Rotationsmolekularluftpumpe

936,175. Axial-flow pumps. SOC. NATIONALE D'ETUDE ET DE CONSTRUCTION DE MOTEURS D'AVIATION. April 4, 1962 [May 15, 1961], No. 13013/62. Class 110(1). A rotary high-vacuum pump of the kind designed to operate in series with and upstream of an ordinary vacuum pump, comprises a succession of alternately rotary and stationary blade rings, the blades of each of the rings having a triangular cross-section (Fig. 3) with a sharp rectilinear edge a and a planar transverse rear face s in a plane substantially perpendicular to the rotation axis, successive rotary and stationary blade rings being mutually arranged so that the sharp edges of one blade ring are immediately adjacent the planar faces of the next preceding blade ring. The pump, which may be driven by a built-in motor, is provided with an inlet E, Fig. 1, and outlets S connected by a pipe T to the suction end P of a backing pump (not shown), and has rotary discs R separated by fixed discs F, which discs have the blades arranged on their periphery. The gas molecules are assisted in moving in the direction f to the outlets S by inclining the axis of the ducts, between the blades on the fixed and mobile discs, in a direction in accordance with the direction of rotation r. Any back-flowing molecules impinge on the transverse surfaces s and the lateral walls of the ducts, to be redespatched with a component of speed which tends to send them downstream.