| 摘要 |
<p>PCT No. PCT/JP95/01090 Sec. 371 Date Jan. 23, 1996 Sec. 102(e) Date Jan. 23, 1996 PCT Filed Jun. 2, 1995 PCT Pub. No. WO95/33594 PCT Pub. Date Dec. 14, 1995Oxygen and nitrogen contained in air is separated by an air separator. The separated nitrogen gas is supplied to an optical path cover of a laser beam machine as a protective gas for bend mirrors. Further, the separated nitrogen gas or oxygen gas can be selectively supplied to a laser beam head as an assist gas. The purity of the separated nitrogen gas can be kept within a predetermined range (94 to 99.5%) on the basis of a difference in pressure between a first conduit for supplying nitrogen gas and a second conduit for supplying oxygen gas. It is preferable to provide a filter for removing dust from air supplied to the air separator and a second filter for removing oil mist from the separated nitrogen supplied to the optical path cover.</p> |
