Abstract:
Plasma gas is ejected from inner gas ejection ports that are formed in a downstream side housing, and nitrogen gas is supplied as protective gas to a protective gas source between a housing and a cover section. Nitrogen gas is sucked in accompanying exhaust from inner gas ejection ports of plasma gas, and is ejected from the outer gas ejection ports. In this case, since a layer of nitrogen gas is formed in the periphery of plasma gas, it is possible to make it difficult to bring the plasma gas into contact with air, and it is possible to make it difficult to react a reactive species such as a radical in the plasma gas, oxygen in the air, and the like.
Abstract:
A plasma arc torch includes an annular baffle defining distinct faces A, B, C, and D. Faces A and C are opposite from each other, and faces B and D are opposite from each other. First passages for fluid flow extend between the faces A and C, and second passages extend between the faces B and D. The baffle is installable in an annular space between an inner wall and an outer wall, in either of two orientations. In a first orientation, the first passages are open to fluid flow and the second passages are closed by engagement of the inner and outer walls with the faces B and D, and in a second orientation, flipped over relative to the first orientation, the second passages are open to fluid flow and the first passages are closed by engagement of the inner and outer walls with the faces A and C.
Abstract:
A plasma arc torch includes an annular baffle defining distinct faces A, B, C, and D. Faces A and C are opposite from each other, and faces B and D are opposite from each other. First passages for fluid flow extend between the faces A and C, and second passages extend between the faces B and D. The baffle is installable in an annular space between an inner wall and an outer wall, in either of two orientations. In a first orientation, the first passages are open to fluid flow and the second passages are closed by engagement of the inner and outer walls with the faces B and D, and in a second orientation, flipped over relative to the first orientation, the second passages are open to fluid flow and the first passages are closed by engagement of the inner and outer walls with the faces A and C.
Abstract:
An apparatus includes a plasma generator aligned with a beam generator for producing a plasma to shield an energized beam. An electrode is coaxially aligned with the plasma generator and followed in turn by a vortex generator coaxially aligned with the electrode. A target is spaced from the vortex generator inside a fluid environment. The electrode is electrically biased relative to the electrically grounded target for driving the plasma toward the target inside a vortex shield.
Abstract:
An apparatus includes a plasma generator aligned with a beam generator for producing a plasma to shield an energized beam. An electrode is coaxially aligned with the plasma generator and followed in turn by a vortex generator coaxially aligned with the electrode. A target is spaced from the vortex generator inside a fluid environment. The electrode is electrically biased relative to the electrically grounded target for driving the plasma toward the target inside a vortex shield.
Abstract:
A plasma arc torch has a secondary gas flow that is extremely large during piercing of a workpiece to keep splattered molten metal away from the torch and thereby prevent "double arcing". The secondary flow exits the torch immediately adjacent the transferred plasma arc and is an extremely uniform, swirling flow. A swirl ring is located in the secondary gas flow path at the exit point. A prechamber feeds gas to the swirl ring, which is in turn fed through a flow restricting orifice. For certain applications the secondary gas is a mixture of an oxidizing gas, preferably oxygen, and a non-oxidizing gas, preferably nitrogen, in a flow ratio of oxygen to nitrogen in the range of 2:3 to 9:1. Preferably the flow ratio is about 2:1. A network of conduits and solenoid valves operated under the control of a central microprocessor regulates the flows of plasma gas and secondary gas and mixes the secondary gas. The network includes valved parallel branches that provide a quick charge capability and a set of venting valves, also electrically actuated by the microprocessor, to provide a quick discharge. In a preferred high-definition embodiment, a nozzle with a cut back outer surface and a large, conical head allows a metal seal and enhanced cooling. A two-piece cap protects the nozzle during cutting.
Abstract:
An improved plasma torch nozzle which has a substantially barrel shaped body having a longitudinal opening therethrough for directing the flow of gas for a plasma arc from rearward portions of the body downstream to forward portions of the body and then out of a face at the forward portions to form a plasma arc in the presence of a sufficient electrical potential difference. The nozzle body particularly comprises a rear section for which the outer surface portions diverge with respect to the downstream direction, a center section for which the outer surface portions are cylindrical with respect to the downstream direction, and a forward section for which the outer surface portions converge with respect to the downstream direction so that the respective outer surface portions form a continuous outer surface for the nozzle body that encourages the flow of gases that is directed along the outer surface of the nozzle body to follow the outer surface and converge at the face of the nozzle body.
Abstract:
A process and apparatus for reducing wear of an electrode in a plasma arc torch involves providing a substantial pressure drop in a flow of plasma gas from the torch to a plasma arc chamber defined by the electrode and a nozzle. The pressure drop is immediately before the plasma arc chamber. There is also a small, localized supply of the plasma gas located between the pressure drop and the plasma chamber. The supply is sufficient to stabilize the arc when the gas flow is cut off upstream of the pressure drop and the arc current is cut off very shortly thereafter. The pressure drop is small enough to permit an adequate flow of plasma gas to the plasma arc chamber during normal operations, but large enough to isolate residual gas in the torch from the plasma arc chamber when the arc current is cut off. The apparatus is preferably a swirl ring with an annular pre-chamber fed by a set of choke holes to feed gas to the chamber and create the pressure drop. A set of swirl holes feed gas from the pre-chamber to the plasma arc chamber.
Abstract:
Nozzle for plasma arc torch includes internal and external forming nozzles mounted one within other and fitted to the torch housing to form first and second gaps. The first gap is formed between the torch cathode and the internal nozzle, an internal vortex generator mounted in it. An external vortex generator is fitted in the second gap and is connect to races machined in the torch housing. A forming canal is designed in the front end of the internal nozzle and an intermediary nozzle is mounted between the internal and external nozzles. A third gap is formed between it and the internal nozzle, and the second gap is formed between the intermediary and the external nozzle. A second forming race coaxial with that of the internal nozzle is provided in the front part of the intermediary nozzle, thus forming a common forming race. An intermediary vortex generator with tangential races is included in the contact surface of the intermediary and internal nozzles. The tangential races are connected by their ends to the common forming race, and to an internal circular race on the intermediary nozzle. This race is connected by holes to an external circular race connected with a pipe connection. The second gap is connected to the housing races by means of the external vortex generator, connecting races of the intermediary nozzle and third gap. The connecting races are designed above the intermediary vortex generator.
Abstract:
A transferred-arc plasma reactor is disclosed. The reactor comprises a bottom portion defining a crucible for collecting molten material, an anode adapted to contact the molten material in the crucible, a sleeve mounted on top of the crucible and electrically insulated therefrom, a cathode assembly including a cathode mounted on top of the sleeve and electrically insulated therefrom, means for introducing feed material conveyed by a carrier gas near the top of the sleeve so that the material is fed against the inner wall of the sleeve, melted under the heating energy radiated by a plasma arc formed between the cathode and the molten material to form a falling film of molten material which flows down along the inner wall of the sleeve and drops into the crucible underneath, and outlet ports in the bottom portion of the reactor for exiting the carrier gas and the non-reacted plasma forming gas.