Abstract: A plasma arc torch is provided that comprises a set of torch consumable components secured to a torch head, wherein a supply of cooling fluid flows coaxially through the torch to cool torch components and a supply of plasma gas and secondary gas flows through the torch to generate and stabilize a plasma stream for operations such as cutting workpieces. The torch consumable components, in part, comprise an electrode and a tip that include a variety of configurations for improved cooling, electrical contact, and attachment to adjacent torch components. Further, a consumables cartridge is provided for ease of use and replacement of the torch consumable components. Additionally, methods of operating the plasma arc torch at relatively high current levels are also provided by the present invention.

Abstract: A variety of electrodes for use in a plasma arc torch are provided that improve cooling between the electrode and an adjacent cathodic element such as a cathode. At least one passageway is formed between the electrode and the cathode for the flow of a fluid, e.g. cooling fluid, wherein the flow of the fluid is proximate, or through an adjacent vicinity of, electrical contact between the cathode and the electrode. The passageway is formed through the electrode, through the cathode, between the electrode and the cathode, and through a third element in the various forms of the present invention. Further, methods of operating a plasma arc torch using the electrodes according to the various forms of the invention are also provided.

Abstract: A consumables cartridge for use in a plasma arc torch is provided that comprises a cartridge body and at least one other consumable component such as a tip or an electrode, for example. The consumables cartridge provides for ease of use and replacement of the torch consumable components by replacing the consumables cartridge when consumable components require replacement rather than replacing consumable components individually or one at a time. Further, methods of installing, removing, and replacing the consumables cartridge are also provided by the present invention.

Abstract: A plasma arc torch and method for improving the life of the consumable parts of the plasma arc torch, including the electrode, the tip and the shield cap. The method includes turbulating gas as it flows over the exposed surfaces of the electrode, tip and shield cap to increase turbulence in the hydrodynamic boundary layer of the gas flow, thereby enhancing convective heat transfer. The result of enhanced cooling is improved consumable parts life. For example, to increase the turbulence of the gas flow over the outer surface of the electrode, the plasma arc torch electrode has a roughened, or textured outer surface formed with dimples, axially extending grooves or spiraling grooves formed in the outer surface of the electrode. The inner and outer surfaces of the tip and the inner surface of the shield cap are similarly textured.

Abstract: A system for controlling gas flow from a gas source, through a gas conduit, and to a plasma arc torch during a transition from a cold flow when no arc is present to a hot flow when an arc is provided by the present invention. The system comprises a first solenoid in communication with the gas source, a second solenoid disposed proximate the plasma arc torch, and a bypass circuit in communication with the gas source and the second solenoid. The bypass circuit comprises a bypass solenoid that controls the gas pressure within the gas conduit to reduce gas flow fluctuations when transitioning from cold flow to hot flow. Additional gas control systems and methods are also provided that cause the gas pressure to be higher during cold flow, prior to arc ignition, which overcomes the rapid drop in flow that typically occurs during the transition to hot flow.

Abstract: A cooling system for a plasma arc torch is provided that comprises a coaxial fluid flow that improves cooling of components within the plasma arc torch and that provides a more compact torch design. The coaxial fluid flow, namely, the cooling fluid flow, is distributed circumferentially about the central longitudinal axis of the torch and is flowing in the same direction at any radial location from the central longitudinal axis. The cooling fluid flows distally towards the consumable components, then proximally towards the torch head, then distally again, and then proximally again for recirculation. Additionally, both the plasma gas flow and the secondary gas flow are also flowing coaxially in addition to the cooling fluid flow.

Abstract: A dual mode plasma arc torch is provided that preferably comprises a start cartridge disposed between an electrode and a tip. In one form, the start cartridge comprises an initiator that is in electrical contact with the electrode and that is resiliently biased into contact with the tip, such that when the plasma arc torch is in a contact start mode, the initiator is movable against the resilient bias to separate from the tip and establish a pilot arc between the initiator and the tip. Further, when the plasma arc torch is in a high frequency start mode, the start cartridge spaces the tip from the electrode such that a pilot arc is established between the electrode and the tip. In other forms, a contact start torch is provided that is operable under high frequency, and conversely, a high frequency start torch is provided that is operable under low voltage.

Abstract: A tip for a plasma arc torch includes a ridge for improved electrical contact with a starting member.

Abstract: A plasma arc torch is provided that comprises torch head connections that are made between consumable components and a torch head independent of rotational alignment of the consumable components. Accordingly, connections for the flow of a cooling fluid, plasma gas, and/or a secondary gas are made independent of rotational alignment. Additionally, electrical connections are also provided that are independent of rotational alignment of the various plasma arc torch components.

Abstract: Vented shield systems for plasma arc torches are provided that comprise a shield cup body defining a distal end portion, a vented retainer secured to the distal end portion of the shield cup body, and a shield cap secured to the vented retainer. The vented retainer defines at least one vent passageway that directs a flow of secondary gas inward toward the shield cap, and the vented shield system blocks at least a portion of molten metal from contacting components, such as a tip or nozzle, of the plasma arc torch. The shield cap may comprise a mechanized cap, a drag cap, a gouging cap, or a deflector cap, among others. Accordingly, various shield caps may be employed without removal or replacement of the vented retainer. The same vented retainer may be used throughout a variety of plasma arc torch applications.

Abstract: A contact start plasma arc torch is provided that comprises an electrode, a tip, and an initiator that is resiliently biased into contact with the tip, the initiator being movable against the resilient bias to separate from the tip and establish a pilot arc between the initiator and the tip. The initiator is disposed within a start cartridge, which preferably comprises a coil spring that biases the initiator into contact with the tip. The plasma arc torch further comprises a plurality of head vent holes to vent gas from within the start cartridge during operation of the torch. Additionally, the tip defines a plurality of swirl holes and secondary gas holes to generate and control a plasma stream that is subsequently blown from a central exit orifice in the tip.