Method and Apparatus for Alignment of Components of a Plasma Arc Torch

Abstract

A coolant tube and electrode are adapted to mate with each other to align the tube relative to the electrode during operation of the torch. Improved alignment ensures an adequate flow of coolant along an interior surface of the electrode. In one aspect, an elongated body of the coolant tube has a surface adapted to mate with the electrode. In another aspect, an elongated body of the electrode has a surface adapted to mate with the coolant tube. The surfaces of the tube and electrode may, for example, be flanges, tapered surfaces, contours, or steps.

1 - 37 . (canceled) 
   
   
       38 . A coolant tube for a plasma arc torch, the coolant tube comprising:
 an elongated body having a first end, a second end, and a coolant passage extending therethrough, wherein the elongated body is not rigidly attachable to and is replaceably located within a torch body;   a surface of the elongated body adapted to be biased by hydrostatic pressure such that a plurality of slots located at the second end of the elongated body is biased against an inner surface of an electrode along a direction of a longitudinal axis of the elongated body, the slots adapted to permit coolant to flow out of the coolant passage.   
   
   
       39 . The coolant tube of  claim 38  wherein the inner surface is a bottom end of the electrode. 
   
   
       40 . The coolant tube of  claim 38  wherein the hydrostatic pressure is from a flow of coolant fluid. 
   
   
       41 . The coolant tube of  claim 38  wherein the surface of the elongated body comprises a flange. 
   
   
       42 . A replaceable coolant tube for a plasma arc torch, the coolant tube comprising:
 an elongated body having a first end, a second end, and a coolant passage extending there through, wherein the elongated body is not rigidly attachable to a torch body;   a surface of the coolant tube located at the first end of the elongated body for receiving a hydrostatic pressure from a coolant;   a plurality of slots located at the second end of the elongated body, the second end adapted to be biased against an interior surface of an electrode along a direction of a longitudinal axis of the elongated body by means of the hydrostatic pressure; and   a means for aligning respective longitudinal axes of the coolant tube and the electrode.   
   
   
       43 . The replaceable coolant tube of  claim 42  wherein the interior surface is a bottom end of the electrode. 
   
   
       44 . The replaceable coolant tube of  claim 42  wherein the surface of the coolant tube is a flange. 
   
   
       45 . The replaceable coolant tube of  claim 42  wherein the hydrostatic pressure is from a flow of coolant fluid. 
   
   
       46 . The replaceable coolant tube of  claim 42 , further comprising an outwardly facing annular recess for receiving an o-ring located at the first end of the coolant tube, the o-ring providing a fluid seal between the coolant tube and the torch body while allowing movement of the coolant tube along a direction of the longitudinal axis of the elongated body of the coolant tube. 
   
   
       47 . A method of locating a replaceable coolant tube relative to an electrode in a plasma arc torch comprising the steps of:
 providing the coolant tube having a first surface located at a first end of the coolant tube, a contact surface at a second end of the coolant tube, and a coolant passage extending therethrough; and   hydrostatically biasing the first surface to align the contact surface of the coolant tube with a mating contact surface of the electrode, while still permitting a coolant to flow out of the coolant passage at the second end.   
   
   
       48 . The method of  claim 47  wherein the first surface is a flange. 
   
   
       49 . The method of  claim 47  wherein the contact surface at the second end of the coolant tube is a plurality of slots. 
   
   
       50 . The method of  claim 47  wherein the hydrostatic pressure is from a flow of coolant fluid.