Patent ID: 8152442
Filing Date: 2012-04-10
Classification: F04D

Abstract:
1. A molecular spiral vacuum pumping stage comprising: a rotor disk having smooth surfaces and co-operating with a stator body, said stator body having at least one spiral channel at least on the surface facing said rotor disk; said at least one spiral channel with a cross-section area (σ) comprising: an inlet for a gas to be pumped at or close to an outer periphery of said stator body; and an outlet for the gas at or close to a center of said stator body, so that the gas flows through said at least one channel in a centripetal direction from the inlet to the outlet; wherein the cross-section area (σ) of said at least one channel is reduced from the center to the periphery of said stator body in a direction opposite to the centripetal direction.