Plasma torch for melting material to be processed in a container

Details Plasma torch for melting material to be processed in a container Plasma torch for melting material to be processed in a container

1993-12-13

1995-04-11

Paschall, Mark H.

Electric heating

Metal heating

By arc

21912136, 21912137, 21912148, 373 18, 373 22, B23K 1000

Patent

active

054060478

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

1. Field of the Invention
The invention concerns a plasma torch which projects into a vessel or container and is fastened at a supporting device and has a nozzle arranged at a burner lance, as well as a main electrode pipe with a main electrode arranged inside the burner lance, gaseous and liquid media as well as electric current being supplied to the main electrode via coaxially arranged pipes, wherein an annular insulating member is provided around the main electrode in the region of its foot end and encloses the electrode annularly, the outer wall or casing of the double-walled burner lance which is held by the supporting device being fastened at this insulating member, specifically for plasma torches with or without ignition lance.
2. Description of the Prior Art
Plasma torches are subjected to high thermal loading when used in containers. The main electrode is substantially acted upon thermally by electric current heat, while the casing of the burner lance is subjected to heat particularly from the melting bath, the furnace wall and the heat radiated from the arc. The resulting changes in temperature in the work materials cause considerable changes in length of the structural component parts.
A relative axial displacement of the main electrode and nozzle is caused particularly as a result of individual structural component parts of the plasma torch being acted upon thermally to varying degrees. These changes have a negative effect on the formation of the plasma arc. In plasma torches provided with ignition electrodes, comparable changes in length occur between the ignition electrode and the main electrode.
It is known from DE-OS 29 00 330 to cool the individual structural component parts of a plasma torch, namely the ignition electrode, the main electrode and the nozzle, independently of one another.
The plasma torch known from DE-OS 29 00 330 is not only expensive to produce, but also has hardly any influence on the set of problems relating to the relative displacement of the individual cooling structural component parts, since the lances are fixed in each instance at the portion of the burner remote of the melt. The individual lances can expand along their entire length with the result that the greatest axial displacements are to be found precisely in the critical region of the main electrode and nozzle.
A plasma torch is known from U.S. Pat. No. 3,463,957 in which the main nozzle and the main electrode are fixed in the region of the tip of the nozzle and are moreover connected to a common cooling water system.
The plasma torch known from this U.S. Patent is used for flame-cutting metal. Plasma torches of this type have no burner lances subjected to high heat radiation precisely when used in containers so as to result particularly in longitudinal expansion.
A plasma torch is known from DE 38 40 485 in which the ignition lance pipe is positioned within the main electrode pipe by centering sleeves. These centering sleeves serve for electric insulation and are therefore manufactured from plastic.
The plasma torch known from DE 38 40 485 forms a unit combining the ignition electrode and the ignition electrode pipe, which is not displaceable at the end remote of the ignition electrode.
It is the object of the present invention to provide a plasma torch which has a simple constructive design, operates in a reliable manner and with low maintenance when used at high temperatures and allows an adjustable, constant formation of the plasma arc.
This object is met by the invention in the characterizing part of claims I and 11.
Without recourse to a prototype, the present Inventor suggests a two-point bearing support of individual structural component parts of the plasma torch. In so doing, the structural component part which is thermally loaded to the highest degree, and accordingly also subject to the greatest changes in length of the structural component parts, acts as the supporting member. In the plasma torch according to the invention, this is the casing of the burner lance, wh

REFERENCES:
patent: 3242305 (1966-03-01), Kane et al.
patent: 3250893 (1966-05-01), Nestor
patent: 4018973 (1977-04-01), Paton
patent: 4766286 (1988-08-01), Iceland
patent: 4788408 (1988-11-01), Wlodarczyk et al.
patent: 4896016 (1990-01-01), Broberg et al.
patent: 4902871 (1990-02-01), Sanders et al.
patent: 5206481 (1993-04-01), Rossner et al.

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