US3644782A - Method of energy transfer utilizing a fluid convection cathode plasma jet - Google Patents

Method of energy transfer utilizing a fluid convection cathode plasma jet Download PDF

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US3644782A
US3644782A US1388A US3644782DA US3644782A US 3644782 A US3644782 A US 3644782A US 1388 A US1388 A US 1388A US 3644782D A US3644782D A US 3644782DA US 3644782 A US3644782 A US 3644782A
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cathode
anode
fluid medium
gas
arc
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Charles Sheer
Samuel Korman
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SHEET KORMAN ASSOCIATES Inc
SHEET-KORMAN ASSOCIATES Inc
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H01J37/32431—Constructional details of the reactor
    • H01J37/32623—Mechanical discharge control means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/26—Plasma torches
    • H05H1/32—Plasma torches using an arc

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  • Demeo At!orneyHammond 8 Littell ABSTRACT A process of energizing a fluid medium by means of an arc discharge between an anode and a cathode having a conical tip, said are discharge forming a contraction of the currentcarrying area in the transition region in the vicinity of said cathode, the points of inflection of said contraction of the current-carrying area forming, when extended, an angle a, which comprises forcefully projecting a fluid medium along said conical tip of said cathode into and through said contraction of the current-carrying area in the transition region in the vicinity of said cathode at a mass flow density at substantially constant convection rate which is at least sufficient to effect a rise in the temperature of said are column at a constant current level, and below a total fluid medium convection rate at substantially constant mass flow density which is sufficient to reduce the angle below 40 at a constant current level.
  • ahierarc is an electric discharge between a cathode and an anode of such intensity that the material of the anode face is vaporized and converted into a plasma jet, shooting off into space, avoiding the cathode. This is sometimes referred to as the consumable anode hierarc.
  • the performance criteria required to achieve the desired results are the following:
  • the average diameter of the pores on the surface of the anode is less than the thickness of the anode fall space which is normally established in the absence of fluid flow adjacent to the active area, i.e., the fall space thickness of a conventional are operating under noflow conditions.
  • the fluid is forced to flow through the passageways in the porous electrode so that the fluid emerges directly from the electrode surface into the fall space over the area integrally congruent with the arc terminus on the porous electrode surface, and preferably nowhere else.
  • the surface distribution of orifices, through which the fluid emerges from the electrode into the fall space, is sufficiently uniform that the individual streams of fluid from each orifice will diffuse laterally, merging with each other stream adjacent to it to form a homogeneous stream, as though it were issuing as a vapor from a solid surface, and further, the average interorifice distance on the active surface is sufficiently small that essentially complete flow homogeneity is established before the fluid penetrates an appreciable distance into the fall space.
  • the rate of fluid transpiration through the porous anode is adjusted so that it is greater than the value required to effect a transition to the hierarc mode of arc operation.
  • PTA fluid transpiration arc
  • the PT A from the other forms of plasma generators and which emphasize the potential utility of this technique as an addition to the roster of high-temperature devices.
  • One of the most striking properties of the ET A is the energy transfer efiiciency (ratio of effluent jet enthalpy to power input). This results largely from the elimination of the need for thermal constriction of the arc column, which is the basic means of stabilizing the column against fluid flow in the wall-stabilized are. In the latter device, a large fraction (e.g., 30 to 60 percent) of the power input is unavoidably lost by heat transfer to the cooling circuit of the constricting channel. In the case of the PTA, when the fluid emerging from the porous anode penetrates the anode sheath,
  • the plasma properties of the emerging column are relatively invariant in the radial direction. Furthermore, the radial invariance persists for several column diameters downstream, providing an appreciable volume characterized by only axial variation of plasma parameters. This means that a small axial increment of the column may be treated as a uniform medium, thus vastly simplifying the theoretical interpretation of diagnostic data.
  • One of the most interesting features of the PT A is the abnormally high-electrical conductivity of the effluent plasma, particularly in the region near the anode.
  • a macroscopic plasma zone characterized by a high degree of nonequilibrium.
  • the electron temperature is much higher than the gas temperature throughout most of this region. This feature has been observed in low-pressure 0.l atm.) discharges, but never before at atmospheric pressure.
  • the high-electron temperature is in itself insufficient to explain the measured electrical conductivity (two-temperature model).
  • Spectroscopic measurements indicate a higher degree of ionization than can be correlated with the Saha equation.
  • the high density of free electrons in a relatively dense plasma suggests an enhancement of continuum radiation and provides the basis for an efficient source of radiation.
  • the FTA in which the working fluid is first energized in the anode sheath and then fully permeates the column in the vicinity of the anode.
  • the natural cathode jet collides with the transpiration gas at some point between the electrodes.
  • the injected gas permeates only the positive column, i.e., the portion of the conduction column between the anode and the point of impingement of the two jets.
  • the negative column (between the cathode tip and the point of impingement) is characterized by the flow of ambient gas which may not be the same as the injected gas.
  • An object of the present invention is the development of a method which enables the bulk of the fluid to be injected into the negative column extending from the cathode tip.
  • a further object of the present invention is the development of a process of energizing a fluid medium by means of an arc discharge between an anode and a cathode having a conical tip, said are discharge forming a contraction of the currentcarrying area in the transition region in the vicinity of said cathode, the points of inflection of said contraction of the current-carrying area forming, when extended, an angle a, which comprises forcefully projecting a fluid medium along said conical tip of said cathode into and through said contraction of the current-carrying area in the transition region in the vicinity of said cathode at a mass flow density at substantially constant convection rate which is at least sufficient to effect a rise in the temperature of said are column at a constant current level and below a total fluid medium convection rate at substantially constant mass flow density which is sufficient to reduce the angle or below 40 at a constant current level.
  • FIG. 1 is a schematic diagram illustrating the arc column contraction and the angle a in the vicinity of the cathode.
  • FIG. 2 is an enlarged cross section of operation of the method of the invention including the cathode.
  • FIG. 3 is a medial section of one embodiment of operation of the method of the invention.
  • FIG. 4 is a medial section of another embodiment of the operation of the invention.
  • FIG. 5 is a medial section of a still other embodiment of the invention.
  • FIG. 6 is a medial section of a yet further embodiment of the invention.
  • FIG. 7 is a graph of the unexpected temperature rise using the process of the invention.
  • FIG. 8 is a graph of the unexpected reduction in the angle a with increased convection rate at constant current level and mass flow density.
  • the current density and, therefore, the self-magnetic field due to the arc current increases toward the cathode as a result of the contraction.
  • This nonuniform magnetic field exerts a body force on the conductive plasma, propelling it in the direction of maximum decrease in magnetic field, i.e., along the arc axis away from the cathode tip.
  • the streaming of plasma away from the cathode tip decreases the local pressure in the immediate vicinity of the cathode tip and causes the arc to aspirate gas from the surrounding atmosphere.
  • This mechanism establishes the well-known natural cathode jet, which has been observed to flow along the axis of the column away from the cathode tip in all arcs characterized by a contraction zone adjacent to the cathode.
  • this contraction zone 3 can serve as an injection window across which a fluid medium in the form of a gas may be injected directly into the arc column 2 at flow rates in excess of what can be forced across the cylindrical column boundary of the arc.
  • Gas flow rates of a magnitude much greater than that aspirated naturally can be injected into the column without disturbing the stability of the are when the gas is forced to follow the conical configuration of the cathode tip.
  • the increase in gas convection rate does effect the angle a and if the angle a is reduced below 40", no substantial amounts of addition gas can be injected into the arc column 2.
  • the effect of the forced convection is to increase the voltage gradient in and near the transition region, thereby increasing the volume rate of energy dissipation and making available the additional energy needed to heat the increased quantity of gas introduced to the column temperature.
  • the injection window is not only possible but actually increases the heat transfer effectiveness of this part of the are, as long as it does not exceed the convection rate which will reduce the angle or below 40.
  • the boundaries of the gas which is forced to follow the conical configuration of the cathode tip are on one hand the surface of the cathode, and on the other hand a line parallel to the surface of the cathode which intersects the cathode column at the outermost limit of the contraction zone 3.
  • the gas is forced to follow the conical configuration of the cathode tip in such a manner that its essential entirety enters the contraction zone at its region of maximum convergence. This region can be determined by trial.
  • a cone with reference to the cathode is defined as a converging segment which may be a true cone having a circular cross section or may be pyramidal in shape, comprising a number of converging planar surfaces whose cross section is a polygon of any convenient number of sides.
  • the term cone angle shall refer to the vertex angle of the converging segment.
  • the gas can be made to cross the column boundary in essentially the same general direction as would the aspirated ambient gas stream in the absence of forced convection.
  • the optimum cone angle for this purpose appears to be between 45 and 60.
  • cone angle is an important parameter. Variations in cone angles of from 20 to may be employed depending partially on the material of the cathode, and type of fluid material injected, and the work purpose of the device. We prefer to use a cone angle in the range of 30 to 60, and more particularly, have used angles of 45 to 60 with good results.
  • a second critical parameter is the injection velocity. This can be varied without altering the total mass flow (convection) rate by varying the area of the annular orifice and changing the inlet gas pressure as required to maintain a fixed flow rate. It has been observed, for example, that as the injection velocity (mass flow density) is varied, the column temperature passes through a peak, with the maximum temperature rising to two or three times that obtained when the velocity is several times higher or lower than its optimum value. it should also be mentioned that the creation of a high-velocity gas layer flowing along the surface of the cathode is effective in regenerating some of the heat lost by thermal conduction back from the cathode tip.
  • a third critical parameter is the total mass flow of the injected fluid medium. As-the total mass flow of the injected fluid medium is varied at substantially constant current levels and mass flow density, an alteration of the shape of the contraction zone 3 occurs. When the total mass flow or convection rate of the injected fluid medium is increased from zero, little or no change in the shape of the contraction zone 3 is observed and substantially all of the injected fluid enters the arc column through the injection window. However, as the total mass flow of the injected fluid medium is increased further, at a point depending on the medium injected, the contraction zone begins to elongate thus decreasing the space rate of contraction of the arc column diameter. This space rate of contraction may be called the window angle and is depicted in P16. 1 as the angle a. When the angle a is sufficiently reduced, that is, to about 40 or less, the major portion of the flow of the fluid medium does not enter the arc column.
  • the above technique of injecting the working fluid into the contraction region of the column will be henceforth termed the forced convection cathode" arc (FCC).
  • FCC forced convection cathode
  • Excellent operational stability is achieved without energy-wasting thermal constraints, providing the basis for excellent efficiency along with a high degree of accessibility to the primary energy transfer zone.
  • the FTA it provides a means whereby the working fluid can be made to penetrate significantly all portions of the conduction column, from anode to cathode, absorb otherwise unavailable energy in the electrode transition zones, and regenerate some of the heat normally lost to the electrodes.
  • a gas such as nitrogen, argon or hydrogen can be introduced into the injection window" and in a highly energized condition is projected so as to contact an anode.
  • a gas such as nitrogen, argon or hydrogen can be introduced into the injection window" and in a highly energized condition is projected so as to contact an anode.
  • plasma jet may be utilized to heat other materials, for example, in cutting and welding.
  • a reactive gas such as nitrogen or hydrogen
  • a reactive gas can be introduced as above into the injection window to form a highly energized plasma jet which is projected into the jet of plasma vapor issuing from the anode of a consumable anode hierarc.
  • an anode is a carbon anode
  • hydrogen is introduced through the FCC
  • the mixture of the two jets is favorable to the production of hydrocarbons.
  • the consumable anode contains a metal or metaloid
  • the gases so projected will unite with the plasma of the hierarc to form the corresponding nitride or hydride of the metal of the anode.
  • two different gases may be introduced into the cathode injection window and the anode fall space, respectively, to perform such operations as the synthesis and reformation of organic compounds and inorganic compounds such as ammonia.
  • the device can also be employed in other fields as in the case of the PT A.
  • any powdered material including metals, oxides, etc.
  • any powdered material may be passed through the are at such a rate relative to the power level that the material is melted, but not appreciably vaporized, during its transit through the column and effluent jet.
  • inert gas such as argon
  • any powdered material including metals, oxides, etc.
  • the familiar process of flame spraying may be achieved with greater material application rates and better quality coatings than otherwise possible.
  • the entrained particulates can be made to vaporize during their passage through the arc zone. Upon emerging from the jet, the vapors will recondense into extremely fine particles in the submicron range, thus providing an efficient process for the comminution of coarser powdered materials.
  • the powder of a stable refractory ore may be entrained in an appropriate carrier gas and passed through the device at a predetermined rate relative to the power level, so that the ore particles are rendered chemically unstable.
  • this may or may not require heating the particles above their melting point, and the optimum throughput rate for a given power level for a given ore is best determined empirically.
  • the particles are rendered amenable to chemical attack by ordinary reagents for the economic recovery and separation of the ore values,
  • a reactive gas such as hydrogen may be used as the carrier gas to entrain powdered coal so as to produce a mixture of active hydrogen and carbon vapor, from which acetylene and other hydrocarbons may be condensed.
  • droplets of liquid hydrocarbons may be entrained in the hydrogen for hydrocarbon reformation.
  • metals or metalloidal powders may be entrained in hydrogen or nitrogen to produce hydrides or nitrides. The introduction of metal oxides with hydrogen to produce metals, or with ammonia to produce nitrides, may also be accomplished.
  • Many other similar applications of the device for chemical processing are possible in which greater efficiency and higher yields are obtainable from the use of this device than can be obtained from other methods of treatment.
  • the invention can be practiced and the high energization of the gas introduced at the cathode can be achieved in the following manner.
  • H6. 2 is a cross section of a cathode nozzle 4 designed to optimize a gas injection 5 into the arc column 2 via the injection window at the contraction zone 3 at the end of the cathode 1.
  • the nozzle 4 forms a narrow annular orifice 6, upstream of the conical cathode tip 7, directing the gas 5 to flow in a high-velocity layer along the conical cathode surface.
  • FIG. 3 shows the apparatus for conducting the process by means of which the cathode gases the anode plasma jet is to be generated.
  • FIG. shows a similar construction in which the material of the anode jet is in the form of a gas, which is caused to transpire through the porous refractory anode block.
  • FIG. 3 the cathode l and cathode nozzle 4 are depicted as in FIG. 2.
  • the arc column 2 emitting from the cathode tip is directed to and contacts a water-cooled solid anode 9, such as a water-cooled copper block.
  • the plasma jet 8 flows away from the anode.
  • the numeral 10 represents a consumable rod electrode of the material to be converted, having an active face 11. Spaced from the face 11, but not directly in front of it, is a cathode 12 of a refractory material such as tungsten, in the form of a rod having a conical end 13. This rod 12 is negatively charged from a suitable source 14, the positive terminal of which is the rod 10.
  • the active conical end 13 of the cathode 12 is surrounded closely by a preferably nonconducting box 15 having an opening 16 for the gas to be added.
  • the box 15 has a conical end 17 surrounding the pointed end 13 of the cathode 12, but ter minating before reaching the point of the cone.
  • the velocity of the gas may be readily controlled by the pressure exerted on it at 16 and by adjusting, in a known manner, the cathode 12 within the nozzle formed by the conical end 17 ofbox 15.
  • FIG. 5 shows how the process may be applied to the treatment of a material in fluid or gaseous form.
  • the refractory anode ll of FIG. 4 is replaced by an anode box U having an inlet 20 for the reaction gas, and having on the opposite face a porous block 18 through which the material is forced, exposing the fluid material to the jet from the cathode 12 in a fixture which is identical with that shown in FIG. 3.
  • the effluent gas streams are caused to interact at high temperatures while the anode box, itself, is held at a more moderate temperature.
  • the device depicted in FIG. 6 is similar in effect to that of FIG. 3.
  • the cathode l and its nozzle 4 are identical to that described in FIG. 3.
  • the anode 9 in this embodiment is a flat circular water-cooled anode.
  • the anode spot 21 is made to rotate around the circular anode 9 by means of a magnetic field introduced through the solenoid winding 22.
  • a gastight housing 23 encloses the arc column 2.
  • the effluent plasma jet 8 emerges from the circular anode 9.
  • the voltages employed to carry out the process are determined by the result achieved.
  • FIG. 2 The principle by which this cathode gas stream is employed is illustrated in FIG. 2, in which is shown a conical cathode 1 over which the cathode gas 5 is caused to flow over the conical surface of the cathode 1 and beyond the tip 7.
  • FIG. 2 shows a conical cathode 1 over which the cathode gas 5 is caused to flow over the conical surface of the cathode 1 and beyond the tip 7.
  • FIG. 3 The simplest form of the operation of the method is shown diagrammatically in FIG. 3. It consists of a tungsten rod threeeighths inch in diameter having a conical tip with a 60 cone angle as the cathode. Surrounding 'the cathode is an envelop ing nozzle 4 having a conical section whose inside surface also has a cone angle of 60 so that it mates with the conical cathode surface. The conical section of the nozzle is truncated so that it terminates several millimeters behind the cathode tip 7, and thus forms an annular orifice 6 about the cathode.
  • the annular passage between the nozzle and cathode is effective in directing the flow of input gas 5 in the form of converging conical layer flowing close to the cathode surface, finally impinging on the arc column 2 largely on the injection window of the contraction zone 3.
  • the mass flow rate of gas can be controlled by adjusting the inlet pressure, and, for the experiment being described, was varied from as little as 2 grams per minute of argon gas to over 50 grams per minute.
  • the nozzle itself was initially fabricated of boron nitride ceramic, although, owing to its proximity to the arc, in later tests it was found expedient to make the nozzle out of a metal such as brass and provide it with a separate water-cooling circuit to prevent overheating. However, in the latter case, care was taken to insulate the nozzle electrically from the cathode to avoid the formation of undesired secondary arcs.
  • the orifice area of the cathode nozzle is made variable by moving the nozzle section relative to the cathode in the axial direction. This is done by mounting the nozzle itself on a micrometer screw. Rotation of the nozzle in either direction thus, causes the latter to move horizontally relative to the stationary cathode, opening or closing the nozzle orifice.
  • various nozzle orifice areas were used varying from 1.00 to 4.5 square millimeters, corresponding to annulus widths ofO. l 8 mm. to 1.16 mm.
  • the anode 9 of the arc in this apparatus is composed of a linch-diameter. copper tube with one-eighth inch thick wall, closed at one end with a rounded cap which serves as the current-receiving area. The interior of the tube is fitted with water passages and the anode is vigorously water cooled to inhibit erosion of the surface during operation. Provision is made to change the position of the anode with respect to the cathode, thus effectively varying the arc gap. It was also found convenient for starting the arc to provide means for altering the angle as well as the position of the anode rod with respect to the cathode axis. The procedure used for igniting the arc is as follows.
  • the anode is rotated about 45 and raised so that the rounded end of the anode points toward the cathode tip, and the cathode axis intersects the anode rod near its center. Simultaneously, the anode rod is brought close to the cathode tip, to leave a gap of about 5 mm.
  • a moderate flow of gas is turned on. For argon, a startup flow of 10 to 15 grams per minute was usually used.
  • the arc is then ignited, using a momentary high-frequency spark to form a conductive path between the electrodes with the main power supplyv turned on, following which a rapid spark to arc transition occurs. This technique of arc ignition is well known in the art.
  • the arc gap is increased to its desired value by withdrawing the anode.
  • the anode is rotated to a convenient lateral position, preferably normal to the arc axis, and retracted so that the end cap is just below the plasma stream.
  • the effluent jet leaves the conduction column in essentially the axial direction.
  • care must be taken to keep the end of the anode sufficiently close to the column to prevent the are from being blown out.
  • the device has been operated in this relatively simple configuration in a stable and continuous manner.
  • the following are the ranges of the pertinent operating parameters which were observed during the testing of this device, using argon as the working fluid:
  • Parameter Test 1 Test 2 are current 50 av 200 a.
  • FIG. 6 shows an alternative configuration of the device wherein the cathode l and its nozzle 4 is identical to that described in FIG. 3, the main difference being the type of anode 9 used.
  • a flat circular copper anode 9 is used, about it inch thick and 2 inches in diameter, with a z-inch diameter hole in the center.
  • the interior of the ring is fitted with water passages for rapid cooling of the cylindrical surface of the hole during operation. This surface serves as the attachment area for the anode spot 21.
  • the anode spot When using the ring-shaped anode, it is useful to rotate the anode spot on the inside cylindrical surface. This may be done by placing the device inside a solenoid winding 22 which establishes an axial magnetic field. If sufficient magnetic flux is generated, the anode spot will rotate very rapidly, spreading out essentially into a continuous ring. This reduces anode erosion by distributing the heat transferred to the anode over a larger area.
  • a magnetic field of 2,400 gauss, measured on the axis midpoint of the solenoid was found to be effective. This is a technique well known in the art for increasing the thermal loading capacity of are devices.
  • the housing may be constructed of any convenient material. However, because it must absorb a considerable amount of radiation from the arc column, it is convenient to fabricate the housing from a metal, such as brass, and provide it with its own water-cooling circuit to prevent overheating. in such a case, care must be taken to provide adequate electrical insulation where the housing is attached to the anode and cathode structures.
  • the dimensions of the housing are not critical except that the internal dimensions must be large enough so that the housing walls exert a negligible influence on the arc column. This preserves the freebuming character of the FCC arc and represents an important distinction from prior art devices in which the arc column housing consists of a water-cooled channel in close proximity to the column. ln such devices, the housing serves to constrict essential to their operation.
  • the are in this configuration may be ignited in the same manner as described for the configuration shown in FIG. 3,
  • the capability of changing the arc gap involves a complexity of construction which it is desirable to avoid in many applications where a fixed gap may be employed.
  • a fixed gap is used, the application of a high frequency spark to ignite the arc would require an inordinately high voltage for the spark generator with consequent complications in the form of high-voltage insulation.
  • an alternative procedure of arc ignition is desirable. This consists of using an auxiliary striker" rod, which may consist of a long narrow graphite rod, which is inserted through the hole in the ring anode and made to contact both cathode and anode, while the are power supply is connected. Rapid withdrawal of the rod through the anode hole then results in a fully established arc.
  • the cathode nozzle orifice area was varied to change the injection velocity, the total quantity of gas injected per unit time being maintained constant.
  • the effect of variation of injection velocity on the column was observed by observing the intensity of radiation emitted by the first centimeter of the plasma jet emerging from the ring anode.
  • the light from this segment of the jet was focused on the entrance slit of a prism monochromator.
  • the latter was adjusted to pass a bandwidth angstroms in the neighborhood of 5,000 angstroms.
  • this lies in the so-called continuum" range of the spectrum and, under the conditions of the experiment, the intensity of the light in this spectral region increases with the temperature of the source and vice versa.
  • a suitable photomultiplier, amplifier and recorder following wellknown techniques.
  • the quantity which was adjusted to obtain variation in injection velocity was the area of the cathode nozzle annular orifice. This is based on the following well-known formula:
  • Example I The apparatus of Example I was utilized in this example; however, the cone angle of the cathode was 30.
  • the total mass flow or convection rate riz was varied at constant arc current and mass flow density rir utilizing argon as the fluid medium.
  • the configuration of the arc column 2 in the contraction zone 3 was visually inspected as the total mass flow M was varied.
  • FIG. 8 An example of the effect of M on a is shown in FIG. 8.
  • two curves are drawn, for 50 amps, and 100 amps, respectively, showing the variation of a with M.
  • This effect is relatively independent of riz, which is the mass flow density referred to the annular nozzle orifice 6. This is given by the ratio M/A where A is the orifice area, and can be shown to be approximately proportional to the injected gas velocity (see Example II).
  • the following table illustrates the effect of m on a for a fixed arc current of 150 amps and a fixed total mass flow M of 12 grams per minute utilizing argon.
  • EXAMPLE IV A further example, in which the FCC is used to energize a stream of fluid which is then mixed with a vapor stream emerging from a vaporizing refractory solid anode, in accordance with the drawing of FIG. 4, is illustrated by the following two tests.
  • the are configuration used in this experiment was one in which the anode and cathode axes are inclined at 45 to each other. This, however, is not critical and we have operated at angles ranging from 0 to It is, however, preferable, when streams of plasma are energized at both anode and cathode, to incline the axes of the two electrodes so that the two jets merge smoothly into a single jet of mixed fluids.
  • the gas injected via the cathode nozzle was nitrogen so that the effluent stream contained carbon and nitrogen, chemically combined.
  • the anode consisted of a solid rod, 1 inch in diameter and 20 inches long, consisting of a mixture of 34 percent carbon and 66 percent boric oxide. These ingredients had previously been mixed with a binder, extruded, and baked to form a hard, homogeneous electrically conducting rod, in accordance with well-known procedures.
  • the gas injected via the cathode nozzle was nitrogen, so that the effluent jet consisted initially of a mixture of boric oxide vapor, carbon vapor and nitrogen, from which issued boron nitride and carbon monoxide.
  • Test 5 Cathode gas nitrogen nitrogen Anode composition I00% carbon 34% carbon 66% boric oxide Arc current 200 a. 50 a. Are voltage I20 volts I60 volts Arc gap 3 cm. 2 cm. Nitrogen flow rate I5 g./min. l2 g./min. Anode feed rate I inch/min. I inch/min. Anode rotation rate I rev. per. sec. l rev. per sec.
  • EXAMPLE V In place of the vaporizing anode of Example IV an arrangement using the porous anode assembly (FTA) in conjunction with the FCC has also been operated successfully for heating gases with high efficiency.
  • the arrangement used is shown in the drawing of FIG. 5.
  • the configuration involving a 45 angle between electrodes is shown, although the device has been operated at all angles between 0 and 135.
  • porous anode used in these tests was fabricated by hotpressing spherical tungsten powder having a size range of to 200 mesh, and sintered to a density approximately 70 percent of the density of solid tungsten. The procedures used are well known.
  • cathode gas mass flow rate cathode nozzle orifice area anode gas mass flow rate 0.5 to 40 gJmin. 2.1 to 4.8 mm.
  • I Test 7 arc current 200 a. arc voltage 48 volts arc gap 3 cm. cathode gas mass flow rate gJmin.
  • said fluid medium is a mixture of at least one finely divided solid and at least one liquid dispersed in at least one gas.
  • said fluid medium is a mixture of a finely divided solid selected from the group consisting of oxides of metals, and metalloids, dispersed in a gascontaining ammonia.
  • said fluid medium is a mixture of finely divided carbon, and a finely divided solid selected from the group consisting of oxides of metals and metalloids, dispersed in a gas-containing nitrogen.

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US1388A 1969-12-24 1970-01-08 Method of energy transfer utilizing a fluid convection cathode plasma jet Expired - Lifetime US3644782A (en)

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FR (1) FR2074301A5 (fr)
NL (1) NL7018798A (fr)

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3770935A (en) * 1970-12-25 1973-11-06 Rikagaku Kenkyusho Plasma jet generator
US3931542A (en) * 1973-06-28 1976-01-06 Sheer-Korman Associates, Inc. Method and apparatus for energizing materials in an electric arc
US4039800A (en) * 1974-03-27 1977-08-02 U.S. Philips Corporation Method of and device for arc welding
US4080550A (en) * 1976-12-30 1978-03-21 Sheer-Korman Associates, Inc. Method and apparatus for projecting solids-containing gaseous media into an arc discharge
US4363656A (en) * 1979-12-10 1982-12-14 Centre De Recherches Metallurgiques-Centrum Voor Research In De Metallurgie Injection of hot gases into shaft furnace
US4536640A (en) * 1981-07-14 1985-08-20 The Standard Oil Company (Ohio) High pressure, non-logical thermal equilibrium arc plasma generating apparatus for deposition of coatings upon substrates
US4594496A (en) * 1982-11-10 1986-06-10 Fried. Krupp Gesellschaft Mit Beschrankter Haftung Apparatus for introducing ionizable gas into a plasma of an arc burner
US4695448A (en) * 1985-09-26 1987-09-22 Grand Junction Reality Co., Inc. Reduction and disposal of toxic waste
US5017752A (en) * 1990-03-02 1991-05-21 Esab Welding Products, Inc. Plasma arc torch starting process having separated generated flows of non-oxidizing and oxidizing gas
US5070274A (en) * 1989-03-20 1991-12-03 Onoda Cement Company, Ltd. Method for making diamond and apparatus therefor
US6163009A (en) * 1998-10-23 2000-12-19 Innerlogic, Inc. Process for operating a plasma arc torch
US6215089B1 (en) * 1998-06-02 2001-04-10 Inocon Technologie Gesellschaft M.B.H. Plasma welding torch
US6326583B1 (en) 2000-03-31 2001-12-04 Innerlogic, Inc. Gas control system for a plasma arc torch
US6498317B2 (en) 1998-10-23 2002-12-24 Innerlogic, Inc. Process for operating a plasma arc torch
US6677551B2 (en) 1998-10-23 2004-01-13 Innerlogic, Inc. Process for operating a plasma arc torch
US20040045807A1 (en) * 2002-06-17 2004-03-11 Sarkas Harry W. Process for preparing nanostructured materials of controlled surface chemistry
US20120261392A1 (en) * 2011-04-14 2012-10-18 Thermal Dynamics Corporation Method for starting a multi-gas plasma arc torch
US20160021728A1 (en) * 2013-02-27 2016-01-21 Hho Heating Systems B.V. Plasmatron and heating devices comprising a plasmatron
US9949356B2 (en) 2012-07-11 2018-04-17 Lincoln Global, Inc. Electrode for a plasma arc cutting torch
US10354845B2 (en) * 2016-02-18 2019-07-16 Southwest Research Institute Atmospheric pressure pulsed arc plasma source and methods of coating therewith
US10440808B2 (en) 2015-11-17 2019-10-08 Southwest Research Institute High power impulse plasma source

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3770935A (en) * 1970-12-25 1973-11-06 Rikagaku Kenkyusho Plasma jet generator
US3931542A (en) * 1973-06-28 1976-01-06 Sheer-Korman Associates, Inc. Method and apparatus for energizing materials in an electric arc
US4039800A (en) * 1974-03-27 1977-08-02 U.S. Philips Corporation Method of and device for arc welding
US4080550A (en) * 1976-12-30 1978-03-21 Sheer-Korman Associates, Inc. Method and apparatus for projecting solids-containing gaseous media into an arc discharge
US4363656A (en) * 1979-12-10 1982-12-14 Centre De Recherches Metallurgiques-Centrum Voor Research In De Metallurgie Injection of hot gases into shaft furnace
US4536640A (en) * 1981-07-14 1985-08-20 The Standard Oil Company (Ohio) High pressure, non-logical thermal equilibrium arc plasma generating apparatus for deposition of coatings upon substrates
US4594496A (en) * 1982-11-10 1986-06-10 Fried. Krupp Gesellschaft Mit Beschrankter Haftung Apparatus for introducing ionizable gas into a plasma of an arc burner
US4695448A (en) * 1985-09-26 1987-09-22 Grand Junction Reality Co., Inc. Reduction and disposal of toxic waste
US5070274A (en) * 1989-03-20 1991-12-03 Onoda Cement Company, Ltd. Method for making diamond and apparatus therefor
US5017752A (en) * 1990-03-02 1991-05-21 Esab Welding Products, Inc. Plasma arc torch starting process having separated generated flows of non-oxidizing and oxidizing gas
US6215089B1 (en) * 1998-06-02 2001-04-10 Inocon Technologie Gesellschaft M.B.H. Plasma welding torch
US6163009A (en) * 1998-10-23 2000-12-19 Innerlogic, Inc. Process for operating a plasma arc torch
US6498317B2 (en) 1998-10-23 2002-12-24 Innerlogic, Inc. Process for operating a plasma arc torch
US6677551B2 (en) 1998-10-23 2004-01-13 Innerlogic, Inc. Process for operating a plasma arc torch
US6326583B1 (en) 2000-03-31 2001-12-04 Innerlogic, Inc. Gas control system for a plasma arc torch
US20040045807A1 (en) * 2002-06-17 2004-03-11 Sarkas Harry W. Process for preparing nanostructured materials of controlled surface chemistry
US20120261392A1 (en) * 2011-04-14 2012-10-18 Thermal Dynamics Corporation Method for starting a multi-gas plasma arc torch
US9024230B2 (en) * 2011-04-14 2015-05-05 Victor Equipment Company Method for starting a multi-gas plasma arc torch
US9949356B2 (en) 2012-07-11 2018-04-17 Lincoln Global, Inc. Electrode for a plasma arc cutting torch
US20160021728A1 (en) * 2013-02-27 2016-01-21 Hho Heating Systems B.V. Plasmatron and heating devices comprising a plasmatron
US10440808B2 (en) 2015-11-17 2019-10-08 Southwest Research Institute High power impulse plasma source
US10354845B2 (en) * 2016-02-18 2019-07-16 Southwest Research Institute Atmospheric pressure pulsed arc plasma source and methods of coating therewith

Also Published As

Publication number Publication date
CH549930A (de) 1974-05-31
NL7018798A (fr) 1971-06-28
BE760844A (fr) 1971-06-24
FR2074301A5 (fr) 1971-10-01

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