Method of and apparatus for generating aerosols by electric arc

Claim 2

Method of producing an aerosol comprising passing an electric arc between a counter electrode and a source material with the net current flow being in the direction from the counter electrode to the source material, providing enough energy in the arc to cause droplets of the source material to be ejected from it to form an aerosol, simultaneously flowing a selected gas through the region of the arc to carry the aerosol composed of the gas and droplets ejected from the material away from the source material, the counter electrode being arranged to avoid sputtering from it.

Claim 3

Method according to claim 1 wherein the selected gas is selecTed from the group consisting of argon, helium, and nitrogen.

Claim 4

Method of producing an aerosol comprising passing an electric arc between a counter electrode and a source material with the net current flow being in the direction from the counter electrode to the source material, providing enough energy in the arc to cause droplets of the source material to be ejected from it to form an aerosol, simultaneously flowing a selected gas through the region of the arc to carry the aerosol so formed away from the material, and to solidify the droplets, the counter electrode being arranged to avoid sputtering from it.

Claim 5

Method of producing an aerosol comprising passing an electric arc between a counter electrode and a source material with the net current flow being in the direction from the counter electrode to the source material, providing enough energy in the arc to cause droplets of the source material to be ejected from it to form an aerosol, simultaneously flowing a selected gas through the region of the arc to carry the aerosol so formed away from the material, and to solidify the droplets, the counter electrode being arranged to avoid sputtering from it.

Claim 6

Method of producing an aerosol from a molten source material comprising passing a direct current electric arc between a counter electrode an an anode and the source material as a cathode with sufficient energy to cause droplets of the source material to be ejected from its surface to form an aerosol, simultaneously flowing a selected gas through the region of the arc to carry the aerosol so formed away from the material, the counter electrode being arranged to avoid sputtering from it.

Claim 7

Method of producing an aerosol from a molten source material comprising passing a direct current electric arc between a counter electrode an an anode and the source material as a cathode with sufficient energy to cause droplets of the source material to be ejected from its surface to form an aerosol, simultaneously flowing a selected gas through the region of the arc to carry the aerosol so formed away from the material, the counter electrode being arranged to avoid sputtering from it.

Claim 8

Method of producing a specimen the composition of which is representative on a microscopic scale of the composition of a fairly large region of a solid body comprising passing an electric arc between a counter electrode an an anode and the solid body as a cathode with sufficient energy to cause droplets of the material of the body to be ejected from its surface to form an aerosol, simultaneously flowing a selected gas through the region of the arc to carry the aerosol so formed away from the surface of the body, the counter electrode being arranged to avoid sputtering from it.

Claim 9

Method of producing a specimen the composition of which is representative on a microscopic scale of the composition of a fairly large region of a solid body comprising passing an electric arc between a counter electrode an an anode and the solid body as a cathode with sufficient energy to cause droplets of the material of the body to be ejected from its surface to form an aerosol, simultaneously flowing a selected gas through the region of the arc to carry the aerosol so formed away from the surface of the body, the counter electrode being arranged to avoid sputtering from it.

Claim 10

Method according to claim 5 including also the step of maintaining a sufficient current in the arc to melt at least a macroscopic portion of the body.

Claim 11

Method according to claim 6 including the step of heating the body by electromagnetic induction and thereby stirring the molten portion thereof.

Claim 12

Method of chemical analysis comprising the steps of producing an aerosol in accordance with the method of claim 1, and analyzing the solids portion of the aerosol so produced.

Claim 13

Method of monitoring the composition of a bath of a molten, electrically conductive material comprising producing an aerosol in accordance with the method of claim 1, conducting it to a spectrometric analytical device, and analyzing the solid particles of the aerosol spectrometrically.

Claim 14

Apparatus for producing an aerosol from a source material comprising: a. an electrode, b. enclosure means for enclosing a region adjacent to a selected surface of the source material, said enclosure means enabling said electrode to be positioned within said region and adjacent to the surface of the source material, said enclosure means also including inlet means and outlet means, d. a unipotential source of electric current, e. means for connecting the source material to the cathode of said current source and said electrode to the anode of said current source, and f. means for flowing a selected gas through said enclosure means via said inlet and outlet means while said connecting means is operative, to facilitate the striking and maintenance of an arc between said electrode and the source material and to carry particles of the source material dislodged by the arc out of said region through said outlet means.

Claim 15

Apparatus for producing an aerosol from a source material comprising: a. an electrode, b. enclosure means for enclosing a region adjacent to a selected surface of the source material, said enclosure means enabling said electrode to be positioned within said region and adjacent to the surface of the source material, said enclosure means also including inlet means and outlet means, d. a unipotential source of electric current, e. means for connecting the source material to the cathode of said current source and said electrode to the anode of said current source, and f. means for flowing a selected gas through said enclosure means via said inlet and outlet means while said connecting means is operative, to facilitate the striking and maintenance of an arc between said electrode and the source material and to carry particles of the source material dislodged by the arc out of said region through said outlet means.

Claim 16

A lance for producing an aerosol from a bath of a molten material comprising: a. a tube having an open end for withdrawing an aerosol from a region adjacent to the surface of the molten material, said tube being electrically conductive, b. means defining an open-ended enclosure around a terminal portion of said tube and extending beyond the end of said tube, c. means for flowing a gas into the enclosure defined by said enclosure means from a point spaced from the open end thereof and outside of said tube, and thence out of the enclosure through said tube; d. means for mAking electrical contact with a molten material at a point spaced from said tube when said tube with said enclosure means is placed open and first into the molten material, whereby a source of electric current may be connected between said tube and the source material to produce an electric arc between them strong enough to dislodge small particles of the source material from its surface, and e. said gas means being operative to carry particles dislodged from the source material by an arc out of the enclosure through said tube.

Claim 17

A lance for producing an aerosol from a bath of a molten material comprising: a. a tube having an open end for withdrawing an aerosol from a region adjacent to the surface of the molten material, said tube being electrically conductive, b. means defining an open-ended enclosure around a terminal portion of said tube and extending beyond the end of said tube, c. means for flowing a gas into the enclosure defined by said enclosure means from a point spaced from the open end thereof and outside of said tube, and thence out of the enclosure through said tube; d. means for mAking electrical contact with a molten material at a point spaced from said tube when said tube with said enclosure means is placed open and first into the molten material, whereby a source of electric current may be connected between said tube and the source material to produce an electric arc between them strong enough to dislodge small particles of the source material from its surface, and e. said gas means being operative to carry particles dislodged from the source material by an arc out of the enclosure through said tube.

Claim 18

Apparatus in accordance with claim 11 including dynamic cooling means to enable the lance to withstand continued exposure to elevated temperatures.

Claim 19

Apparatus in accordance with claim 11 including a cap of an insulating, refractory material covering the open end of said tube for limiting an arc struck therefrom to the inner wall surface thereof, said cap having an aperture coaxially aligned with said tube to permit striking the arc and passage of aerosols into said tube.

Claim 20

Apparatus in accordance with claim 11, wherein said electrical contact means is a cylindrical conductive member and constitutes the outer wall portion of said enclosure means.

Claim 21

Apparatus for producing an aerosol from a source material comprising: a. a tubular electrode open at one end, and having an exhaust opening spaced from said one end, b. means for supporting said electrode with said open end adjacent to and spaced from a source material, c. enclosure means for enclosing a region adjacent to the source material and including said open end of said electrode, d. gas flow means for introducing a carrier gas into the region enclosed by said enclosure means and withdrawing it from the region through the open end of said electrode, e. an unipotential source of electric current, f. means for connecting the source material to the cathode of said current source and said electrode to the anode thereof, and g. said gas flow means being effective to sweep small particles such as may be produced by an arc energized by said current source out of said enclosure means through said electrode.

Claim 22

Apparatus for producing an aerosol from a source material comprising: a. a tubular electrode open at one end, and having an exhaust opening spaced from said one end, b. means for supporting said electrode with said open end adjacent to and spaced from a source material, c. enclosure means for enclosing a region adjacent to the source material and including said open end of said electrode, d. gas flow means for introducing a carrier gas into the region enclosed by said enclosure means and withdrawing it from the region through the open end of said electrode, e. an unipotential source of electric current, f. means for connecting the source material to the cathode of said current source and said electrode to the anode thereof, and g. said gas flow means being effective to sweep small particles such as may be produced by an arc energized by said current source out of said enclosure means through said electrode.

Claim 23

Apparatus according to claim 15 including an annular insulating shield fixed to the open end of said electrode for confining an arc struck from said electrode to the internal surface thereof.