Electrostatic coating apparatus
AssigneeRansburg Corporation
InventorsRichard L. LaFave, Richard O. Probst
Life of this patent
Estimating the term…
Abstract
An apparatus for electrostatically coating conductive articles with powder. A mixture of powder and air is delivered through a passage of uniform cross-section and a short section of rotating tube to a rotating bell of nonconductive material having a surface angle with the axis of 50.degree. to 90.degree.. The powder is directed from a nozzle over the bell surface and the entraining air is dissipated laterally. The powder is discharged from the bell into an electrostatic field where the particles acquire a charge and are attracted to and deposited on the grounded articles. A pneumatic jet pump for entraining the powder particle in an air stream has a nozzle and venturi so related that the expanding air from the nozzle blends with the expanding portion of the venturi.
Claims13
An apparatus for coating an article with particles of powder comprising:
- a source of powder particles entrained in air;
- means establishing an electrostatic field with respect to said article, charging particles therein and effecting deposition thereof on said article;
- a distributor having a smooth, unobstructed rotating surface of nonconductive material to distribute said particles into the electrostatic field;
- passage means connected to said source for delivering said entrained powder particles to the non-conductive surface, said passage means having a non-rotating portion and a rotating portion;
- and
- a nozzle connected with the rotating portion of the passage means to receive the entrained powder particles therefrom and having an aperture through which said mixture is discharged to impinge on and flow outwardly across said distributor surface.
An apparatus for coating an article with particles of powder comprising:
- a source of powder particles entrained in air;
- means establishing an electrostatic field with respect to said article, charging particles therein and effecting deposition thereof on said article;
- a rotating bell distributor having a smooth unobstructed inner surface with an angle between the axis of rotation and the inner surface greater than 50.degree. and less than 90.degree., to distribute said particles into the electrostatic field;
- passage means connected to said source for delivering said entrained powder to the bell surface;
- and
- a nozzle connected with said passage means and extending into the bell along the axis thereof, said nozzle having an aperture through which said entrained powder is discharged to impinge on and flow across said distributor surface into said electrostatic field.
An apparatus for coating an article with particles of powder comprising:
- a source of powder particles entrained in air;
- means establishing an electrostatic field with respect to said article, charging particles therein and effecting deposition thereof on said article;
- a distributor having a rotating surface to distribute said particles into the electrostatic field;
- passage means connected to said source for delivering said entrained powder particles to the rotating surface, said passage means having a nonrotating portion and a rotating portion;
- a nozzle connected with the rotating portion of the passage means to receive the air-powder mixture therefrom and having an aperture through which said mixture is discharged to impinge on and flow outwardly across said distributor surface;
- and
- sealing means between the rotating and non-rotating portions of said passage means and comprising a rotating element fixed to an end of said rotating passage portion and sealed with an element fixed to the end of said nonrotating passage portion.
An apparatus for coating an article with particles of powder comprising:
- a fluidized bed of powder particles;
- an injector pump in said fluidized bed, having an inlet for connection with a source of pressurized air, an inlet for particles and an outlet for powder entrained in air;
- means establishing an electrostatic field with respect to said article, charging said particles and effecting deposition thereof on said article;
- means of nonconductive material having a smooth rotary surface to distribute said particles into the electrostatic field;
- and
- passage means of substantially uniform cross-section connected with the outlet of said pump for delivering entrained powder to the distributor means for distribution into said electrostatic field.
A hand held apparatus for coating an article with particles of powder, comprising:
- a hand gun having a handle portion and a barrel portion extending forwardly therefrom;
- a source of powder particles entrained in air connected with the rear of said barrel;
- means for establishing an electrostatic field with respect to said article, charging said particles and effective deposition thereof on said article;
- a distributor having a smooth, unobstructed rotary surface of nonconducting material to distribute said particles into the electrostatic field, at the front of the barrel;
- a rotary passage for the entrained powder extending through said barrel and connecting said source with said distributor;
- and
- a motor at the rear of said barrel adjacent said handle, for rotating said passage and said distributor, said motor being laterally offset from the rotary passage.
Dependencies are inferred from the claim text.