Method for heat treating with a microwave plasma torch
US4652723A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 1, 1984 |
| Grant date | Mar 24, 1987 |
| Priority date | — |
| Expiry date | Nov 1, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05H1/3405
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A heat treating method in which a microwave plasma torch is used, comprising an outlet nozzle and a sleeve surrounding and spaced from the nozzle. The nozzle has a central passage surrounded by a generally annular passage formed preferably by a series of conduits arranged in a ring around the central passage. A plasmagenic gas is supplied to the central passage and a combustible gas to the annular passage, while microwave energy is supplied between the sleeve and the nozzle, thereby to form a central plasma jet sheathed by a flame of the burning combustible gas having a generally annular shape. The resulting plasma jet sheathed by a flame is much more stable and much longer, with a much more distinct contour, than in the absence of the flame. The plasma is stable both in the free atmosphere and when it is directed onto an object such as a metal plate. The heat transferred by the plasma sheathed by flame exceeds the sum of the quantities of heat transferred by the nonsheathed plasma alone and by the annular flame alone.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.