Automatic gas control for a plasma arc torch
First Claim
Patent Images
1. A method for piercing a workpiece with a plasma arc torch comprising the steps of:
- establishing a plasma gas flow to a plasma chamber in the plasma arc torch, the plasma chamber defined at least in part by an electrode and a nozzle;
initiating a plasma arc in the plasma chamber between the electrode and the nozzle;
transferring the plasma arc to the workpiece; and
adjusting a flow of the shield gas based on cut characteristics of the workpiece, without significantly adjusting the plasma gas flow.
6 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for controlling a gas supply to a plasma arc torch uses a proportional control solenoid valve positioned adjacent the torch to manipulate the gas flow to the torch, thereby extending electrode life during arc transfer and shutdown. Swirl ring design can be simplified and gas supply and distribution systems become less complicated. The invention also allows manipulation of shield gas flow to reduce divot formation when making interior cuts. The system can be controlled with a digital signal processor utilizing a feedback loop from a sensor.
178 Citations
20 Claims
-
1. A method for piercing a workpiece with a plasma arc torch comprising the steps of:
-
establishing a plasma gas flow to a plasma chamber in the plasma arc torch, the plasma chamber defined at least in part by an electrode and a nozzle;
initiating a plasma arc in the plasma chamber between the electrode and the nozzle;
transferring the plasma arc to the workpiece; and
adjusting a flow of the shield gas based on cut characteristics of the workpiece, without significantly adjusting the plasma gas flow. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A plasma arc torch for cutting a workpiece, the plasma torch having a plasma gas source to supply a plasma chamber and a shield gas source to supply a shield gas to pass through a space between a nozzle and a shield, such that an electrical current passing between an electrode and a nozzle produces a plasma arc that exits the torch through a nozzle exit orifice, the plasma torch comprising:
-
a means for sensing a parameter in a first fluid line that supplies at least one of a plasma gas from the plasma gas source or a shield gas from the shield gas source; and
a means for controlling a flow of the first gas based on the sensed parameter using a programmable control valve disposed in the first fluid line adjacent the plasma torch. - View Dependent Claims (9, 10)
-
-
11. A method for control of a gas flow to a plasma arc torch including a plasma chamber disposed within a torch body comprising:
-
providing a first fluid line for supplying a first gas to the torch;
positioning a programmable control valve in the first fluid line adjacent the torch to control a flow of the first gas; and
manipulating the programmable control valve thereby a) controlling the flow of the first gas to the torch during operation of the torch; and
b) compensating for a volume in the first fluid line between the programmable control valve and the torch. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
-
Specification