Claims
- 1. Apparatus for atomizing liquid coating material for electrostatic deposition on an article, comprising an annular housing rotatable about its axis and accommodating introduction of coating material therein, said housing having a smooth inner surface and a single row of discrete, individual and circumferentially spaced passages extending therethrough in directions outwardly of said axis; and means for introducing coating material into said housing, said housing upon rotation of said housing and introduction of coating material into said housing, causing the material to flow under centrifugal force in a thin film across said smooth inner surface toward, into and through said passages, said discrete passages causing the material therein to attain the same rotational velocity as said housing and to be atomized as it is projected from and beyond said passages, whereby to effect improved atomization of the material, said housing further having a relatively sharp and circumferentially extending edge on the outer periphery thereof in close proximity with outlets from said passages for enhancing an electrostatic charge imparted to projected material when a voltage gradient is established between said housing and the article.
- 2. Apparatus as in claim 1, wherein said housing comprises a circular front wall rotatable about said axis and an annular side wall connected with and extending axially from said front wall, said passages extending through said housing between points in proximity with the junctures of inner and outer surfaces of said front and side walls, said means for introducing accommodating introduction of liquid coating material onto said inner surface of said front wall, whereby upon rotation of said housing and introduction of material onto said inner surface of said front wall the material flows in a continuous thin film under centrifugal force radially outwardly along said surface and to said passages and then into and through said passages for being atomized as it is projected therefrom.
- 3. Apparatus as in claim 1, wherein said housing has a circular front wall rotatable about said axis and an annular side wall connected with and extending axially therefrom, said side wall has an inner surface extending both radially and axially outwardly of said axis and said passages extend through said housing in close proximity with the juncture of said front and side walls, and wherein said introducing means introduces coating material onto said side wall rearwardly of said front wall, so that upon rotation of said housing the material flows in a continuous thin film under centrifugal force across said side wall inner surface to and through said passages.
- 4. Apparatus as in claim 2, wherein said front and side wall outer surfaces define said relatively sharp peripheral edge at their juncture and said passages extend into said edge.
- 5. Apparatus as in claim 2, wherein said front and side wall outer surfaces define said relatively sharp peripheral edge at the juncture, said front wall has an annular recess in said outer surface thereof inwardly of said edge in close proximity therewith and said passages extend into said recess.
- 6. Apparatus as in claim 2, wherein said front wall outer surface extends radially outwardly of said side wall outer surface and defines said relatively sharp peripheral edge at its outermost end, and said passages extend to said side wall outer surface in close proximity to the juncture thereof with said front wall outer surface.
- 7. Apparatus as in claim 2, wherein said passages extend to said side wall outer surface at points toward the juncture thereof with said front wall outer surface.
- 8. Apparatus as in claim 3, wherein said side wall inner surface has first and second annular and conical surface portions, and said second portion extends between said first portion and said front wall and defines with said axis an acute angle which is less than the acute angle defines by said first surface portion.
- 9. Apparatus as in claim 8, wherein said introducing means introduces coating material onto said first surface portion.
- 10. Apparatus as in claim 9, wherein said introducing means introduces coating material onto said first surface portion at a point slightly vertically below and horizontally to the side of said axis and in a direction generally along the direction of rotation of said first surface portion thereat.
- 11. Apparatus as in claim 3, wherein a rearward end of said housing is substantially closed to atmosphere to impede any free flow of air therethrough upon rotation thereof.
- 12. A method of atomizing liquid coating material using a rotary atomizing device for electrostatically coating an article with a film of material, wherein an electrostatic field is established between a peripheral edge of the rotating device and the article to be coated and the liquid material flows across a smooth material feed surface of the device and toward the edge as a continuous thin film, characterized by increasing the rotational velocity of the material as it approaches the peripheral edge by flowing the material into and through a single row of a series of discrete, individual and circumferentially spaced passages which extend through the device in directions toward the edge, constrain the material to the same rate of rotation thereas and terminate in proximity with the edge, atomizing the material as it is projected out of and beyond the passages, and enhancing an electrostatic charge imparted to the material by providing on the outer periphery of the device a relatively sharp and circumferentially extending edge in close proximity with outlets from the passages.
Parent Case Info
This application is a continuation in part of application Ser. No. 245,899, filed Mar. 20, 1981, now abandoned.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
3411715 |
Wallis |
Nov 1968 |
|
3442688 |
Pettigrew |
May 1969 |
|
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
245899 |
Mar 1981 |
|