| 摘要 |
1284561 Heat cutting of rock WESTING- HOUSE ELECTRIC CORP 6 Aug 1969 [30 Aug 1968] 39333/69 Heading E1F [Also in Divisions H1 and H5] Minerals, rocks, glass &c are cut by a high energy electron beam having a total power of at least 5kw and a radiance of at least 10<SP>8</SP>w/ cm<SP>2</SP>sr. The beam is used to melt-cut a cavity in the rock and thereafter to heat the bottom of the cavity to a temperature substantially higher than that of the face of the rock. The electron beam generator may be of a conventional type using electron voltages up to 100 million V generated e.g. by a Marx generator, a Van-de-Graff machine or a betation. The beam passes into the atmosphere through differential pressure chambers and, finally, through a nozzle to which is applied an annular gas jet. The expelled gas serves to protect the apparatus from molten material, combustion products and enables it to be used for operations under water. In addition, a jet of gas, steam or fluid (e.g. water) may be applied to the working area for clearing molten material &c. The jet and the beam may be applied simultaneously or in alternate pulses. A jet which alternates between gas and water may be used. In order to decrease the attenuation of the beam, the density of the atmosphere between the nozzle and the work piece may be reduced by heating it to high temperature e.g. by means of an annular oxymethane or oxy-acetylene burner. For the same purpose, a plasma jet may be used (Fig. 2). In this embodiment, the beam E passes through a differential pressure chamber 53 and then through a nozzle 41 surrounded co-axially by a plasma torch 81. The torch comprises two chambers 63, 65 provided with oppositely poled electrodes 67, 69. A gas such as helium or argon is supplied to the chamber 65. |
