The invention relates to a wear part for an arc torch, plasma torch or plasma cutting torch, characterised in that the wear part or at least one part or a region of the wear part consists of an alloy formed from silver and zirconium, silver and hafnium, or silver and zirconium and hafnium.

A plasma generator that detects whether a connector of a head is electrically connected to a power cable. The plasma generator includes the head including the connector with a terminal to supply electricity to electrodes that generate plasma by electrical discharge, and a first terminal and a second terminal that are connected to each other; a power cable to supply electricity to the terminal; a cable to transmit a signal to the first terminal; a first ground cable to ground the second terminal; and a detector to detect a signal current that flows in a path from the cable to the first ground cable in accordance with transmission of the signal.

In some aspects, electrodes can include a front portion shaped to matingly engage a nozzle of the plasma cutting system, the front portion having a first end comprising a plasma arc emitter disposed therein; and a rear portion thermally connected to a second end of the front portion, the rear portion shaped to slidingly engage with a complementary swirl ring of the plasma cutting system and including: an annular mating feature extending radially from a proximal end of the rear portion of the electrode to define a first annular width to interface with the swirl ring, the annular mating feature comprising a sealing member configured to form a dynamic seal with the swirl ring to inhibit a flow of a gas from a forward side of the annular mating feature to a rearward side of the annular mating feature.

A discharge electrode E in an electrode chamber C comprises a plurality of electrode members 8, 9. The electrode members 8, 9 are disposed facing each other by having a supporting member 4 therebetween, a gap is formed between the facing portions of the electrode members 8, 9, and by having the gap as a gas passageway 15, the gas passageway is opened in the leading end of the discharge electrode. A replacement gas having been supplied from a manifold pipe 3 is supplied to the gas passageway 15 via an orifice.

An electrode-supporting assembly for a contact-start plasma arc torch has an insulator that partially houses an electrode, and employs a spring-loaded plunger to bias the electrode to a forward position. The spring is engaged between the plunger and a contact element attached to the insulator, and may conduct electrical current to the electrode. The plunger, spring, and contact element are retained in the insulator when the torch is opened to replace the electrode, which is a consumable part. The electrode and the plunger have axially-engagable mating surfaces to assure good thermal and electrical conductivity therebetween. Conductivity can be further enhanced by forming the plunger of silver or a silver-bearing alloy. In some embodiments, a passage through the insulator is partitioned into forward and rear chambers, with the plunger, spring, and contact element trapped in the rear chamber.

A plasma spraying apparatus includes a main torch and an auxiliary torch. The main torch includes a first electrode including a spraying material discharge hole, a first mantle, and a first insulator including a first plasma gas introducing port. The auxiliary torch includes a second electrode, a second mantle, and a second insulator including a second plasma gas introducing port. A spraying material supplied from the spraying material discharge hole is melted at the axial center of plasma that is formed on the central axis of the first electrode by the first electrode and the second electrode, and a gas introducing part that introduces gas is provided on an inlet side of an opening part and/or in a tapered part provided between the opening part and the first insulator in the first mantle.

A nozzle for a plasma arc torch is provided with a distal region sidewall formed by rotation of a variably curved element about a nozzle axis. The distal region sidewall has an inclination to the nozzle axis that increases at an increasing rate as it approached a nozzle terminal plane that terminates an orifice of the nozzle. The distal region sidewall is substantially tangent to the nozzle terminal plane where it intersect the same. The desired curvature can be formed by rotation of a portion of an ellipse or parabola. The curvature of the distal region sidewall appears to draw a portion of the shield gas along the nozzle to provide improved cooling and greater stability to the plasma arc, which can improve the quality of cuts made by the arc and can increase nozzle life.

The invention relates to a plasma cutting arrangement having at least one plasma cutting torch which is formed by a torch body, an electrode and a nozzle having a nozzle bore. An outer contour AK of the plasma cutting torch is present in cross-section with respect to a longitudinal axis which is aligned perpendicular through the nozzle bore. A smallest spacing between the longitudinal axis extending through the center of the nozzle bore of the nozzle and the radially outer margin of the outer contour AK is observed in at least one axial direction and corresponds at a maximum to ¾ of the length of a largest spacing d between the central longitudinal axis extending through the center of the nozzle bore of the nozzle and the radial outer margin of the outer contour AK. A smallest spacing c can also correspond to a maximum of ⅜ of the length of a largest distance b between two points of the outer margin of the outer contour AK whose virtual straight connection line extends through the central longitudinal axis extending through the center of the nozzle bore of the nozzle.

The invention features methods and apparatuses for liquid cooling a plasma arc torch. An electrode is provided including a body having a longitudinal axis defining a first end, a second end, and a middle portion. The electrode includes a first sealing element disposed on an exterior of the body near the first end; a second sealing element disposed on the exterior of the body located in the middle portion, the second sealing element configured to provide a first gas seal to a swirl gas chamber and defining a portion of the swirl gas chamber; and a third sealing element disposed on the exterior of the body, the third sealing element located between the second sealing element and the second end, the third sealing element configured to provide a second gas seal to the swirl gas chamber and defining a portion of the swirl gas chamber.

A component for a plasma arc torch includes a body portion, a tapered surface on the body portion, the tapered surface including a compressible member that provides a disengagement force relative to the body portion, and an axially disposed surface on the body portion for coupling a mating surface on an adjacent structure of the torch. The component can be a nozzle and/or an electrode.