The Esab Group Inc.

Esab Welding Products, Inc.

Union Carbide Corporation

L-tec Company

Donald W Carkhuff

Clifford W Hill

Jeffrey S Everett

Frank J Pilia

Jule Conner

Peter R Schaefer

A plasma arc torch includes a torch body defining a discharge axis, an electrode coaxially aligned on the discharge axis, a nozzle assembly positioned adjacent the discharge end of the electrode, and a heat shield removably secured on the torch body. A power supply delivers electrical current to the electrode to create an electrical arc, and a plasma gas is delivered so as to surround the arc. Also, a pressure sensing system is provided for sensing the pressure of the plasma gas and for disabling the power supply if there is insufficient gas pressure, such as when the heat shield is removed.

Plasma arc torch including means for disabling power source

Nozzle for a plasma arc torch

Plasma torch electrode

Electrode for plasma arc torch

Nozzle for plasma arc torch

A plasma arc torch for minimizing delay in exchanging gases within the torch. The torch includes a metallic electrode, a conductive nozzle spaced apart from the electrode, and a gas plenum between the electrode and nozzle. Two gas passageways are provided for communicating non-oxidizing and oxidizing gases into the plenum. A plenum inlet check valve is associated with each gas passageway and is located in close proximity to the plenum. The check valves are normally biased in a closed position but may be opened by gas pressure within the passageways to selectively introduce gas into the plenum. Solenoid valves located upstream of the plenum check valves regulate the pressure and flow of gas within the passageways so as to open and close the plenum check valves. Pilot arc and main arc power supplies are provided for generating an arc between the electrode and nozzle while the non-oxidizing gas flows through the plenum and for transferring the arc and sustaining it between the electrode and workpiece when oxidizing gas is introduced into the plenum. Operation of the check valves and power supplies is coordinated so that the oxidizing and non-oxidizing gases are exchanged substantially simultaneously with transfer or termination of the arc.

Plasma arc torch with integral gas exchange

A plasma arc torch has an outer heat shield removably secured onto the torch body. The heat shield includes an electrically conductive member secured on the interior surface of the heat shield and in electrical contact with the nozzle assembly or a nozzle assembly retainer member when the nozzle assembly and heat shield are secured onto the torch body. A closed loop electrical circuit is completed through a portion of the nozzle assembly and the electrically conductive member of the heat shield when both the nozzle assembly and the heat shield are secured onto the torch body. When the heat shield or the nozzle assembly are removed, the electrical circuit is open and the electrical voltage flow to the electrode is disabled.

Plasma arc torch power disabling mechanism

A plasma torch assembly that provides a removable and replaceable barrier to prevent catastrophic failure of a plasma arc torch following failure of an electrode. The torch assembly comprises the combination of an electrode body for providing an electrical path in a plasma arc torch, an electrode, and an electrode adaptor positioned between the electrode body and the electrode and formed of an electrically conductive material. The adaptor comprises an adaptor body portion having structure for removably fitting the adaptor body to the electrode body and structure for removably fitting the adaptor body to the electrode so that the adaptor forms an electrically conductive path between the electrode body and the electrode and contains features and components essential to the gas distribution.

Electrode adaptor

A plasma cutting and gouging torch has a torch body and a torch head that defines a longitudinal axis. A nozzle is aligned with the longitudinal axis and is secured to the torch head at the plasma discharge end for discharging plasma through the nozzle outlet and onto a workpiece. A handle is secured onto the head and extends outward from the torch head. A shield is secured to the torch head and extends substantially around the periphery of the torch head opposite the handle and extends along the surface of the handle confronting toward the nozzle. The shield extends in close, spaced relation to the torch head and handle to define a narrow, insulating air gap between the torch body and the shield. A flow of air may be introduced into the formed air gap to aid in cooling the torch body during cutting or gouging.

Plasma torch having heat shield for torch body

A nozzle for use with a plasma arc torch having a first gas flow within the nozzle for engaging an electrode and generating a plasma and a second gas flow in surrounding engagement to the outer surface of the nozzle is disclosed. The nozzle includes an outer surface of substantially hourglass configuration in longitudinal cross-section so that the second gas remains in close contact with the outer hourglass surface of the nozzle to provide efficient heat transfer from the nozzle to the surrounding second gas flow.

Plasma arc torch having extended nozzle of substantially hourglass

Supplemental electrode cooling mechanisms are provided for a plasma arc torch, which mechanisms form a part of the gas flow mechanisms through the torch head for circulating the flowing gas through the current transfer assembly of the torch in direct contact with a maximum portion of the entire longitudinal extent of the surface of the upper portion of an electrode received within the current transfer assembly for additional cooling of the electrode to increase the life thereof, while maintaining desired seating of the electrode in the current transfer assembly and transfer of current to the electrode from the current transfer assembly.

Plasma arc torch having supplemental electrode cooling mechanisms

The plasma torch of the present invention includes safety control means which responds to the removal or partial removal of the torch heat shield from the torch body for interrupting the flow of plasma gas and a switch system responsive to the interruption of the flow of plasma gas for disengaging the power supply from the torch.

Plasma torch safety device

An arc cutting and gouging torch in combination with nozzle assemblies for suspending a carbon electrode and discharging a combined air stream relative to the carbon electrode centerline. The nozzle assemblies include exit orifices which are disposed in a non-parallel alignment relative to one another and the electrode to cause the air jet discharged from each exit orifice to merge at a location upstream of the arc and substantially about the centerline of the electrode.

Method of air cutting and gouging and a combined torch and nozzle

A metal inert gas welding torch having a wire guide assembly threadably secured at one end to a torch body and a collet nut assembly threadably secured to the other end of the wire guide assembly. A spidered collet is mounted in the collet nut assembly and forms a plenum chamber with the wire guide assembly and collet nut. A contact tip is gripped by the spidered collet and extends into the plenum chamber whereby the shielding gas cools the contact tip prior to the distribution of such gas into a nozzle.

Growing community of inventors

Florence, SC, United States of America

Donald W Carkhuff