초록 ▼

A plasma arc torch comprises relatively displaceable electrode and nozzle components having first and second positions relative to one another in which the electrode respectively contacts the nozzle and is spaced an operating distance therefrom. Arrangements are disclosed for relatively displacing t

A plasma arc torch comprises relatively displaceable electrode and nozzle components having first and second positions relative to one another in which the electrode respectively contacts the nozzle and is spaced an operating distance therefrom. Arrangements are disclosed for relatively displacing the electrode and nozzle between the first and second positions thereof with a pre-determined force of engagement therebetween in the first position, and without having to interrupt the flow of arc gas and/or the flow of arc current during such relative displacement. A torch start up safety test procedure is performed by sequentially displacing the electrode and nozzle between the two positions thereof, sensing for appropriate open and closed circuit conditions therebetween, and enabling the creation of a pilot arc only when a pre-determined sequence of circuit conditions is sensed. Sequential displacement of the electrode and nozzle together with the application of a pre-determined force of engagement therebetween promotes cleaning of oxides from the area of contact between the electrode and nozzle.

대표청구항 ▼

[ We claim:] [1.] A plasma torch comprising relatively displaceable electrode and nozzle means having first and second positions relative to one another in which said electrode respectively contacts said nozzle means and is spaced an operating distance from said nozzle means, said nozzle means provi

[ We claim:] [1.] A plasma torch comprising relatively displaceable electrode and nozzle means having first and second positions relative to one another in which said electrode respectively contacts said nozzle means and is spaced an operating distance from said nozzle means, said nozzle means providing a gas chamber having a plasma outlet opening, means for flowing gas into said chamber, means including an arc current power supply for flowing an arc current between said electrode and nozzle means, said power supply having interrupted and uninterrupted conditions, means for relatively displacing said electrode and nozzle means between said first and second positions, whereby when said power supply is in said uninterrupted condition a starting arc is created as said electrode and nozzle means move from said first toward said second position and said gas flows from said chamber through said outlet opening, and said means for relatively displacing said electrode and nozzle means including means selectively operable for relatively displacing said electrode and nozzle means from said second position toward said first position during the flow of gas into said chamber and through said outlet opening when said power supply is in said uninterrupted condition.