Nozzle for electrostatic spray gun
AssigneeAtlas Copco Aktiebolag
InventorsAlf Georg Bertilsson, Sten Gunnar Hugo Svensson, Claes Erik Soderman
Life of this patent
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Abstract
An electrostatic spray gun for liquid paint has a nozzle that comprises an inner body formed of a sintered material that consists of an electrically non-conductive matrix, e.g. polytetrafluoroethylene, with conductive particles, e.g. bronze powder, dispersed in the matrix, and an outer body of electrically insulating plastic material. The rear end of the inner body is connected to high voltage, and it has an annular front surface around a paint discharge orifice. This surface shows a lot of such bronze particles that form point electrodes for producing air ions. Two additional needle electrodes are clamped between the two bodies. The paint is dispersed by air jets and the air ions attach to the paint particles.
Claims31
Electrostatic spray gun comprising a paint nozzle with a paint discharge orifice, means to convey paint to said orifice, and means coupling high voltage to said nozzle, said nozzle comprising:
- a non-conductive first body and a second body at least partly covered by said first body, said second body consisting essentially of a non-conductive matrix and a large number of electrically conductive particles dispersed therein, said discharge orifice being an orifice in said second body;
- said high voltage being coupled to said second body of said nozzle;
- and
- said second body having an annular surface around the paint discharge orifice which includes a plurality of exposed particle surfaces forming a plurality of electrodes for producing air ions, a plurality of said exposed particle surfaces comprising a substantial portion of the maximum cross-section of the respective particle, the exposed particle surfaces being substantially coplanar with the immediately adjacent surface of said non-conductive matrix.
Electrostatic spray gun comprising:
- an air nozzle of electrically insulating material and having an orifice therein;
- a paint nozzle extending through said orifice with a clearance thereto to form an air passage, said paint nozzle comprising a central body having a paint passage therein and forming a paint discharge orifice and an outer body of electrically insulating material closely covering at least part of said central body;
- means to convey atomizing air to said air passage;
- valve means in said paint passage in said central body to selectively open and close said paint passage;
- means to convey paint to said paint passage;
- said central body consisting essentially of a non-conductive matrix and a large number of electrically conductive particles dispersed therein, said central body having an annular surface around the paint discharge orifice which includes a plurality of exposed particle surfaces forming a plurality of electrodes for producing air ions, a plurality of said exposed particle surfaces comprising a substantial portion of the maximum cross-section of the respective particle, the exposed particle surfaces being substantially coplanar with the immediately adjacent surface of said non-conductive matrix;
- and
- means coupling high voltage to said central body.
A nozzle for use in an electrostatic spray gun, comprising a non-conductive first body and a second body at least partly covered by said first body, said second body consisting essentially of a non-conductive matrix and a large number of electrically conducting particles dispersed therein, said second body having a paint discharge orifice therein, said second body further having an annular surface around said paint discharge orifice which includes a plurality of exposed particle surfaces forming a plurality of electrodes for producing air ions, a plurality of said exposed particle surfaces comprising a substantial portion of the maximum cross-section of the respective particle, the exposed particle surfaces being substantially coplanar with the immediately adjacent surface of said non-conductive matrix.
Dependencies are inferred from the claim text.