US3602595A - Method of and apparatus for generating aerosols by electric arc - Google Patents
Method of and apparatus for generating aerosols by electric arc Download PDFInfo
- Publication number
- US3602595A US3602595A US737252*A US3602595DA US3602595A US 3602595 A US3602595 A US 3602595A US 3602595D A US3602595D A US 3602595DA US 3602595 A US3602595 A US 3602595A
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- arc
- aerosol
- source material
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/66—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light electrically excited, e.g. electroluminescence
- G01N21/67—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light electrically excited, e.g. electroluminescence using electric arcs or discharges
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/22—Devices for withdrawing samples in the gaseous state
Definitions
- This invention relates to a novel method of and apparatus for nebulizing a material to obtain a sample for chemical analysis or the like, or for any other purpose when it is desired that the composition of the nebulized material be closely representative of the average composition of a reasonably large region of the body from which it is taken.
- the invention arose in connection with efforts to improve spectrochemical analytical methods, and its background and advantages will be described herein primarily with respect to spectrochemical work. It is expected, however, that the invention will also be of significant value for other purposes such as for use in preparing samples for other methods of chemical analysis including wet processes, and for obtaining fine powders for any purpose where it is desired that the powders be composed of extremely small particles, or that the composition of the powders be closely representative of the composition of a fairly large region of the material from which they are taken.
- spectrochemical methods of analysis are widely used and have been found to be especially advantageous for process control, largely because of the high speed with which analyses can be made by these methods. For example, the manufacture of steel can be more closely controlled if the composition of the heat is known at the time it is poured.
- the composition of the heat is known at the time it is poured.
- the present invention arose out of efforts both to, reduce the time needed for analysis still further and to improve the quality of the samples so that they would be more truly representative of the actual averagecomposition of the heat than samples heretofore obtainable.
- the advantages of increased speed are obvious and need not be discussed herein.
- the problem of compositional representativeness, however, is more subtle.
- an electron beam In analysis by electron microprobe, an electron beam, usually less than 1 micron in diameter, is directed upon the sample to generate X-rays, which are then spectrometrically analyzed.
- the volume of the material involved in analysis of this type is limited to the volume required to stop the electrons of the beam. This is typically a few cubic microns.
- the practice of the invention not onlyenables a reduction in the time needed for preparing samples and presenting them to the spectrometric apparatus, but also overcomes difficulties of obtaining samples that are, homogeneous throughout on a microscopic scale. Moreover, due to the way in which the samples are formed, they are more readily dissolved than samples made by casting, and thus enable a reduction in time required for wet chemical analysis.
- the practice of the invention contemplates the use of an electric arc together with a stream of gas to produce.
- the are is struck directly to the, surface of the material, and causes the ejection of very fine particles.
- the current of the arc may be controllably varied, and the nature of the gas selected to achieve optimum particle emission from the material being sampled, both as to quantity and as to the sizes of the individual particles.
- the material is electrically conductive, there is no effective limitation as to its temperature, and samples may readily be obtained from molten materials.
- the aerosol particles produced in accordance with the present invention may readily be made, predominantly 1 micron and smaller in diameter. They may be conducted directly to a plasma flame chamber for immediate analysis by optical emission, or otherwise analyzed as desired. The aerosol may be passed through a filter to collect its solid particles. Which may then be analyzed by X-ray spectrometric techniques or otherwise as desired. The collected solid particles, being very finely divided may also be very quickly the solved for analysis by wet processes, so that even for wet analyses, the practice of the invention enables a significant improvement in speed as well as in homogeneity and representativeness.
- the practice of the invention enables the production of a fine metal powder of a very high degree of homogeneity, which is truly representative composition-wise of the material from which the aerosol droplets are ejected.
- the material to be nebulized is made the cathode for a DC arc, which appears to produce cavitation, or some generally similar effect on the surface of molten materials accompanied by the ejection of fine particles. Similar action is obtained when the arc is applied to solid surfaces, apparently accompanied by highly localized melting of the material on the surface. The action is presently thought to be caused by a very steep potential gradient immediately adjacent to the cathode. Even when the arc is of low voltage, the potential gradient appears to be very high at the cathode.
- the quantity of particles ejected from the surface has been found to depend upon the selection of the gas used to sustain the arc, which, if a large flow of aerosol is desired, should be one capable of producing a large number of positive ions in the arc.
- the quantity of aerosol produced also depends upon the flow of gas, which determines the rate at which the particles are removed from the region adjacent to the surface of the material.
- FIG. I is a schematic, cross-sectional view of an aerosol generator in accordance with the invention arranged for nebulizing a solid material;
- FIG. 2 is a schematic, cross-sectional view showing apparatus according to a modified form of the invention, as arranged for producing an aerosol from a small body of molten material or from a flowing stream of molten material;
- FIG. 3 is'a schematic, cross-sectional view of a lance in accordance with the invention for obtaining an aerosol from a large body of molten material, such as, for example, a heat of steel in an open hearth furnace;
- FIG. 4 is a chart showingthe arc current produced by a periodic high voltage discharge
- FIG. 5 is a chart showing the arc current produced by application of a constant direct current source of fairly low internal impedance
- FIG. 6 is a chart showing the arc current produced by a periodic low voltage discharge, with certain reactors in series between the arc and the discharge source to damp oscillations to a small extent;
- FIG. 7 is a chart showing the arc current produced as in the case of FIG. 6, but with the reactors selected to achieve critical damping;
- FIG. 8 is a chart showing the arc current produced as in the cases of FIGS. 6 and 7, but with the reactors chosen to produce greater than critical damping.
- an aerosol 10 is produced from a solid, electrically conductive body 12, and withdrawn through an exhaust tube 14 for any desired use.
- the open tip 16 of the exhaust tube is placed closely adjacent to the surface of the body 12 to be analyzed, and serves as an anode for striking an arc between the tube 14 and the body 12.
- the tube 14 is preferably of copper, and water cooled, as shown, so that it does not become heated by the are sufficiently to eject its own constituent materials.
- Its open end 16 is preferably additionally protected, as shown, by a centrally apertured cap 17 of highly refractory and corrosion resistant, insulating material, which operates to restrict the arc to the inner wall surface of the tube 14, to stabilize the arc, to distribute its upper end around the inner circumference of the tube 14, and to concentrate its lower end toward a region on the surface of the body 12 near the central axis of the tube 14.
- a centrally apertured cap 17 of highly refractory and corrosion resistant, insulating material which operates to restrict the arc to the inner wall surface of the tube 14, to stabilize the arc, to distribute its upper end around the inner circumference of the tube 14, and to concentrate its lower end toward a region on the surface of the body 12 near the central axis of the tube 14.
- the cap 17 also produces a jetlike, restrictive effect upon the arc, confining it to a fairly small region on the surface of the material being sampled directly opposite the central aperture 19.
- the effect is thought to be due, at least in part, to the reduction in gas pressure caused by the flow of gas through the aperture 19, which is accelerated by heating of the gas by the arc itself.
- the effect may be enhanced by imparting a tangential motion to the gas to create a swirling effeet as it enters the aperture 19, further to reduce the pressure along the central axis of the aperture.
- the enclosure 18 may be of a conductive material, in which case it should be insulated from the exhaust tube 14 and of adequate internal diameter to insure against striking of an arc between it and the exhaust tube l4.
- the working gas which may, typically, be helium, argon, or nitrogen, is introduced through an inlet 20 in the enclosure 18.
- the enclosure 18 and the exhaust tube 14 are first flushed by flowing the working gas through them to remove air and to provide the desired working atmosphere.
- the are is then struck by passing a momentary high voltage discharge between the anode l4 and the body 12, and may thereafter be maintained at a low voltage sufficient to maintain an average current of at least about -3 amperes, and preferably less than about 50 amperes.
- the are strikes the surface of the body 12 at a very small point and tends to move rapidly over the surface in what may be called a random scanning pattern. After a few minutes, the whole surface of the body 12 beneath the open end of the exhaust tube 14 presents an etched appearance. Local melting and sputtering occur wherever the arc strikes the body 12.
- the arc has a natural tendency to avoid molten portions of the body and to anchor itself to a solid surface. It is seen to be constantly moving over the surface, thereby providing successive very small samples from successive different portions of the body 12, thus insuring that the aerosol is highly representative in composition of a fairly large region of the body 12.
- the working gas continues to flow through the enclosure picking up droplets of the material that are ejected from the surface of the body 12, and carrying the droplets through the exhaust tube in the form of an aerosol 10.
- the droplets freeze rapidly, without coalescing, to form an aerosol of minute solid particles, typically smaller than 1 micron in diameter.
- the flow of the working gas tends to concentrate the arc and to stabilize it, depending upon the nature of the gas and its flow rate in relation to the physical dimensions of the exhaust tube 14 and its spacing from the surface of the body 12 under analysis. Maximum concentration of the arc and the most satisfactory results have been achieved in the work done thus far by the use of helium, which has been found to be effective at much lower rates than, for example, argon.
- the embodiment of the invention illustrated in FIG. 2 is intended primarily for obtaining aerosols from molten materials. It includes a cover 24 of an insulating material enclosing a crucible 26, which has insulating sidewalls 27, and a conductive bottom wall 30 to provide electrical contact with the material 28 in the crucible.
- the bottom wall 30 is preferably water cooled, as shown, for use with materials that melt at high temperatures.
- the crucible 26 may be of any desired configuration. It may, for example, be in the form of an elongated trough for conducting a continuous stream of molten mate 2'? ill through the sampling zone.
- an induction coil 32 is mounted around the crucible 26 for electromagnetically heating and stirring the molten material 28.
- the combination exhaust tube and arcing anode 14 extends through one wall of the cover 24 and terminates adjacent to the upper surface of the molten specimen material 28.
- the lance shown in FIG. 3 is proposed for use in monitoring on a continuous or intermittent basis, as desired, the composition of a large mass of molten material such as, for example, a heat in an open hearth furnace.
- the lance includes an exhaust tube 40 generally similar to the exhaust tubes 14 shown in the embodiments of FIGS. 1 and 2, but preferably of more rigid and rugged construction to enable it better to withstand the buffeting it may be subjected to in this type of environment.
- a lower end portion of the tube 40 of any desired length is surrounded by an enclosure arrangement, which as shown is constituted by a water cooled, cylindrical contact electrode 41.
- the contact electrode 41 extends beyond the open end of the tube 40 and is insulated from the tube 40 by any desired means such as the cup-shaped mounting element 36 shown.
- the contact electrode 41 may be in the form of a rod, in which case the insulating mounting element would constitute the enclosure arrangement and would extend beyond the end of the tube 40,
- the mounting element 36 may be a simple annulus, in which case insulation in the form either of a coating or of additional spacing would be provided between the exhaust tube 40 and the contact electrode 41.
- the contact electrode 41 extends beyond the lower end of the exhaust tube 40 sufficiently far so that when the lance is lowered into the molten bath, only moderate pressure of the working gas will be required to keep the surface of the melt 44 spaced away from the open end of the exhaust tube 40.
- the contact electrode 41 makes a relatively large area electrical contact with the melt 44 in a region reasonably close to the exhaust tube 40, thereby minimizing the loss of energy by joulean heating of the melt.
- the lance is simply lowered into the melt 44 to any desired depth short of immersing the entire length of the contact electrode 41, and the working gas is introduced into the annular space 42 within the electrode 41. If the surface of the melt 44 is contaminated as, for example, by slag or an oxide coating, the contaminants may be swept away and a clean surface provided by increasing the pressure of the working gas to cause it to escape radially outwardly from the lower end of the electrode 41.
- the pressure is reduced before starting the arc to a value that holds the melt below the end of the exhaust tube 40 but does not cause the gas to escape outwardly from the contact electrode 41.
- aerosols may readily be generated containing at least about 100 milligrams of solids per minute.
- the solid particles make an excellent sample for X-ray fluorescence analysis, and also may be rapidly dissolved for use in wet chemical processes.
- the process will be found advantageous also for the production of powders such as powdered iron in cases where it is desired that the particles of the powders be of very small size or of very uniform composition, or both.
- the particles produced in the practice of the invention are highly uniform in composition, and may easily be made smaller than 1 micron in diameter, on the average, by suitable control of arcing current and gas flow rate.
- the material from which the aerosol is to be generated is always connected to the negative terminal of the source of electricity used to sustain the are.
- cathodic DC arcing may be used to characterize the invention.
- the chart of FIG. 4, for example, shows the damped current oscillations that occur in an arc in the practice of the invention during one discharge of a high voltage spark generator of a conventional type.
- the generator was set for a repetition rate of 240 sparks per second at 18,000 volts. As may be seen, the
- the chart of FIG. 5 shows schematically the current an are produced in the practice of the invention in a case wherein the arc was energized by a DC power supply of fairly low internal impedance, set to indicate a nominal average output of about 3 amperes.
- FIGS. 6, 7, and 8 show the arc currents produced by the discharge of a capacitor through the arc in series with selected reactors.
- the arc was initiated by a very brief high voltage pulse, and then sustained by current from the capacitor, which was charged to 1000 volts at the beginning of each discharge.- The repetition rate was 60 per second.
- the capacitor was 5 microfarads in value, and a 360 microhenry inductor was connected in series with it.
- the discharge was underdamped, and the current in the arc oscillated, as shown, at about 3500 hertz for about 1500 microseconds following the initiation of the arc.
- the circuit was arranged to produce critical damping.
- the capacitor was 10 microfarads in value.
- a resistor of 5 ohms, and an inductor of 50 microhenries were connected in series between the capacitor and the arc electrodes. After arc initiation by the high voltage pulse, the current in the arc responded quickly to the voltage impressed by the capacitor, and decayed within about 400 microseconds without oscillation.
- FIG. 8 overdamping was provided.
- the capacitor was of 30 microfarads, and connected to the arc electrodes through a 3 ohm resistor and a 360 microhenry inductor. In this case also, there was no detectable reversal of current once the capacitive discharge assumed control after arc initiation.
- Movement of the arc insures sampling over a macroscopic portion of the cathode. Lack of intense local heating tends to avoid excessive volatization and the effects of preferential volatization of the various different components of the cathode.
- unipotential source seems to be the most apt one to describe the principal limiting feature of the invention.
- it is intended to include not only conventional batteries and direct current power supplies, but also high voltage spark generators in which the output voltage at the time of spark initiation is always of a predetermined polarity, and repetitive capacitive discharge sources in which the output capacitor is always charged in a predetermined polarity at the start of each discharge.
- the material to be nebulized is connected to the nominally negative terminal of the source, and serves as the cathode for the arc current on a time average basis. Although the arc current may reverse momentarily, the net current taken over the arcing period flows from the counter electrode to the material to be nebulized.
- Method of producing an aerosol comprising passing an electric are 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.
- the selected gas is selected from the group consisting of argon, helium, and nitrogen.
- Method of producing an aerosol comprising passing an electric are 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.
- Method of producing an aerosol from a molten source material comprising passing a direct current electric are 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.
- 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 are 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.
- 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.
- Method according to claim 6 including the step of heating the body by electromagnetic induction and thereby stirring the molten portion thereof.
- 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.
- 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.
- 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,
- 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
- a lance for producing an aerosol from a bath of a molten material comprising:
- 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,
- said gas means being operative to carry particles dislodged from the source material by an are out of the enclosure through said tube.
- Apparatus in accordance with claim 11 including dynamic cooling means to enable the lance to Withstand continued exposure to elevated temperatures.
- 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.
- said electrical contact means is a cylindrical conductive member and constitutes the outer wall portion of said enclosure means.
- Apparatus for producing an aerosol from a source material comprising:
- a tubular electrode open at one end, and having an exhaust opening spaced from said one end
- enclosure means for enclosing a region adjacent to the source material and including said open end of said electrode
- 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
- said gas flow means being effective to sweep small parti cles such as may be produced by an arc energized by said current source out of said enclosure means through said electrode.
- 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.
Abstract
Description
Claims (16)
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Application Number | Priority Date | Filing Date | Title |
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US73725268A | 1968-05-20 | 1968-05-20 |
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US3602595A true US3602595A (en) | 1971-08-31 |
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US737252*A Expired - Lifetime US3602595A (en) | 1968-05-20 | 1968-05-20 | Method of and apparatus for generating aerosols by electric arc |
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Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3659944A (en) * | 1970-02-27 | 1972-05-02 | Siderurgie Fse Inst Rech | Apparatus for continuous spectral analysis of molten substances |
US3791743A (en) * | 1973-03-21 | 1974-02-12 | Bethlehem Steel Corp | Portable flame photometer and sampling probe |
EP0194492A2 (en) * | 1985-03-13 | 1986-09-17 | Allied Corporation | In-situ analysis of a liquid conductive material |
US4806150A (en) * | 1988-01-21 | 1989-02-21 | The United States Department Of Energy | Device and technique for in-process sampling and analysis of molten metals and other liquids presenting harsh sampling conditions |
US5183481A (en) * | 1991-06-07 | 1993-02-02 | Aerochem Research Laboratories, Inc. | Supersonic virtual impactor |
DE4242215C1 (en) * | 1992-12-15 | 1994-05-11 | Fraunhofer Ges Forschung | Road surface condition measuring system - uses gas and gas/liquid jets operated sequentially during measuring cycle of electrical, optical or radiometric sensor |
WO1995017656A1 (en) * | 1993-12-23 | 1995-06-29 | Compagnie Generale Des Matieres Nucleaires | Method for determining the surface contamination of a solid, and device therefor |
US5537206A (en) * | 1993-11-02 | 1996-07-16 | Nkk Corporation | Method for analyzing steel and apparatus therefor |
US5784153A (en) * | 1995-06-12 | 1998-07-21 | Nkk Corporation | Method for detecting cause of abnormal portion present on surface of steel product |
US20050200442A1 (en) * | 2002-06-13 | 2005-09-15 | Roger Boen | Electromagnetic device for interfacial melting and strirring of diphasic systems in particular for accelerating metallurgical of pyrochemical processes |
NL1029612C2 (en) * | 2005-07-26 | 2007-01-29 | Corus Technology B V | Method for analyzing liquid metal and device for use therein. |
-
1968
- 1968-05-20 US US737252*A patent/US3602595A/en not_active Expired - Lifetime
Cited By (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3659944A (en) * | 1970-02-27 | 1972-05-02 | Siderurgie Fse Inst Rech | Apparatus for continuous spectral analysis of molten substances |
US3791743A (en) * | 1973-03-21 | 1974-02-12 | Bethlehem Steel Corp | Portable flame photometer and sampling probe |
FR2222647A1 (en) * | 1973-03-21 | 1974-10-18 | Bethlehem Steel Corp | |
JPS49123393A (en) * | 1973-03-21 | 1974-11-26 | ||
EP0194492A2 (en) * | 1985-03-13 | 1986-09-17 | Allied Corporation | In-situ analysis of a liquid conductive material |
US4615225A (en) * | 1985-03-13 | 1986-10-07 | Allied Corporation | In-situ analysis of a liquid conductive material |
EP0194492A3 (en) * | 1985-03-13 | 1987-06-16 | Allied Corporation | In-situ analysis of a liquid conductive material |
US4806150A (en) * | 1988-01-21 | 1989-02-21 | The United States Department Of Energy | Device and technique for in-process sampling and analysis of molten metals and other liquids presenting harsh sampling conditions |
US5183481A (en) * | 1991-06-07 | 1993-02-02 | Aerochem Research Laboratories, Inc. | Supersonic virtual impactor |
DE4242215C1 (en) * | 1992-12-15 | 1994-05-11 | Fraunhofer Ges Forschung | Road surface condition measuring system - uses gas and gas/liquid jets operated sequentially during measuring cycle of electrical, optical or radiometric sensor |
US5537206A (en) * | 1993-11-02 | 1996-07-16 | Nkk Corporation | Method for analyzing steel and apparatus therefor |
WO1995017656A1 (en) * | 1993-12-23 | 1995-06-29 | Compagnie Generale Des Matieres Nucleaires | Method for determining the surface contamination of a solid, and device therefor |
FR2714464A1 (en) * | 1993-12-23 | 1995-06-30 | Cogema | A method of controlling surface contamination of a solid and a device for carrying out the work. |
US5784153A (en) * | 1995-06-12 | 1998-07-21 | Nkk Corporation | Method for detecting cause of abnormal portion present on surface of steel product |
US20050200442A1 (en) * | 2002-06-13 | 2005-09-15 | Roger Boen | Electromagnetic device for interfacial melting and strirring of diphasic systems in particular for accelerating metallurgical of pyrochemical processes |
US7799270B2 (en) * | 2002-06-13 | 2010-09-21 | Commissariat A L'energie Atomique | Electromagnetic device for fusion and interfacial agitation of diphase systems, particularly for the acceleration of metallurgic or pyrochemical processes |
NL1029612C2 (en) * | 2005-07-26 | 2007-01-29 | Corus Technology B V | Method for analyzing liquid metal and device for use therein. |
WO2007012440A1 (en) * | 2005-07-26 | 2007-02-01 | Aleris Switzerland Gmbh | Method for analyzing liquid metal and device for use in this method |
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Owner name: JAMES TALCOTT, INC., NEW YORK Free format text: SECURITY INTEREST;ASSIGNORS:APPLIED RESEARCH LABORATORIES, INC.;ARL APPLIED RESEARCH LABORATORIES, S.A.;REEL/FRAME:004326/0899 Effective date: 19840828 Owner name: LLOYDS BANK INTERNATIONAL LIMITED, NEW YORK Free format text: SECURITY INTEREST;ASSIGNORS:APPLIED RESEARCH LABORATORIES, INC.;ARL APPLIED RESEARCH LABORATORIES, S.A.;REEL/FRAME:004326/0899 Effective date: 19840828 Owner name: E.I. DU PONT DE NEMOURS AND COMPANY, DELAWARE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BUCKFELDER, JOHN J.;SCHLEINITZ, HENRY M.;REEL/FRAME:004326/0513 Effective date: 19840925 Owner name: JAMES TALCOTT, INC., 1633 BROAWAY NEW YORK, NY 10 Free format text: SECURITY INTEREST;ASSIGNORS:APPLIED RESEARCH LABORATORIES, INC., A MA CORP.;ARL APPLIED RESEARCH LABORATORIES, S.A. A SWITZERLAND CORP.;REEL/FRAME:004326/0899 Effective date: 19840828 Owner name: LLOYDS BANK INTERNATIONAL LIMITED, ONE SEAPORT PLA Free format text: SECURITY INTEREST;ASSIGNORS:APPLIED RESEARCH LABORATORIES, INC., A MA CORP.;ARL APPLIED RESEARCH LABORATORIES, S.A. A SWITZERLAND CORP.;REEL/FRAME:004326/0899 Effective date: 19840828 Owner name: E.I. DU PONT DE NEMOURS AND COMPANY, WILMINGTON, D Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:BUCKFELDER, JOHN J.;SCHLEINITZ, HENRY M.;REEL/FRAME:004326/0513 Effective date: 19840925 |