Arc plasma torch and method using contact starting
US4791268A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 30, 1987 |
| Grant date | Dec 13, 1988 |
| Priority date | — |
| Expiry date | Jan 30, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05H1/3489
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
An arc plasma torch includes a moveable cathode and a fixed anode which are automatically separated by the buildup of gas pressure within the torch after a current flow is established between the cathode and the anode. The gas pressure draws a nontransferred pilot arc to produce a plasma jet. The torch is thus contact started, not through contact with an external workpiece, but through internal contact of the cathode and anode. Once the pilot arc is drawn, the torch may be used in the nontransferred mode, or the arc may be easily transferred to a workpiece. In a preferred embodiment, the cathode has a piston part which slidingly moves within a cylinder when sufficient gas pressure is supplied. In another embodiment, the torch is a hand-held unit and permits control of current and gas flow with a single control.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.