Claims
- 1. An electrostatic spray coating assembly (10) for atomizing electrically conductive material and depositing the atomized material upon the surface of an object, said assembly (10) comprising; a rotary atomizer spray head (12) having an annular atomizing spraying edge (14) with a predetermined diameter (d) for centrifugally atomizing the material and projecting the atomized material radially therefrom, an external housing (22) supporting said spray head (12), feed line means (18) for supplying the material from a supply system to said spraying edge (14) of said spray head (12), said feed line means (18) and the material supplied thereby and said spray head (12) being electrically grounded, electrode means (32) in spaced relationship circumferentially at uniform angular intervals with respect to said spray head (12), said electrode means (32) being connected to a source of high voltage potential for producing an electrical field charging the conductive material, said assembly (10) characterized by the electrode means (32) being positioned radially outwardly from said spraying edge (14) of said spray head (12) a predetermined radial distance (R) which is at least twice said predetermined diameter (d) of said spraying edge (14) of said spray head (12), said spraying edge (14) being positioned in a plane and defining the forward end of said assembly (10) and said electrode means (32) including a tip portion (38) located axially rearward from said forward end of said spraying edge (14) of said spray head (12) a distance (X) not greater than half said predetermined radial distance (R).
- 2. An assembly as set forth in claim 1 wherein said electrode means (32) includes three charging electrodes (36).
- 3. An assembly as set forth in claim 1 wherein said electrode means (32) further includes an electrode holder (40) having a radial portion (42) extending substantially radially from said external housing (22) and an axial portion (44) extending axially from said radial portion (42) toward said forward end.
- 4. An assembly as set forth in claim 3 wherein said electrode means (32) further includes a support ring (48) supporting said electrode holders (40), said support ring (48) being removably disposed onto said housing (26).
- 5. An assembly as set forth in 4 wherein said electrode means (32) includes three charging electrodes (36), each having a needle (36) disposed within said electrode holders (40), said axial portion (44) of said electrode holder (40) including a holding portion (46), said electrode (36) having said tip portion (38) located at least axially with the forward end of said holding portion (46) of said electrode holder (40).
- 6. An assembly as set forth in claim 5 wherein said electrode holder (40) is further characterized by said radial portion (42) being longer than said axial portion (44).
- 7. An assembly as set forth in claim 6 further including a high voltage cable (34) connected to each of said charging electrodes (36) and being continuously disposed within said electrode holder (40) and said support ring (48).
- 8. An assembly as set forth in claim 7 including a high impedance-dampening resistor (50) interconnecting said cable (34) and said charging electrode (36).
- 9. An assembly as set forth in claim 8 wherein said external housing (22) includes a front portion (24) made of an insulating material.
- 10. An assembly as set forth in claims 1 or 9 wherein said external housing (22) further includes deflecting gas ducts (52) having at least two of first apertures (52') in spaced relationship circumferentially with respect to the axis of said housing (28), said apertures (52') of said duct (52) having a radial distance from said axis of said housing (22) at least greater than the radius of said spraying edge (14) of said spray head (12), second deflecting gas ducts (54) having apertures (54) located on said front portion (24) of said housing (22) having a radial distance from said axis of said housing (22) at least less than the radius of said spray edge (14) of said spray head (12), and third deflecting gas ducts (58) having apertures (58') having a radial distance from said axis of said housing (22) at least greater than the radius of said spraying edge (14) of said spray head (12).
- 11. An assembly as set forth in claim 9 wherein said electrode holder (40) is made of a plastic material.
- 12. An assembly as set forth in claim 1, further including a plurality of assemblies (10) being adjacent one another in a common plane, said axis of said assemblies (10) being mutually spaced from each other a distance at least fifteen times said predetermined diameter (d) of said spraying edge (14) of said spray head (12).
RELATED APPLICATION
This application is a continuation-in-part of application Ser. No. 665,932 filed Oct. 29, 1984, now abandoned.
US Referenced Citations (5)
Number |
Name |
Date |
Kind |
2960273 |
Croskey et al. |
Nov 1960 |
|
3393662 |
Blackwell |
Jul 1968 |
|
3408985 |
Sedlacsik, Jr. |
Nov 1968 |
|
4555058 |
Weinstein et al. |
Nov 1985 |
|
4589597 |
Robisch et al. |
May 1986 |
|
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
665932 |
Oct 1984 |
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