Electric arc apparatus
First Claim
1. Apparatus for treating a flow of material by an electric arc comprising:
- a cathode and an anode arranged for striking an arc across a gap between the cathode and the anode and arranged to provide a pathway for flow of material through the gap between the cathode and the anode,means for producing movement of the arc around the anode-cathode gap, andadjustment means for selectively increasing and decreasing the distance across the anode-cathode gap by rearward and forward axial movement of the cathode for fine control of the internal energy imparted to material passing through the anode-cathode gap,the cathode being a substantially non-consumable cathode having an edge at an end thereof opposite the anode for providing a continuous closed path for the cathode root to travel around in operation,the anode having an inwardly tapering frusto-conical surface arranged opposite the said edge on the cathode in a position such as to provide on the frusto-conical surface a continuous closed path for the anode spot to travel around in operation,the distance across the anode-cathode gap being sufficiently small for the arc channel to be substantially straight between the cathode root and anode spot in normal operation during the said movement of the arc around the gap, and the angles of inclination of the surfaces forming the said edge on the cathode being such relative to each other and relative to the frusto-conical surface of the anode as to prevent the cathode root wandering from the edge along which it is intended to travel during the said movement of the arc around the anode-cathode gap,the arrangement being such that the anode spot and cathode root travel around their respective paths in the same sense and in substantially the same time with the arc free from uncontrolled changes in arc length during travel of the anode spot and cathode root around the said respective paths.
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Accused Products
Abstract
Apparatus for treating a flow of material by an electric arc generates free radicals and/or atoms, and charged species, in ground or excited states. A cathode (13) and an anode (14) are arranged for striking an arc across a preferably annular gap and provide a pathway for flow of material through the gap between the cathode and anode. Each electrode has a region providing a continuous closed path for the anode spot or cathode root respectively to travel around, and means, preferably magnetic means (19), for producing movement of the arc cause the anode spot and cathode root to travel around their paths in the same sense and in substantially the same time. Preferably the paths are circular paths in parallel planes on the anode and cathode respectively, and the length of the arc remains substantially constant during travel of the anode spot and cathode root around the paths. Preferably the cathode (13) comprises a rod having a plane end face with a circumferential edge for striking the arc. Preferably the cathode has a sharp edge for striking the arc and for providing the said continuous closed path for the cathode root.
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Citations
57 Claims
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1. Apparatus for treating a flow of material by an electric arc comprising:
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a cathode and an anode arranged for striking an arc across a gap between the cathode and the anode and arranged to provide a pathway for flow of material through the gap between the cathode and the anode, means for producing movement of the arc around the anode-cathode gap, and adjustment means for selectively increasing and decreasing the distance across the anode-cathode gap by rearward and forward axial movement of the cathode for fine control of the internal energy imparted to material passing through the anode-cathode gap, the cathode being a substantially non-consumable cathode having an edge at an end thereof opposite the anode for providing a continuous closed path for the cathode root to travel around in operation, the anode having an inwardly tapering frusto-conical surface arranged opposite the said edge on the cathode in a position such as to provide on the frusto-conical surface a continuous closed path for the anode spot to travel around in operation, the distance across the anode-cathode gap being sufficiently small for the arc channel to be substantially straight between the cathode root and anode spot in normal operation during the said movement of the arc around the gap, and the angles of inclination of the surfaces forming the said edge on the cathode being such relative to each other and relative to the frusto-conical surface of the anode as to prevent the cathode root wandering from the edge along which it is intended to travel during the said movement of the arc around the anode-cathode gap, the arrangement being such that the anode spot and cathode root travel around their respective paths in the same sense and in substantially the same time with the arc free from uncontrolled changes in arc length during travel of the anode spot and cathode root around the said respective paths. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A method of treating a flow of material by an electric arc, comprising:
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passing a flow of material through a gap between a substantially non-consumable cathode having an edge for striking the arc and an anode having an inwardly tapering frusto-conical surface positioned opposite the edge of the cathode, the angles of inclination of the surfaces forming the said edge of the cathode being arranged to be such relative to each other and relative to the frusto-conical surface of the anode as to prevent the cathode root wandering from the said edge during normal operation, striking an arc across the anode-cathode gap between the edge of the cathode and the frusto-conical surface of the anode, selectively increasing and decreasing the distance across the anode-cathode gap by axial movement of the cathode to control the internal energy imparted to the material passing through the anode-cathode gap and adjusting the cathode to a position in which the distance across the anode-cathode gap is sufficiently small for the arc channel to be substantially straight between the cathode root and anode spot during normal operation, and producing movement of the arc around the anode-cathode gap such that the cathode root travels along a continuous closed path around the said edge of the cathode and the anode spot travels along a continuous closed path around the said frusto-conical surface, and the cathode root and anode spot travel around their respective paths in the same sense and in substantially the same time with the arc free from uncontrolled changes in arc length during the travel of the anode spot and the cathode root. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53)
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54. Apparatus for treating a flow of material by an electric arc comprising:
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a cathode and an anode arranged for striking an arc across a gap between the cathode and the anode and arranged to provide a pathway for flow of material through the gap between the cathode and the anode, means for maintaining the arc by supplying across the anode-cathode gap a potential difference in the range 40 to 120 volts with a power consumption in operation in the range 400 to 1500 watts, means for producing movement of the arc around the anode-cathode gap, and adjusting means for selectively increasing and decreasing the distance across the anode-cathode gap without change in the geometrical relationship between the arc and the surfaces of the anode and cathode by rearward and forward axial movement of the cathode for fine control of the internal energy imparted to the material passing through the anode-cathode gap, the cathode being a substantially non-consumable cathode having an average width in the range 1 to 5 mm and having an edge at an end thereof opposite the anode for providing a continuous closed path for the cathode root to travel around in operation, the anode having an inwardly tapering frusto-conical surface arranged opposite the said edge on the cathode in a position such as to provide on the frusto-conical surface a continuous closed path for the anode spot to travel around in operation, the distance across the anode cathode gap lying in the range 250 to 350 microns and being sufficiently small for the arc channel to be substantially straight between the cathode root and anode spot in normal operation during the said movement of the arc around the gap, the said frusto-conical surface of the anode having a semi-angle in the range 30°
to 50° and
the angles of inclination of the surfaces forming the said edge on the cathode being such relative to each other and relative to the frusto-conical surface of the anode as to prevent the cathode root wandering from the edge along which it is intended to travel during the said movement of the arc around the anode cathode gap,the arrangement being such that the anode spot and cathode root travel around their respective paths in the same sense and in substantially the same time with the arc free from uncontrolled changes in arc length during travel of the anode spot and cathode root around the said respective paths.
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55. Apparatus for treating a flow of material by an electric arc comprising:
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a cathode and an anode arranged for striking an arc across a gap between the cathode and the anode and arranged to provide a pathway for flow of material through the gap between the cathode and the anode, means for producing movement of the arc around the anode cathode gap, and adjustment means for selectively increasing and decreasing the distance across the anode cathode gap without change in the geometrical relationship between the arc and the surfaces of the anode and cathode by rearward and forward axial movement of the cathode for fine control of the internal energy imparted to material passing through the anode cathode gap, the cathode being a substantially non-consumable cathode having a circular edge at an end thereof opposite the anode for providing a continuous closed path for the cathode root to travel around in operation, the anode having an inwardly tapering frusto-conical surface arranged coaxially with and opposite to the said circular edge on the cathode in a position such as to provide on the frusto-conical surface a continuous closed circular path for the anode spot to travel around in operation, the distance across the anode cathode gap being sufficiently small for the arc channel to be substantially straight between the cathode root and anode spot in normal operation during the said movement of the arc around the gap, with the arc channel lying substantially at right-angles to a tangent to the said edge of the cathode taken at the cathode root, and at right-angles to the frusto-conical surface of the anode, the said circular edge being defined by a right circular cylindrical outer surface of the cathode meeting a plane end surface of the cathode at right-angles to the plane end surface, and the said frusto-conical surface of the anode being coaxial with the cylindrical cathode and having a semi-angle of 45°
, whereby the angles of the inclination of the surfaces forming the said edge on the cathode are such relative to each other and relative to the frusto-conical surface of anode so as to prevent the cathode root wandering from the edge along which it is intended to travel during the said movement of the art around the anode cathode gap,the arrangement being such that the anode spot and cathode root travel together around their respective paths with the arc length substantially constant during the travel of the anode spot and cathode root.
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56. A method of treating a flow of material by an electric arc, comprising:
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passing a flow of material through a gap between a substantially non-consumable cathode and an anode having an inwardly tapering frusto-conical surface of semi-angle in the range 30°
to 50°
positioned opposite the end of the cathode,striking across the anode-cathode gap between an edge of the cathode and the frusto-conical surface of the anode an arc which is substantially straight between the cathode root and anode spot, the angles of inclination of the surfaces forming the said edge on the cathode being arranged to be such relative to each other and relative to the frusto-conical surface of the anode as to prevent the cathode root wandering from the said edge during normal operation, maintaining the arc during normal operation by supplying across the anode-cathode gap a potential difference in the range 40 to 120 volts with a power consumption in the range 400 to 1500 watts, producing movement of the arc around the anode-cathode gap such that the cathode root travels along a continuous closed path around the said edge of the cathode and the anode spot travels along a continuous closed path around the said frusto-conical surface, and the cathode root and anode spot travel around their respective paths in the same sense and in substantially the same time with the arc free from uncontrolled changes in arc length during the travel of the anode spot and cathode root, and selectively increasing and decreasing the distance across the anode-cathode gap without change in the geometrical relationship between the arc and the surfaces of the anode and cathode by rearward and forward axial movement of the cathode to control the internal energy imparted to the material passing through the anode-cathode gap, the distance across the anode-cathode gap being adjusted so as to lie in the range 250 to 350 microns in normal operation.
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57. A method of treating a flow of material by an electric arc, comprising:
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passing a flow of material through a gap between a substantially non-consumable cathode having a circular edge for striking the arc and an anode having an inwardly tapering frusto-conical surface positioned coaxially with and opposite to the edge of the cathode, the said circular edge being defined by a right circular cylindrical outer surface of the cathode meeting a plane end surface of the cathode at right angles to the plane end surface, and the said frusto-conical surface of the anode being coaxial with the cylindrical cathode and having a semi-angle of 45°
, whereby the angles of inclination of the surfaces forming the said edge on the cathode are arranged to be such relative to each other and relative to the frusto-conical surface of the anode as to prevent the cathode root wandering from the said edge during normal operation,striking across the anode-cathode gap between the edge of the cathode and the frusto-conical surface of the anode an arc which is substantially straight between the cathode root and anode spot during normal operation and which lies substantially at right-angles to a tangent to the said edge of the cathode taken at the cathode root and at right-angles to the frusto-conical surface of the anode, producing movement of the arc around the anode-cathode gap such that the cathode root travels along a continuous closed circular path around the said edge of the cathode and the anode spot travels along a continuous closed circular path around the said frusto-conical surface, and the cathode root and anode spot travel around their respective paths in the same sense and in substantially the same time with the arc length substantially constant during the travel of the anode spot and cathode root, and selectively increasing and decreasing the distance across the anode-cathode gap without change in the geometrical relationship between the arc and the surfaces of the anode and cathode by rearward and forward axial movement of the cathode to control the internal energy imparted to the material passing through the anode-cathode gap.
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Specification