| 摘要 |
<p>A vacuum pump includes a housing having an inlet port and an exhaust port, a plurality of vacuum pumping stages located within the housing and disposed between the inlet port and the exhaust port, and a motor. 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 rotates the impellers such that gas is pumped from the inlet port to the exhaust port.</p> |
