Methods and apparatus for material processing using plasma thermal source

Patent metadata

Field	Value
Publication number	US-9550694-B2
Application number	US-201414231008-A
Country	US
Kind code	B2
Filing date	Mar 31, 2014
Priority date	Mar 31, 2014
Publication date	Jan 24, 2017
Grant date	Jan 24, 2017

Abstract

Methods and apparatus provide for: feeding glass batch material into a plasma containment vessel in such a way that the glass batch material is dispensed as a sheet of glass batch material particles; directing one or more sources of plasma gas into the inner volume of the plasma containment vessel in such a way that the plasma gas enters the plasma containment vessel as at least one sheet of plasma gas; and applying an alternating electric field to facilitate production of a plasma plume within the inner volume of the plasma containment vessel, where the plasma plume is of dimensions sufficient to envelope the sheet of glass batch material particles, and is of sufficient thermal energy to cause the glass batch material to react and melt thereby forming substantially homogeneous, spheroid-shaped glass intermediate particles.

First claim

The invention claimed is:

1. An apparatus, comprising:
a plasma containment vessel having at least first and second opposing wall members defining an inner volume of X, Y, Z orthogonal dimensions and directions, an inlet end, and an opposing outlet end separated from the inlet end in the Y direction;
an inlet structure disposed at the inlet end of the plasma containment vessel and including: (i) a material inlet for receiving glass batch material, and an opposing material outlet, where the material inlet and the material outlet are elongate in the X direction such that the glass batch material is dispensed as a substantially planar sheet of glass batch material particles into the inner volume of the plasma containment vessel, (ii) at least one gas inlet for receiving one or more sources of plasma gas, and (iii) a plurality of gas outlets disposed in a linear arrangement around a periphery of the material outlet, each of the plurality of gas outlets including at least one bore extending from the at least one gas inlet to the periphery of the material outlet, and the gas outlets for directing the plasma gas into the inner volume of the plasma containment vessel; and
first and second electrode plates covering portions of respective exterior surfaces of the first and second wall members of the plasma containment vessel, wherein:
the first and second electrode plates are operable to receive a source of alternating current (AC) power having characteristics sufficient to produce an alternating electric field in the Z direction, and facilitate production of a plasma plume within the plasma containment vessel,
the plasma plume is of a substantially planar sheet shape having dimensions sufficient to envelope the planar sheet of glass batch material particles, and is of sufficient thermal energy to cause the glass batch material to thermally react.

2. The apparatus of claim 1 , wherein the plasma plume is of sufficient thermal energy to cause thermal reaction of sufficient characteristics to at least one of:
at least partially melt the glass batch material,
at least partially melt at least one of the glass batch material and one or more further materials thereby forming coated glass batch material particles, and
at least partially melt the glass batch material to form substantially homogeneous, spheroid-shaped glass intermediate particles.

3. The apparatus of claim 1 , wherein:
the material outlet includes at least first and second opposing peripheral edges extending in the X direction in which the material outlet is elongate; and
the plurality of gas outlets are disposed at intervals along at least one of the first and second opposing peripheral edges of the material outlet, and are operable to direct the plasma gas into the inner volume of the plasma containment vessel as at least one planar sheet of plasma gas.

4. The apparatus of claim 3 , wherein the plurality of gas outlets are disposed at intervals along both of the first and second opposing peripheral edges of the material outlet, and are operable to direct the plasma gas into the inner volume of the plasma containment vessel as two planar sheets of plasma gas.

5. The apparatus of claim 4 , wherein the plurality of gas outlets are directed at an angle with respect to the Y direction such that the two planar sheets of plasma gas are directed both in the Y direction and toward one another in order to envelop the planar sheet of glass batch material particles.

6. The apparatus of claim 1 , further comprising:
a magnetic source operating to produce a magnetic field characterized by a plurality of lines of magnetic flux directed through the inner volume of the plasma containment vessel in the X direction,
wherein the first and second electrode plates are oriented in respective planes that are parallel to a reference X-Y plane extending in the X and Y directions, and the plurality of lines of magnetic flux are directed in the X direction and parallel with the reference X-Y plane.

7. The apparatus of claim 6 , wherein:
at periodic instances of time, the first and second electrode plates produce respective electric fields, each electric field being characterized by lines of electric flux emanating from one of the first and second electrode plates toward the other of the first and second electrode plates in the Z direction, and
the interaction of the electric flux and the magnetic flux is such that an electron cyclotron frequency of electrons about the magnetic flux is produced of sufficient magnitude to produce the plasma plume of sufficient thermal energy to cause the glass batch material to thermally react.

8. The apparatus of claim 6 , wherein the magnetic field is one of: (i) at least about 2.0×10 −3 Tesla, (ii) at least about 3.0×10 −3 Tesla, and (iii) at least about 4.0×10 −3 Tesla.

9. The apparatus of claim 7 , wherein the electron cyclotron frequency is one of: (i) at least about 2.0×10 8 radians/second, (ii) at least about 3.0×10 8 radians/second, and at least about 4.0×10 8 radians/second.

10. The apparatus of claim 1 , wherein the plasma plume has a temperature ranging from one of: (i) about 9,000° K to about 18,000° K; (ii) about 11,000° K to about 15,000° K; and (iii) at least about 11,000° K.

11. The apparatus of claim 1 , wherein the first and second opposing wall members include respective internal channels operating to carry fluid therethrough in order to cool the plasma containment vessel in the presence of the plasma plume.

12. The apparatus of claim 1 , wherein the inlet structure includes one or more internal channels operating to carry fluid therethrough in order to cool the inlet structure in the presence of the plasma plume.

13. The apparatus of claim 1 , wherein the inlet opening is of a construction capable of receiving the glass batch material having an average particle size ranging from about 5 to about 1,000 microns.

14. The apparatus of claim 1 , wherein the plasma gas includes at least one of argon, air, helium, nitrogen, oxygen, and mixtures thereof.

15. The apparatus of claim 1 , wherein the thermally reacted glass batch material exit the plasma containment vessel through the outlet end.

Assignees

• Corning Inc

Inventors

• Boughton Daniel Robert

Classifications

• H05H1/46

  using applied electromagnetic fields, e.g. high frequency or microwave energy (H05H1/26 takes precedence) · CPC title

• H05H1/42

  with provisions for introducing materials into the plasma, e.g. powder or liquid {(arc stabilising or constricting arrangements H05H1/3405; coaxial protecting fluids H05H1/341)} · CPC title

• C03B19/109 Primary

  Glass-melting furnaces specially adapted for making beads · CPC title

• C03B5/185

  Electric means · CPC title

• C03B5/025 Primary

  by arc discharge or plasma heating · CPC title