the surface of the member. The rotating and delivery mechanisms are preferably situated along the same direction as the extension of the axis of rotation through the surface of the member. The apparatus may include a device for electrically charging the material prior to coating. A method for applying the coating of atomizable material to the inside surface of a glass tube comprises positioning a rotatable member within the tube, delivering the material to a surface of the member adapted to receive the material, and rotating the member at a predetermined velocity to atomize the material and inpact the surface of the tube with at least a portion of the atomized material.

Abstract: An improved rotary atomizer bell is disclosed for use in an electrostatic rotary atomizer liquid paint applicator. The bell has a paint discharge edge at a front end and has a predetermined wall thickness at the front end. In one embodiment, a radius of from 0.040 inch up to the front end wall thickness is provided between an exterior surface and a flat front end surface. In a modified embodiment, the front end surface on the bell lies on a right conical surface of revolution having an apex located on the axis of revolution of the bell and spaced outwardly from the bell and having a base angle of between about 7.degree. to 20.degree..

Abstract: An electrostatic spraying nozzle, particularly for agricultural use, provides for a high rate of liquid delivery, up to 6 or 7 mL/s, while maintaining uniform charging of the atomized spray by means of a low-current supply. Atomization is produced centrifugally from a conical rotor and the liquid is charged by contact with an electrically isolated conductive coating on the surface of the rotor. The coating is raised to the potential of a high-voltage needle electrode by conduction through one or more air-gaps between the needle point and the conductive surface. The conductive surface is of sufficient extent in relation to the position of the electrode to shield the electrode from any external surface at earth potential and thus to ensure that only the required charging current is passed by the electrode. A shielding action is produced by a relatively deep conical form which also allows a high flow rate. For a frustro-conical surface of apical angle 60.degree. a ratio of end radii in the range 0.85 to 0.

Abstract: An electrostatic coating machine comprises a coating machine main body having a rotary atomizing head and a cleaning shroud, a plurality of color change valve mechanisms for feeding paints and cleaning fluids to the rotary atomizing head, a first change-over valve provided at a position close to the rotary atomizing head, paint feed passages respectively connected to each of the color change valve mechanisms and selectively communicating with the rotary atomizing head by way of the first change-over valve, a drain passage for recovering the drainage from the cleaning shroud and the first change-over valve, a discharging section for forcively discharging the drainage from the drain passage, and a second change-over valve provided in the midway of the drain passage communicating from the cleaning shroud to the discharging section.

Abstract: A device for feeding an electrically conductive coating material from a supply system to a coating material dispensing device wherein a high electrostatic potential is maintained between the supply system and the device, comprising an intermediate storage container fillable in controlled manner from the supply system to a maximum fill level and connected to the coating material dispensing device by a coating material conduit maintained at substantially the electrostatic potential of the coating material dispensing device, a device provided in the intermediate storage container for breaking up the supply of coating material into the intermediate storage container into electrically separated individual particles, and means for coupling the breakup device to a source of coating material, the breakup device being arranged above the fill level such that, between the breakup device and the interior of the intermediate storage container, a minimum spacing is maintained so that no electrostatic discharge occurs.

Abstract: Process for electrostatically coating objects with a fluid, for instance liquid paint, by applying a high voltage to a spray bell and by feeding the fluid to a revolving, driven spray bell. The flow-rate of the fluid supplied to the center of the spray bell is decelerated nearly to zero when it enters the bell, then the rate of the fluid is increased by being accelerated by the bell to 15,000 to 60,000 rpm, and the fluid thereupon is centrifuged off the spray rim of the bell and is guided to the object to be coated.

Abstract: A method of atomizing liquid paint using a rotating atomizing device and electrostatically coating an article with a smooth homogeneous film of paint and without the generation of foam or other surface irregularities on the article being coated, wherein an electrostatic field is established between the peripheral edge of the rotating atomizing device and the article to be coated and the liquid paint flows toward the edge of the atomizing device as a continuous thin film, which film is formed into a circumferential series of branch flows of narrow width flowing in the peripheral direction of the atomizing edge, and the liquid paint is atomized from the series of branch flows as they are projected beyond the edge of the atomizing device. The rotary atomizing device may be in the form of a bell or disk and includes a plurality of shallow grooves near its periphery preferably extending radially and of increasing depth in the direction of paint flow and terminating at the discharge edge.