Electric heating – Metal heating – By arc
Patent
1991-05-21
1994-03-22
Paschall, Mark H.
Electric heating
Metal heating
By arc
21912149, 21912151, 21912148, B23K 900
Patent
active
052966720
DESCRIPTION:
BRIEF SUMMARY
This invention is concerned with the generation of electric arc and is particularly concerned with electric arc reactors.
In the context of this specification an electric arc is to be understood as an electric discharge in a gaseous medium sustained between two electrodes by the passage of relatively large currents and characterised by low voltage drops at the cathode. The properties of the electric arc are influenced by a number of parameters such as the arc current, the fluid dynamics, the containment, the electrode material temperature and shape, the external magnetic fields (if used), and the gas in which the arc burns.
Electric arc reactors have the potential to generate high temperatures and for that reason have been proposed for use in furnaces and particularly furnaces intended for the destruction of noxious and toxic material. U.S. Pat. No. 3,832,519 (Westinghouse) is directed to an electric arc reactor which has been considered to be useful in a waste destruction plant. That prior reactor involves generation of an axial magnetic field between large tubular and co-axial electrodes, and the arc is rotated about the electrode axis so that the arc roots move in an approximately circular path. An advantage of that arrangement is that electrode wear is distributed over the surface of each electrode so that the life of the electrodes is increased.
A disadvantage of the Westinghouse reactor is that although material to be treated may be injected radially near the arc, an injection directly into the hot arc region is not achieved, and that reduces the effectiveness of the furnace. Furthermore, in accordance with conventional practice the material to be treated (feed material) is introduced downstream of the arc zone in a generally radial direction.
It is an object of the present invention to provide an electric arc reactor which involves rotation of the arc roots as in prior reactors, such as the Westinghouse reactor, but which is more effective in operation than those prior reactors. In particular, a reactor according to the invention is able to operate at relatively high power density levels whilst retaining a relatively low rate of electrode wear. It is a further object of the invention, in one form, to provide such a reactor which is of relatively compact form.
In accordance with the present invention, there is provided an electric arc reactor including, an upstream electrode and a downstream electrode which are connectable to a power source such as to enable an arc to be generated between them, a feed material passage extending in a substantially straight path through said electrodes and being connectable to a source of feed material at an injection end thereof, an electrode gap formed between adjacent inner ends of said electrodes which are spaced apart in the direction of said passage, said injection end being at an outer end of said upstream electrode remote from said gap, manifold means arranged to direct a flow of gas into said gap so as to confine the upstream root of a said arc to an exposed surface of said upstream electrode, and rotation inducing means whereby said arc is caused to rotate about the axis of said passage to create a hollow arc column through which feed material can pass.
Reference to "upstream" and "downstream" throughout this specification is to be understood in the context of the direction in which feed material flows through the aforementioned passage.
Rotation of the arc root results in production of a hollow ar column which is substantially coaxial with the feed passage, and the flow of gas within the gap across which the arc extends serves to confine the lateral extent of the arc column and also the location of the upstream root of the arc. Feed material is caused to move into and pass through the interior of that column and is thereby subjected to the hot core of the column.
It will generally happen that the flow of gas within the gap will cause the upstream root of the arc to attach to an internal surface of the portion of the passage extending through the upstream ele
REFERENCES:
patent: 4587397 (1986-05-01), Camacho et al.
patent: 4668853 (1987-05-01), Fey et al.
patent: 4891490 (1990-01-01), Labrot
patent: 5004888 (1991-04-01), Wolf et al.
patent: 5076051 (1991-12-01), Naff
patent: 5147998 (1992-09-01), Tsantrizos et al.
Mundy Alan E.
Ogilvy Ian M.
Oppenlander, deceased Walter T.
Ramakrishnan Subramania
Commonwealth Scientific and Industrial Research Organisation
Irons Edward S.
Paschall Mark H.
Siddons Ramset Limited
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