Plasma torch, and electrode means therefor

Claim 2

An elongated electrical plasma-jet torch adapted to be manufactured in various desired lengths, which comprises: an insulating housing, a metallic front housing mounted in the forward portion of said insulating housing, first and second concentric tubes removably and sealingly inserted into said front housing, said tubes having diameters sufficiently different from each other to form a first annulus therebetween, at least one of said first and second tubes being an electrical conductor, and being electrically connected to said front housing, a third tube mounted concentrically within said first and second tubes, said third tube having a diameter sufficiently small that a second annulus is defined outwardly adjacent said third tube, said third tube being inserted rearwardly through said front housing into said insulating housing and being sealingly associated with said insulating housing, an anode nozzle removably and sealingly mounted at the forward ends of said first and second tubes, said anode nozzle having coolant flow means therein, an inlet portion of said coolant flow means communicating with one of said first and second annuli, an outlet portion of said coolant flow means communicating with the other of said first and second annuli, said anode nozzle being electrically connected to at least said electrically conductive one of said first and second tubes, an elongated cathode assembly removably inserted forwardly through said insulating housing, through said front housing, and through said third tube, the forward portion of said cathode assembly being a cathode which is mounted in said anode nozzle, said cathode assembly having an outer diameter sufficiently small that a gas-flow path is formed therearound and within said third tube, means to effect flow of coolant in series through said first and second annuli and through said coolant flow means in said anode nozzle, means to connect a source of power to said front housing and to the rear end of said cathode assembly, and means to pass arc gas into said gas-flow path around said cathode assembly and thus to said nozzle, said means to pass arc gas into said gas-flow path including gas flow means defined by said insulating housing and communicating with the interior of said third tube.

Claim 3

An elongated electrical plasma-jet torch adapted to be manufactured in various desired lengths, which comprises: an insulating housing, a metallic front housing mounted in the forward portion of said insulating housing, first and second concentric tubes removably and sealingly inserted into said front housing, said tubes having diameters sufficiently different from each other to form a first annulus therebetween, at least one of said first and second tubes being an electrical conductor, and being electrically connected to said front housing, a third tube mounted concentrically within said first and second tubes, said third tube having a diameter sufficiently small that a second annulus is defined outwardly adjacent said third tube, an anode nozzle removably and sealingly mounted at the forward ends of said first and second tubes, said anode nozzle having coolant flow means therein, an inlet portion of said coolant flow means communicating with one of said first and second annuli, an outlet portion of said coolant flow means communicating with the other of said first and second annuli, said anode nozzle being electrically connected to at least said electrically conductive one of said first and second tubes, an elongated cathode assembly removably inserted forwardly through said insulating housing, through said front housing, and through said third tube, the forward portion of said cathode assembly being a cathode which is mounted in said anode nozzle, said cathode assembly having an outer diameter sufficiently small that a gas-flow path is formed therearound and within said third tube, said cathode assembly including fourth and fifth concentric tubes which are concentric with said first, second and third tubes, said fourth and fifth tubes being connected to an electrically and thermally conductive holder for said cathode, at least one of said fourth and fifth tubes being an electrical conductor, said fourth and fifth tubes having diameters sufficiently different from each other that a third annulus is defined therebetween, means provided at the forward ends of said fourth and fifth tubes to effect communication between said third annulus and the central passage through the innermost one of said fourth and fifth tubes, a metallic rear housing mounted in the rear portion of said insulating housing and connected to said fourth and fifth tubes, means to effect flow of coolant in series through said first and second annuli and through said coolant flow means in said anode nozzle, means to pass coolant in series through said third annulus and through said central passage, means to connect a source of power to said front housing and to said rear housing, and means to pass arc gas into said gas-flow path around said cathode assembly and thus to said nozzle.

Claim 4

An elongated electrical plasma-jet torch adapted to be manufactured in various desired lengths, which comprises: an insulating housing, a metallic front housing mounted in the forward portion of said insulating housing, first and second concentric tubes removably and sealingly inserted into said front housing, said tubes having diameters sufficiently different from each other to form a first annulus therebetween, at least one of said first and second tubes being an electrical conductor, and being electrically connected to said front housing, a third tube mounted concentrically within said first and second tubes, said third tube having a diameter sufficiently small that a second annulus is defined outwardly adjacent said third tube, an anode nozzle removably and sealingly mounted at the forward ends of said first and second tubes, said anode nozzle having coolant flow means therein, an inlet portion of said coolant flow means communicating with one of said first and second annuli, an outlet portion of said coolant flow means communicating with the other of said first and second annuli, said anode nozzle being electrically connected to at least said electrically conductive one of said first and second tubes, an elongated cathode assembly removably inserted forwardly through said insulating housing, through said front housing, and through said third tube, the forward portion of said cathode assembly being a cathode which is mounted in said anode nozzle, said cathode assembly having an outer diameter sufficiently small that a gas-flow path is formed therearound and within said third tube, said cathode assembly including fourth and fifth concentric tubes which are concentric with said first, second and third tubes, said fourth and fifth tubes being connected to an electrically and thermally conductive holder for said cathode, at least one of said fourth and fifth tubes being an electrical conductor, said fourth and fifth tubes having diameters sufficiently different from each other that a third annulus is defined therebetween, means provided at the forward ends of said fourth and fifth tubes to effect communication between said third annulus and the central passage through the innermost one of said fourth and fifth tubes, a metallic rear housing mounted in the rear portion of said insulating housing and connected to said fourth and fifth tubes, means to effect flow of coolant in series through said first and second annuli and through said coolant flow means in said anode nozzle, means to pass coolant in series through said third annulus and through said central passage, means to connect a source of power to said front housing and to said rear housing, and means to pass arc gas into said gas-flow path around said cathode assembly and thus to said nozzle.

Claim 5

The invention as claimed in claim 2, in which said means to pass coolant through said third annulus and through said central passage includes a series connection with said means to effect series flow of coolant through said first and second annuli, said series connection comprising: an annular groove defined by said insulating housing around the rear end of said third tube and communicating with said second annulus, passage means formed in said insulating housing and extending therethrough from said annular groove to an annular groove around said rear housing, and port means in said rear housing and extending from said last-mentioned annular groove to said third annulus between said fourth and fifth tubes.

Claim 6

An electrical plasma-jet torch the forward portion of which may have a very small diameter in comparison to the electrical power supplied to the torch, said torch comprising: an anode nozzle, said anode nozzle comprising a thick-walled tube formed of highly conductive metal, the thick wall of said tube having a substantial number of circumferentially spaced longitudinal bores extending therethrough, means to connect to each other the forward portions of one group of said bores and the forward portions of another group of said bores, whereby said one group may conduct water in one direction and said other group may conduct water in the opposite direction and in series with sAid one group, first, second and third concentric tubes extending longitudinally of said anode nozzle and having sufficiently different diameters that a first annulus is defined between the outer two of said three tubes and a second annulus is defined between the inner two of said three tubes, at least one of said three concentric tubes being an electrical conductor, said third tube being the innermost one of said three tubes, means to connect said first annulus to the rear portions of said one group of bores, means to connect said second annulus to the rear portions of said other group of bores, an elongated and electrically conductive cathode assembly mounted longitudinally within said third tube, said cathode assembly including an elongated cathode at least the forward part of which is disposed coaxially within said anode nozzle, said cathode assembly having an outer diameter sufficiently small that gas may be passed forwardly therearound and within said third tube, a temperature-resistant insulating sleeve mounted closely around at least the forward part of said cathode assembly and within said third tube, the outer diameter of at least parts of said sleeve being sufficiently small that gas flowing forwardly within said third tube will pass between the inner wall of said third tube and the exterior surface of said parts of said sleeve, passage means extending inwardly through said sleeve at said small-diameter parts thereof, and conducting gas to the interior of said anode nozzle adjacent said cathode and rearwardly of the forward portion of said cathode, means to pass current through the conductive one of said three tubes to said anode nozzle, and to pass current through said cathode assembly to said cathode, means to pass water into the rear portion of one of said first and second annuli and to draw water out of the rear portion of the other of said first and second annuli, and means to pass gas forwardly through said third tube, around at least said parts of said sleeve, and through said passage means to the interior of said anode nozzle.

Claim 7

An electrical plasma-jet torch the forward portion of which may have a very small diameter in comparison to the electrical power supplied to the torch, said torch comprising: an anode nozzle, said anode nozzle comprising a thick-walled tube formed of highly conductive metal, the thick wall of said tube having a substantial number of circumferentially spaced longitudinal bores extending therethrough, means to connect to each other the forward portions of one group of said bores and the forward portions of another group of said bores, whereby said one group may conduct water in one direction and said other group may conduct water in the opposite direction and in series with sAid one group, first, second and third concentric tubes extending longitudinally of said anode nozzle and having sufficiently different diameters that a first annulus is defined between the outer two of said three tubes and a second annulus is defined between the inner two of said three tubes, at least one of said three concentric tubes being an electrical conductor, said third tube being the innermost one of said three tubes, means to connect said first annulus to the rear portions of said one group of bores, means to connect said second annulus to the rear portions of said other group of bores, an elongated and electrically conductive cathode assembly mounted longitudinally within said third tube, said cathode assembly including an elongated cathode at least the forward part of which is disposed coaxially within said anode nozzle, said cathode assembly having an outer diameter sufficiently small that gas may be passed forwardly therearound and within said third tube, a temperature-resistant insulating sleeve mounted closely around at least the forward part of said cathode assembly and within said third tube, the outer diameter of at least parts of said sleeve being sufficiently small that gas flowing forwardly within said third tube will pass between the inner wall of said third tube and the exterior surface of said parts of said sleeve, passage means extending inwardly through said sleeve at said small-diameter parts thereof, and conducting gas to the interior of said anode nozzle adjacent said cathode and rearwardly of the forward portion of said cathode, means to pass current through the conductive one of said three tubes to said anode nozzle, and to pass current through said cathode assembly to said cathode, means to pass water into the rear portion of one of said first and second annuli and to draw water out of the rear portion of the other of said first and second annuli, and means to pass gas forwardly through said third tube, around at least said parts of said sleeve, and through said passage means to the interior of said anode nozzle.

Claim 8

The invention as claimed in claim 4, in which a powder port is provided in said anode nozzle at a portion thereof which is not penetrated by said bores, and in which a powder tube is connected at the forward end thereof to said powder port, said powder tube extending longitudinally and exteriorly of the outermost one of said three concentric tubes.

Claim 9

The invention as claimed in claim 4, in which the diameter of the central passage through said anode nozzle tube is in excess of one-third the outer diameter of said anode nozzle tube.

Claim 10

The invention as claimed in claim 4, in which said insulating sleeve has a substantial number of circumferentially spaced longitudinal flutes formed exteriorly thereon, the grooves between said flutes being outwardly adjacent said small-diameter parts of said sleeve, said flutes engaging the interior surface of said third tube, whereby gas flowing forwardly through said third tube and around said cathode assembly is constrained to enter said grooves and pass there-through to said passage means and then to the interior of said anode nozzle.

Claim 11

The invention as claimed in claim 7, in which said insulating sleeve is formed of a material selected from a group consisting of boron nitride and transite.

Claim 12

The invention as claimed in claim 4, in which an additional insulating sleeve is provided around the rear portion of said cathode assembly and extends forwardly to said temperature-resistant insulating sleeve.

Claim 13

The invention as claimed in claim 4, in which a generally tubular electrically conductive front housing is mounted coaxially around the rear ends of the outer two of said first, second and third concentric tubes, in which the outermost one of said three tubes is electrically conductive, in which said means to pass current includes a low-resistance connection between said front housing and said outermoSt tube, in which said front housing is shaped to define an annulus around the rear end of the intermediate one of said three tubes, said rear end of said intermediate tube protruding rearwardly from the rear end of said outermost tube, in which said annulus forms part of said means to pass water, in which an insulating housing is mounted around said front housing and around the rear end of said third tube, said rear end of said third tube protruding rearwardly from said intermediate one of said three tubes, and in which said insulating housing defines an annulus around the rear end of said cathode assembly, said last-mentioned annulus forming part of said means to pass gas.

Claim 14

The invention as claimed in claim 10, in which O-rings are provided to removably and sealingly associate said outermost tube and said intermediate tube with said front housing, and to removably and sealingly associate said third tube with said insulating housing, in which said cathode assembly extends rearwardly through said front housing and said insulating housing to a rear housing, in which said cathode assembly has water passages therethrough, and in which means are provided in said insulating housing and in said rear housing to conduct water to said water passages from the rear end of the annulus defined between said third tube and said intermediate tube.

Claim 15

The invention as claimed in claim 11, in which said cathode assembly comprises fourth and fifth concentric tubes at least one of which is electrically conductive, said tubes defining an annulus therebetween and which forms one of said water passages in said cathode assembly, the other water passage in said cathode assembly being through the innermost one of said fourth and fifth tubes, in which means are provided to effect communication between the forward ends of said water passages in said cathode assembly, in which the rear ends of said fourth and fifth tubes are mounted sealingly in said rear housing, and in which said rear housing is an electrical conductor and forms part of the means to pass current.

Claim 16

The invention as claimed in claim 4, in which protuberances are provided exteriorly at spaced points on said third tube and on said intermediate one of said three tubes, said protuberances being dimensioned to maintain said three tubes in concentric relationship.

Claim 17

An anode nozzle for an electrical plasma-jet torch, which comprises: a thick-walled tube of highly conductive metal, the central passage in said tube being an arc passage or chamber of the anode nozzle, said tube having a substantial number of bores formed longitudinally therethrough in circumferentially spaced relationship around said central passage, the outermost part of said thick-walled tube being adapted to be inserted coaxially into the end of a first elongated tube and in sealed relationship to such end, a portion of the rear end of said thick-walled tube having a reduced diameter and being adapted to be partially inserted coaxially into the end of a second elongated tube having a diameter smaller than that of said first elongated tube, whereby a first generally cylindrical portion of said thick-walled tube is adapted to be exposed to an annulus defined between said first and second elongated tubes, a second portion of the rear end of said thick-walled tube having a further reduced diameter and being adapted to be partially inserted coaxially into the end of a third elongated tube having a diameter smaller than that of said second elongated tube, whereby a second generally cylindrical portion of said thick-walled tube is adapted to be exposed to an annulus defined between said second and third elongated tubes, said second generally cylindrical portion being offset from said first generally cylindrical portion in a direction longitudinally of said thick-walled tube, means to connect the forward end portions of one group of said bores to the forward end portions of another group of said bores, first connector means adapted to connect the rear end portions of said one group to a coolant-inlet means, said first connector means comprising bores to extend said one group of said bores to said first generally cylindrical portion for communication with said annulus defined between said first and second elongated tubes, and second connector means adapted to connect the rear end portions of said other group to a coolant-outlet means, said second connector means comprising bores to extend said other group of said bores to said second generally cylindrical portion for communication with said annulus defined between said second and third elongated tubes.

Claim 18

An anode nozzle for an electrical plasma-jet torch, which comprises: a thick-walled tube of highly conductive metal, the central passage in said tube being an arc passage or chamber of the anode nozzle, said tube having a substantial number of bores formed longitudinally therethrough in circumferentially spaced relationship around said central passage, the outermost part of said thick-walled tube being adapted to be inserted coaxially into the end of a first elongated tube and in sealed relationship to such end, a portion of the rear end of said thick-walled tube having a reduced diameter and being adapted to be partially inserted coaxially into the end of a second elongated tube having a diameter smaller than that of said first elongated tube, whereby a first generally cylindrical portion of said thick-walled tube is adapted to be exposed to an annulus defined between said first and second elongated tubes, a second portion of the rear end of said thick-walled tube having a further reduced diameter and being adapted to be partially inserted coaxially into the end of a third elongated tube having a diameter smaller than that of said second elongated tube, whereby a second generally cylindrical portion of said thick-walled tube is adapted to be exposed to an annulus defined between said second and third elongated tubes, said second generally cylindrical portion being offset from said first generally cylindrical portion in a direction longitudinally of said thick-walled tube, means to connect the forward end portions of one group of said bores to the forward end portions of another group of said bores, first connector means adapted to connect the rear end portions of said one group to a coolant-inlet means, said first connector means comprising bores to extend said one group of said bores to said first generally cylindrical portion for communication with said annulus defined between said first and second elongated tubes, and second connector means adapted to connect the rear end portions of said other group to a coolant-outlet means, said second connector means comprising bores to extend said other group of said bores to said second generally cylindrical portion for communication with said annulus defined between said second and third elongated tubes.

Claim 19

An anode nozzle for an electrical plasma-jet torch, which comprises: a thick-walled tube of highly conductive metal, the central passage in said tube being an arc passage or chamber of the anode nozzle, said tube having a substantial number of bores formed longitudinally therethrough in circumferentially spaced relationship around said central passage, said tube having a port extended through one side portion thereof for injection of powder into said central passage, means to connect the forward end portions of one group of said bores to the forward end portions of another group of said bores, said one group of bores and said other group of bores not extending through said side portion of said thickwalled tube in which said injector port is located, first connector means adapted to connect the rear end portions of said one group to a coolant-inlet means, second connector means adapted to connect the rear end portions of said other group to a coolant-outlet means, two additional bores formed longitudinally through said thick-walled tube on the same side thereof as that on which said injection port is located, said two additional bores being disposed rearwardly of said injection port, the forward ends of said two additional bores being connected to each other, means for connecting the rear end of one of said two additional bores to said coolant-inlet means, and means provided for connecting the rear end of the other of said two additional bores to said coolant-outlet means.

Claim 20

An anode nozzle for an electrical plasma-jet torch, which comprises: a thick-walled tube of highly conductive metal, the central passage in said tube being an arc passage or chamber of the anode nozzle, said tube having a substantial number of bores formed longitudinally therethrough in circumferentially spaced relationship around said central passage, said tube having a port extended through one side portion thereof for injection of powder into said central passage, means to connect the forward end portions of one group of said bores to the forward end portions of another group of said bores, said one group of bores and said other group of bores not extending through said side portion of said thickwalled tube in which said injector port is located, first connector means adapted to connect the rear end portions of said one group to a coolant-inlet means, second connector means adapted to connect the rear end portions of said other group to a coolant-outlet means, two additional bores formed longitudinally through said thick-walled tube on the same side thereof as that on which said injection port is located, said two additional bores being disposed rearwardly of said injection port, the forward ends of said two additional bores being connected to each other, means for connecting the rear end of one of said two additional bores to said coolant-inlet means, and means provided for connecting the rear end of the other of said two additional bores to said coolant-outlet means.

Claim 21

The invention as claimed in claim 15, in which said central passage bends at an angle from the axis of the rear portion of said thick-walled tube, in which said injection port communicates with the downstream portion of said central passage on the opposite side of the bend from the upstream end of said central passage, and in which said downstream of said central passage is on the same side portion of said thick-walled tube as is said injection port, whereby said two additional bores permit water cooling of said side of said thick-walled tube despite the bend in said central passage and despite the presence of said injection port.

Claim 22

The invention as claimed in claim 16, in which the angle of said bend is in the range of about 45* to about 90* .

Claim 23

An electrical plasma-jet torch, which comprises: wall means to define an elongated cylindrical passage, an elongated anode nozzle having a central arc passage therethrough, the rear end of said arc passage being adjacent and communicating coaxially with the forward end portion of said cylindrical passage, an elongated cathode slug having an outer diameter substantially smaller than the diameter of at least the rear portion of said arc passage, the forward portion of said cathode slug being positioned coaxially within the rear portion of said arc passage and spaced radially inwardly from the wall of said arc passage, whereby an annulus is defined around said cathode slug and within said arc passage, an electrically conductive cylindrical cathode base mounted longitudinally of and within said cylindrical passage, said cathode base having an outer diameter substantially smaller than the diameter of said cylindrical passage, said cathode base being connected coaXially to the rear end of said cathode slug to support the same and conduct current thereto, an elongated temperature-resistant ceramic sleeve mounted coaxially around said cathode base, the forward end of said sleeve extending forwardly past the forward end of said cathode base and defining a second annulus around said cathode slug, said second annulus communicating coaxially with said first-mentioned annulus, means to pass gas from the rear portion of said cylindrical passage around the exterior of said sleeve to the forward end portion of said sleeve, said means to pass said gas comprising a substantial number of circumferentially spaced longitudinal grooves formed in the exterior of said sleeve, said grooves being separated from each other by flutes which extend radially outwardly to said wall means, passage means formed through the forward end portion of said sleeve and communicating with said second annulus to inject said gas therein, said passage means comprising a bore formed through said sleeve at the forward end portion of each of said grooves, the inner end of each of said bores terminating at said second annulus, and means to pass electricity to said anode nozzle and to said cathode base whereby to generate an arc in said arc passage forwardly of said cathode slug to thus heat said gas prior to discharge thereof from said arc passage.

Claim 24

An electrical plasma-jet torch, which comprises: wall means to define an elongated cylindrical passage, an elongated anode nozzle having a central arc passage therethrough, the rear end of said arc passage being adjacent and communicating coaxially with the forward end portion of said cylindrical passage, an elongated cathode slug having an outer diameter substantially smaller than the diameter of at least the rear portion of said arc passage, the forward portion of said cathode slug being positioned coaxially within the rear portion of said arc passage and spaced radially inwardly from the wall of said arc passage, whereby an annulus is defined around said cathode slug and within said arc passage, an electrically conductive cylindrical cathode base mounted longitudinally of and within said cylindrical passage, said cathode base having an outer diameter substantially smaller than the diameter of said cylindrical passage, said cathode base being connected coaXially to the rear end of said cathode slug to support the same and conduct current thereto, an elongated temperature-resistant ceramic sleeve mounted coaxially around said cathode base, the forward end of said sleeve extending forwardly past the forward end of said cathode base and defining a second annulus around said cathode slug, said second annulus communicating coaxially with said first-mentioned annulus, means to pass gas from the rear portion of said cylindrical passage around the exterior of said sleeve to the forward end portion of said sleeve, said means to pass said gas comprising a substantial number of circumferentially spaced longitudinal grooves formed in the exterior of said sleeve, said grooves being separated from each other by flutes which extend radially outwardly to said wall means, passage means formed through the forward end portion of said sleeve and communicating with said second annulus to inject said gas therein, said passage means comprising a bore formed through said sleeve at the forward end portion of each of said grooves, the inner end of each of said bores terminating at said second annulus, and means to pass electricity to said anode nozzle and to said cathode base whereby to generate an arc in said arc passage forwardly of said cathode slug to thus heat said gas prior to discharge thereof from said arc passage.