Plasma arc torch nozzle with curved distal end region
AssigneeThermacut, K.S.
InventorGeorge A. Crowe
Life of this patent
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Abstract
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.
Claims16
A nozzle for a plasma arc torch that provides a flow of shield gas about a portion of the nozzle, the nozzle comprising:
- a nozzle distal end region having,
- a longitudinal nozzle orifice that is symmetrically disposed about a longitudinal nozzle axis, said nozzle orifice terminating at a nozzle terminal plane which is normal to the nozzle axis, and
- a distal region sidewall that has a convex form that is symmetrical about the nozzle axis, being defined by rotation of a curvilinear element about the nozzle axis, where the curvilinear element is a curve that terminates at the nozzle terminal plane in a substantially tangential manner and has a smoothly changing curvature and an inclination with respect to the nozzle axis that increases at an increasing rate with decreasing longitudinal distance from the nozzle terminal plane, wherein the curvilinear element is essentially formed as a portion of an ellipse which terminates at the nozzle terminal plane at a point closer in proximity to a terminal end of a major axis of the ellipse than to a terminal end of a minor axis, wherein the ellipse has a major axis length LMaj and a minor axis length Lmin where the ratio of LMaj:Lmin is between 3:1 and 10:1,
- whereby the curvature of said distal region sidewall promotes flow of a portion of the shield gas along its surface toward said nozzle orifice.
A nozzle for a plasma arc torch having a torch axis and a gas-directing component having a gas-directing surface that is symmetrically disposed about the torch axis, the nozzle being configured to attach to the plasma arc torch so as to mount at least partially inside the gas-directing component so as to be cooled by a flow of shield gas passed between the nozzle and the gas-directing surface, the nozzle comprising:
- a distal end region having,
- a longitudinal nozzle orifice that is symmetrically disposed about a longitudinal nozzle axis, said nozzle orifice terminating at a nozzle terminal plane which is normal to the nozzle axis;
- a distal region sidewall having a convex shape that is symmetrical about the nozzle axis, being defined by rotation of a curvilinear element about the nozzle axis, where the curvilinear element terminates at the nozzle terminal plane in a substantially tangential manner and has a smoothly changing curvature and an inclination with respect to the nozzle axis that increases at an increasing rate with decreasing longitudinal distance from the nozzle terminal plane, wherein the curvilinear element is essentially formed as a portion of an ellipse which terminates at the nozzle terminal plane at a point closer in proximity to a terminal end of a major axis of the ellipse than to a terminal end of a minor axis, wherein the ellipse has a major axis length LMaj and a minor axis length Lmin where the ratio of LMaj:Lmin is between 3:1 and 10:1,
- said distal region sidewall being positioned relative to the gas-directing surface of the gas-directing component such that the curvature of said distal region sidewall promotes flow of a portion of the shield gas along its surface toward said nozzle orifice.
A nozzle for a plasma arc torch that provides a flow of shield gas about a portion of the nozzle, the nozzle comprising:
- a nozzle distal end region having,
- a longitudinal nozzle orifice that is symmetrically disposed about a longitudinal nozzle axis, said nozzle orifice terminating at a nozzle terminal plane which is normal to the nozzle axis, and
- a distal region sidewall that has a convex form that is symmetrical about the nozzle axis, being defined by rotation of a curvilinear element about the nozzle axis, where the curvilinear element has a smoothly changing curvature and an inclination to the nozzle axis that increases at an increasing rate with decreasing longitudinal distance from the nozzle terminal plane, and where the curvilinear element curvature element terminates at the nozzle terminal plane such that a line tangent to the curvilinear element where the curvilinear element terminates at the nozzle terminal plane is inclined to the nozzle terminal plane by an inclination of less than 15°, wherein the curvilinear element is essentially formed as a portion of an ellipse which terminates at the nozzle terminal plane at a point closer in proximity to a terminal end of a major axis of the ellipse than to a terminal end of a minor axis, wherein the ellipse has a major axis length LMaj and a minor axis length Lmin where the ratio of LMaj:Lmin is between 3:1 and 10:1,
- whereby the curvature of said distal region sidewall promotes flow of a portion of the shield gas along its surface toward said nozzle orifice.
Dependencies are inferred from the claim text.