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(11) | EP 0 351 847 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Modular segmented cathode plasma generator |
| (57) A supersonic plasma system in which a vacuum source creates a low static pressure
environment within an enclosure containing a plasma gun (16) and a workpiece (24)
has plural cathodes (84, 86, 88) of sealed, modular constructicn in conjunction with
a common anode, to provide higher levels of operating power and other advantages which
flow from a segmented cathode gun configuration. Inert gas independently introduced
into the plural cathodes (84, 86, 88) undergoes swirling notion over the cathode tips.
The anode is of modular construction for easy replacement in order to change the configuration
of a nozzle, a plurality of arc chambers receiving the plural cathodes or a central
mixing chamber between the nozzle and the arc chambers within the anode and coupled
to a central powder feed (72). The powder feed includes a replaceable insert which
includes at least one and preferably a plurality of powder feed ports into the various
arc chambers. Alternatively, metal which has already been heated to a molten state
can be fed directly into the central mixing chamber. The modular cathodes which are
independently powered by separate D.C. power sources (99A, 99B, 99C) are also independently
cooled by separate cooling water systems as is the common anode. The cooling systems
are configured to produce swirling of the cooling water so that cooling action is
maximized. |