A coating-powder spray gun includes a gun housing (2) of which the front end face is sealed pressure-hermetically with respect to compressed gas by a front end wall (28). A current-limiting resistor (32) and at least a portion of a high-voltage generator (10) are potted in an integral electrically insulating block. The potted block may be received in the gun housing (2).

An electrostatic spray gun is disclosed which comprises a high valued resistance in the barrel portion of the gun, and a second resistor in the nozzle of the gun closely adjacent to a charging electrode projecting from the nozzle to provide safer operation.

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 ...

A hand-held electrostatic sprayer for use in a process for the electrostatic spraying of pesticides by producing a descending cloud of charged pesticide particles and impressing a lateral component of motion upon the cloud with the aid of a laterally disposed electrode charged in the same sense as the cloud, the sprayer including an elongated body forming the sprayer handle and having: a neck supporting a downwardly-directed electrostatic sprayhead; a reservoir for supplying liquid to the sprayh...

A method and apparatus for making artificial snow wherein a stream of compressed air and liquid water is expanded into a nucleating in which there is established an electrostatic field. By subjecting the expanding stream of compressd air and liquid water to the electrostatic field, the mean particle size of the ice nuclei formed in the nucleating zone is decreased and the number of ice nuclei particles produced for a given water flow is increased. Additionally, a stream of pressure water may be ...

The invention relates to a powder sprayer with electrostatic charging capacity and by means of which in a simple and effective manner by way of example a coloring powder can be electrostatically charged, so that it will be completely charged all over the entire surface of the particles. The powder sprayer (1) comprises a number of curved charging ducts (6, 6') of long extension made of electrically non-conducting material which ducts are coated with an electrically conducting layer (7) along the...

Electrostatic coating apparatus including apparatus for establishing an electrostatic field for indirectly charging atomized droplets of paint or other coating material discharged from an atomizer. A flexible tube is formed into an annulus and is positioned coaxially with the atomizer. Pins extend through the tube and have short ends which project towards a workpiece to be coated. The tube is formed from an insulating outer layer and a semi-conducting inner layer having a high distributed resist...

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.

An electrostatic atomizer comprises a power source for powering a charge injection device, a controller for controlling the net charge injected by the charge injection device, and a sensor for sensing breakdown precursors in the vicinity of the orifice and producing a feedback signal upon the occurrence of the breakdown precursors. The sensor is in communication with the controller and the controller is responsive to the feedback signal so that upon occurrence of the feedback signal, the control...

An electrostatic atomizer has a power source powering a charge injection device. The power source is arranged to vary the net charge injected by the charge injection device cyclically in accordance with a pattern of variation so that the net charge repeatedly increases to a higher value at or above a long-term breakdown value. The net charge injected is reduced by the power source to a lower value below the long-term breakdown value so that corona-induced breakdown is reduced. A method for elect...