Electrostatic fluid bed powder coating system

Claim 2

In an electrostatic fluid bed powder coating system having a powder fluidizing bed, a source of fluidizing gas therefor, and means for moving an elongated workpiece horizontally and axially across said bed above the surface of fluidized powder therein, charging apparatus comprising: a voltage source; a pair of elongated charging electrodes in said bed below the surface of the fluidized powder therein, said electrodes extending parallel to the axis of said workpiece and being located symmetrically on opposite sides of said axis and radially equidistant therefrom; means connecting said electrodes to said voltage source; a control electrode located above said workpiece and having portions directly above and extending parallel to and substantially coextensive with each of said charging electrodes, said portions being located the same radial distance from the axis of said workpiece as are said charging electrodes; means connecting said control electrode portions and said workpiece to a voltage different from that of the charging electrodes.

Claim 3

In an electrostatic fluid bed powder coating system having a powder fluidizing bed, a source of fluidizing gas therefor, and means for moving a wire horizontally and axially across said bed above the surface of fluidized powder therein, charging apparatus comprising: a voltage source; a pair of similar elongated charging bar electrodes in said bed below the surface of the fluidized powder therein, said electrodes being round in transverse section and having rounded ends, and said electrodes extending parallel to the axis of said wire and being located symmetrically on opposite sides of said wire and radially equidistant from the axis thereof; means connecting said electrodes to said voltage source; a control electrode of smaller diameter than said charging electrodes located above said wire and having portions directly above and extending parallel to and substantially coextensive with each of said charging electrodes, said portions being located the same radial distance from the axis of said wire as are said charging electrodes; and means connecting said control electrode portions and said wire to ground.

Claim 4

In an electrostatic fluid bed powder coating system having a powder fluidizing bed, a source of fluidizing gas therefor, and means for moving a wire horizontally and axially across said bed above the surface of fluidized powder therein, charging apparatus comprising: a voltage source; a pair of similar elongated charging bar electrodes in said bed below the surface of the fluidized powder therein, said electrodes being round in transverse section and having rounded ends, and said electrodes extending parallel to the axis of said wire and being located symmetrically on opposite sides of said wire and radially equidistant from the axis thereof; means connecting said electrodes to said voltage source; a control electrode of smaller diameter than said charging electrodes located above said wire and having portions directly above and extending parallel to and substantially coextensive with each of said charging electrodes, said portions being located the same radial distance from the axis of said wire as are said charging electrodes; and means connecting said control electrode portions and said wire to ground.

Claim 5

In an electrostatic fluid bed powder coating system having a powder fluidizing bed, a source of fluidizing gas therefor, and means for moving an elongated workpiece horizontally and axially across said bed above the surface of fluidized powder therein, charging apparatus comprising: a voltage source; an outer pair of elongated charging electrodes in said bed below the surface of the fluidized powder therein, said electrodes extending parallel to the axis of said workpiece and being located symmetrically on opposite sides of said axis and radially equidistant therefrom; an inner pair of elongated charging electrodes in said bed between and extending parallel to said outer electrodes, each one of said inner electrodes being spaced the same distance from its adjacent outer electrode as the other inner electrode is spaced from its adjacent outer electrode, said inner electrodes being located the same radial distance from the axis of said workpiece as are said outer charging electrodes; means connecting said outer and inner electrodes to said voltage source; a control electrode located above said workpiece and having portions directly above and extending parallel to and substantially coextensive with each of said outer charging electrodes, said portions being located the same radial distance from the axis of said workpiece as are said outer charging electrodes; and means connecting said control electrode portions and said workpiece to a voltage different from that of the charging electrodes.

Claim 6

In an electrostatic fluid bed powder coating system having a powder fluidizing bed, a source of fluidizing gas therefor, and means for moving an elongated workpiece horizontally and axially across said bed above the surface of fluidized powder therein, charging apparatus comprising: a voltage source; an outer pair of elongated charging electrodes in said bed below the surface of the fluidized powder therein, said electrodes extending parallel to the axis of said workpiece and being located symmetrically on opposite sides of said axis and radially equidistant therefrom; an inner pair of elongated charging electrodes in said bed between and extending parallel to said outer electrodes, each one of said inner electrodes being spaced the same distance from its adjacent outer electrode as the other inner electrode is spaced from its adjacent outer electrode, said inner electrodes being located the same radial distance from the axis of said workpiece as are said outer charging electrodes; means connecting said outer and inner electrodes to said voltage source; a control electrode located above said workpiece and having portions directly above and extending parallel to and substantially coextensive with each of said outer charging electrodes, said portions being located the same radial distance from the axis of said workpiece as are said outer charging electrodes; and means connecting said control electrode portions and said workpiece to a voltage different from that of the charging electrodes.

Claim 7

In an electrostatic fluid bed powder coating system having a powder fluidizing bed, a source of fluidizing gas therefor, and means for moving a wire horizontally and axially across said bed above the surface of fluidized powder therein, charging apparatus comprising: a voltage source; an outer pair of elongated charging bar electrodes in said bed below the surface of the fluidized powder therein, said electrodes being round in transverse section and having rounded ends, and said electrodes extending parallel to the axis of said wire and being located symmetrically on opposite sides of said wire and radially equidistant from the axis thereof; an inner pair of elongated charging bar electrodes in said bed between and extending parallel to said outer electrodes, each inner electrode being substantially the same size and shape as said outer electrodes and each being spaced the same distance from its adjacent outer electrode as the other inner electrode is spaced from its adjacent outer electrode, and said inner electrodes being located the same radial distance from the axis of said wire as are the outer charging electrodes; means connecting said inner and outer electrodes to said voltage source; a control electrode of smaller diameter than said charging electrodes located above said wire and having portions directly above and extending parallel to and substantially coextensive with each of said outer charging electrodes, said portions being located the same radial distance from the axis of said wire as are said outer charging electrodes; and means connecting said control electrode portions and said wire To ground.

Claim 8

In an electrostatic fluid bed powder coating system having a powder fluidizing bed, a source of fluidizing gas therefor, and means for moving a wire horizontally and axially across said bed above the surface of fluidized powder therein, charging apparatus comprising: a voltage source; an outer pair of elongated charging bar electrodes in said bed below the surface of the fluidized powder therein, said electrodes being round in transverse section and having rounded ends, and said electrodes extending parallel to the axis of said wire and being located symmetrically on opposite sides of said wire and radially equidistant from the axis thereof; an inner pair of elongated charging bar electrodes in said bed between and extending parallel to said outer electrodes, each inner electrode being substantially the same size and shape as said outer electrodes and each being spaced the same distance from its adjacent outer electrode as the other inner electrode is spaced from its adjacent outer electrode, and said inner electrodes being located the same radial distance from the axis of said wire as are the outer charging electrodes; means connecting said inner and outer electrodes to said voltage source; a control electrode of smaller diameter than said charging electrodes located above said wire and having portions directly above and extending parallel to and substantially coextensive with each of said outer charging electrodes, said portions being located the same radial distance from the axis of said wire as are said outer charging electrodes; and means connecting said control electrode portions and said wire To ground.