Importance

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Abstract

Turbomolecular vacuum pumps having structures which provide increased pumping speed, increased discharge pressure and decreased operating power in comparison with prior art turbomolecular vacuum pumps. In a first embodiment, the staters of one or more axial flow vacuum pumping stages in proximity to the exhaust port of the vacuum pump have progressively lower conductance so that the bulk velocity of the gas being pumped is increased. In a second embodiment, one or more stages near the inlet port of the vacuum pump are provided with a peripheral channel to utilize the centrifugal component of the gas being pumped. In a third embodiment, one or more stages in the vacuum pump are molecular drag stages, each including a disk rotor. One or more pumping channels in the stator adjacent to the upper surface of the disk are connected in series with one or more pumping channels adjacent to the lower surface of the disk. In a fourth embodiment, one or more stages of the vacuum pump are regenerative stages, each including a regenerative impeller. Pumping channels in the upper and lower portions of the stator are connected in series. The stator channels can be provided with fixed, spaced-apart ribs for improved performance.

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First Claim