| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a vacuum pump system having a high compression ratio to light gas, and a method thereof. <P>SOLUTION: This vacuum pump system includes a primary vacuum pump having an introducing port to be connected to another system, and a secondary pump having an introducing port connected to a discharge port of the primary vacuum pump. The primary vacuum pump is an oil-free displacement type vacuum pump having a plurality of gap seals between the introducing port and the discharge port. The primary vacuum pump may possibly be a scroll type vacuum pump. The secondary vacuum pump may be an oil-free diaphragm pump. The system is connected to the discharge port of the primary vacuum pump. It may include a valve composed to connect the discharge port of the vacuum pump to a discharge passage between both pumps based on a selected condition, that is, for example, a pressure level at the discharge port of the primary vacuum pump. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
