EP0351847A2 - Plasmagenerator mit modular geteilter Kathode - Google Patents

Plasmagenerator mit modular geteilter Kathode Download PDF

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Publication number
EP0351847A2
EP0351847A2 EP89113342A EP89113342A EP0351847A2 EP 0351847 A2 EP0351847 A2 EP 0351847A2 EP 89113342 A EP89113342 A EP 89113342A EP 89113342 A EP89113342 A EP 89113342A EP 0351847 A2 EP0351847 A2 EP 0351847A2
Authority
EP
European Patent Office
Prior art keywords
anode
plasma
cathode
powder
chamber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP89113342A
Other languages
English (en)
French (fr)
Other versions
EP0351847A3 (de
Inventor
Masamichi Koga
Koichi Takeda
Tsuyoshi Shinoda
Erich Muehlberger
Albert Sickinger
Stephan Erich Muehlberger
Don Everett Bailey
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
Original Assignee
Nippon Steel Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nippon Steel Corp filed Critical Nippon Steel Corp
Publication of EP0351847A2 publication Critical patent/EP0351847A2/de
Publication of EP0351847A3 publication Critical patent/EP0351847A3/de
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • H05H1/44—Plasma torches using an arc using more than one torch
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
    • C23C4/12—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying
    • C23C4/137—Spraying in vacuum or in an inert atmosphere
    • 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
    • H05H1/28—Cooling arrangements

Definitions

  • the plasma gun 16 is separately operated under control of a plasma control console 58.
  • Transfer arc control circuits 60 control switching of the transfer arc polarity.
  • Fig. 1 is essentially identical to the plasma system described in previously referred to U.S. Patent 4,328,257 of Muehlberger et al, and reference thereto is made to the extent that further explanation of one or more portions of the plasma system may be needed.
  • Fig. 2 shows the plasma gun 16 of Fig. 1.
  • the plasma gun 16 includes a generally cylindrical gun body 70 which houses an anode and a cooling system therefor together with certain powder delivery apparatus as described hereafter. Powder or other material to be sprayed is advanced into the plasma gun 16 via a powder tube 72 extending through an anode connection plate 74 at the top of the body 70.
  • the water booster pump 52 is coupled to the body 70 of the plasma gun 16 to provide cooling water to an anode cooling system within the body 70.
  • the water booster pump 52 which is coupled to the plasma gun 16 by two of a plurality of cooling water supply conduits 75 emanating from the upper portion of the water booster pump 52 provides a supply of cooling water to the body 70 via fittings 76 and 78 mounted on the anode connection plate 74.
  • Water which is passed through the cooling system for the anode is returned to the water booster pump 52 via two of a plurality of cooling water return conduits 79 emanating from the lower portion of the water booster pump 52.
  • the two cooling water return conduits are coupled to fittings 80 and 82 mounted on the anode connection plate 74.
  • the plasma gun 16 is provided with three different cathode assemblies 84, 86 and 88 which are described in detail hereafter in connection with Figs. 4 and 5.
  • Each of the cathode assemblies 84, 86 and 88 is of elongated, generally cylindrical configuration and extends into the body 70 through an outer wall such that an axis of elongation 90 of the cathode assembly intersects and forms an angle of approximately 45° with a central axis 92 of the body 70.
  • the cathode assemblies 84, 86 and 88 are generally equally spaced around the body 70 so as to be displaced from one another by approximately 120° relative to the central axis 92.
  • the cathode assembly 84 receives cooling water from the water booster pump 52 of Fig. 1 via a separate conduit 93 comprising one of the cooling water supply conduits 75.
  • the cathode assem­blies 86 and 88 are supplied by separate conduits 94 and 95 respectively. Cooling water which is supplied to each cathode assembly 84, 86 and 88 via the conduits 93, 94 and 95 circulates through the cathode assembly to provide internal cooling as described hereafter in connection with Fig. 5 before exiting the cathode assembly via fitting 96 at the side thereof.
  • Each of the fittings 96 is coupled to the water booster pump 52 via a different one of the cooling water return con­duits 79.
  • a further fitting 98 on the side of each cathode assembly 84, 86 and 88 is coupled via a con­duit (not shown) to the plasma gas source 54 of Fig. 1 for providing a supply of plasma gas to the cathode assembly.
  • the plasma gun 16 is shown and described in Fig. 2 and hereafter as being comprised of the three cathode assemblies 84, 86 and 88 for purposes of illustration only. It will be understood by those skilled in the art that numbers other than three of the electrodes of common polarity may be employed in accordance with the principles of the invention. Also, as discussed here thoughafter, the cathode assemblies 84, 86 and 88 can be mounted so that their axes of elongation 90 form angles other than 45° with the central axis 92 of the body 70.
  • the plasma supplies 46 of Fig. 1 comprise three different plasma power sources 99A, 99B and 99C respectively coupled to the cathode assemblies 84, 86 and 88.
  • Each of the plasma power sources 99A, 99B and 99C is comprised of a D.C. power source having the positive terminal thereof coupled to the anode within the gun body 70 and the negative terminal thereof coupled to the associated one of the cathode assemblies 84, 86 and 88.
  • the plasma power sources 99A, 99B and 99C are separately adjustable so that the plasma power to the cathode assemblies 84, 86 and 88 is independently variable.
  • the switchable transfer arc power supplies 50 are coupled between the anode within the body 70 and the workpiece 24.
  • the high frequency power supplies 48 which are not shown in Fig. 2 are preferably comprised of a different high frequency power supply for and coupled to each of the cathode assemblies 84, 86 and 88 to initiate the plasma transfer arc by superimposing high frequency voltage discharges on the plasma power sources 99A, 99B and 99C.
  • the body 70 is of generally cylindrical configuration and has a cylindrical bore 100 extending through the center thereof along the central axis 92 between a top 102 of the body 70 and an opposite bottom 104 of the body 70.
  • the central bore 100 has an anode assembly 106 mounted therein at a lower portion thereof.
  • the anode assembly 106 is held in place within the lower end of the bore 100 by an anode retainer 108 coupled to the bottom 104 of the body 70.
  • the anode retainer 108 is shown and described in detail hereafter in connection with Fig. 28.
  • 29-31 has a hollow, generally cylindrical upper portion 132 thereof seated within a lower portion of the cylindrical bore 118 of the anode connector plug 110 adjacent the powder tube spout 124.
  • the insert clamp 126 has an opposite lower portion 134 of hollow, generally cylindrical configuration disposed within the top portion 128 of the anode assembly 106.
  • the central mixing chamber 148 within the body 150 of the anode assembly 106 communicates with the outside of the plasma gun 16 at the base 130 of the anode assembly 106 via a central nozzle chamber 152.
  • the central mixing chamber 148 also communicates with a plurality of arc chambers 154 formed within the body 150 of the anode assembly 106 and each being associated with a different one of the cathode assemblies 84, 86 and 88.
  • One of the arc chambers 154 is shown in Fig. 3 in conjunction with the cathode assembly 84.
  • the cathode assembly 84 is operative to cause the flow of an inert gas in a swirling pattern along a gas passage 164 formed by an annular space between the cathode tip 162 and an inner wall 166 of a generally cylindrical bore 168 of the chamber insulator 160.
  • the plasma power source 99A shown in Fig. 2 is coupled between the cathode tip 162 of the cathode assembly 84 and the body 150 of the anode assembly 106 to provide a desired electrical potential difference therebetween.
  • the plasma stream exiting the nozzle chamber 152 continues on to the workpiece 24 and then out of the bottom collector cone 14 of the plasma chamber 10 at supersonic speeds due to the action of the vacuum pumps 42 shown in Fig. 1.
  • a transfer arc is produced between the anode assembly 106 and the work­piece 24 by the switchable transfer arc power sup­plies 50 shown in Figs. 1 and 2.
  • the portion of the body 170 of the cathode assembly 84 extending outside of the body 70 of the plasma gun 16 includes the water fitting 96 and the gas fitting 98.
  • the conduit 93 supplying cooling water from the water booster pump 52 shown in Figs. 1 and 2 extends through an insulator nut 172 secured to an outer end of the body 170. Cooling water which enters the cathode assembly 84 via the conduit 93 and which passes through the cooling system for the cathode 84 exits from the cathode assembly 84 via the water fit­ting 96 which, as noted in connection with Fig. 2, is coupled via one of the cooling water return conduits 79 to the water booster pump 52. Also, as previously noted, inert gas from the plasma gas source 54 shown in Fig. 1 is applied to the gas fitting 98.
  • the cathode insulator connector 184 has a generally cylindrical bore 196 therein in which is seated a hollow, generally cylindrical gas conductor tube 198.
  • the gas conductor tube 198 extends along a portion of the cylindrical bore 196 from the chamber insulator 160. the remaining portion of the cylindrical bore 196 is occupied by a portion of a cathode connector tube 200.
  • the cathode connector tube 200 which is of elongated, generally cylindrical, stepped configuration has an axis of elongation coincident with the axis of elongation 90 of the cathode assembly 84.
  • the cathode connector tube 200 extends from a region adjacent the first end 190 of the cathode insulator connector 184 all the way to a region adjacent an outer end 202 of the chamber insulator 160 to mount the cathode tube 162 therein.
  • the cathode connector tube 200 is stepped down in outer diameter along a portion of the gas conductor tube 198 and again along a substantial portion of the chamber insulator 160 to form an annular space within an inner wall 204 of the gas conductor tube 198 and the inner wall 166 of the chamber insulator 160.
  • Such annular space forms a gas passage 206 having a first portion 208 thereof of generally uniform diameter extending along a major portion of the gas conductor tube 198 and a second portion 210 thereof of generally uniform diameter smaller than the uniform diameter of the first por­tion 208 extending along most of the length of the chamber insulator 160.
  • the cathode connector tube 200 has an annular collar 212 thereon extending into the gas passage 206 adjacent a juncture 214 of the first and second portions 208 and 210 of the gas passage 206.
  • the cathode insulator connector 184 has an annular recess in the cylindrical bore 196 thereof which forms an annular gas inlet chamber 216.
  • the annular gas inlet chamber 216 surrounds a portion of the outside of the gas conductor tube 198 and communicates with the first portion 208 of the gas passage 206 on the opposite side of the gas conductor tube 198 via a plurality of aper­tures 218 in the gas conductor tube 198.
  • the aper­tures 218 are spaced around the circumference of the gas conductor tube 198 at the annular gas inlet chamber 216, and one of the apertures 218 is shown in Fig. 5.
  • the gas fitting 98 which is mounted on the outside of the body 170 of the cathode assembly 84 as shown in Fig. 4 is used to feed a supply of pressurized, substan­tially inert gas to the first portion 208 of the gas passage 206 via the annular gas inlet chamber 216 and the apertures 218 in the gas conductor tube 198.
  • the gas fitting 98 which is not shown in Fig. 5 is coupled to the annular gas inlet chamber 216 by a passage 220 in the cathode insulator connector 184.
  • the passage 220 is shown in dotted outline in Fig. 5, and the flow of gas therethrough is represented by a dotted arrow 222.
  • the gas which flows through the passage 220 under pressure fills the annular gas inlet chamber 216 and from there flows through the apertures 218 into the first por­tion 208 of the gas passage 206.
  • the gas within the first portion 208 flows to the annular collar 212 of the cathode connector tube 200 where the gas is forced into a spiral flow pattern in the second portion 210 of the gas passage 206 by an arrangement of apertures in the annular collar 212.
  • the annular collar 212 is shown in detail in Figs. 6 and 7, with Fig. 7 being a sectional view of a portion of Fig. 6. As shown in Fig. 6, the annular collar 212 is provided with a plurality of apertures 224 therein disposed in a spaced-apart circumferential pattern just outside of the cathode connector tube 200. It was previously noted that the cathode connector tube 200 has an axis of elongation which is coincident with the axis of elongation 90 of the cathode assem­bly 84. the apertures 224 are disposed obliquely relative to the axis of elongation 90, and this is brought out by Fig.
  • the swirling pattern of the inert gas continues as the gas passage over the cathode tip 162 and into the arc chamber 154 in the anode assembly 106.
  • Such spi­raling motion enhances the stability of the resulting plasma arc that forms within the arc chamber 154.
  • the cathode tip 162 is mounted on the end of the cathode connector tube 200 adjacent the outer end 202 of the chamber insulator 160.
  • the cathode tip 162 which may be constructed of conven­tional materials such as tungsten or copper, may be attached to the end of the cathode connector tube 200 by any appropriate technique such as gold soldering.
  • the cathode tip 162 is preferably attached by a threaded arrangement to facilitate removal and replace­ment of the cathode 162.
  • the cathode tip 162 has a threaded end 226 thereof which is received within a mating threaded aperture 228 in the end of the cathode connector tube 200.
  • a supply of cooling water is provided to the cathode assembly 84 by the conduit 93 from the water booster pump 52.
  • the conduit 93 extends through the insulator nut 172 at the end of the cable insulator 174 and into the cylindrical bore 180 of the cable insulator 174 where the conduit 93 couples to the fitting 178.
  • the fitting 178 is mounted on an end 230 of an inner connector tube 232 of elongated, generally cylindrical configuration.
  • the inner connector tube 232 which is mounted on a portion of the cathode insulator connector 184 opposite the cable insulator 174 and adjacent the first end 190 of the cathode insulator connector 184 by threads 234 thereon extends into an elongated hollow interior 236 of the cathode connector tube 200.
  • the inner connector tube 232 which forms an elongated cooling tube member includes a water tube 238 at a forward end thereof which terminates just short of an end 240 of the hollow interior 236 of the cathode connector tube 200 adjacent the cathode tip 162.
  • Cooling water introduced into the fitting 178 flows along a hollow interior 242 of the inner connector tube 232 and then through a hollow interior 244 of the water tube 238.
  • the water flow is represented by a series of arrows 246.
  • the water flows out the open end of the water tube 238 at the end 240 of the hollow interior 236, at which point the water flow reverses in direction and enters an annular space 248 formed between the elongated hollow interior 236 of the cathode con­nector tube 200 and the outsides of the water tube 238 and the inner connector tube 232.
  • the annular space 248 leads into an annular chamber 250 which encircles the inside of the cathode connector tube 200.
  • An annular recess in the cathode insulator connector 184 on the outside of the cathode connector tube 200 opposite the annular chamber 250 forms an annular cooling water outlet chamber 252.
  • the annular chamber 250 communicates with the annular cooling water outlet chamber 252 via a plurality of apertures 254 spaced around the cathode connector tube 200.
  • One of the apertures 254 is shown in Fig. 5. Cooling water in the annular space 248 which enters the annular chamber 250 enters the annular cooling water outlet chamber 252 by way of the apertures 254 in the cathode connector tube 200.
  • the annular cooling water outlet chamber 252 is coupled to the fluid coupling 96 shown in Fig. 4 but not in Fig. 5 by a passage 256 which is shown in dotted outline in Fig. 5.
  • the flow of cooling water through the passage 246 is represented by a dotted arrow 258.
  • the dotted representations of the gas passage 220 and the water passage 256 in the cathode insulator connector 184 are shown as being generally parallel to one another and in the same circumferential position in Fig. 5 for convenience of illustration only.
  • the passages 200 and 256 are offset from one another around the circumference of the cathode insu­lator connector 184 as will be appreciated by the offset positioning of the water fitting 96 and the gas fit­ting 98 as shown in Figs. 2 and 4.
  • the cathode cooling system provided by the fitting 178, the inner connector tube 232, the water tube 138, the annular chambers 250 and 252 and the passage 256 provide cooling action along a substantial portion of the region of gas flow within the cathode assembly 84.
  • Such cooling system provides more than adequate cooling in the face of the delivery of substan­tial volumes of inert gas under relatively high pressure and including the substantial friction which occurs as the swirling pattern of the gas is created at the annular collar 212.
  • the modular anode assembly 106 is comprised principally of the integrally formed body 150.
  • Fig. 8 is a sectional view of the body 150. As shown therein the body 150 has a central axis 260.
  • the central axis 260 is generally coincident with the central axis 92 of the body 70 of the plasma gun 16.
  • the top portion 128 of the anode assembly 106 has a generally cylindrical bore 262 therein having a threaded portion 264 thereof.
  • the threaded portion 264 receives the insert clamp 126 shown in Fig. 3 and in Figs. 29 - 31 which are described hereafter.
  • the cylindrical bore 262 tapers to a circular chamber 266.
  • the circular chamber 266 is configured to receive a lower end of the powder insert holder 136 shown in Fig. 3 and in Fig. 15.
  • a generally cylindrical aperture 268 extends downwardly from the circular chamber 266 to a first end 270 of the central mixing chamber 148 and is configured to receive the powder insert 138 shown in Figs. 3 and 15.
  • An opposite second end 272 of the central mixing chamber 148 denotes the juncture between the central mixing chamber 148 and the central nozzle chamber 152.
  • the anode assembly 106 has three of the arc chambers 154 therein which are spaced equally about the central axis 92 of the body 70 and thus the central axis 260 of the anode assembly 106. Only one of the arc chambers 154 is shown in Fig. 8.
  • the arc chamber 154 extends into the body 150 from the bottom of an opening 274 in the side of the body 150.
  • the opening 174 receives the outer end of the chamber insulator 160 when the cathode assembly 84 is mounted in the body 70 of the plasma gun 16. This places the cathode tip 162 of the cathode assembly 84 in an opera­tive position within the arc chamber 154.
  • the arc chamber 154 extends from the bottom of the opening 274 of the housing 150 to the central mixing chamber 148 along a central axis 276.
  • the arc chamber 154 is comprised of a generally cylindrical portion 278 which communicates with the central mixing chamber 148 adjacent the first end 270 thereof.
  • the arc chamber 154 also has a portion 280 thereof which is of partial conical configuration and which diverges in the direc­tion from the cylindrical portion 278 to the bottom of the opening 274.
  • the body 150 of the anode assembly 106 has an annular cavity 282 therein which surrounds the body 150 adjacent the base 130. As described hereafter, cooling water within the anode cooling system is forced into a swirling pattern within the annular cavity 282 before passing upwardly through a plurality of apertures in the body 150 to the cylindrical bore 262. Two such aper­tures 284 and 286 are shown in Fig. 8.
  • Fig. 9 is a front view of the anode assembly 106 which is taken from the left side of the sectional view of Fig. 8 so that the opening 274 appears at the center thereof.
  • Fig. 10 is a top view of the anode assembly 106 with a portion of the body 150 being broken away to reveal the opening 274 and the associated arc chamber 154.
  • the anode assembly 106 has two additional openings of like configuration to the opening 274 for receiving the cathode assemblies 86 and 88. The two additional openings do not appear in the views of Figs. 9 and 10.
  • a lower portion of the body 150 is provided with an annular rim 288.
  • the rim 288 which protrudes outwardly from the remainder of the body 150 seats within an annular recess 290 at the lower end of the cylindrical bore 100 in the body 70 when the anode assembly 106 is mounted within the body 70.
  • the rim 288 seats within the recess 290 to properly position the anode assembly 106 within the body 70 and prevent upward movement of the anode assembly 106 within the bore 100.
  • a circular flange 292 within the anode retainer 108 and which is shown in Fig. 3 abuts a lower surface of the rim 288 to hold the rim 288 within the recess 290 and thereby secure the anode assembly 106 within the body 70.
  • Fig. 11 is a sectional representation of the arc chamber 154 together with the central mixing chamber 148 and the central nozzle chamber 152.
  • the arc chamber 154 is comprised of a partial conical portion 280 for receiving the cathode tip 162 and an adjoining cylindrical portion 278.
  • the cylin­drical portion 278 communicates with the central mixing chamber 148 adjacent the first end 270 thereof.
  • the swirling inert gas which flows over the cathode tip 162 and into the central mixing chamber 148 via the arc chamber 154 combines with the electrical potential difference between the cathode tip 162 and the body 150 of the anode assembly 106 to produce a plasma arc.
  • the plasma arc extends from the cathode tip 162 through the arc chamber 154 to the region of the central mixing chamber 148.
  • the shape and the size of the arc chamber 154 combine with such things as the pressure and the amount of spiral of the gas to determine the path of the arc.
  • the path of the arc in turn controls the tempera­ture within the mixing chamber 148.
  • the spiraling motion of the gas enhances the stability of the arc by moving the arc slightly so that it does not concentrate in one location on the walls of the central mixing chamber 148.
  • the arc chamber 154 is contained within the body 150 of the anode assembly 106. Due to the modular nature of the anode assembly 106, the anode assembly 106 can easily be replaced within the plasma gun 16.
  • the anode assembly 106 can easily be changed to provide arc chambers 154 of different size and/or shape for different applications of the plasma system.
  • Fig. 11 depicts four different arrangements of the arc chamber 154.
  • the arrangement shown in Fig. 11 in solid outline is preferred for most applications of the plasma gun 16 in the present example. However, other arrangements shown may be preferred for different applications of the plasma gun 16.
  • the cylindrical portion 278 is consid­erably shorter in length than in the case of the first arrangement, and terminates at a location 294 where the partial conical portion 280 begins.
  • the outline of the partial conical portion 280 in the second arrangement is shown by a dashed line 296.
  • the cathode tip 162 in the second arrangement assumes a position represented by a dashed line 298.
  • the cylindrical portion 278 is even shorter and terminates at a location 300 where partial conical portion 280 begins.
  • the configuration of the partial conical portion 280 is represented by a line 302 of alternating dots and dashes.
  • the position of the cathode tip 162 in the third arrangement is represented by a line 304 of alternating dots and dashes.
  • the anode assembly 106 can be changed to install an anode assembly 106 with a mixing chamber 148 that will optimize performance.
  • the mixing chamber 148 also influences the shape of the spray pattern of the powdered material, which pattern tends to be generally triangular where three cathodes are present. Variations in the mixing chamber 148 have been found to produce variations in the triangular shape of the spray pattern.
  • the portion 308 extends from the second end 272 of the mixing chamber 148 with a gen­erally constant rate of divergence to a location 312 where the portion 310 begins.
  • the portion 310 extends from the location 312 to the base 130 with a constant rate of divergence that is greater than the rate of divergence of the portion 308.
  • the powder insert holder 136 which is shown in section in Fig. 3 is shown in Fig. 15 together with the powder insert 138 which is adapted to be mounted therein. As shown in Fig. 3, the powder insert holder 136 extends along the inside of the insert clamp 126 and terminates within the circular chamber 266 shown in Fig. 8. As shown in Fig. 15 the powder insert holder 136 has an annular recess 314 therein adjacent the upper end thereof for receiving an O-ring (not shown) to form a seal with the upper portion 132 of he insert clamp 126. The powder insert holder 136 also has an annular recess 316 adjacent a lower end thereof for receiving an O-ring (not shown) to form a seal with the circular chamber 266 within the body 150 of the anode assembly 106.
  • One of the major advantages of a multi-cathode configuration is that by locating plural cathodes around the anode, a central powder delivery is facilitated.
  • the use of the separate, replaceable powder insert 138 in accordance with a feature of the invention provides for considerable flexibility.
  • the ability to use different powder inserts allows for variations in the material injection point within the mixing chamber 148.
  • the configuration and the diameter of the powder feed port or ports can be varied, as can the material of the powder insert 138.
  • each of the three different arc chambers 154 is provided with its own powder feed port.
  • Powder inserts 138 having a variety of different multi-feed port configurations are described hereafter in connection with Figs. 15 - 25.
  • An important aspect of having the separate, replaceable powder insert 138 is that the angle of the various feed ports within the respective arc chambers can be varied to optimize performance.
  • Figs. 16 and 17 show one arrangement of the powder insert 138 in which a single powder feed port is employed.
  • powder insert 138 has a central bore 322 therein ex­tending along a portion of the length of the powder insert 138 from a threaded end 324 thereof opposite the lower tip 320.
  • the central bore 322 extends along a portion of the length of the powder insert 138 from the threaded end 324 to a location 326 at which the bore 322 terminates.
  • a single powder feed port 328 extends along the remainder of the length of the powder insert 138 from the location 326 to the lower tip 320.
  • the terminus of the powder feed port 328 comprises a portion 330 of diverging, partially conical configuration.
  • the powder feed port 328 including the portion 330 thereof extends along a central axis 332 of the powder insert 138, as does the central bore 322.
  • the central axis 332 thereof is coincident with the central axis 260 of the anode body 150 and the central axis 92 of the body 70 of the plasma gun 16.
  • the lower tip 320 of the powder insert 138 terminates at the first end 270 of the central mixing chamber 148 so that powder introduced into the central bore 322 of the powder insert 138 is introduced into the mixing chamber 148 along the central axis of the mixing chamber 148.
  • the lower tip 320 of the powder insert 138 is provided with three different rounded grooves or flutes 334 generally equally spaced about the tip 320.
  • Figs. 18 and 19 show one particular arrangement of the powder insert 138 which employs three different powder feed ports 336, 338 and 340. All three of the powder feed ports 336, 338 and 340 are shown in Fig. 19. Only the lower powder feed port 338 is shown in the sectional view of Fig. 18. The three powder feed ports 336, 338 and 340 extend from the location 326 at the end of the central bore 322 to the lower tip 320 in gen­erally straight-line fashion so as to form relatively small acute angles with the central axis 322.
  • Each of the powder feed ports 336, 338 and 340 terminates at the lower tip 320 in an outwardly diverging portion 342 thereof.
  • each of the powder feed ports 336, 338 and 340 terminates at a different one of the arc chambers 154 adjacent the juncture of the arc chamber 154 with the first end 270 of the central arc chamber 148.
  • the performance of the gun has been found to vary in accordance with such things as the angle and the size of the powder feed ports. Because of the easily replace­able nature of the powder insert 138, it may be advanta­geous to provide a number of different configurations of the powder insert 138 for different applications.
  • Figs. 20 and 21 The arrangement shown in Figs. 20 and 21 is similar to the arrangement of Figs. 18 and 19 to the extent that the central bore 322 extends from the threaded end 324 to a location 344 within a central portion of the length of the powder insert 138. Beyond the location 344, the central bore 322 terminates in a generally conical portion 346 thereof. Three different powder feed ports 348, 350 and 352 which are generally equally spaced about the central axis 332 extend from the conical portion 346 to the lower tip 320 of the powder insert 138. In the arrangement of Figs. 20 and 21, most of the lower tip 320 is comprised of three relatively large flutes 354, 356 and 358.
  • the powder feed ports 348, 350 and 352 terminate at portions of the flutes 354, 356 and 358 adjacent a cylindrical side surface 360 of the powder insert 138.
  • the powder feed ports 348, 350 and 352 do not terminate in outwardly diverging portions such as the portion 330 of the arrangement of Figs. 16 and 17 and the portion 342 of the arrangement of Figs. 18 and 19.
  • the powder feed ports 348, 350 and 352 form acute angles with the central axis 332 which are substantially larger than the acute angles formed by the powder feed ports 336, 338 and 340 with the central axis 332 in the arrangement of Figs. 18 and 19.
  • the central bore 322 is shorter in length than in the arrangements of Figs. 16 - 21.
  • the central bore 322 terminates at a location 362.
  • Three different powder feed ports 364, 366 and 368 which are generally equally spaced about the central axis 332 extend from the end of the central bore 322 at the location 362 to the lower tip 320.
  • the lower tip 320 is principally comprised of three different flutes 370, 372 and 374, with each of the powder feed ports 364, 366 and 368 terminating at one of the flutes 370, 372 and 374.
  • the powder feed ports 364, 366 and 368 are of considerably larger diameter than are the powder feed ports 336, 338 and 340 of the arrange­ment of Figs. 18 and 19 or for that matter the powder feed ports 348, 350 and 352 of the arrangement of Figs. 20 and 21.
  • the powder feed ports 364, 366 and 368 of the arrangement of Figs. 22 and 23 terminate at the flutes 370, 372 and 374 without the presence of outwardly diverging portions.
  • the central bore 322 extends from the threaded end 324 along a substantial portion of the length of the insert 138 to a location 376.
  • Three different powder feed ports 378, 380 and 382 which are generally parallel to and equally spaced about the central axis 332 extend from the end of the central bore 322 adjacent the location 376 to different ones of three different flutes 384, 386 and 388 within the lower tip 320 of the powder insert 138.
  • the powder feed ports 378, 380 and 382 are of relatively large diameter as in the case of the powder feed ports 364, 366 and 368 of the arrangement of Figs. 22 and 23.
  • a major advantage of multi-segmented electrodes in plasma guns such as the multi-segmented cathode plasma gun 16 is the ability to scale up operation thereof to power levels considerably in excess of those which are achievable in connection with single cathode plasma guns. Such scale up is made possible by the presence of the multi-segmented electrodes and by observing and adjusting the various factors previously described to optimize operation of the plasma system in the face of the multi-segmented electrodes. However, the increased power levels bring with them a greater cooling require­ment, particularly in the case of the anode assembly which is common to the entire plasma gun 16.
  • the cathode assemblies 84, 86 and 88 are independently and separately cooled with each having its own cooling system, as previously described in connection with Figs. 2 and 5.
  • Fig. 26 is a bottom view of the anode connection plate 74 showing the locations of the fittings 76, 78, 80 and 82 on the other side thereof in dotted outline.
  • the fittings 76 and 78 which are spaced at like radial distances from the central axis 92 on opposite sides of the central axis 92 communicate with the underside of the anode connection plate 74 via apertures 390 and 392 respectively.
  • the fittings 80 and 82 which are disposed on opposite sides of the central axis 92 by like radial distances smaller than the radial distances of the fittings 76 and 78 from the axis 92 and 90° removed from the fittings 76 and 78 relative to the central axis 92 are coupled to the bottom of the anode connection plate 74 by apertures 394 and 396 respectively.
  • the apertures 390 and 392 lie within an annular path 398 around the bottom of the anode connector plate 74, which annular path 398 is defined by a pair of concentric grooves 400 and 402 in the bottom of the anode connec­tion plate 74.
  • the grooves 400 and 402 contain seals 404 and 406 respectively which are shown in Fig. 3.
  • the seals 404 and 406 act to seal the annular path 398 around the bottom of the anode connection plate 74 from areas of the plate 74 outside of the groove 400 and from an inner annular path 408 disposed between the groove 402 and the central aperture 112 of the anode connection plate 74.
  • the apertures 394 and 396 which communicate with the fittings 80 and 82 reside within the inner annular path 408.
  • Fig. 27 is a top view of the gun body 70 with the anode connection plate 74 removed. As such, Fig. 27 shows the top 102 of the body 70 together with the cylindrical bore 100 through the body 70.
  • the top 102 of the body 70 is provided with three threaded apertures 410, 412 and 414 which align with corresponding aper­tures 416, 418 and 414 which align with corresponding apertures 416, 418 and 420 at the outer periphery of the anode connection plate 74 when the plate 74 is mounted on the top 102 of the body 70.
  • Bolts are placed through the apertures 416, 418 and 420 in the anode connection plate 74 and are screwed into the threaded apertures 410, 412 and 414 to secure the anode connection plate 74 on the top 102 of the body 70.
  • One such bolt 422 is shown in Fig. 3.
  • the cooling water flows downwardly through the groups of apertures 426, 428 and 430 to the bottom 104 of the gun body 70.
  • the flow of cooling water is represented by arrows 434 within the aperture 432 and elsewhere throughout Fig. 3
  • Fig. 28 is a top view of the anode retainer 108.
  • the anode retainer 208 has three different apertures 436, 438 and 440 therein adjacent the outer periphery thereof.
  • the anode retainer 108 is secured to the bottom 104 of the gun body 70 by bolts which extend through the apertures 436, 438 and 440 and into mating threaded apertures in the bottom 104 of the body 70.
  • Fig. 3 shows one such bolt 442 extending into one such threaded aperture 444 through the aperture 436 in the anode retainer 108.
  • the annular cavity 450 which extends between the circular flange 292 and a circular wall 452 just inside of and concentric with the annular groove 448 is disposed beneath and in communica­tion with the groups of apertures 426, 428 and 430 in the gun body 70.
  • This gas pressure is communicated upwardly through the hollow interior of the feed tube 482 and the annular passage 494 to the cop of the melt bowl 492 where such gas pressure prevents the molten metal from flowing over the top of the melt bowl 492.
  • the resulting state of equilibrium is maintained in the presence of the molten metal until such time as it is desired to deliver the molten metal into the central mixing chamber 148 of the anode assembly 106.
  • the molten metal flows down through the hollow interior of the feed tube 482 and into the central mixing chamber 148 within the anode assembly 106 where it is mixed into the plasma stream.
  • the D.C. power source 522 provides enough heat to prevent unwanted solidification of the molten metal as it flows through this downward path.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Chemical & Material Sciences (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Plasma Technology (AREA)
  • Nozzles (AREA)
EP19890113342 1988-07-21 1989-07-20 Plasmagenerator mit modular geteilter Kathode Withdrawn EP0351847A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US22250788A 1988-07-21 1988-07-21
US222507 1998-12-29

Publications (2)

Publication Number Publication Date
EP0351847A2 true EP0351847A2 (de) 1990-01-24
EP0351847A3 EP0351847A3 (de) 1991-03-20

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ID=22832511

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Country Link
EP (1) EP0351847A3 (de)
JP (1) JPH0766872B2 (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2673352A1 (fr) * 1991-02-25 1992-08-28 Lincoln Electric Co Torche a plasma a refroidissement perfectionne.
WO1996018283A1 (en) * 1994-12-05 1996-06-13 The University Of British Columbia Plasma jet converging system
WO2003084294A1 (fr) * 2002-03-28 2003-10-09 Apit Corp. S.A. Procede de traitement de surface par plasma atmospherique et dispositif pour sa mise en oeuvre
CN105682334A (zh) * 2016-02-03 2016-06-15 中国科学技术大学先进技术研究院 一种电弧等离子体反应器装置
CN107124814A (zh) * 2017-06-20 2017-09-01 四川大学 一种多阴极层流等离子体粉末球化装置
DE102019126640A1 (de) * 2019-10-02 2021-04-08 Gebr. Heller Maschinenfabrik Gmbh Lichtbogen-Drahtspritzeinrichtung

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005085917A (ja) 2003-09-08 2005-03-31 Sharp Corp プラズマプロセス装置
JP5515277B2 (ja) * 2008-11-04 2014-06-11 株式会社日本セラテック プラズマ溶射装置

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3823302A (en) * 1972-01-03 1974-07-09 Geotel Inc Apparatus and method for plasma spraying
US3839618A (en) * 1972-01-03 1974-10-01 Geotel Inc Method and apparatus for effecting high-energy dynamic coating of substrates
WO1986002024A1 (en) * 1984-09-27 1986-04-10 Regents Of The University Of Minnesota Multiple arc plasma device with continuous gas jet
FR2611340A1 (fr) * 1987-02-24 1988-08-26 Pechiney Aluminium Generateur de plasma multicathodique comportant un gainage de cathode
EP0297637A1 (de) * 1987-06-30 1989-01-04 Technische Universiteit Eindhoven Methode zur Behandlung der Substratoberflächen mit Hilfe von Plasma und Reaktor für die Durchführung dieser Methode

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS517556A (en) * 1974-07-08 1976-01-21 Rikiichi Kimata Keifunnadono mushiukikansoho
JPS61230300A (ja) * 1985-04-05 1986-10-14 プラズマ技研工業株式会社 プラズマア−ク用ト−チ

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3823302A (en) * 1972-01-03 1974-07-09 Geotel Inc Apparatus and method for plasma spraying
US3839618A (en) * 1972-01-03 1974-10-01 Geotel Inc Method and apparatus for effecting high-energy dynamic coating of substrates
WO1986002024A1 (en) * 1984-09-27 1986-04-10 Regents Of The University Of Minnesota Multiple arc plasma device with continuous gas jet
FR2611340A1 (fr) * 1987-02-24 1988-08-26 Pechiney Aluminium Generateur de plasma multicathodique comportant un gainage de cathode
EP0297637A1 (de) * 1987-06-30 1989-01-04 Technische Universiteit Eindhoven Methode zur Behandlung der Substratoberflächen mit Hilfe von Plasma und Reaktor für die Durchführung dieser Methode

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2673352A1 (fr) * 1991-02-25 1992-08-28 Lincoln Electric Co Torche a plasma a refroidissement perfectionne.
WO1996018283A1 (en) * 1994-12-05 1996-06-13 The University Of British Columbia Plasma jet converging system
WO2003084294A1 (fr) * 2002-03-28 2003-10-09 Apit Corp. S.A. Procede de traitement de surface par plasma atmospherique et dispositif pour sa mise en oeuvre
CN105682334A (zh) * 2016-02-03 2016-06-15 中国科学技术大学先进技术研究院 一种电弧等离子体反应器装置
CN107124814A (zh) * 2017-06-20 2017-09-01 四川大学 一种多阴极层流等离子体粉末球化装置
DE102019126640A1 (de) * 2019-10-02 2021-04-08 Gebr. Heller Maschinenfabrik Gmbh Lichtbogen-Drahtspritzeinrichtung

Also Published As

Publication number Publication date
EP0351847A3 (de) 1991-03-20
JPH02256200A (ja) 1990-10-16
JPH0766872B2 (ja) 1995-07-19

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