Thermal Dynamics Corporation

David A Small

Kevin D Horner-Richardson

Jesse A Roberts

Joseph P Jones

Gene V Hewes

Roger W Hewett

Geoffrey H Putnam

Milind G Kelkar

Roger W Hewitt

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.

Plasma arc torch and method for improved life of plasma arc torch consumable parts

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

Tips and contact members having ridges for use in a contact start plasma arc torch

A contact start plasma torch and method of starting the torch includes a negatively charged cathode body and a positively charged anode body. A conductive element in the torch is constructed of an electrically conductive material and is free from fixed connection with the cathode body and the anode body. The torch is operable between an idle mode wherein the conductive element provides an electrically conductive path between the cathode body and the anode body and an pilot mode wherein a pilot arc is formed between the conductive element and at least one of the cathode body and the anode body. The pilot arc is blown by working gas flowing through the torch toward an exit orifice of the torch whereby the working gas is exhausted from the torch in the form of an ionized plasma.

Contact start plasma torch

A plasma arc torch and method for cutting a workpiece in which the torch has a primary gas flow path for receiving a primary working gas and directing it through the torch to a central exit opening of the torch for exhaustion from the torch onto the workpiece in the form of an ionized plasma. A secondary gas flow path in the torch receives a secondary gas separate from the primary working gas and directs it through the torch. The primary gas flow path is in fluid communication with the secondary gas flow path substantially upstream of the central exit opening of the torch to bleed primary working gas in the primary gas flow path into the secondary gas flow path for admixture therewith to form a secondary gas mixture to be exhausted from the torch.

Plasma arc torch and method for cutting a workpiece

A plasma arc torch has a cathode and electrode having connecting ends configured for a coaxial telescoping connection with one another on a central longitudinal axis of the torch. The connecting ends have interengageable detents thereon, with at least one of the detents being movable in a generally radial direction relative to the central longitudinal axis of the torch between an undeflected state and a deflected state. The at least one detent is movable from the undeflected state to the deflected state when the cathode and electrode are telescoped one into the other, and is movable from the deflected state back toward the undeflected state when the cathode and electrode are further telescoped tc, a point where the detents on the cathode and electrode are generally axially aligned. In this position, the at least one detent is engageable with the other detent to interconnect the cathode and electrode and inhibit axial movement of the electrode away from the cathode.

Growing community of inventors

Sharon, VT, United States of America

David A Small