Electrogasdynamic coating device having composite non-conductive flow channel, and hollow ionization electrode for an air jet

Claim 2

An electrogasdynamic system for applying a coating to an article comprising: a. a non-conductive conduit for conveying a stream of particles from a reservoir and for directing the particles toward the article to be coated; b. a conductive needle axially positioned within said conduit for forming a corona discharge to ionize the particles passing through the adjoining space; c. an electrode adjacent to the needle for forming an electric field between the electrode and the needle; d. a source of potential connected between the electrode and the needle for creating a corona discharge; e. an axial flow channel for forming a non-conductive boundary for the ionized particles as they move toward an article to be coated; and f. an insert of tetrafluoroethylene which is positioned within said flow channel adjacent to said electrode for assuming an electric charge and thereby repulsing the ionized particles.

Claim 3

A system as claimed in claim 1 wherein said electrode is a conductive ring embedded in the flow channel and connected to a terminal of the electric power source.

Claim 4

A system as claimed in claim 1 wherein said axial flow channel is directed toward the interior of a conductive article for coating its interior surface.

Claim 5

A system as claimed in claim 1 wherein said non-conductive conduit is part of a block which includes a support for the non-conductive flow chamber.

Claim 6

A system as claimed in claim 1 wherein a conductive washer is positioned adjoining the non-conductive conduit and supports said conductive needle.

Claim 7

A system as claimed in claim 5 wherein said conductive washer is formed with a plurality of holes for passage of the particles.

Claim 8

An electrogasdynamic system for applying a coating to an article comprising: a. a non-conductive conduit for conveying a stream of particles from a reservoir and for directing the particles toward the article to be coated; b. a conductive needle axially positioned within said conduit for forming a corona discharge to ionize the particles passing through the adjoining space, said conductive needle being hollow and positioned for receiving air under pressure from an air reservoir for passage of the pressurized air through said needle and towards the article to be coated; c. an electrode adjacent to the needle for forming an electric field between the electrode and the needle; d. a source of potential connected between the electrode and the needle for creating a corona discharge; and, e. an axial flow channel for forming a non-conductive boundary for the ionized particles as they move toward an article to be coated, said particles being aided in moving through said flow channel by the air received by said hollow conductive needle.

Claim 9

An electrogasdynamic system for applying a coating to an article comprising: a. a non-conductive conduit for conveying a stream of particles from a reservoir and for directing the particles toward the article to be coated; b. a conductive needle axially positioned within said conduit for forming a corona discharge to ionize the particles passing through the adjoining space, said conductive needle being hollow and positioned for receiving air under pressure from an air reservoir for passage of the pressurized air through said needle and towards the article to be coated; c. an electrode adjacent to the needle for forming an electric field between the electrode and the needle; d. a source of potential connected between the electrode and the needle for creating a corona discharge; and, e. an axial flow channel for forming a non-conductive boundary for the ionized particles as they move toward an article to be coated, said particles being aided in moving through said flow channel by the air received by said hollow conductive needle.

Claim 10

A system as claimed in claim 7 wherein said electrode is a conductive ring embedded in the flow channel and connected to a terminal of the electric power source.

Claim 11

A system as claimed in claim 7 wherein said axial flow channel is directed toward the interior of a conductive article for coating its interior surface.

Claim 12

A system as claimed in claim 7 wherein said nonconductive conduit is part of a block which includes a support for the nonconductive flow chamber.

Claim 13

A system as claimed in claim 7 wherein a conductive washer is positioned adjoining the nonconductive conduit and supports said conductive needle.

Claim 14

A system as claimed in claim 11 wherein said conductive washer is formed with a plurality of holes for passage of the powder.

Claim 15

A nonconducting channel for the transfer of nonconducting particles propelled by an air stream under pressure, said channel made of a material which generates one type of static charge when subjected to the frictional engagement of the moving particles; said channel containing a nonconductive insert in the channel wall made of a material which generates the opposite type of static charge when subjected to the frictional engagement of the moving particles.

Claim 16

A nonconducting channel for the transfer of nonconducting particles propelled by an air stream under pressure, said channel made of a material which generates one type of static charge when subjected to the frictional engagement of the moving particles; said channel containing a nonconductive insert in the channel wall made of a material which generates the opposite type of static charge when subjected to the frictional engagement of the moving particles.

Claim 17

A channel as claimed in claim 13 wherein said channel is made of an acetal resin of formaldehyde and wherein the insert is made of tetrofluoroethylene.

Claim 18

A nonconductive channel for the transfer of nonconductive particles propelled by an air stream under pressure, said channel being of composite construction including a first dielectric material, and an insert coaxial with and coextensive with said first material, the dielectric constant of said second material being different than the dielectric constant of said first material.

Claim 19

A nonconductive channel for the transfer of nonconductive particles propelled by an air stream under pressure, said channel being of composite construction including a first dielectric material, and an insert coaxial with and coextensive with said first material, the dielectric constant of said second material being different than the dielectric constant of said first material.

Claim 22

An electrogasdynamic system for applying a coating to an article comprising: a. a non-conductive conduit for conveying a stream of powder particles from a reservoir and for directing the particles toward the article to be coated; b. a conductive needle axially positioned within said conduit for forming a corona discharge to ionize the particles passing through the adjoining space; c. an electrode adjacent to the needle for forming an electric field between the electrode and the needle; d. a source of potential connected between the electrode and the needle for creating a corona discharge; e. an axial flow channel for forming a non-conductive boundary for the ionized particles as they move toward an article to be coated, said axial flow channel being made of an acetal resin of formaldehyde; and f. an insert of tetrafluorethylene disposed adjacent to said electrode for forming the electric field.

Claim 23

An electrogasdynamic system for applying a coating to an article comprising: a. a non-conductive conduit for conveying a stream of powder particles from a reservoir and for directing the particles toward the article to be coated; b. a conductive needle axially positioned within said conduit for forming a corona discharge to ionize the particles passing through the adjoining space; c. an electrode adjacent to the needle for forming an electric field between the electrode and the needle; d. a source of potential connected between the electrode and the needle for creating a corona discharge; e. an axial flow channel for forming a non-conductive boundary for the ionized particles as they move toward an article to be coated, said axial flow channel being made of an acetal resin of formaldehyde; and f. an insert of tetrafluorethylene disposed adjacent to said electrode for forming the electric field.

Claim 24

An electrogasdynamic system for applying a coating to an article comprising: a. a non-conductive conduit for conveying a stream of particles from a reservoir and for directing the particles toward the article to be coated; b. a conductive needle axially positioned within said conduit for forming a corona discharge to ionize the particles passing through the adjoining space; c. an electrode adjacent to the needle for forming an electric field between the electrode and the needle; d. a source of potential connected between the electrode and the needle for creating a corona discharge; and e. an axial flow channel for forming a non-conductive boundary for the ionized particles as they move toward an article to be coated, said channel being made of a material which generates one type of static charge when subjected to the frictional engagement of moving particles, and wherein an insert is disposed within the channel, said insert made of a material which generates the opposite type of static charge when subjected to the frictional engagement of the moving particles.

Claim 25

An electrogasdynamic system for applying a coating to an article comprising: a. a non-conductive conduit for conveying a stream of particles from a reservoir and for directing the particles toward the article to be coated; b. a conductive needle axially positioned within said conduit for forming a corona discharge to ionize the particles passing through the adjoining space; c. an electrode adjacent to the needle for forming an electric field between the electrode and the needle; d. a source of potential connected between the electrode and the needle for creating a corona discharge; and e. an axial flow channel for forming a non-conductive boundary for the ionized particles as they move toward an article to be coated, said channel being made of a material which generates one type of static charge when subjected to the frictional engagement of moving particles, and wherein an insert is disposed within the channel, said insert made of a material which generates the opposite type of static charge when subjected to the frictional engagement of the moving particles.