CA2004226A1 - Liquid-cooled plasma torch with transferred arc - Google Patents
Liquid-cooled plasma torch with transferred arcInfo
- Publication number
- CA2004226A1 CA2004226A1 CA002004226A CA2004226A CA2004226A1 CA 2004226 A1 CA2004226 A1 CA 2004226A1 CA 002004226 A CA002004226 A CA 002004226A CA 2004226 A CA2004226 A CA 2004226A CA 2004226 A1 CA2004226 A1 CA 2004226A1
- Authority
- CA
- Canada
- Prior art keywords
- plasma torch
- ignition
- torch according
- electrode
- main electrode
- 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.)
- Abandoned
Links
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
- H05H1/28—Cooling arrangements
-
- 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
- H05H1/34—Details, e.g. electrodes, nozzles
-
- 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
- H05H1/34—Details, e.g. electrodes, nozzles
- H05H1/341—Arrangements for providing coaxial protecting fluids
-
- 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
- H05H1/34—Details, e.g. electrodes, nozzles
- H05H1/3421—Transferred arc or pilot arc mode
-
- 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
- H05H1/34—Details, e.g. electrodes, nozzles
- H05H1/3478—Geometrical details
Abstract
ABSTRACT
The invention relates to a liquid-cooled plasma torch with transferred arc, its coolant, current and gas being guided to the ignition and main electrode via ignition electrode and main electrode lances consisting of coaxial tubes. To structurally improve the torch, to minimize the heat losses of the torch jacket and to increase the efficiency of the torch, a common coolant circuit is provided for the ignition electrode lance and the main electrode lance.
The invention relates to a liquid-cooled plasma torch with transferred arc, its coolant, current and gas being guided to the ignition and main electrode via ignition electrode and main electrode lances consisting of coaxial tubes. To structurally improve the torch, to minimize the heat losses of the torch jacket and to increase the efficiency of the torch, a common coolant circuit is provided for the ignition electrode lance and the main electrode lance.
Description
Z~0~ 6 20337~375 The present invention relates to a liquid-cooled plasma torch with transferred arc, its coolant, current and gas being guided to the ignition and main electrode via ignition electrode and main electrode lances consisting of coaxial tubes.
Plasma torches of this kind are known, for example, from German OS 29 00 330, their main components consisting essentially of a torch jacket with nozzles r a main electrode lance with a main electrode and an ignition electrode lance with an ignition electrode.
According to the state of the art all three aforenamed components are as such structural units electrically insulated from one another with their own water cooling. Both the ignition electrode lance as well as the main electrode lance are liquid-cooled, each lance consisting of tubes arranged coaxially to one another. The end face of the outer tube o the ignition electrode lance Eacing the ignition electrode is closed, this outer tube accommodating the ignition electrode. The inner tube o~ the ignition electrode lance leaves a gap towards the end wall of the outer tube or the ignition electrode, the connection for the coolant between the central bore of the inner tube and the annular channel between the inner and the outer tube being established through this gap. The current is guided via the outer tube to the ignition electrode.
The outer tube of the ignition electrode lance is guided via electrically insulating spacers or sleeves in the inner tube of the main electrode lance. The ignition plasma gas is conducted via the annular channel resulting between the outer tube of the ' -' i -ignition electrode lance and the inner tube of the main electrode lance to the ignition electrode and the enclosing, nozzle-shaped central bore of the main electrode.
According to the state of the art, a main electrode lance consisting of three coaxially arranged tubes is used to cool the main electrode. Through this an output and return annular channel is provided for the coolant diverted at the inner end wall of the main electrode. Depending on the design of the connection between the electrode and the lance, the current can be supplied to the main electrode via the inner and/or outer tube of the main electrode lance. Electric insulation between the outer tube of the main electrode lance and the inner tube of the torch jacket and the nozzle is carried out by means of spacers in the manner described above with respect to the front electrode lance. The main plasma gas is also conducted in a corresponding manner in the region between the main electrode and the nozzle.
Plasma torches known according to the state of the art have the drawback that they are structurally verv expensive and the heat losses along their jacket surface are relatively high.
It is therefore desirable to further develop the plasma torch described at the beginning in such a way that its construction can be simplified, that the heat losses occurring hitherto can be reduced and that better efficiency can be achieved.
The present invention provides a liquid-cooled plasma torch with transferred arc, its coolant, current and gas being guided to the ignition and main electrode via ignition electrode " ` ~
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lances and main electrode lances consisting of coaxial tubes, characterized by a common cooling circuit for the ignition electrode lance and main electrode lance. Not only can this advantageously result in a cost saving for tubes and seals~ but the entire supply of cooling water to the plasma torch is simplified considerably. ~oreover, the aiameter of the plasma torch shaft can be kept substantially smaller, this corresponding to a direct reduction in the torch jacket surface affected by the outside temperature, i.e. the heat losses of the jacket are reduced and the efficiency of the torch is improved. A smaller diameter of the torch shaft also permits greater universality with respect to the possibilities for using and installing plasma torches in vessels of various types and sizes, for example ln a smelting furnace, a ladle, a tundish or a vacuum installation.
Further developments of the inventive thought are described in the sub-claims. Since the ignition electrode lance is sealed vis-à-vis the coolant chann~ls and electrically insulated vis-à-vis the main electrode lance or main electrode, the ignition gas can be guided directly into the ignition electrode lance, whereby it is simultaneously cooled from the outside. The main electrode and ignition electrode lances preferably comprise, all told, only three tubes arranged coaxially to one another, whereby the coolant is guided in the interconnected annular channels between the outer tube and the centre tube on the one hand and between the centre tube and the inner tube on the other hand. This thus takes into consideration the fact that the main electrode is the structural member requiring the greatest cooling.
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The main electrode current is thereby guided via the outer tube and the ignition electrode current is guided via the inner tube.
So that the inner tube is adequately cooled despite the insulating hose that is pulled over it from the outside, an accordingly thin-walled insulating hose is selected w~ich should, however, preferably be resilient and unaffected by high tempera-tures. One or a plurality of sleeves are used to centre the ignition electrode lance.
The centre tube is continued in the area of the main electrode by an essentially annular deflecting member which at the end face leaves open a connection between the coolant annular channels lying on either side thereof. The centre tube, the aforenamed deflecting member and the s:Leeve for centering the ignition electrode lance are thereby made of non-conductive material, preferably plastic. This pr~3vents a reduction in the contact resistance between the ignition and m~in electrode possibly caused by the coolant. On the other hand, the ignition electrode and the gas nozzle into which the cylindrical interior of the ignition electrode lance merges is electrically conductive.
The nozzle effect of the gas nozzle is favoured in that the corresponding ignition gas guide channels are guided conically outwards, preferably in the form of a plurality of individual bores that are brought together again in the area of the main electrode or the outlet.
The gas nozzle and the main alectrode are connected to one another via an annular insulating sleeve, whereby this sleeve can be made from a plastic unaffected by high temperatures, from Z~
~0337-375 a pressure liquid sealed ceramic or from a composite material made from a plastic, a metal and a ceramic. The insulating hose overlaps and seals the gas nozzle and part of the insulating sleeve in order to improve the liquid insulation. The tightness to the liquid is optimized by the O-ring seal provided between the outer surface of the gas nozzle and the inner surface of the insulating sleeve and which lies in a corresponding groove of the gas nozzle. The main electrode itself has a cup-shaped design and is connected in electrically conductive manner to the outer tube.
an O-ring seal is inserted between these parts for the purpose of tightness to the liquid. An additional O-ring seal is provided in the overlapping area of the insulating sleeve and the main electrode.
It has proved advantageous to manufacture the inner tube and/or the gas nozzle from coppe.r. The ignition electrode should consist of tungsten, whereby for reasons involving manufacturing technology the upper conical portion of the ignition electrode can be cast round with copper and the relevant ingot forms the gas nozzle.
To achieve an as laminar flow as possible in the flow channels for the ignition gas, the lower portion of the inner tube is widened conically and the conical form is adapted to the adjacent bores.
An exemplary embodiment of the present in~ention is illustrated in the drawings and is explained in greater detail herebelow. The drawings show in Figure 1 a plasma torch according to the invention in . ~
2~
longitudinal section, and Figure 2 an enlarged illustration of the fastening of the ignition electrode in longitudinal section.
The main components of the plasma torch include an ignition or auxiliary electrode 11, a main or nozzle electrode 12 and a nozzle 13, each of which are electrically insulated from one another.
The upper, conical end 11' of the, in cross-section, circular ignition electrode 11 is embedded in a gas nozzle 14 which in turn is fastened to an ignition lance which, unlike the known plasma torches, comprises only a single tube 16. The lower region of the cylindrical interior or hollow 17 of the tube 16 adjacent the gas nozzle 14 merges into a conical enlargement ].~
with the angle of taper ~. The gas nozzle 14 has a plurality of, for example, ten bores or through holes 19 uniformly distributed over the circumference. The axes oE the bores 19 are arranged on an ~imaginary) conclcal surface (19') in such a way that the ends of the bcres 19 facing the tube 16 are closer together than the ends facing the ignition electrode 11 and the ends of the bores facing the tube 16 all lie within the hollow section of the conical enlargement 1~. The cone angle of the (imaginary) conical surface 19' is identified in Figure 2 as ~. The inner tube 16 is preferably manufactured from copper, whereas the ignition electrode 11 is made of tungsten. It is hereby possible to pre-fabricate the ignition electrode 11 to a semifinished product as follows. The ignition electrode 11 is semifinished to a rod with a cone 11' having an angle of taper and in the casting process it - - . -.. : . . - , .
- : . , ':
2~ 2Z~, is subsequently cast round with copper in the dimensions required for the gas nozzle 14. The thus manufactured semifinished product is finished by preparing the bores 19 and is connected to tube 16.
The position of the area cooled by the gas flow and the intensity of cooling are determined by the angle of inclination (= half the angle of taper ~1 of the bores 19 in the ~as nozzle 14. The area of the gas nozzle facing the tube 16 is cooled more intensely than of the area facing the ignition electrode 11 due to the proximity of the bores 19. Accordingly, the angle of taper ~ of the upper conical portion lli of the ignition electrode 11 is selected such that the entire section of the connection between the gas nozzle 14 and the ignition electrode 11 is used uniformly for current transmission and thermal conduction.
The gas nozzle 14 is surrounded on the outside by one end of an electrically insulating sleeve 20. The other end of the insulating sleeve 20 surrounds a cylindrical flange 21 of the main electrode 12. The gas nozzle 14 and the main electrode 12 with its flange 21 are kept at a distance by the annular projection 22 on the inside of the sleeve 20. The insulating sleeve 20 accordingly serves as a mechanical connecting member between the gas nozzle 14 and the main electrode 12 and causes the ignition electrode 11 to be positioned exactly with respect to the main electrode 12. The insulating sleeve 20 preferably consists of a plastic unaffected by high temperatures and/or of a pressure liquid sealed ceramic or of a composite material of plastic, metal and ceramic.
The main electrode 12 has a central opening 23 which .
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over a partial length, particularly in the area of the cylindrical flange 21, forms an annular channel 24 with the outer surface of the ignition electrode 11. The inside diameter of the annular projection 22 equals the inside diameter of the flange 21 connected thereto or of the opening 23 of the main electrode 12.
The bore 19 outlets all lie within the area given by this diameter.
Tube 16 is covered on its outside by a thin-walled, resilient insulating hose 25 unaffected by high temperatures which can be easily assembled and disassembled, this hose also annularly enclosing the gas nozzle 14 and part of the insulating sleeve 20.
An electrically insulating coating can also be provided instead of the insulating hose.
The main electrode 12 is connected to an outer cylindrical part 26 in electrically conductive manner and to a tube 28 in a pressure liquid sealed manner. An additional tube 27t which has a de~lecting member 29 ~at its lower end, is arranged between tube 28 and tube 16.
Due to their coaxial arrangement, the tubes 16, 27, 28 will be referred to herebelow as inner tube 16, centre tube 27 and outer tube 28. The inner tube 16 with the gas nozzle 14 thereby constitutes the ignition electrode lance and these parts together with the sleeve 20 and the centre and outer tubes 27 and 28 foxm the main electrode lance.
Sleeves 31 made of electrically insulating material and provided with axially parallel openings serve to coaxially centre the inner tube 16, the sleeves abutting on the one hand the g insulating hose 25 and on the other hand the inner surface of the centre tube 27.
The centre tube 27 as well as the deflecting member 29 connected thereto and the centering sleeves 31 are preferably made of plastic which brings with it a saving in weight in addition to electric insulation.
The gas for the ignition electrode 11 flows via the symbolically indicated ignition gas connection 32, the hollow space 17, the bores 19 and the annular channel 24. The ignition electrode lance formed by the tube 16 is cooled internally by the ignition plasma gas. If the ignition arc between the ignition electrode 11 and the main electrode 12 is fired, the ignition plasma gas emerges from the central bore 23 of the main electrode 12 as a plasma jet.
The gas for the main or power arc to be ired, which is between the main electrode 12 and another pole, for example a metal melt, flows via the symbolically indicated plasma gas connection 33 and the annular channe1 34 formed on the one hand by the outer surface of the outer tube 28 and the main electrode 12 and by the inner surface of the torch jacket and the nozæle 13 on the other hand.
An annular channel 35 or 36 for the flow-through of a liquid coolant is respectively provided between the inner tube 16 and the centre tube 27 and between the centre tube 27 and the outer tube 28. Both annular channels 35, 36 are joined together between the deflecting member 29 and the face end of the main electrode 12. The coolant likewise flows over the ignition - : :
,2;6 electrode lance formed by the inner tube 16.
The ignition electrode 11 is electrically connected to a pole of a current or voltage source (not illustrated~ via the gas nozzle 14, the inner tube 16 and its symbolically indicated current connection 37. The main electrode 12 is connected to another pole of the current or voltage source via the outer tube 28 and its likewise symbolically indicated current connection 39.
To cool both the ignition electrode 11 and the main electrode 12, a liquid coolant is introduced into the annular channel 35 via the symbolically indicated coolant connection or inlet 41 and fed back below the deflecting member 29 through the annular channel 36 to the symbolically indicated coolant discharge or outlet 43. The outer tube 28 guiding the current to the main electrode 12 is thereby cooled internally by the flow of coolant.
Xn addition, the outer tube 28 is cooled by the cold main plasma gas flowing to the main electrode 12 through the annular channel 34.
Seals in the form of O-rings are respectively provided between the sleeve 20 and the gas nozzle 14 (O-ring 45) and the cylindrical inner flange 21 of the main electrode 12 (O-ring 46 and between the outer flange 26 of the main electrode and the outer tube 28 (O-xing 47) to seal the coolant circuit through the annular channels 35, 36. The O-rings 45...47 are held in annular groo~es, of which annular groove 48 in the gas nszzle 14 for O~ring 45 and annular groove 49 in the sleeve 20 for O-ring 46 are illustxated by example.
In addition to the liquid coolant, the inner tube 16 is ~0~ ~2~2~
-- 1.1 --also cooled by the plasma gas flowing through its hollow space 17.
The plasma torch described is preferably operated as a three-phase plasma torch. However, it can in addition also be operated with direct and/or alternating current as described in European OS 0 134 961 A2.
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Plasma torches of this kind are known, for example, from German OS 29 00 330, their main components consisting essentially of a torch jacket with nozzles r a main electrode lance with a main electrode and an ignition electrode lance with an ignition electrode.
According to the state of the art all three aforenamed components are as such structural units electrically insulated from one another with their own water cooling. Both the ignition electrode lance as well as the main electrode lance are liquid-cooled, each lance consisting of tubes arranged coaxially to one another. The end face of the outer tube o the ignition electrode lance Eacing the ignition electrode is closed, this outer tube accommodating the ignition electrode. The inner tube o~ the ignition electrode lance leaves a gap towards the end wall of the outer tube or the ignition electrode, the connection for the coolant between the central bore of the inner tube and the annular channel between the inner and the outer tube being established through this gap. The current is guided via the outer tube to the ignition electrode.
The outer tube of the ignition electrode lance is guided via electrically insulating spacers or sleeves in the inner tube of the main electrode lance. The ignition plasma gas is conducted via the annular channel resulting between the outer tube of the ' -' i -ignition electrode lance and the inner tube of the main electrode lance to the ignition electrode and the enclosing, nozzle-shaped central bore of the main electrode.
According to the state of the art, a main electrode lance consisting of three coaxially arranged tubes is used to cool the main electrode. Through this an output and return annular channel is provided for the coolant diverted at the inner end wall of the main electrode. Depending on the design of the connection between the electrode and the lance, the current can be supplied to the main electrode via the inner and/or outer tube of the main electrode lance. Electric insulation between the outer tube of the main electrode lance and the inner tube of the torch jacket and the nozzle is carried out by means of spacers in the manner described above with respect to the front electrode lance. The main plasma gas is also conducted in a corresponding manner in the region between the main electrode and the nozzle.
Plasma torches known according to the state of the art have the drawback that they are structurally verv expensive and the heat losses along their jacket surface are relatively high.
It is therefore desirable to further develop the plasma torch described at the beginning in such a way that its construction can be simplified, that the heat losses occurring hitherto can be reduced and that better efficiency can be achieved.
The present invention provides a liquid-cooled plasma torch with transferred arc, its coolant, current and gas being guided to the ignition and main electrode via ignition electrode " ` ~
~,.
2Z~
lances and main electrode lances consisting of coaxial tubes, characterized by a common cooling circuit for the ignition electrode lance and main electrode lance. Not only can this advantageously result in a cost saving for tubes and seals~ but the entire supply of cooling water to the plasma torch is simplified considerably. ~oreover, the aiameter of the plasma torch shaft can be kept substantially smaller, this corresponding to a direct reduction in the torch jacket surface affected by the outside temperature, i.e. the heat losses of the jacket are reduced and the efficiency of the torch is improved. A smaller diameter of the torch shaft also permits greater universality with respect to the possibilities for using and installing plasma torches in vessels of various types and sizes, for example ln a smelting furnace, a ladle, a tundish or a vacuum installation.
Further developments of the inventive thought are described in the sub-claims. Since the ignition electrode lance is sealed vis-à-vis the coolant chann~ls and electrically insulated vis-à-vis the main electrode lance or main electrode, the ignition gas can be guided directly into the ignition electrode lance, whereby it is simultaneously cooled from the outside. The main electrode and ignition electrode lances preferably comprise, all told, only three tubes arranged coaxially to one another, whereby the coolant is guided in the interconnected annular channels between the outer tube and the centre tube on the one hand and between the centre tube and the inner tube on the other hand. This thus takes into consideration the fact that the main electrode is the structural member requiring the greatest cooling.
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The main electrode current is thereby guided via the outer tube and the ignition electrode current is guided via the inner tube.
So that the inner tube is adequately cooled despite the insulating hose that is pulled over it from the outside, an accordingly thin-walled insulating hose is selected w~ich should, however, preferably be resilient and unaffected by high tempera-tures. One or a plurality of sleeves are used to centre the ignition electrode lance.
The centre tube is continued in the area of the main electrode by an essentially annular deflecting member which at the end face leaves open a connection between the coolant annular channels lying on either side thereof. The centre tube, the aforenamed deflecting member and the s:Leeve for centering the ignition electrode lance are thereby made of non-conductive material, preferably plastic. This pr~3vents a reduction in the contact resistance between the ignition and m~in electrode possibly caused by the coolant. On the other hand, the ignition electrode and the gas nozzle into which the cylindrical interior of the ignition electrode lance merges is electrically conductive.
The nozzle effect of the gas nozzle is favoured in that the corresponding ignition gas guide channels are guided conically outwards, preferably in the form of a plurality of individual bores that are brought together again in the area of the main electrode or the outlet.
The gas nozzle and the main alectrode are connected to one another via an annular insulating sleeve, whereby this sleeve can be made from a plastic unaffected by high temperatures, from Z~
~0337-375 a pressure liquid sealed ceramic or from a composite material made from a plastic, a metal and a ceramic. The insulating hose overlaps and seals the gas nozzle and part of the insulating sleeve in order to improve the liquid insulation. The tightness to the liquid is optimized by the O-ring seal provided between the outer surface of the gas nozzle and the inner surface of the insulating sleeve and which lies in a corresponding groove of the gas nozzle. The main electrode itself has a cup-shaped design and is connected in electrically conductive manner to the outer tube.
an O-ring seal is inserted between these parts for the purpose of tightness to the liquid. An additional O-ring seal is provided in the overlapping area of the insulating sleeve and the main electrode.
It has proved advantageous to manufacture the inner tube and/or the gas nozzle from coppe.r. The ignition electrode should consist of tungsten, whereby for reasons involving manufacturing technology the upper conical portion of the ignition electrode can be cast round with copper and the relevant ingot forms the gas nozzle.
To achieve an as laminar flow as possible in the flow channels for the ignition gas, the lower portion of the inner tube is widened conically and the conical form is adapted to the adjacent bores.
An exemplary embodiment of the present in~ention is illustrated in the drawings and is explained in greater detail herebelow. The drawings show in Figure 1 a plasma torch according to the invention in . ~
2~
longitudinal section, and Figure 2 an enlarged illustration of the fastening of the ignition electrode in longitudinal section.
The main components of the plasma torch include an ignition or auxiliary electrode 11, a main or nozzle electrode 12 and a nozzle 13, each of which are electrically insulated from one another.
The upper, conical end 11' of the, in cross-section, circular ignition electrode 11 is embedded in a gas nozzle 14 which in turn is fastened to an ignition lance which, unlike the known plasma torches, comprises only a single tube 16. The lower region of the cylindrical interior or hollow 17 of the tube 16 adjacent the gas nozzle 14 merges into a conical enlargement ].~
with the angle of taper ~. The gas nozzle 14 has a plurality of, for example, ten bores or through holes 19 uniformly distributed over the circumference. The axes oE the bores 19 are arranged on an ~imaginary) conclcal surface (19') in such a way that the ends of the bcres 19 facing the tube 16 are closer together than the ends facing the ignition electrode 11 and the ends of the bores facing the tube 16 all lie within the hollow section of the conical enlargement 1~. The cone angle of the (imaginary) conical surface 19' is identified in Figure 2 as ~. The inner tube 16 is preferably manufactured from copper, whereas the ignition electrode 11 is made of tungsten. It is hereby possible to pre-fabricate the ignition electrode 11 to a semifinished product as follows. The ignition electrode 11 is semifinished to a rod with a cone 11' having an angle of taper and in the casting process it - - . -.. : . . - , .
- : . , ':
2~ 2Z~, is subsequently cast round with copper in the dimensions required for the gas nozzle 14. The thus manufactured semifinished product is finished by preparing the bores 19 and is connected to tube 16.
The position of the area cooled by the gas flow and the intensity of cooling are determined by the angle of inclination (= half the angle of taper ~1 of the bores 19 in the ~as nozzle 14. The area of the gas nozzle facing the tube 16 is cooled more intensely than of the area facing the ignition electrode 11 due to the proximity of the bores 19. Accordingly, the angle of taper ~ of the upper conical portion lli of the ignition electrode 11 is selected such that the entire section of the connection between the gas nozzle 14 and the ignition electrode 11 is used uniformly for current transmission and thermal conduction.
The gas nozzle 14 is surrounded on the outside by one end of an electrically insulating sleeve 20. The other end of the insulating sleeve 20 surrounds a cylindrical flange 21 of the main electrode 12. The gas nozzle 14 and the main electrode 12 with its flange 21 are kept at a distance by the annular projection 22 on the inside of the sleeve 20. The insulating sleeve 20 accordingly serves as a mechanical connecting member between the gas nozzle 14 and the main electrode 12 and causes the ignition electrode 11 to be positioned exactly with respect to the main electrode 12. The insulating sleeve 20 preferably consists of a plastic unaffected by high temperatures and/or of a pressure liquid sealed ceramic or of a composite material of plastic, metal and ceramic.
The main electrode 12 has a central opening 23 which .
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over a partial length, particularly in the area of the cylindrical flange 21, forms an annular channel 24 with the outer surface of the ignition electrode 11. The inside diameter of the annular projection 22 equals the inside diameter of the flange 21 connected thereto or of the opening 23 of the main electrode 12.
The bore 19 outlets all lie within the area given by this diameter.
Tube 16 is covered on its outside by a thin-walled, resilient insulating hose 25 unaffected by high temperatures which can be easily assembled and disassembled, this hose also annularly enclosing the gas nozzle 14 and part of the insulating sleeve 20.
An electrically insulating coating can also be provided instead of the insulating hose.
The main electrode 12 is connected to an outer cylindrical part 26 in electrically conductive manner and to a tube 28 in a pressure liquid sealed manner. An additional tube 27t which has a de~lecting member 29 ~at its lower end, is arranged between tube 28 and tube 16.
Due to their coaxial arrangement, the tubes 16, 27, 28 will be referred to herebelow as inner tube 16, centre tube 27 and outer tube 28. The inner tube 16 with the gas nozzle 14 thereby constitutes the ignition electrode lance and these parts together with the sleeve 20 and the centre and outer tubes 27 and 28 foxm the main electrode lance.
Sleeves 31 made of electrically insulating material and provided with axially parallel openings serve to coaxially centre the inner tube 16, the sleeves abutting on the one hand the g insulating hose 25 and on the other hand the inner surface of the centre tube 27.
The centre tube 27 as well as the deflecting member 29 connected thereto and the centering sleeves 31 are preferably made of plastic which brings with it a saving in weight in addition to electric insulation.
The gas for the ignition electrode 11 flows via the symbolically indicated ignition gas connection 32, the hollow space 17, the bores 19 and the annular channel 24. The ignition electrode lance formed by the tube 16 is cooled internally by the ignition plasma gas. If the ignition arc between the ignition electrode 11 and the main electrode 12 is fired, the ignition plasma gas emerges from the central bore 23 of the main electrode 12 as a plasma jet.
The gas for the main or power arc to be ired, which is between the main electrode 12 and another pole, for example a metal melt, flows via the symbolically indicated plasma gas connection 33 and the annular channe1 34 formed on the one hand by the outer surface of the outer tube 28 and the main electrode 12 and by the inner surface of the torch jacket and the nozæle 13 on the other hand.
An annular channel 35 or 36 for the flow-through of a liquid coolant is respectively provided between the inner tube 16 and the centre tube 27 and between the centre tube 27 and the outer tube 28. Both annular channels 35, 36 are joined together between the deflecting member 29 and the face end of the main electrode 12. The coolant likewise flows over the ignition - : :
,2;6 electrode lance formed by the inner tube 16.
The ignition electrode 11 is electrically connected to a pole of a current or voltage source (not illustrated~ via the gas nozzle 14, the inner tube 16 and its symbolically indicated current connection 37. The main electrode 12 is connected to another pole of the current or voltage source via the outer tube 28 and its likewise symbolically indicated current connection 39.
To cool both the ignition electrode 11 and the main electrode 12, a liquid coolant is introduced into the annular channel 35 via the symbolically indicated coolant connection or inlet 41 and fed back below the deflecting member 29 through the annular channel 36 to the symbolically indicated coolant discharge or outlet 43. The outer tube 28 guiding the current to the main electrode 12 is thereby cooled internally by the flow of coolant.
Xn addition, the outer tube 28 is cooled by the cold main plasma gas flowing to the main electrode 12 through the annular channel 34.
Seals in the form of O-rings are respectively provided between the sleeve 20 and the gas nozzle 14 (O-ring 45) and the cylindrical inner flange 21 of the main electrode 12 (O-ring 46 and between the outer flange 26 of the main electrode and the outer tube 28 (O-xing 47) to seal the coolant circuit through the annular channels 35, 36. The O-rings 45...47 are held in annular groo~es, of which annular groove 48 in the gas nszzle 14 for O~ring 45 and annular groove 49 in the sleeve 20 for O-ring 46 are illustxated by example.
In addition to the liquid coolant, the inner tube 16 is ~0~ ~2~2~
-- 1.1 --also cooled by the plasma gas flowing through its hollow space 17.
The plasma torch described is preferably operated as a three-phase plasma torch. However, it can in addition also be operated with direct and/or alternating current as described in European OS 0 134 961 A2.
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Claims (23)
1. A liquid-cooled plasma torch with transferred arc, its coolant, current and gas being guided to the ignition and main electrode via ignition electrode lances and main electrode lances consisting of coaxial tubes, characterized by a common cooling circuit for the ignition electrode lance and main electrode lance.
2. A plasma torch according to claim 1, wherein the ignition electrode lance with the ignition electrode is sealed vis-?-vis the channels of the cooling circuit and electrically insulated vis-?-vis the main electrode lance or the main electrode.
3. A plasma torch according to claim 2, wherein the main electrode lance and the ignition electrode lance consist of three tubes arranged coaxially to one another, whereby the coolant is guided in the interconnected annular channels between the outer tube and the centre tube on the one hand and between the centre tube and the inner tube on the other hand.
4. A plasma torch according to claim 3, wherein the current connection for the main electrode current is connected to the outer tube and the current connection for the ignition electrode current is connected to the inner tube.
5. A plasma torch according to one of the claims 1 to 4, wherein the ignition electrode lance is formed from only one tube, the inner tube, which conducts the ignition current, the ignition gas being guided within the interior of this tube, whereby a thin-walled, preferably resilient insulating hose that is unaffected by high temperatures is pulled over the inner tube.
6. A plasma torch according to claim 5, wherein the ignition electrode lance is centred, preferably by a plurality of sleeves, in the radial direction vis-?-vis the main electrode lance consisting of the centre and outer tubes.
7. A plasma torch according to one of the claims 3, 4 or 6, wherein the centre tube is connected to an annular deflecting member which protrudes into the main electrode while forming a connection between the coolant annular channels.
8. A plasma torch according to claim 7, wherein the centre tube, the deflecting member and/or the sleeves consist of electrically non-conductive material, preferably plastic.
9. A plasma torch according to one of the claims 1 to 4, wherein the centre tube, the deflecting member and/or the sleeves consist of electrically non-conductive material, preferably plastic.
10. A plasma torch according to one of the claims 1, 2, 3, 4, 6 or 8, wherein the cylindrical interior of the inner tube of the ignition electrode lance opens into a gas nozzle that is connected in electrically conductive manner to the ignition electrode.
11. A plasma torch according to claim 10, wherein the ignition electrode is designed with a conical upper portion which projects into the gas nozzle, and the gas nozzle is designed with radially inclined, outwardly guided ignition gas guide channels.
12. A plasma torch according to claim 10 wherein the ignition gas interior of the inner tube merges into a plurality, preferably 8 to 12, individual bores which serve as ignition gas guide channels and are arranged symmetrically to the axis of the inner tube and the ignition electrode, these bores being brought together to a common cross-section in the area of the main electrode or its outlet.
13. A plasma torch according to claim 11, wherein the ignition gas interior of the inner tube merges into a plurality, preferably 8 to 12, individual bores which serve as ignition gas guide channels and are arranged symmetrically to the axis of the inner tube and the ignition electrode, these bores being brought together to a common cross-section in the area of the main electrode or its outlet.
14. A plasma torch according to claim 10, wherein the gas nozzle and the main electrode are detachably connected to one another via an annular insulating sleeve.
15. A plasma torch according to claim 14, wherein the insulating sleeve is made from a plastic unaffected by high temperatures, from a pressure liquid sealed ceramic or from a composite material made from a plastic, a metal and a ceramic.
16. A plasma torch according to claim 14, wherein an insulating hose overlaps and seals the gas nozzle and part of the insulating sleeve.
17. A plasma torch according to one of the claims 14 to 16, wherein an O-ring seal is disposed between the outer surface of the gas nozzle and the inner surface of the insulating sleeve, this O-ring lying in a corresponding groove of the gas nozzle.
18. A plasma torch according to one of the claims 1 to 4, wherein the main electrode has a cup-shaped design and is connected in electrically conductive manner to the outer tube.
19. A plasma torch according to claim 17, wherein at least one O-ring seal is respectively provided between the main electrode and the outer tube as well as between the main electrode and the insulating sleeve.
20. A plasma torch according to claim 10, wherein the inner tube and/or the gas nozzle consists of copper.
21. A plasma torch according to one of the claims 1 to 4, wherein the ignition electrode consists of tungsten.
22. A plasma torch according to claim 11, wherein the upper, conically shaped part of the ignition electrode is cast round with a copper block forming the gas nozzle in which the bores converging conically in the interior of the inner tube are accommodated.
23. A plasma torch according to claim 22, wherein the lower portion of the inner tube is widened conically.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3840485.0 | 1988-12-01 | ||
| DE3840485A DE3840485A1 (en) | 1988-12-01 | 1988-12-01 | LIQUID-COOLED PLASMA TORCH WITH TRANSFERED ARC |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2004226A1 true CA2004226A1 (en) | 1990-06-01 |
Family
ID=6368234
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002004226A Abandoned CA2004226A1 (en) | 1988-12-01 | 1989-11-30 | Liquid-cooled plasma torch with transferred arc |
Country Status (10)
| Country | Link |
|---|---|
| EP (1) | EP0446238B1 (en) |
| JP (1) | JP2942354B2 (en) |
| KR (1) | KR900702756A (en) |
| AT (1) | ATE110221T1 (en) |
| CA (1) | CA2004226A1 (en) |
| DD (1) | DD292806A5 (en) |
| DE (2) | DE3840485A1 (en) |
| ES (1) | ES2017440A6 (en) |
| WO (1) | WO1990006666A1 (en) |
| ZA (1) | ZA899174B (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4022112C2 (en) * | 1990-07-11 | 1996-03-14 | Mannesmann Ag | Plasma torch for transmitted arc |
| DE4034731A1 (en) * | 1990-10-30 | 1992-05-07 | Mannesmann Ag | PLASMA BURNER FOR MELTING AND KEEPING WARM MATERIALS TO BE TREATED |
| NO174450C (en) * | 1991-12-12 | 1994-05-04 | Kvaerner Eng | Plasma burner device for chemical processes |
| WO2002068872A1 (en) | 2001-02-27 | 2002-09-06 | Yantai Longyuan Power Technology Co., Ltd. | Assembled cathode and plasma igniter with such cathode |
| KR100708320B1 (en) * | 2004-04-22 | 2007-04-17 | 김기현 | Apparatus for surface modification of casing-parts using atmospheric-pressure microwave plasma and method thereof |
| JP4820317B2 (en) * | 2006-04-06 | 2011-11-24 | 積水化学工業株式会社 | Discharge treatment device |
| DE102009016932B4 (en) * | 2009-04-08 | 2013-06-20 | Kjellberg Finsterwalde Plasma Und Maschinen Gmbh | Cooling tubes and electrode holder for an arc plasma torch and arrangements of the same and arc plasma torch with the same |
| JP4576476B1 (en) * | 2009-12-28 | 2010-11-10 | 株式会社フェローテック | Striker-type plasma generator and plasma processing apparatus |
| JP6522968B2 (en) * | 2015-01-30 | 2019-05-29 | 株式会社小松製作所 | Insulation guide for plasma torch and replacement part unit |
| CN107509299B (en) * | 2016-02-22 | 2019-03-12 | 衢州迪升工业设计有限公司 | A kind of pyrolysis installation of ionization collaboration |
| DE202017000969U1 (en) | 2017-02-23 | 2017-04-03 | CEBra - Centrum für Energietechnologie Brandenburg GmbH | Hochspannungszündvorrichtung |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1256816B (en) * | 1965-04-09 | 1967-12-21 | Inst Badan Jadrowych | Arc plasma torch |
| US3569661A (en) * | 1969-06-09 | 1971-03-09 | Air Prod & Chem | Method and apparatus for establishing a cathode stabilized (collimated) plasma arc |
| US4055741A (en) * | 1975-12-08 | 1977-10-25 | David Grigorievich Bykhovsky | Plasma arc torch |
| DE2900330A1 (en) * | 1978-01-09 | 1979-07-12 | Inst Elektroswarki Patona | PROCESS FOR PLASMA GENERATION IN A PLASMA ARC GENERATOR AND DEVICE FOR CARRYING OUT THE PROCESS |
| US4549065A (en) * | 1983-01-21 | 1985-10-22 | Technology Application Services Corporation | Plasma generator and method |
| DE3435680A1 (en) * | 1984-09-28 | 1986-04-03 | Fried. Krupp Gmbh, 4300 Essen | PLASMA TORCH |
| DE3642375A1 (en) * | 1986-12-11 | 1988-06-23 | Castolin Sa | METHOD FOR APPLYING AN INTERNAL COATING INTO TUBES OD. DGL. CAVITY NARROW CROSS SECTION AND PLASMA SPLASH BURNER DAFUER |
-
1988
- 1988-12-01 DE DE3840485A patent/DE3840485A1/en not_active Withdrawn
-
1989
- 1989-11-24 EP EP89912979A patent/EP0446238B1/en not_active Expired - Lifetime
- 1989-11-24 WO PCT/DE1989/000744 patent/WO1990006666A1/en active IP Right Grant
- 1989-11-24 KR KR1019900701563A patent/KR900702756A/en not_active IP Right Cessation
- 1989-11-24 JP JP2500128A patent/JP2942354B2/en not_active Expired - Lifetime
- 1989-11-24 AT AT89912979T patent/ATE110221T1/en not_active IP Right Cessation
- 1989-11-24 DE DE58908219T patent/DE58908219D1/en not_active Expired - Lifetime
- 1989-11-29 ES ES8904071A patent/ES2017440A6/en not_active Expired - Fee Related
- 1989-11-29 DD DD89335004A patent/DD292806A5/en not_active IP Right Cessation
- 1989-11-30 ZA ZA899174A patent/ZA899174B/en unknown
- 1989-11-30 CA CA002004226A patent/CA2004226A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| EP0446238A1 (en) | 1991-09-18 |
| DE58908219D1 (en) | 1994-09-22 |
| ATE110221T1 (en) | 1994-09-15 |
| WO1990006666A1 (en) | 1990-06-14 |
| ES2017440A6 (en) | 1991-02-01 |
| JPH04502531A (en) | 1992-05-07 |
| KR900702756A (en) | 1990-12-08 |
| JP2942354B2 (en) | 1999-08-30 |
| EP0446238B1 (en) | 1994-08-17 |
| DE3840485A1 (en) | 1990-06-07 |
| DD292806A5 (en) | 1991-08-08 |
| ZA899174B (en) | 1990-09-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |