Patent ID: 7165931

Claim:
A molecular drag vacuum pump, comprising: a housing defining an inlet and an outlet; a rotor rotatably carried within the housing; a plurality of gas passageways, disposed in the housing between the inlet and the outlet and adjacent the rotor, configured to facilitate flow of a gas from the inlet to the outlet and to impart kinetic energy to the gas through contact of the gas with a moving surface of the rotor; at least one wiper carried by the housing, configured to redirect flow of gas from one of the plurality of gas passageways to another of the plurality of gas passageways, the wiper having a facing surface configured to (1) contact a moving surface of the rotor upon initial operation of the pump, and (2) rapidly wear down so as to create a conformable fit between the facing surface and the moving rotor surface, the facing surface being formed with a plurality of parallel ridges so as to reduce friction with the rotor during said initial operation.