| 摘要 |
PURPOSE:To prevent degrading of a medium gas and to extend its life by using a magnetic fluid shaft seal between the medium gas and a bearing lubricant so as to prevent touching with each other. CONSTITUTION:A medium gas 13 is charged unto a space consisting of both a case 1 and a lid 2. When a voltage is applied a between negative electrode 8 and a positive electrode 9, an electric discharge takes place so that a laser beam is emitted, as indicated by an arrow A, through a window 12 provided on the case 1 toward outside of the case 1. Rotating shafts 3a and 3b of a blower 3 support the blower 3 by bearings 6 and 7 within bearing boxes 4 and 5, and in addition, the bearing boxes 4 and 5 are fixed to the case 1. In the bearing boxes 4 and 5, a magnetic fluid shaft seals 10 and 11 are fitted to the rotating shafts 3a and 3b, between the bearings 6 and 7 and the blower 3. Thus, the medium gas 13 on the side of the blower 3 is prevented from touching with the bearings 6 and 7, and further, fine particles in a lubricant are prevented from mixing with the medium gas 13.
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