| 摘要 |
<p>A vacuum pump includes a housing 10 having an inlet port 14 and an exhaust port 16, a plurality of vacuum pumping stages 30,32...,46 located within the housing 10 and disposed between the inlet port 14 and the exhaust port 16, and a motor 52. The vacuum pumping stages include gas drag stages, each including a stator and an impeller. The impellers of successive ones of the gas drag stages are configured for efficient operation at progressively higher pressures. The impellers of the gas drag stages may have pumping surfaces with a surface topography for efficient operation at progressively higher pressures. The motor 52 rotates the impellers such that gas is pumped from the inlet port 14 to the exhaust port 16.</p> |
